Wing morphology is linked to stable isotope composition of nitrogen and carbon in ground beetles (Coleoptera: Carabidae)

Abstract

As movement is expensive in terms of energy required, mobile animals might have to utilize more energy rich resources than less mobile animals. As mobile animals are possibly more effective foragers we hypothesize a positive correlation between mobility and trophic niche width. We address this link using information on the trophic level of 35 winged, wingless and wing dimorphic species of ground beetles studied on 18 lake islands and at two mainland sites in northern Poland. Trophic analyses using stable isotope values (δ15 N, δ13C) revealed that winged individuals of wing dimorphic species are characterized by broader isotopic niches than wingless individuals. Macropterous species are characterized by depleted δ13C values, which can be interpreted in terms of lipid-rich prey selection. Wing dimorphic species are characterized by higher trophic levels, as inferred from δ15 N values, than winged species. Numbers of islands colonized by particular species were not correlated with δ15 N values, δ13C values or isotopic niche width. Our results point to a relationship between diet and wing morphology in ground beetles.

Keywords

• coleoptera
• carabidae
• mobility
• island
• niche width
• stable isotopes
• trophic level
• wing dimorphism
• δ15 n
• δ13c