Journal article
Juvenile hormone regulates extreme mandible growth in male stag beetles
PloS one, Vol.6(6), pp.e21139-e21139
2011
Handle:
https://hdl.handle.net/2376/109448
PMCID: PMC3120829
PMID: 21731659
Abstract
The morphological diversity of insects is one of the most striking phenomena in biology. Evolutionary modifications to the relative sizes of body parts, including the evolution of traits with exaggerated proportions, are responsible for a vast range of body forms. Remarkable examples of an insect trait with exaggerated proportions are the mandibular weapons of stag beetles. Male stag beetles possess extremely enlarged mandibles which they use in combat with rival males over females. As with other sexually selected traits, stag beetle mandibles vary widely in size among males, and this variable growth results from differential larval nutrition. However, the mechanisms responsible for coupling nutrition with growth of stag beetle mandibles (or indeed any insect structure) remain largely unknown. Here, we demonstrate that during the development of male stag beetles (Cyclommatus metallifer), juvenile hormone (JH) titers are correlated with the extreme growth of an exaggerated weapon of sexual selection. We then investigate the putative role of JH in the development of the nutritionally-dependent, phenotypically plastic mandibles, by increasing hemolymph titers of JH with application of the JH analog fenoxycarb during larval and prepupal developmental periods. Increased JH signaling during the early prepupal period increased the proportional size of body parts, and this was especially pronounced in male mandibles, enhancing the exaggerated size of this trait. The direction of this response is consistent with the measured JH titers during this same period. Combined, our results support a role for JH in the nutrition-dependent regulation of extreme mandible growth in this species. In addition, they illuminate mechanisms underlying the evolution of trait proportion, the most salient feature of the evolutionary diversification of the insects.
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Details
- Title
- Juvenile hormone regulates extreme mandible growth in male stag beetles
- Creators
- Hiroki Gotoh - Laboratory of Ecological Genetics, Graduate School of Environmental Science, Hokkaido University, Sapporo, JapanRichard CornetteShigeyuki KoshikawaYasukazu OkadaLaura Corley LavineDouglas J EmlenToru Miura
- Publication Details
- PloS one, Vol.6(6), pp.e21139-e21139
- Academic Unit
- Entomology, Department of
- Publisher
- United States
- Identifiers
- 99900546924801842
- Language
- English
- Resource Type
- Journal article