1. Insect cuticular hydrocarbons (CHCs) serve a role in both desiccation resistance and sexual attractiveness. These two functions are thought to be maximised by different CHC compositions, which should lead to local adaptation between populations experiencing different natural and sexual selection pressures. 2. The Pacific field cricket (Teleogryllus oceanicus) is distributed throughout Oceania, including the Hawaiian and Cook Islands. In Hawaii, these crickets face strong natural selection from a parasitoid fly that has promoted the evolution of a novel male reproductive morph, dramatically altering sexual selection in the Hawaiian populations. The parasitoid and male polymorphism do not occur in the Cook Islands. 3. We captured male and female T. oceanicus on two Hawaiian Islands and three Cook Islands, and quantified their CHCs. We also measured temperature and RH at our collection sites to test for associations with cricket CHC profiles. 4. We discovered significant sexual dimorphism in CHC profiles, as well as differences between both island chains and particular islands. The two male reproductive morphs in Hawaii showed distinct CHC expression. There were no associations between weather variables and CHC profiles. 5. Observed differences in T. oceanicus CHC profiles appear to reflect geographic isolation rather than selection in response to local and environmental and social conditions.
Bibliographical noteFunding Information:
This work was funded by the Daniel and Margaret Carper Foundation. We thank Spencer Ingley (Brigham Young University) and Patrick Hart (University of Hawaii, Hilo) for logistical field support in Hawaii. In the Cook Islands, we are grateful to Gerald McCormack (Cook Islands National Heritage Trust), and Teina Tuatei and Kirby Morejohn (Ministry of Marine Resources) who provided significant field support. John Rotenberry aided with the data collection and analysis. The Cook Islands government granted us permission to perform this research. We heartily thank Stephen Harvey and Sean Murray at the University of Minnesota Mass Center for Mass Spectrometry and Proteomics for their invaluable help in CHC extraction and analysis. We conducted this research in the absence of any competing commercial or financial interests. While invertebrates are not subject to IACUC regulation, we adhered to ABS/ASAB guidelines for the ethical treatment of animals in behavioral research.
© 2021 The Royal Entomological Society
- Cuticular hydrocarbons
- geographic variation
- sexual selection
- signal evolution
- Teleogryllus oceanicus