title: Diet specialization in an extreme omnivore: nutritional regulation in glucose-averse German cockroaches.
abstract: Organisms have diverse adaptations for balancing dietary nutrients, but often face trade-offs between ingesting nutrients and toxins in food. While extremely omnivorous cockroaches would seem excluded from such dietary trade-offs, German cockroaches (Blattella germanica) in multiple populations have rapidly evolved a unique dietary specialization - an aversion to glucose, the phagostimulant in toxic baits used for pest control. We used factorial feeding experiments within the geometric framework to test whether glucose-averse (GA) cockroaches with limited access to this critical metabolic fuel have compensatory behavioural and physiological strategies for meeting nutritional requirements. GA cockroaches had severely constrained intake, fat and N mass, and performance on glucose-based diets relative to wild-type (WT) cockroaches and did not appear to exhibit digestive strategies for retaining undereaten nutrients. However, a GA × WT 'hybrid' had lower glucose aversion than GA and greater access to macronutrients within glucose-based diets - while still having lower intake and survival than WT. Given these intermediate foraging constraints, hybrids may be a reservoir for this maladaptive trait in the absence of positive selection and may account for the rapid evolution of this trait following bait application.
authors: Department of Entomology, North Carolina State University, Raleigh, NC, USA; Smithsonian Tropical Research Institute, Washington, Ancon, Panama; Centre for Social Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
authors: J Z
authors: JZ
authors: Shik
authors: C
authors: C
authors: Schal
authors: J
authors: J
authors: Silverman
mesh_terms: D000220:Adaptation, Biological / Q000235:genetics; D000818:Animals; D002678:Chimera; D003058:Cockroaches / Q000235:genetics / Q000502:physiology*; D004032:Diet / Q000662:veterinary*; D005947:Glucose; D015233:Models, Statistical; D009751:Nutritional Requirements
chemical_list: D005947:Glucose
keywords: Blattella germanica; geometric framework; nutritional ecology