Abstract
I conducted a detailed morphological analysis of the Japanese horned beetle Trypoxylus dichotomus septentrionalis to clarify the allometric relationship between horn length and body size and examined its mating success and reproductive behaviour in the field. The relationship between horn and body size was not discontinuous at the switch point body size, but the slope of the linear relationship changed at the switch point. Shape of the allometric relationship was initially steep and became flatten around the switch point in both linear and log scales; that is, minor males showed a positive relationship and major males showed a negative one. Major males gained more mating success than minor males. Within major males, individuals with larger horn or body size had higher mating success than individuals with smaller ones. Within minor males there were no differences in horn and body size between mated and unmated individuals. Although sneak-like behaviours were exhibited by both morphs, it is likely that these behaviours rarely lead to direct benefit. These results suggest that dimorphic allometry of T. dichotomus is consistent with the hypothesis of a continuous reaction norm that meets a ceiling, which restrains further allometric growth.
Similar content being viewed by others
References
Andersson M (1994) Sexual Selection. Princeton University Press, Princeton
Bonduriansky R, Day T (2003) The evolution of static allometry in sexually selected traits. Evolution 57:2450–2458
Burkhardt D, Motte I (1988) Big ‘antlers’ are favoured: female choice in stalk-eyed flies (Diptera, Insecta), field collected harems and laboratory experiments. J Comp Physiol A 162:649–652
Clark JT (1977) Aspects of variation in the stag beetle Lucanus cervus (L.) (Coleoptera: Lucanidae). Syst Entomol 2:9–16
Eberhard WG (1979) In: Blum MS, Blum NA (eds) The function of horns in Podischnus agenor and other beetles. Sexual selection and reproductive competition in insects. Academic, New York, pp 231–258
Eberhard WG (1980) Horned beetles. Sci Am 242:124–131
Eberhard WG (1982) Beetle horn dimorphism: making the best of bat lot. Am Nat 119:420–426
Eberhard WG (1998) Sexual behavior of Acanthocephala declivis guatemalana (Hemiptera: Coreidae) and the allometric scaling of their modified hind legs. Ann Entomol Soc Am 91:863–871
Eberhard WG, Gutierrez EE (1991) Male dimorphisms in beetles and earwigs and the question of developmental constraints. Evolution 45:18–28
Emlen DJ (1996) Artificial selection on horn length-body size allometry in the horned beetle Onthophagus acuminatus (Coleoptera: Scarabaeidae). Evolution 50:1219–1230
Emlen DJ (1997a) Alternative reproductive tactics and male dimorphism in the horned beetle Onthophagus acuminatus (Coleoptera: Scarabaeidae). Behav Ecol Sociobiol 41:335–341
Emlen DJ (1997b) Diet alters male horn allometry in the beetle Onthophagus acuminatus (Coleoptera: Scarabaeidae). Proc R Soc Lond B 264:567–574
Emlen DJ (2000) Integrating development with evolution: a case study with beetle horns. Bioscience 50:403–418
Emlen DJ (2001) Costs and diversification of exaggerated animal structures. Science 291:1534–1536
Emlen DJ, Nijhout HF (1999) Hormonal control of male horn length dimorphism in the dung beetle Onthophagus taurus (Coleopera: Scarabaeidae). J Insect Physiol 45:45–53
Emlen DJ, Nijhout HF (2001) Hormonal control of male horn length dimophism in the dung beetle Onthophagus taurus (Coleopera: Scarabaeidae): a second critical period of sensitivity to juvenile hormone. J Insect Physiol 47:1045–1054
Forslund P (2003) An experimental investigation into status-dependent male dimorphism in the European earwig, Forficula auricularia. Anim Behav 65:309–316
Goldsmith SK (1987) The mating system and alternative reproductive behaviours of Dendrobias mandibularis (Coleoptera: Cerambycidae). Behav Ecol Sociobiol 20:111–115
Gross MR (1996) Alternative reproductive strategies and tactics: diversity within sexes. Trends Ecol Evol 11:92–98
Hanley RS (2001) Mandibular allometry and male dimorphism in a group of obligately mycophagous beetles (Insecta: Coleoptera: Staphylinidae: Oxyporinae). Biol J Linn Soc 72:451–459
Hongo Y (2003) Appraising behaviour during male-male interaction in the Japanese horned beetle Trypoxylus dichotomus septentrionalis (Kono). Behaviour 140:501–517
Hunt J, Simmons LW (2001) Status-dependent selection in the dimorphic beetle Onthophagus taurus. Pro R Soc Lond B 268:2409–2414
Huxley JS (1931) Relative growth of mandibles in stag beetles. J Linn Soc Lond 37:675–703
Kawano K (1995) Horn and wing allometry and male dimorphism in giant rhinoceros beetles (Coleoptera: Scarabaeidae) of tropical Asia and America. Ann Entomol Soc Am 88:92–99
Kawano K (1997) Cost of evolving exaggerated mandibles in stag beetles (Coleoptera: Lucanidae). Ann Entomol Soc Am 90:453–461
Knell RJ, Pomfret JC, Tomkins JL (2004) The limits of elaboration: curved allometries reveal the constraints on mandible size in stag beetle. Proc R Soc Lond B 271:523–528
Kotiaho JS, Tomkins JL (2001) The discrimination of alternative male morphologies. Behav Ecol 12:553–557
Madewell R, Moczek AP (2006) Horn possession reduces maneuverability in the horn-polyphenic beetle, Onthophagus nigriventris. J Insect Sci 6:21
McAlpine DK (1979) In: Blum MS, Blum NA (eds) Agonistic behavior in Achias australis (Diptera: Platystomatidae) and the significance of eyestalks. Sexual selection and reproductive competition in insects. Academic, New York, pp 221–230
Miyatake T (1993) Male-male aggressive behavior is changed by body size difference in the leaf-footed plant bug, Leptoglossus australis, Fabricius (Heteroptera: Coreidae). J Ethol 11:63–65
Miyatake T (1997) Functional morphology of the hind legs as weapons for male contests in Leptoglossus australis (Heteroptera: Coreidae). J Insect Behav 10:727–735
Moczek AP (2003) The behavioral ecology of threshold evolution in a polyphenic beetle. Behav Ecol 14:841–854
Moczek AP, Emlen DJ (1999) Proximate determination of male horn dimorphism in the beetle Onthophagus taurus (Coleoptera: Scarabaeidae). J Evol Biol 12:27–37
Moczek AP, Emlen DJ (2000) Male horn dimorphism in the scarab beetle, Onthophagus taurus: do alternative reproductive tactics favour alternative phenotypes. Anim Behav 59:459–466
Moczek AP, Nijhout HF (2002) Developmental mechanisms of threshold evolution in a polyphenic beetle. Evol Devel 4:252–264
Nijhout HF, Emlen DJ (1998) Competition among body parts in the development and evolution of insect morphology. Proc Natl Acad Sci of U S A 95:3685–3689
Nijhout HF, Wheeler DE (1996) Growth models of complex allometries in holometabolous insects. Am Nat 148:40–56
Otte D, Stayman J (1979) In: Blum MS, Blum NA (eds) Beetle horns: some patterns in functional morphology. Sexual selection and reproductive competition in insects. Academic, New York, pp 259–292
Panhuis TM, Wilkinson GS (1999) Exaggerated male eye span influences contest outcome in stalk-eyed flies (Dipsidae). Behav Ecol Sociobiol 46:221–227
Plaistow SJ, Tsuchida K, Tsubaki Y, Setsuda K (2005) The effect of a seasonal time constraint on development time, body size, condition, and morph determination in the horned beetle Allomyrina dichotoma L. (Coleoptera: Scarabaeidae). Ecol Entmol 30:692–699
Rasmussen JL (1994) The influence of horn and body size on the reproductive behavior of the horned rainbow scarab beetle Phanaeus difformis (Coleoptera: Scarabaeidae). J Insect Behav 7:67–82
Rowland JM (2003) Male horn dimorphism, phylogeny and systematics of rhinoceros beetles of the genus Xylotrupes (Scarabaeidae: Coleoptera). Aust J Zool 51:213–258
Setsuda K, Tsuchida K, Watanabe H, Kaei Y, Yamada Y (1999) Size dependent predatory pressure in the Japanese horned beetle, Allomyrina dichotoma L. (Coleoptera: Scarabaeida). J Ethol 17:73–77
Shiokawa T, Iwahashi O (2000) Mandible dimorphism in male of a stag beetle, Prosopocoilus dissimilis okinawanus (Coleoptera: Lucanidae). Appl Entomol Zool 35:487–494
Siva-Jothy MT (1987) Mate securing tactics and the cost of fighting in the Japanese horned beetle Allomyrina dichotoma L. (Coleoptera: Scarabaeidae). J Ethol 5:165–172
Thornhill R, Alcock J (1983) The evolution of insect mating systems. Harvard University Press, Cambridge
Tomkins JL, Kotiaho JS, LeBas NR (2005) Matters of scale: positive allometry and the evolution of male dimorphisms. Am Nat 165:389–402
Tomkins JL, Kotiaho JS, LeBas NR (2006) Major differences in minor allometries: a reply to Moczek. Am Nat 167:612–618
West-Eberhard MJ (1989) Phenotypic plasticity and the origins of diversity. Ann Rev Ecol System 20:249–278
Wilkinson GS, Dodson GN (1997) Function and evolution of antelers and eye stalks in flies. In: Choe J, Crespi B (eds) Mating systems in insects and arachnids. Cambridge University Press, Cambridge, pp 310–328
Acknowledgements
I thank Drs. Michio Imafuku and Ken Yoda for their valuable advices on the manuscript. Especially, I thank Drs. Akira Mori, Douglas Emlen and Joseph Tomkins for their extremely helpful comments for improving the manuscript. I am also grateful to Dr. Simon Cook for his English corrections and Noriyoshi Sato for his assistance of field research. Field observations were conducted under the permission of Kamigamo Experimental Station of Field Science Education and Research Center, Kyoto University. This study was supported in part by a Grant for the Biodiversity Research of the 21st Century COE (A14).
Author information
Authors and Affiliations
Corresponding author
Additional information
Communicated by M. Siva-Jothy
Rights and permissions
About this article
Cite this article
Hongo, Y. Evolution of male dimorphic allometry in a population of the Japanese horned beetle Trypoxylus dichotomus septentrionalis . Behav Ecol Sociobiol 62, 245–253 (2007). https://doi.org/10.1007/s00265-007-0459-2
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00265-007-0459-2