Researcher Profile and Settings

Affiliation

• Research Faculty of Agriculture　Fundamental AgriScience Research　Agrobiology and Bioresources

Job Title

• Associate Professor

URL

http://www.agr.hokudai.ac.jp/ecosys/ecolgy/aml.htm

J-Global ID

• 201201024058772941

Research Interests

• 動物生態学   進化   自然選択   社会性   行動学   

Research Areas

• Life sciences / Biodiversity and systematics
• Life sciences / Ecology and environmental science

Educational Organization

•  Bachelor's degree program　School of Agriculture
•  Master's degree program　Graduate School of Agriculture
•  Doctoral (PhD) degree program　Graduate School of Agriculture

Academic & Professional Experience

• 2010 北海道大学 大学院・農学研究科 准教授

Research Activities

Published Papers

• A unique conjunction:evidence for gynogenesis accompanying haplodiploid sex determination o the Australian ant Myrmecia impaternata Taylor.

  Taylor, R. W, Imai, H. T, Hasegawa, E, Beaton, C. D

  Psyche in press. 2018 [Refereed][Not invited]
  
• The benefits of grouping as a main driver of social evolution in a halictid bee.

  Okubo, Y, Yamamoto, T, Ogusu, N, Watanabe, S, Murakami, Y, Yagi, N, Hasegawa, E

  Science Advances 4 e1700741  2018 [Refereed][Not invited]
  
• Effects of aphid parasitism on host plant fitness in an aphid-host relationship.

  Watanabe, S, Murakami, Y, Hasegawa, E

  PLoS One 13 e0202411  2018 [Refereed][Not invited]
  
• Cricket mate selection as a spatial discounting phenomenon without learning.

  Okubo, Y, Yoshimura, J, Hasegawa, E

  Journal of Ethology in press. 2018 [Refereed][Not invited]
  
• Ants improve the reproduction of inferior morphs to maintain polymorphism in symbiont aphids.

  Watanabe, S, Yoshimura, J, Hasegawa, E

  Scientific Reports 8 2313  2018 [Refereed][Not invited]
  
• Adaptive phenotypic variation among clonal ant workers.

  Hasegawa, E, Watanabe, S, Murakami, Y, Ito, F

  Royal Society Open Science 5 170816  2018 [Refereed][Not invited]
  
• Response threshold variance as a basis of collective rationality.

  Yamamoto, T, Hasegawa, E

  Royal Society Open Science 4 170097  2017 [Refereed][Not invited]
  
• The promotion of cooperation by the poor in dynamic chicken games.

  Ito, H, Katsumata, Y, Hasegawa, E, Yoshimura, J

  Scientific Reports 7 43377  2017 [Refereed][Not invited]
  
• Morph-specific weapon-correlated traits in a male dimorphic stag beetle Prosopocolilus inclinatus, (Coleoptera: Lucanidae).

  Ito, J, Ohkubo, Y, Hasegawa, E

  Annals of Entomological Society of America 1 - 5 2017 [Refereed][Not invited]
  
• Nature of collective decision-making by simple yes/no decision units.

  Hasegawa,E, Mizumoto, N, Kobayashi, K, Tobata, S, Yoshimura, J, Watanabe, S, Murakami, Y, Matsuura, K

  Scientific Reports 17 14436  2017 [Refereed][Not invited]
  
• Evolution of the optimal reproductive schedule in the ant Camponotus (Colobopsis) nipponicus (Wheeler): A demographic approach.

  Hasegawa,E, Watanabe, S, Murakami, Y

  Ecological Entomology 43 126 - 133 2017 [Refereed][Not invited]
  
• The first workers of the ant Camponotus obscuripes are a different allometric morph with relatively long antennae to communicate with other larger colony members.

  Watanabe, S, Terayama, M, Kawachiya, R, Ogusu, N, Fujita, Y, Mikami, S, Murakami, Y, Hasegawa, E

  Psyche 4520109  2017 [Refereed][Not invited]
  
• Difference in evolutionary patterns of strongly or weakly selected characters among ant populations

  Shuichiro Imai, Kazuya Kobayashi, Yusaku Ohkubo, Norihiro Yagi, Eisuke Hasegawa

  SCIENTIFIC REPORTS 6 39451  2045-2322 2016/12 [Refereed][Not invited]
   

  Despite being a central issue in evolutionary biology, few studies have examined the stasis of characters in populations with no gene flow. A possible mechanism of such stasis is stabilizing selection with similar peaks in each population. This study examined the evolutionary patterns of morphological characters with and without strong selection in ant populations. We show that compared to a character that seems to be less important, characters that are more important were less variable within and among populations. Microsatellite analyses showed significant genetic differences between populations, implying limited gene flow between them. The observed levels of genetic differentiation cannot be attributed to recent population separations. Thus, the observed differences in morphological variance seem to reflect the degree of selection on each character. The less important character changed proportionately with time, but such a pattern was not observed in more important characters. These results suggest that stabilizing selection maintains morphological stasis between populations of the same species with minimal gene flow independent of divergence times.
• Female preference for both behavior and morphology traits of the male Japanese newt Cynops pyrrhogaster

  Takako Kutsuki, Eisuke Hasegawa

  JOURNAL OF ETHOLOGY 34 (3) 337 - 342 0289-0771 2016/09 [Refereed][Not invited]
   

  Males of the Japanese newt (Cynops pyrrhogaster) display complex courtship behaviors and are sexually dimorphic in terms of tail morphology. Pair encounter experiments were conducted to investigate which males are preferred by female newts. Male courtship behavior consisted of four stages, namely, Approach, Fan, Creep and Spermatophore deposition. The Fan behavior was classified into four sub-patterns. Males which showed a specific sub-pattern were accepted at a significantly higher probability by females than males which showed the other sub-patterns. The accepted males had a smaller snout-vent length, higher tail, and larger body mass than the rejected males, and their body weight was relatively heavier. Our results suggest that females of C. pyrrhogaster select their mates based on both behavioral patterns and morphological characters.
• Co-occurrence of ecologically equivalent cryptic species of spider wasps

  Hiroaki Kurushima, Jin Yoshimura, Jeong-Kyu Kim, Jong-Kuk Kim, Yutaka Nishimoto, Katsuhiko Sayama, Manabu Kato, Kenta Watanabe, Eisuke Hasegawa, Derek A. Roff, Akira Shimizu

  ROYAL SOCIETY OPEN SCIENCE 3 (8) 160119  2054-5703 2016/08 [Refereed][Not invited]
   

  Many cryptic species have been discovered in various taxonomic groups based on molecular phylogenetic analyses and mating experiments. Some sympatric cryptic species share equivalent resources, which contradicts the competitive exclusion principle. Two major theories have been proposed to explain the apparent lack of competitive exclusion, i.e. niche-based coexistence and neutral model, but a conclusive explanation is lacking. Here, we report the co-occurrence of cryptic spider wasp species appearing to be ecologically equivalent. Molecular phylogenetic analyses and mating experiments revealed that three phylogenetically closely related species are found sympatrically in Japan. These species share the same resources for larval food, and two of the species have the same niche for nesting sites, indicating a lack of competitive exclusion. This evidence may suggest that ecologically equivalent species can co-occur stably if their shared resources are sufficiently abundant that they cannot be over-exploited.
• What Is True Halving in the Payoff Matrix of Game Theory?

  Hiromu Ito, Yuki Katsumata, Eisuke Hasegawa, Jin Yoshimura

  PLOS ONE 11 (8) e0159670  1932-6203 2016/08 [Refereed][Not invited]
   

  In game theory, there are two social interpretations of rewards (payoffs) for decision- making strategies: (1) the interpretation based on the utility criterion derived from expected utility theory and (2) the interpretation based on the quantitative criterion (amount of gain) derived from validity in the empirical context. A dynamic decision theory has recently been developed in which dynamic utility is a conditional (state) variable that is a function of the current wealth of a decision maker. We applied dynamic utility to the equal division in dove-dove contests in the hawk-dove game. Our results indicate that under the utility criterion, the half-share of utility becomes proportional to a player's current wealth. Our results are consistent with studies of the sense of fairness in animals, which indicate that the quantitative criterion has greater validity than the utility criterion. We also find that traditional analyses of repeated games must be reevaluated.
• Male guppies change courtship behaviour in response to their own quality relative to that of a rival male

  Takashi Yoshikawa, Yusaku Ohkubo, Kenji Karino, Eisuke Hasegawa

  ANIMAL BEHAVIOUR 118 33 - 37 0003-3472 2016/08 [Refereed][Not invited]
   

  Compared with female mate choice, male mate choice has been an important but minor topic in the past two decades. In the guppy, Poecilia reticulata, a male approaching a female abandons his courtship when a rival male appears next to the focal female; however, the effect of the relative quality of the males on this behavioural change is unknown. We show here that male guppies abandon their approach to a female only when the rival male is phenotypically superior. Both natural and artificially induced brightly coloured males continued to approach a female even when the rival male was brightly coloured, but both natural and induced dull-coloured males abandoned their approach to a female when the rival was brightly coloured. Males decided their behaviours on the basis of their own appearance, not on their genotypes, because artificially induced brightly and dull- coloured brothers differed in their behaviour. Our results show that male mate choice behaviour is finely tuned to maximize the probability of acceptance by the approached female. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
• A female-biased sex ratio reduces the twofold cost of sex

  Kazuya Kobayashi, Eisuke Hasegawa

  SCIENTIFIC REPORTS 6 23982  2045-2322 2016/04 [Refereed][Not invited]
   

  The evolution of sexual reproduction remains a fascinating enigma in biology. Theoretically, populations of sexual organisms investing half of their resources into producing male offspring that don't contribute to reproduction should grow at only half the rate of their asexual counterparts. This demographic disadvantage due to male production is known as the twofold cost of sex. However, the question of whether this cost is truly twofold for sexual females remains unanswered. The cost of producing males should decrease when the number of male offspring is reduced. Here, we report a case where the cost of males is actually less than twofold. By measuring the numbers of sexual strain coexisting with asexual strain among thrips, our survey revealed that the sexual strain showed female-biased sex ratios and that the relative frequency of sexual strain is negatively correlated with the proportion of males in the sexual strain. Using computer simulations, we confirmed that a female-biased sex ratio evolves in sexual individuals due to the coexistence of asexual individuals. Our results demonstrate that there is a cost of producing males that depends on the number of males. We therefore conclude that sexual reproduction can evolve with far fewer benefits than previously assumed.
• Lazy workers are necessary for long-term sustainability in insect societies

  Eisuke Hasegawa, Yasunori Ishii, Koichiro Tada, Kazuya Kobayashi, Jin Yoshimura

  SCIENTIFIC REPORTS 6 20846  2045-2322 2016/02 [Refereed][Not invited]
   

  Optimality theory predicts the maximization of productivity in social insect colonies, but many inactive workers are found in ant colonies. Indeed, the low short-term productivity of ant colonies is often the consequence of high variation among workers in the threshold to respond to task-related stimuli. Why is such an inefficient strategy among colonies maintained by natural selection? Here, we show that inactive workers are necessary for the long-term sustainability of a colony. Our simulation shows that colonies with variable thresholds persist longer than those with invariable thresholds because inactive workers perform the critical function of replacing active workers when they become fatigued. Evidence of the replacement of active workers by inactive workers has been found in ant colonies. Thus, the presence of inactive workers increases the long-term persistence of the colony at the expense of decreasing short-term productivity. Inactive workers may represent a bet-hedging strategy in response to environmental stochasticity.
• Color polymorphism in an aphid is maintained by attended ants.

  Watanabe, S, Murakami, T, Yoshimura, J, Hasegawa, E

  Science Advances 2 e16000606  2016 [Refereed][Not invited]
  
• The contribution of seed dispersers to tree species diversity in tropical rainforests

  Satoshi Kakishima, Satoru Morita, Katsuhiko Yoshida, Atsushi Ishida, Saki Hayashi, Takahiro Asami, Hiromu Ito, Donald G. Miller, Takashi Uehara, Shigeta Mori, Eisuke Hasegawa, Kenji Matsuura, Eiiti Kasuya, Jin Yoshimura

  ROYAL SOCIETY OPEN SCIENCE 2 (10) 150330  2054-5703 2015/10 [Refereed][Not invited]
   

  Tropical rainforests are known for their extreme biodiversity, posing a challenging problem in tropical ecology. Many hypotheses have been proposed to explain the diversity of tree species, yet our understanding of this phenomenon remains incomplete. Here, we consider the contribution of animal seed dispersers to the species diversity of trees. We built a multilayer lattice model of trees whose animal seed dispersers are allowed to move only in restricted areas to disperse the tree seeds. We incorporated the effects of seed dispersers in the traditional theory of allopatric speciation on a geological time scale. We modified the lattice model to explicitly examine the coexistence of new tree species and the resulting high biodiversity. The results indicate that both the coexistence and diversified evolution of tree species can be explained by the introduction of animal seed dispersers.
• Sexual and asexual reproduction of queens in a myrmicine ant, Vollenhovia emeryi (Hymenoptera: Formicidae)

  Misato Okamoto, Kazuya Kobayashi, Eisuke Hasegawa, Kyohsuke Ohkawara

  MYRMECOLOGICAL NEWS 21 13 - 17 1994-4136 2015/09 [Refereed][Not invited]
   

  Sexual reproduction is more common than asexual reproduction in eukaryotes. There are few species with obligate clonality, and most clonal organisms maintain sexual reproduction. Organisms tend to couple sexual reproduction with dispersal, or changes in the environment. These facultatively clonal species use both reproductive systems to reduce the costs of clonality, and to gain benefits of sexuality. In recent decades, clonal reproductive systems have been discovered in some eusocial insects. In the myrmicine ant Vollenhovia emeryi previous research has documented that new queens are produced clonally with complete, diploid, maternal genomes. Usually, new queens have short rudimentary wings and cannot fly, suggesting that dispersal of new colonies is limited. However, some new queens with functional long wings occur in natural colonies, in addition to short-winged queens. In this study, we analyzed the reproductive modes of long-winged queens and short-winged queens. In agreement with previous data, most short-winged queens were produced asexually. However, mature colonies and nutritionally rich colonies tend to produce long-winged queens sexually. Since long-winged queens may encounter different environments after dispersal, higher genetic diversity should be advantageous to increase adaptability. Thus, V. emeryi may have evolved a reproductive strategy to maximize advantages of both clonal and sexual reproduction, as in other facultatively clonal organisms.
• A NEW HOST RECORD OF BLAESOXIPHA RUFIPES (DIPTERA: SARCOPHAGIDAE) IN JAPAN

  Saori Watanabe, Eisuke Hasegawa

  ENTOMOLOGICAL NEWS 124 (2) 139 - 140 0013-872X 2014/09 [Refereed][Not invited]
  
• Evolutionary optimality in sex differences of longevity and athletic performances

  Hiromi Asanuma, Satoshi Kakishima, Hiromu Ito, Kazuya Kobayashi, Eisuke Hasegawa, Takahiro Asami, Kenji Matsuura, Derek A. Roff, Jin Yoshimura

  SCIENTIFIC REPORTS 4 5425  2045-2322 2014/06 [Refereed][Not invited]
   

  Many sexual differences are known in human and animals. It is well known that females are superior in longevity, while males in athletic performances. Even though some sexual differences are attributed to the evolutionary tradeoff between survival and reproduction, the aforementioned sex differences are difficult to explain by this tradeoff. Here we show that the evolutionary tradeoff occurs among three components: (1) viability, (2) competitive ability and (3) reproductive effort. The sexual differences in longevity and athletic performances are attributed to the tradeoff between viability (survival) and competitive ability that belongs to the physical makeup of an individual, but not related to the tradeoff between survival and reproduction. This provides a new perspective on sex differences in human and animals: females are superior in longevity and disease recovery, while males are superior in athletic performance.
• Coexistence of sexual individuals and genetically isolated asexual counterparts in a thrips

  Kazuya Kobayashi, Jin Yoshimura, Eisuke Hasegawa

  SCIENTIFIC REPORTS 3 3286  2045-2322 2013/11 [Refereed][Not invited]
   

  Sex is a paradoxical phenomenon because it is less efficient compared with asexual reproduction. To resolve this paradox we need a direct comparison between sexual and asexual forms. In many organisms, however, sexual and asexual forms do not occur in the same habitat, or at the same time. In a few cases where sexual and asexual forms are found in a single population, some (though rare) genetic exchange is usually detected between the two forms. When genetic exchange occurs a direct comparison is impossible. Here we investigate a thrips exhibiting both sexual and asexual forms (lineages) that are morphologically indistinguishable. We examine if the two forms are genetically isolated. Phylogeny based on nuclear genes confirms that the sexual and asexual lineages are genetically differentiated. Thus we demonstrate that the current system has certain advantages over existing and previously used model systems in the evolution of sexual reproduction.
• Sex allocation in the ant Camponotus (Colobopsis) nipponicus (Wheeler): II. The effect of resource availability on sex-ratio variability

  E. Hasegawa

  INSECTES SOCIAUX 60 (3) 329 - 335 0020-1812 2013/08 [Refereed][Not invited]
   

  Sex-ratio studies have played a prominent role in tests of kin selection theory in the eusocial Hymenoptera. The winner in sex-ratio conflict between queens and workers must control the ratio through proximate mechanisms. To determine how a colony adjusts its sex ratio, the mechanism of sex-ratio determination was analyzed in the field in colonies of the ant Camponotus (Colobopsis) nipponicus. A path model including five colony characteristics showed that the resource availability of the colony (quantified as the amount of stored fat in the bodies of the workers) has a large positive effect on the proportion of new queens in the female larvae, but has little effect on male production. The results indicated that a colony adjusts the sex ratio by altering the proportion of new queens obtained from a diploid brood in response to resource availability rather than by eliminating male larvae.
• Sex ratio biases in termites provide evidence for kin selection

  Kazuya Kobayashi, Eisuke Hasegawa, Yuuka Yamamoto, Kazutaka Kawatsu, Edward L. Vargo, Jin Yoshimura, Kenji Matsuura

  NATURE COMMUNICATIONS 4 2048  2041-1723 2013/06 [Refereed][Not invited]
   

  Inclusive fitness theory, also known as kin selection theory, is the most general expansion of Darwin's natural selection theory. It is supported by female-biased investment by workers in the social Hymenoptera where relatedness to sisters is higher than to brothers because of haplodiploidy. However, a strong test of the theory has proven difficult in diploid social insects because they lack such relatedness asymmetry. Here we show that kin selection can result in sex ratio bias in eusocial diploids. Our model predicts that allocation will be biased towards the sex that contributes more of its genes to the next generation when sex-asymmetric inbreeding occurs. The prediction matches well with the empirical sex allocation of Reticulitermes termites where the colony king can be replaced by a queen's son. Our findings open broad new avenues to test inclusive fitness theory beyond the well-studied eusocial Hymenoptera.
• The mechanism underlying the regulation of work-related behaviors in the monomorphic ant, Myrmica kotokui

  Yasunori Ishii, Eisuke Hasgeawa

  JOURNAL OF ETHOLOGY 31 (1) 61 - 69 0289-0771 2013/01 [Refereed][Not invited]
   

  The mechanism underlying the regulation of the work performed by the members of a colony is a crucial factor in the colonial life of eusocial organisms. If the response thresholds of the workers vary, greater-than-chance variation in the prevalence of work-related behaviors (i.e., in the "working degree") is expected, and the distribution of these behaviors should be reestablished after demographic changes. We show that greater-than-chance variation in the working degree is restored after a demographic change in the ant Myrmica kotokui. The working degree varied markedly among workers, and the degree of variation could not be explained by chance alone. Moreover, the degree of variation could not be attributed to intrinsic factors such as reproductive potential or age. After a demographic change, some previously inactive workers started to work, whereas some previously active workers became inactive. These shifts resulted in the restoration of a substantial amount of variation in the working degree. These observations all support the hypothesis that variance in the response threshold is the basis of the regulation of work-related behaviors in this ant.
• Effect of morph types, body size and prior residence on food-site holding by males of the male-dimorphic stag beetle Prosopocoilus inclinatus (Coleoptera: Lucanidae)

  Akio Inoue, Eisuke Hasegawa

  JOURNAL OF ETHOLOGY 31 (1) 55 - 60 0289-0771 2013/01 [Refereed][Not invited]
   

  Mate-securing tactics of small males in male-polymorphic species exhibiting male-male combat is an important issue in behavioral ecology. While most studies have focused on the outcomes of such combat encounters, the holding of a mating resource like a feeding site has a greater impact for obtaining reproductive success. We examined the effects of the prior residence at a feeding site on resource acquisition in the male-dimorphic stag beetle, Prosopocoilus inclinatus. More than 70 % of encounters did not result in combat. While larger males tended to occupy a food site after a combat, smaller males with prior residence tended to occupy food sites when no fighting occurred. Morph types or body size have no effect on the occurrence of combat, meaning that small males do not hesitate to fight with large males. These findings show that, under experimental conditions, the prior residence has a positive effect to hold food site in P. inclinatus.
• Isolation of microsatellite loci from the onion thrips, Thrips tabaci.

  Kobayashi, K, Hasegawa, E

  Journal of Insect Science 13 12  2013 [Refereed][Not invited]
  
• Gall distribution as a compromise between the optimal gall-site selection and the synchrony to host-plant phenology in the aphid Kaltenbachiella japonica

  Tomohiko Aoyama, Shin-ichi Akimoto, Eisuke Hasegawa

  ARTHROPOD-PLANT INTERACTIONS 6 (3) 461 - 469 1872-8855 2012/09 [Refereed][Not invited]
   

  Gall-site selection by the aphid Kaltenbachiella japonica was evaluated in relation to leaf position in a shoot, and gall positions within a leaf. First-instar fundatrices induce closed galls on the midribs of host leaves, and several galls were often induced on one leaf. Leaves with many galls were often withered before emergence of sexuparae from the galls. Within a leaf, gall volume was positively correlated with the sum of lateral-vein length in the leaf segment at which the gall was induced. The observed pattern in gall volume among the leaf segments corresponded with that in the lateral-vein length. These results show that a foundatrix selects the most vigorous position within a leaf to produce more offspring. Although distal leaves grew faster than did basal leaves, gall density was highest on leaves at the middle order when a shoot has more than seven leaves. Optimal gall-site selection seems to be constrained by the asynchrony in timing between the hatching of fundatrices and leaf growth within a shoot. These results suggest that the observed gall distribution is affected by both the distribution of suitable galling sites within a leaf and the synchrony with leaf phenology of the host plant.
• A halictid bee with sympatric solitary and eusocial nests offers evidence for Hamilton's rule

  Norihiro Yagi, Eisuke Hasegawa

  NATURE COMMUNICATIONS 3 939  2041-1723 2012/07 [Refereed][Not invited]
   

  The validity of Hamilton's rule has been confirmed among cooperative breeders where helping behaviour is transient; however, Hamilton's rule has not been validated among eusocial insects where helpers commit for life. Here we conduct a direct test of Hamilton's rule using field populations of Lasioglossum baleicum bees, which inhabit sympatric solitary and eusocial nests. Our results show that the indirect fitness of sterile first-brood workers is higher than the direct fitness of solitary first-brood females, and spring foundresses achieve a large direct fitness by having helpers. These fitness benefits are attributed to markedly higher larval survival rates in multiple-female nests, and intruding into an unrelated nest yields a moderate degree of direct fitness, but coexistence with unrelated females also increase overall brood survival. We discuss reasons why various types of cooperation are maintained in Lasioglossum baleicum with relation to that how a multiple-female nesting improves larval survival.
• Discrimination of Reproductive Forms of Thrips tabaci (Thysanoptera: Thripidae) by PCR With Sequence Specific Primers

  Kazuya Kobayashi, Eisuke Hasegawa

  JOURNAL OF ECONOMIC ENTOMOLOGY 105 (2) 555 - 559 0022-0493 2012/04 [Refereed][Not invited]
   

  In agriculture, although it is important to identify species of pest insects, the morphological identification is often difficult. DNA genotyping is useful for the identification of species in morphologically indiscriminable species. Thrips tabaci (Lindeman) can be divided into two reproductive forms (arrhenotoky and thelytoky, each of which different in pesticide resistance) but morphological discrimination is not possible. Here, we establish a simple method to discriminate the strains based on their mitochondrial DNA sequences. Phylogenetic analysis including the T. tabaci and congeneric species provided ancestor sequences of each strain of T. tabaci. Based on the ancestor sequences, we developed a primer set that include strain specific primers on sense strand and common primer on anti sense strand. Using this primer set, the strains of 196 individuals of T. tabaci were successfully assigned to each of genotypic forms. As the phylogeny and ancestor sequences were based on worldwide samples, this method will work well on most populations around the world.
• Isolation of microsatellite loci from the millipede, Brachycybe nodulosa Verhoeff

  Eisuke Hasegawa, Izumi Yao, Kyoko Futami, Norihiro Yagi, Kazuya Kobayashi, Shin-ichi Kudo

  CONSERVATION GENETICS RESOURCES 4 (1) 89 - 91 1877-7252 2012/03 [Refereed][Not invited]
   

  Brachycybe nodulosa is a fungivorous millipede that distributed in Japan and Korea. This species shows patchy distributions and the exclusive paternal care of eggs, and thus is an important subject for both conservation and evolutionary biology. Thirteen polymorphic microsatellite loci were newly isolated from the taxon. Moderate to high levels of polymorphism were observed, with numbers of alleles ranged from 2 to 10. The mean observed and expected heterozygosities ranged from 0.200 to 1.000 and 0.405 to 0.886, respectively. Two loci showed lower heterozygosities than the expectation under HWE. No linkage disequilibrium was detected for any pair of the loci. These new loci will be useful in conservation genetics and evolutionary ecology studies of this species.
• Paternally inherited alleles in male body parts of an ant (Diacamma sp.) sex mosaic: implication for androgenetic male production in the Hymenoptera

  S. Dobata, H. Shimoji, H. Ohnishi, E. Hasegawa, K. Tsuji

  INSECTES SOCIAUX 59 (1) 55 - 59 0020-1812 2012/02 [Refereed][Not invited]
   

  Sex mosaicism, also called gynandromorphism, refers to an accidental phenomenon in dioecious organisms (mainly animals) in which an individual phenotype includes both female and male characteristics. Despite the rarity of this phenomenon, elucidating the mechanisms of naturally occurring sex mosaicism should deepen our understanding of diverse sex determination and differentiation systems in nature. We report the results of a genetic study of a sex mosaic individual of the ant Diacamma sp. from Japan's Okinawa Island. Parentage analysis using microsatellite markers revealed that the female and male parts of the sex mosaic showed different inheritance patterns: female parts had alleles consistent with their biparental inheritance, whereas most of the male parts had alleles consistent with their paternal inheritance (i.e., androgenesis). We discuss plausible cytogenetic mechanisms that gave rise to the male parts of this individual: polyspermy and the subsequent independent cleavage by a surplus sperm pronucleus, and maternal genome elimination after fertilization of an ovule. Moreover, we hypothesize that the androgenetically produced males found in some Hymenoptera might share the same underlying cytogenetic mechanism with hymenopteran sex mosaicism.
• Phylogenetic relationships among populations of Vollenhovia ants, with particular attention on the evolution of wing morphology.

  Kobayashi, K, Tamura, K, Okamoto, M, Hasegawa, E, Ohkawara, K

  Annals of Entomological Society of America 103 456 - 461 2012 [Refereed][Not invited]
  
• A trade-off between number and size within the first workers of the ant Camponotus japonicus

  Eisuke Hasegawa, Syuichiro Imai

  JOURNAL OF ETHOLOGY 30 (1) 201 - 204 0289-0771 2012/01 [Refereed][Not invited]
   

  In social insects, the limited amount of resources during the claustral founding predicts a trade-off between the number and size of the first-generation of workers. Here, we demonstrate this predicted trade-off in founding colonies of the ant Camponotus japonicus. Worker size was found to correlate negatively with the number of first workers produced when the amount of investment was controlled. Both size and number of the first generation of workers increased when a queen invested more resources. We also examined how a queen adjusts the size and number of the first workers depending on her condition.
• No gene flow between wing forms and clonal reproduction by males in the long-winged form of the ant Vollenhovia emeryi

  K. Kobayashi, E. Hasegawa, K. Ohkawara

  INSECTES SOCIAUX 58 (2) 163 - 168 0020-1812 2011/05 [Refereed][Not invited]
   

  In Vollenhovia emeryi, males produced by the short-winged queens (S males) have the same genotype of genomic opsin gene as the long-winged queens (L queens) rather than the cohabiting S queens. This fact suggests that either one of the following two events might have occurred, (1) a recent gene flow between the S males and the L queens or (2) a past hybridization event between them. In order to test these hypotheses, we analyzed the nuclear genome and the mitochondrial DNA of L males, L queens, and sperm from the L queens' spermathecae. Results showed that genotype frequencies differed significantly between L males and L queens and between the sperm and L queens. Mitochondrial haplotypes of the sperm were consistent with their queen. These indicate that (1) queens of the L form mated only with the males that have been produced by L queens, and thus there is no gene flow from S males to L queens; (2) males of the L-form clonally produce sons as males of the S-form do; and (3) genotype similarity between S males and L queens indicates a past hybridization event.
• Persistence of the single lineage of transmissible 'social cancer' in an asexual ant

  S. Dobata, T. Sasaki, H. Mori, E. Hasegawa, M. Shimada, K. Tsuji

  MOLECULAR ECOLOGY 20 (3) 441 - 455 0962-1083 2011/02 [Refereed][Not invited]
   

  How cooperation can arise and persist, given the threat of cheating phenotypes, is a central problem in evolutionary biology, but the actual significance of cheating in natural populations is still poorly understood. Theories of social evolution predict that cheater lineages are evolutionarily short-lived. However, an exception comes from obligate socially parasitic species, some of which thought to have arisen as cheaters within cooperator colonies and then diverged through sympatric speciation. This process requires the cheater lineage to persist by avoiding rapid extinction that would result from the fact that the cheaters inflict fitness cost on their host. We examined whether this prerequisite is fulfilled, by estimating the persistence time of cheaters in a field population of the parthenogenetic ant Pristomyrmex punctatus. Population genetic analysis found that the cheaters belong to one monophyletic lineage which we infer has persisted for 200-9200 generations. We show that the cheaters migrate and are thus horizontally transmitted between colonies, a trait allowing the lineage to avoid rapid extinction with its host colony. Although horizontal transmission of disruptive cheaters has the potential to induce extinction of the entire population, such collapse is likely averted when there is spatially restricted migration in a structured population, a scenario that matches the observed isolation by distance pattern that we found. We compare our result with other examples of disruptive and horizontally transmissible cheater lineages in nature.
• Social-organization shift in the sweat bee, Lasioglossum baleicum (Hymenoptera, Halictidae) corresponds to change in foraging activity of the predatory ant, Tetramorium tsushimae (Hymenoptera, Formicidae).

  Yagi, N, Hasegawa, E

  Sociobiology 58 1 - 10 2011 [Refereed][Not invited]
  
• Complete mitochondrial genomes of normal and cheater morphs in the parthenogenetic ant Pristomyrmex punctatus (Hymenoptera: Formicidae).

  Hasegawa, E, Kobayashi, K, Yagi, N, Tsuji, K

  Myrmecological News 15 85 - 90 2011 [Refereed][Not invited]
  
• Both cooperation and nest position improve larval survival in the sweat bee, Lasioglossum (Evylaeus) baleicum

  Norihiro Yagi, Eisuke Hasegawa

  JOURNAL OF ETHOLOGY 29 (1) 63 - 67 0289-0771 2011/01 [Refereed][Not invited]
   

  Nesting by multiple females in sweat bees raises the question of the benefits associated with grouping. Adult numbers of the sweat bee, Lasioglossum (Evylaeus) baleicum, exhibited variation within a nest population. The effects of adult number and nest position on larval survival were analyzed in a nest aggregation. Both variables independently affected larval survival, with the presence of multiple adults in a nest markedly improving survival rate. Nests located near the periphery of the aggregation of nests suffered high larval mortalities. Increased frequency of cell-inspection in multiple-female nests seems to be associated with a concomitant increase in larval cell protection from external predation. Such predation pressure was assumed, given the existence of an underground ant colony that employs a recruitment system while foraging in the study area.
• Cheater genotypes in the parthenogenetic ant Pristomyrmex punctatus

  Shigeto Dobata, Tomonori Sasaki, Hideaki Mori, Eisuke Hasegawa, Masakazu Shimada, Kazuki Tsuji

  PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES 276 (1656) 567 - 574 0962-8452 2009/02 [Refereed][Not invited]
   

  Cooperation is subject to cheating strategies that exploit the benefits of cooperation without paying the fair costs, and it has been a major goal of evolutionary biology to explain the origin and maintenance of cooperation against such cheaters. Here, we report that cheater genotypes indeed coexist in field colonies of a social insect, the parthenogenetic ant Pristomyrmex punctatus. The life history of this species is exceptional, in that there is no reproductive division of labour: all females fulfil both reproduction and cooperative tasks. Previous studies reported sporadic occurrence of larger individuals when compared with their nest-mates. These larger ants lay more eggs and hardly take part in cooperative tasks, resulting in lower fitness of the whole colony. Population genetic analysis showed that at least some of these large-bodied individuals form a genetically distinct lineage, isolated from cooperators by parthenogenesis. A phylogenetic study confirmed that this cheater lineage originated intraspecifically. Coexistence of cheaters and cooperators in this species provides a good model system to investigate the evolution of cooperation in nature.
• Isolation and characterization of eleven nuclear microsatellite loci for the parthenogenetic ant Pristomyrmex punctatus

  Dobata, S, Hasegawa, E, Tsuji, K

  Molecular Ecology Resources 9 1375 - 1379 2009 [Refereed][Not invited]
  
• Clonal reproduction by males of the ant Vollenhovia emeryi (Wheeler)

  Kazuya Kobayashi, Eisuke Hasegawa, Kyohsuke Ohkawara

  ENTOMOLOGICAL SCIENCE 11 (2) 167 - 172 1343-8786 2008/06 [Refereed][Not invited]
   

  In colonies of the queen-polymorphic ant Vollenhovia emeryi, some colonies produce only long-winged (L) queens, while others produce only short-winged (S) queens. At four nuclear microsatellite loci, males in the S colony had alleles that were different from those of their queen. This suggests that the nuclear genome of males is not inherited from their colony queen, as has also been described for Wasmannia auropunctata (Roger). In V emeryi the possibility of male transfer from other colonies has not been ruled out because previous studies of this species have obtained only nuclear gene information. We analyzed both mitochondrial and nuclear genes for S queens, S males and L queens to clarify the origins of males. Sequence analyses showed that although S queens and S males shared the same mtDNA haplotype, they had a different genotype at a nuclear gene (long-wavelength opsin) locus. Neighbor-joining analysis based on the four microsatellite loci also suggested gene pool separation between S queens and S males. These results are consistent with predictions of clonal reproduction by males. While L queens share opsin genotypes with S males, they have very different mtDNA sequences. Hybridization in the near past between S queens and L males or gene transmission from S males to L queen populations in the present would explain these differences.
• Morph dependent form of asymmetry in mandibles of the stag beetle Prosopocoilus inclinatus (Coleoptera: Lucanidae).

  Okada, Y, Fujisawa, H, Kimura, Y, Hasegawa, E

  Ecological Entomology 33 1 - 6 2008 [Refereed][Not invited]
  
• Allometric dimorphism in the larvae of salamander Hynobius retardatus that exhibit primitive cannibalist specialization.

  Okada, Y, Hasegawa, E

  Ecology Ethology and Evolution 19 113 - 126 2007 [Refereed][Not invited]
  
• Phylogenetic analysis of the insect order Odonata using 28S and 16S rDNA sequences: a comparison between data sets with different evolutionary rates

  E Hasegawa, E Kasuya

  ENTOMOLOGICAL SCIENCE 9 (1) 55 - 66 1343-8786 2006/03 [Refereed][Not invited]
   

  Molecular phylogenetic analyses were conducted for the insect order Odonata with a focus on testing the effectiveness of a slowly evolving gene to resolve deep branching and also to examine: (i) the monophyly of damselflies (the suborder Zygoptera); and (ii) the phylogenetic position of the relict dragonfly Epiophlebia superstes. Two independent molecular sources were used to reconstruct phylogeny: the 16S rRNA gene on the mitochondrial genome and the 28S rRNA gene on the nuclear genome. A comparison of the sequences showed that the obtained 28S rDNA sequences have evolved at a much slower rate than the 16S rDNA, and that the former is better than the latter for resolving deep branching in the Odonata. Both molecular sources indicated that the Zygoptera are paraphyletic, and when a reasonable weighting for among-site rate variation was enforced for the 16S rDNA data set, E. superstes was placed between the two remaining major suborders, namely, Zygoptera and Anisoptera (dragonflies). Character reconstruction analysis suggests that multiple hits at the rapidly evolving sites in the 16S rDNA degenerated the phylogenetic signals of the data set.
• Phylogenetic relationships among species groups of the ant genus Myrmecia

  E Hasegawa, RH Crozier

  MOLECULAR PHYLOGENETICS AND EVOLUTION 38 (3) 575 - 582 1055-7903 2006/03 [Refereed][Not invited]
   

  Phylogenetic relationships among the nine species groups of the predominately Australian ant genus Myrmecia were inferred using 38 Myrmecia species and an outgroup using DNA sequences from two nuclear genes (622 nt from 28S rRNA and 1907 nt from the long-wave opsin gene). Nothomyrmecia macrops was selected as the most appropriate outgroup based on recent reliable studies showing monophyly of Myrmecia with Nothomyrmecia. The four species groups with an occipital carina (those of gulosa, nigrocincta, urens, and picta) were found to form a paraphyletic and basal assemblage out of which the five species groups lacking an occipital carina (those of aberrans, mandibularis.. tepperi, cephalotes, and pilosula) arise as a strongly supported monophyletic assemblage. Monophyly was supported for four groups (those of gulosa., nigrocincta, picta, and mandibularis) but the situation is unclear for four others (those of urens, aberrans, tepperi, and pilosula). The aberrans group appears to be basal within the group lacking an occipital carina; a previous suggestion that it is the sister group to the rest of the genus is thus not supported. (c) 2005 Elsevier Inc. All rights reserved.
• アリの行動と化学物質.

  長谷川英祐

  化学と生物 43 817 - 824 2005 [Refereed][Not invited]
  
• Size-dependent precopulatory behavior as mate-securing tactic in the Japanese stag beetle, Prosopocoilus inclinatus (Coleoptera; Lucanidae)

  Y Okada, E Hasegawa

  JOURNAL OF ETHOLOGY 23 (2) 99 - 102 0289-0771 2005 [Refereed][Not invited]
   

  Males of the Japanese stag beetle Prosopocoilus inclinatus show dimorphism in body size. Since females frequently resist male courtship behavior, males often fail to mate after encounters with females. The males of two morphs showed different precopulatory behavior. During encounters with females, small males acted more persistently against females' resistance than large males by grasping the female more solidly and as a result, succeeded in copulation more frequently. This persistent precopulatory behavior could be regarded as an alternative mating tactic of small males that are inferior to large males in direct physical competition.
• Isolation of six microsatellite markers from the pea aphid, Acyrthosiphon pisum (Homoptera, Aphididae)

  T Kurokawa, Yao, I, SI Akimoto, E Hasegawa

  MOLECULAR ECOLOGY NOTES 4 (3) 523 - 524 1471-8278 2004/09 [Refereed][Not invited]
   

  Using the magnetic particles method, we isolated six polymorphic microsatellite loci from the pea aphid, Acyrthosiphon pisum (Harris), which feeds on a wide range of legume species. The isolated loci were polymorphic, with three to six alleles in 40 aphids. Expected heterozygosities ranged from 0.12 to 0.65. These loci can be used to quantify clonal diversity and compare genetic population structure between sexual and asexual populations.
• Characterization of microsatellite loci in red wood ants Formica (s. str.) spp. and the related genus Polyergus

  E Hasegawa, S Imai

  MOLECULAR ECOLOGY NOTES 4 (2) 200 - 203 1471-8278 2004/06 [Refereed][Not invited]
   

  Ants are interesting subjects for studies of evolution of altruism. We developed 13 microsatellite loci in a red wood ant Formica (s. str.) yessensis from random amplified polymorphic DNA fragments to study genetic structure within populations and colonies. Five loci bore two to five alleles in both F. (s. str.) yessensis and F. (s. str.) truncorum and two were also polymorphic in a related species, Polyergus samurai. Results suggest that the loci will be useful in evolutionary studies on Formica and Polyergus species.
• Mating structure and male production in the giant hornet Vespa mandarinia (Hymenoptera : Vespidae)

  J Takahashi, S Akimoto, SJ Martin, M Tamukae, E Hasegawa

  APPLIED ENTOMOLOGY AND ZOOLOGY 39 (2) 343 - 349 0003-6862 2004/05 [Refereed][Not invited]
   

  Queen mating frequency, genetic relatedness between workers and worker reproduction were estimated in Vespa mandarinia by microsatellite DNA markers. Of 20 colonies examined, eighteen contained queens inseminated by a single male and two colonies contained queens inseminated by two males. The estimated effective number of matings was 1.03+/-0.023 (mean-SE) with 85% of the offspring of the two multiply-mated queens being sired by one of the two males. The genetic relatedness between workers was 0.738+/-0.008, which was almost identical to the predicted value of 0.75 under monogyny and monandry. For this low paternity, kin selection theory predicts a potential conflict between queens and workers over male production. To learn whether males are derived from queens or workers, 400 males from 20 colonies were genotyped at four microsatellite loci. We found that queens produced all males. This finding was confirmed by the observation that 4,317 dissected workers had not developed ovaries. There was no relationship between queen mating frequency and the frequency of worker reproduction, and workers did not produce any male offspring. These results strongly suggest that male production dominated by queens in V. mandarinia is possibly due to worker policing.
• Kin structure and colony male reproduction in the hornet Vespa crabro (Hymenoptera : Vespidae)

  J Takahashi, J Nakamura, S Akimoto, E Hasegawa

  JOURNAL OF ETHOLOGY 22 (1) 43 - 47 0289-0771 2004/01 [Refereed][Not invited]
   

  We estimated queen mating frequency, genetic relatedness among workers, and worker reproduction in Vespa crabro flavofasciata using microsatellite DNA markers. Of 20 colonies examined, 15 contained queens inseminated by a single male, 3 colonies contained queens inseminated by two males, and 2 colonies contained queens inseminated by three males. The genetic relatedness among workers was estimated to be 0.73+/-0.003 (mean+/-SE). For this high relatedness, kin selection theory predicts a potential conflict between queens and workers over male production. To verify whether males are derived from queens or workers, 260 males from 13 colonies were genotyped at four microsatellite loci. We found that all of the males were derived from the queens. This finding was further supported by the fact that only 33 of 2,990 workers dissected had developed ovaries. These workers belonged to 2 of the 20 colonies. There was no relationship between queen mating frequency and worker reproduction, and no workers produced male offspring in any of the colonies. These results suggest that male production dominated by queens in V. crabro flavofasciata is possibly due to worker policing.
• Isolation of microsatellite markers from the drepanosiphid aphid Tuberculatus quercicola (Homoptera, Aphididae)

  Izumi Yao, Shin-Ichi Akimoto, Eisuke Hasegawa

  Molecular Ecology Notes 3 (4) 542 - 543 1471-8278 2003/12 [Refereed][Not invited]
   

  We isolated five polymorphic microsatellite loci from the drepanosiphid aphid Tuberculatus quercicola (Matsumura) that is associated with the Daimyo oak, Quercus dentata Thunberg, using the magnetic particles method. The isolated loci were polymorphic, with four to 16 alleles in 40 aphids. Expected heterozygosities ranged from 0.4 to 0.82. These loci can be used to quantify seasonal changes in clonal diversity in the metapopulation and the extent of clonal mixing in the colonies.
• Worker oviposition and policing behaviour in the myrmicine ant Aphaenogaster smythiesi japonica Forel

  S Iwanishi, E Hasegawa, K Ohkawara

  ANIMAL BEHAVIOUR 66 513 - 519 0003-3472 2003/09 [Refereed][Not invited]
   

  In eusocial Hymenoptera, worker reproduction is affected by various factors, especially the genetic structure of the colony. Kinship theory predicts that hymenopteran workers prefer to produce sons rather than brothers when a single, once-mated queen is in a colony, while such worker reproduction is expected to be mutually inhibited by other workers under multiple mating of the queen. To test these predictions we observed the behaviour of the myrmicine ant Aphaenogaster smythiesi japonica. Observation of the social structure of 60 queenright colonies indicated monogyny and microsatellite DNA analysis of 14 colonies showed monandry. Under laboratory conditions, workers with functional ovaries laid only trophic eggs in the presence of the queen and produced viable eggs in her absence. In an experiment in which colonies split and reunited, workers that had well-developed ovarioles with viable oocytes were frequently attacked by other workers from the queenright groups. The number of cocytes in a worker's ovarioles was positively correlated with the frequency of being attacked. The results show that a worker's production of males in this species is potentially inhibited by worker policing, contrary to the prediction that worker policing is not predominant in monogynous and monandrous societies. (C) 2003 Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour.
• Mating frequency and genetic relatedness among workers in the hornet Vespa analis (Hymenoptera: Vespidae).

  Takahashi, J, Akimoto, S, Nakamura, J, Hasegawa, E

  Entomological Science 61 (3) 119 - 123 1343-8786 2003 [Refereed][Not invited]
  
• Microsatellite loci for genetic research in the hornet Vespa mandarinia and related species

  E Hasegawa, J Takahashi

  MOLECULAR ECOLOGY NOTES 2 (3) 306 - 308 1471-8278 2002/09 [Refereed][Not invited]
   

  We developed 5 microsatelitte loci in the hornet Vespa mandarinia from RAPD fragments. The 5 loci showed 3-7 alleles in V. mandarinia and many were also polymorphic in the related species, V. ducalis, V. analis, Dolichovespula norvegicoides and Vespilla schrenckii. These results suggested the loci will be useful for analyzing genetic structure of Vespinae, at both the colony and population levels.
• Queen mating frequencies and genetic relatedness between workers in the hornet Vespa ducalis (Hymenoptera: Vespidae)

  Jun-Ichi Takahashi, Shin-Ichi Akimoto, Eisuke Hasegawa, Jun Nakamura

  Applied Entomology and Zoology 37 (3) 481 - 486 0003-6862 2002 [Refereed][Not invited]
   

  Vespa ducalis is a monogynous hornet with an annual life cycle. Its colonies are the smallest in the genus Vespa. Generally, it is thought that the number of queen matings and colony size are positively correlated, so we analyzed the queen mating number and genetic relatedness between workers of V. ducalis using microsatellite DNA markers. We examined foundress queens and 20 workers from each of 20 colonies. All colonies were found to have one queen inseminated by one male. The genetic relatedness between workers was 0.724±0.0029 (mean±SE), which is not significantly different from the expected value of 0.75 for full sisters. This result suggests a possible conflict in male production between queens and workers based on kin selection prediction. Therefore, we performed microsatellite analysis of 400 males from 20 colonies to verify whether males are derived from either queens or from workers. No males could be assigned to workers developed ovaries were not found in a total of 880 mature workers. These results strongly suggest that queens dominate production of males in V. ducalis colonies.
• Molecular phylogeny of two slave-making ants: Rossomyrmex and Polyergus (Hymenoptera : Formicidae)

  E Hasegawa, A Tinaut, F Ruano

  ANNALES ZOOLOGICI FENNICI 39 (3) 267 - 271 0003-455X 2002 [Refereed][Not invited]
   

  Using mitochondrial cytochrome oxidase I gene (COI), we established the phylogenetic relationship between two slave-making genera of the tribe Formicini: Polyergus and Rossomyrmex. The resulting phylogenetic tree presents two well-defined groups: Formica + Polyergus, and Proformica + Cataglyphis + Rossomyrmex. Our result contradicts prior classifications which considered Polyergus and Rossomyrmex to be sister genera. These results imply that slave-making in the two taxa evolved independently.
• Microsatellite loci and genetic relatedness among colony members in the parthenogenetic ant Pristomyrmex pungens.

  Hasegawa, E, Sanada, S, Satoh, T, Obara, Y

  Entomological Science 4 399 - 402 2001 [Refereed][Not invited]
  
• Phylogenetic Comparison of Endosymbionts with Their Host Ants Based on Molecular Evidence

  SAMESHIMA Shinya, HASEGAWA Eisuke, KITADE Osamu, MINAKA Nobuhiro, MATSUMOTO Tadao

  ZOOLOGICAL SCIENCE 社団法人 日本動物学会 16 (6) 993 - 1000 0289-0003 1999/12/15 [Refereed][Not invited]
   

  Some Formicid ants have symbiotic intracellular bacteria in the epithelial cells of their midgut. These endosymbionts are believed to be derived from a common ancestor. A recent study revealed that endosymbionts of the ant genus Camponotus are closely related to Enterobacteriaceae, but their relationship to endosymbionts of other genera of ants is unknown. In this study, the nucleotide sequences of 16S ribosomal RNA (rRNA) of endosymbionts and mitochondrial cytochrome oxidase subunit I (COl) of their host were determined in five genera of the subfamily Formicinae (Hymenoptera: Formicidae). Based on these molecular data, we constructed phylogenetic trees in order to characterize the systematic position of the symbionts and to estimate the relationship of symbionts and hosts. The analysis showed that the endosymbionts were all connected with the Enterobacteriaceae but did not constitute a monophylitic group, while the three genera belonging to the tribe Camponotini, the endosymbionts and their hosts made a clade. The topologies of these trees were identical for the most part. These results suggest that the endosymbionts of ants have plural origins, and that in the Camponotini, ancestral symbionts have coevolved with their host ants, which are so divergent to several genera as to construct one tribe.
• Genetic structure of the first brood of workers and mating frequency of queens in a Japanese paper wasp Polistes chinensis antennalis.

  Miyano, S, Hasegawa, E

  Ethology Ecology and Evolution 10 79 - 85 1998 [Refereed][Not invited]
  
• Phylogeny and host-parasite relationships in social parasitism in Lasius ants.

  Hasegawa, E

  Entomological Science Entomological Society of Japan 1 (1) 133 - 135 1343-8786 1998 [Refereed][Not invited]
   

  Phylogenetic relationships and host-parasite relationships are compared among 4 subgenera of the ant genus Lasius. Estimated phylogeny based on mitochondorial DNA sequence indicated that the present host species belonging to phylogenetically ingroups. This result suggests that parasite species parasitize on the most closest species at past speciation and showed that Emery's rule was held in this genus.
• The optimal caste ratio in polymorphic ants: Estimation and empirical evidence

  E Hasegawa

  AMERICAN NATURALIST 149 (4) 706 - 722 0003-0147 1997/04 [Refereed][Not invited]
   

  A simple model is proposed for estimation of the optimal caste composition in polymorphic ants. The model gives the optimal caste composition as the highest point on a hypersurface that represents the total efficiency of the colony as a whole. The hypersurface is the product of all partial efficiency surfaces for all tasks. The model was applied to the dimorphic ant Colobopsis nipponicus to test its utility, The ergonomic efficiency of the colony as a whole was estimated from the quantitative ability of each caste to perform each role. When all partial functions of the major workers were included in the model, the predicted optimal ratio closely reflects the observed caste ratio in the field. In addition, the pattern of changes in brood productivity upon experimental manipulation of the caste ratio was consistent with the pattern predicted from the model. These results suggest that the model is useful for estimations of the optimal caste ratio and that the caste ratio in field colonies is tuned to maximize the ergonomic efficiency of the colony as a whole through colony-level selection.
• 分子情報に基づくアリの系統樹．

  長谷川英祐

  昆虫と自然． ニュ-・サイエンス社 32 (10) 12 - 16 0023-3218 1997 [Not refereed][Not invited]
  
• Effect of slave-raidings of Polyergus samurai on nest persistency of its host, Formica (Serviformica) japonica.

  Hasegawa, E, Yamaguchi, T

  Japanese Journal of Entomology 日本昆虫学会 65 (2) 291 - 294 0915-5805 1997 [Refereed][Not invited]
   

  The effect of slave raiding of Polyergus samurai on nest persistency of its host, Formica (Serviformica) japonica was investigated. Nest persistence rate after the raiding season was not different between raided and unraided nests. Many raided nests stopped aboveground activities for 2-3 weeks after a raiding but surviving workers maintained underground nest structure. These observations suggest that it is required to reconsider the previous interpretation that the raided nests died out from nest site during raiding season.
• POPULATION-STRUCTURE, LOCAL MATE COMPETITION, AND SEX-ALLOCATION PATTERN IN THE ANT MESSOR ACICULATUS

  E HASEGAWA, T YAMAGUCHI

  EVOLUTION 49 (2) 260 - 265 0014-3820 1995/04 [Refereed][Not invited]
   

  Population-genetic structure and sex-allocation ratios were investigated for the ant Messor aciculatus, a species that conducts mass nuptial flights. An electrophoretic survey on two polymorphic loci revealed excessive homozygosities in two populations. Because inbreeding inside nests does not occur, the heterozygote deficiency may result from population subdivision rather than assortative inbreeding during nuptial flights. Assuming no inbreeding, a simulation based on the observed genotype distribution in the study site suggested that, on average, a breeding swarm consists of alates from only 1.7 colonies. This population genetic structure seems to cause local mate competition (LMC), a factor that can shift population sex ratio toward females. The sex-allocation ratio to males in the population (0.166 +/- 0.030; mean +/- SE) was significantly female biased and lower than the expected optima for queens (0.5) and for workers (0.25) without LMC. Sex-ratio variability among colonies was explained by a pattern of constant male investment, which is predictable assuming LMC. Thus, the study provides the first evidence of LMC in ants with mass nuptial flights and contradicts previous assumptions about breeding structure
• PARENTAL ANALYSIS USING RAPD MARKERS IN THE ANT COLOBOPSIS-NIPPONICUS - A TEST OF RAPD MARKERS FOR ESTIMATING REPRODUCTIVE STRUCTURE WITHIN SOCIAL INSECT COLONIES

  E HASEGAWA

  INSECTES SOCIAUX 42 (4) 337 - 346 0020-1812 1995 [Refereed][Not invited]
   

  Previously known parent-offspring relationship for queens and her daughters of the ant Colobopsis nipponicus was examined using RAPD markers in order to test the reliability of this molecular technique for estimating the reproductive structure within colonies of social insects. RAPD markers from 20 oligomers successfully clustered the queen with her daughters among an artificially generated polygynous society, even when paternal information was unavailable. When information from both the queen and her sperm was included in the analysis, 20 polymorphic bands seem to be sufficient to cluster correctly the true parents to their offspring. Lack of father's information considerably decreased accuracy of the analysis. Thus, if RAPD markers are to be used to demonstrate parent-offspring relationship between individuals in the field, sperm from the queen's spermatheca should be incorporated in analysis.
• INTERCOLONIAL DIFFERENCES IN RAIDING ACTIVITIES IN THE JAPANESE SLAVE-MAKING ANT POLYERGUS-SAMURAI

  E HASEGAWA, T YAMAGUCHI

  INSECTES SOCIAUX 42 (2) 187 - 199 0020-1812 1995 [Refereed][Not invited]
   

  Intercolonial differences in raiding activity were investigated in the field on 9 colonies of the slave-making ant Polyergus samurai. Duration of raiding season, the mean start time of the first raiding trip in a day, the mean speed of outbound and inbound trips, and the mean distance to target nests varied significantly among colonies. The variance in start time of raiding was correlated with that in soil temperature and diurnal change pattern in soil temperature at the nest sites. The speed of trips and the first day with trips in the season also correlated with soil temperature at the nest site. Simple environmental factors well explained the observed variances in raiding activity among colonies. Therefore, raiding behaviour of P. samurai seemed to be a stereotyped behaviour that is regulated through simple environmental factors.
• Unique habits of the stomodeal trophallaxis in a ponerine ant Hypoponera sp.

  Hashimoto, Y, Yamauchi, K, Hasegawa, E

  Insectes Sociaux 42 137 - 144 1995 [Refereed][Not invited]
  
• Sex allocation in the ant Colobopsis nipponicus (Wheeler): I. population sex ratio.

  Hasegawa, E

  Evolution 48 1121 - 1129 1994 [Refereed][Not invited]
  
• RAIDING BEHAVIOR OF THE JAPANESE SLAVE-MAKING ANT POLYERGUS-SAMURAI

  E HASEGAWA, T YAMAGUCHI

  INSECTES SOCIAUX 41 (3) 279 - 289 0020-1812 1994 [Refereed][Not invited]
   

  Raiding behavior of the Japanese slave-making ant Polyergus samurai was investigated in the field. Raiding trips occurred from early June to early September. A raiding column of several hundreds workers would rush into a target nest and rob mainly worker pupae of the host species, Formica (Serviformica) japonica. Most trips occurred on sunny days. Air temperature, soil temperature, relative humidity, and radiation energy at the ground surface were significantly different between days with and without raiding trips. Nuptial flights occurred on bot, sunny days, and most Polyergus colonies released alates simultaneously. Behaviors of newly mated queens are also provided and are compared with other Polyergus species.
• NEST DEFENSE AND EARLY PRODUCTION OF THE MAJOR WORKERS IN THE DIMORPHIC ANT COLOBOPSIS-NIPPONICUS (WHEELER) (HYMENOPTERA, FORMICIDAE)

  E HASEGAWA

  BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY 33 (2) 73 - 77 0340-5443 1993/08 [Refereed][Not invited]
   

  Production of the major subcaste and its contribution to nest survival in the dimorphic ant Colobopsis nipponicus was examined in the field. In this species, the first major workers were reared in the second brood, very early in the colony life cycle. A field experiment demonstrated that artificial colonies without major workers could not survive, whereas colonies with at least one major worker per nest entrance could. Because major workers of C. nipponicus defend the nest entrance by head plugging, the lack of nest defenders in the experimental colonies seemed to be a major cause of nest failure. The defensive value of major workers was much higher than that of minor workers. Many artificial colonies without major workers were displaced by competitors for nest sites, especially by those of other conspecific colonies. In addition, more than 90% of field colonies nested with other conspecific colonies on the same tree. The early production of major workers in C. nipponicus seemed to be very important for the survival of incipient colonies.
• Ergatoid queens of slave-making ant Polyergus samurai Yano (Hymenoptera: Formicidae)

  Terayama, M, Yamaguchi,T, Hasegawa, E

  昆蟲 東京昆蟲學會 61 (3) 511 - 514 0915-5805 1993 [Refereed][Not invited]
   

  Ergatoid queens of Polyergus samurai YANO, 1911, are firstly described. This caste is easily distinguishable from the normal queens by the workerlike trunk, and from the workers by the large head and gaster, convex mesonotum, and developed ovaries. The developed reproductive organs suggest that the ergatoid queens can produce female offsprings. The ground activities of the caste were also observed in the field.
• CASTE SPECIALIZATION IN FOOD STORAGE IN THE DIMORPHIC ANT COLOBOPSIS-NIPPONICUS (WHEELER)

  E HASEGAWA

  INSECTES SOCIAUX 40 (3) 261 - 271 0020-1812 1993 [Refereed][Not invited]
   

  Food-storage abilities of both minor and major workers of the dimorphic ant Colobopsis nipponicus were examined to prove the hypothesis that major workers of this species have a trophic role in addition to a defensive one. Both worker subcastes accumulated water, that was supplied with water-soluble food, as well as fat, that probably originated from food given. However, the major, workers accumulated much larger amounts of water and fat than did the minor workers. Difference in water accumulation increased as food supply increased. In spite of their difference in body weight, the residual amount of fat after starvation did not differ between the two subcastes. Although the amount of stored fat increased with colony size in both subcastes, the stored fat per dry weight of the major worker was significantly larger than that of the minor worker regardless of the colony size. When workers of a colony were starved, minor workers with a single major worker survived significantly longer than those without a major worker. In addition, about half the behavioral acts of major workers were regurgitation for minor workers. These results demonstrate that major workers of C. nipponicus functioned as a trophic caste. On the basis of the results, quantitative relationships of storage abilities between the two worker subcastes are discussed.
• 兵隊アリは闘うか？ −ヒラズオオアリのカストの役割−．

  長谷川英祐

  インセクタリウム 29 22 - 27 1992 [Not refereed][Not invited]
  
• 千葉県天津小湊町内浦にみられた樹上営巣性のアリについて．

  長谷川英祐

  千葉大学理学部海洋生態系研究センター年報 12 91 - 92 1992 [Not refereed][Not invited]
  
• ANNUAL LIFE-CYCLE AND TIMING OF MALE-EGG PRODUCTION IN THE ANT COLOBOPSIS-NIPPONICUS (WHEELER)

  E HASEGAWA

  INSECTES SOCIAUX 39 (4) 439 - 446 0020-1812 1992 [Refereed][Not invited]
   

  Life history parameters, including colony boundary, number of queens in a colony, seasonal change in colony-member composition and seasonal change in male-egg production were investigated for the arboreal ant Colobopsis nipponicus in the field. Colonies were shown to be typically monogynous and polydomous, with several different colonies inhabiting the same tree. The queen and workers overwinter only with larvae, which grow rapidly into new adults during early summer. Male-destined eggs were produced throughout the warm season with a conspicuous peak in summer that coincided with adult production. It is suggested that this might be related to seasonal changes in the food available to the queen.
• 小笠原群島のアリ相．

  寺山守, 長谷川英祐

  小笠原研究年報 15 40 - 51 1991 [Not refereed][Not invited]
  
• ヒラズオオアリの婚姻飛行について．

  長谷川英祐

  千葉大学理学部海洋生態系研究センター年報 11 75 - 78 1991 [Not refereed][Not invited]
  
• 小笠原諸島のオカヤドカリ：特にムラサキオカヤドカリの巨大化と矮小化

  林文男, 岡輝樹, 石井裕之, 長谷川英祐, 富山清升, 草野保

  小笠原研究年報 14 1 - 9 1990 [Not refereed][Not invited]
  

Books etc

• コミュニケーションの認知科学 第４巻 社会の中の共存

  長谷川英祐 (Contributor第４章 動物の集団的意思決定におけるコーディネーション問題)
  岩波書店 2014/06
• 科学の罠 -美と快楽と誘惑-

  長谷川英祐 (Single work)
  青志社 2014
• 面白くて眠れなくなる生物学

  長谷川英祐 (Single work)
  PHP 2014
• 働くアリに幸せを

  長谷川英祐 (Single work)
  講談社 2013
• 縮む世界でどう生き延びるか？

  長谷川英祐 (Single work)
  メディアファクトリー 2013
• 働かないアリに意義がある.

  長谷川英祐 (Single work)
  メディアファクトリー 2010
• New Developments on the Biology of Chrysomelidae.

  Kudo, K, Hasegawa, E (ContributorDiversified reproductive strategies in Gonioctena leaf beetles.)
  SPB Academic Publishing 2005
• 親子関係の進化生態学・節足動物の社会

  長谷川英祐 (Contributor第２部第１章 勝者はどちらか −ヒラズオオアリの性比と血縁選択−．)
  北海道大学図書刊行会 1996
• 親子関係の進化生態学

  長谷川英祐 (Contributor第１部第１章 アリの社会の性比をめぐる親子の対立)
  北海道大学図書刊行会 1996
• 世界の知性科学を語る．

  長谷川英祐 (Joint work社会生物学の騎手．Ｅ．Ｏ．ウィルソン)
  日本経済新聞社 1995

MISC

• アリの行動と化学物質

  長谷川 英祐  化学と生物  43-  (12)  817  -824  2005/12/01  [Not refereed][Not invited]
  

Awards & Honors

• 2014/08 日本進化学会 日本進化学会教育啓蒙賞
   

  受賞者: 長谷川英祐
• 2013/11 日本動物行動学会 日本動物行動学会日高賞
   

  受賞者: 長谷川英祐
• 2007/09 日本昆虫学会 日本昆虫学会賞
   

  受賞者: 長谷川英祐

Educational Activities

Teaching Experience