The trade-off to macroptery in the cricket Gryllus firmus: a path analysis in males

Journal

Among the Orthoptera, wing dimorphism, where one morph is long-winged and flight capable while the other is short-winged and flight incapable, is common and believed to be maintained in populations due to trade-offs to flight capability. In males, macropterous individuals call less than micropterous individuals and as a consequence obtain fewer matings. This trade-off is hypothesized to be mediated by the energetic costs of calling. In this paper we report results for a path analysis examining lipid weight and DLM (dorso longitudinal muscle) condition of male Gryllus firmus. We found that as DLM condition changes from a nonfunctional to a functional state, call duration decreases, and as lipid weight increases, call duration increases. The most important linked path was wing morph → DLM condition → call duration. This model is consistent with the prediction that the trade-off between wing morph and call duration is mediated via DLM and lipid stores.