engleski

Is there a difference in diet between geographically distant carabid beetle communities? Implication for metal accumulation in predators

Soil ecosystems contain complex food webs and therefore contamination pathways along trophic chains are not always obvious. The advent of molecular gut-content analysis can quickly reveal previously unidentified trophic interactions between invertebrates. Carabid beetles are important predators in soil ecosystem. Data on their food preferences has, to date, mainly been obtained under the laboratory conditions or in cultivated fields. Here we present data on prey consumption within the carabid beetle communities in forest ecosystems using PCR analyses of the gut-content in geographically distant populations (three sites in Croatia and two in the UK). Extensive screening, using group- and species-specific primers, revealed that the carabids were mainly eating earthworms and slugs, as well as smaller numbers of Lepidoptera, woodlice and springtails. Croatian and Welsh populations were compared. We applied GLMs to investigate the influence of sites, season, presence of other prey groups in the gut, sex, and size on prey consumption. In addition we measured heavy metal concentrations in the tissue of predators and potential prey and analysed the links with prey consumption in the field, in order to identify the main trophic pathways for transport of contaminants from the soil to wildlife. Analysis of prey consumption and heavy metal accumulation at the species and community levels allowed us to assess the role of carabids as bioindicators.

molecular detection of trophic interactions; carabid beetles; UK; Croatia

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