Sex-related variation in δ15N values of ground beetles (Coleoptera, Carabidae): A case study

Intersexual differences in food preferences and patterns of nutrient allocation are well known for a variety of animals, but this factor is not taken into account in the stable isotope-based studies of soil food webs. We used stable isotope composition of carbon and nitrogen (delta C-13 and delta N-15 values) to address the intersexual differences in the trophic niche of 27 species of ground beetles sampled in Northern Poland and Western Russia. Despite a high level of intra- and interspecies variation, males were, on average, enriched in N-15 relative to females by 0.5 +/- 0.1%.. Observed enrichment was most pronounced among species with high delta N-15 values and among spring breeding species collected in June. We did not find significant sex-related differences in delta C-13 values. Our results indicate sex-specific patterns in resource allocation or foraging behavior of predatory Carabidae during the breeding season. (C) 2015 Elsevier GmbH. All rights reserved.