The place of Carabidae in the biosphere – a network approach

Abstract

Whereas they are of high ecological, conservation, and agricultural importance, ground beetles (Coleoptera: Carabidae) are amongst the organisms declining rapidly as a result of human activities. Since they are part of a complex ecological network –in which other taxa’s survival may depend on them, or they may depend on other taxa –in the case of their, hypothetical, extinction these connections would be impaired. In order to gain insight how different taxa would be affected by the extinction of carabids, and thus, how ecosystem functions would be altered, we conceptualised a network between ground beetles and all other organisms they are directly connected with. We used published literature data in building our network, thus interaction occurrences are likely to be skewed by research interest. Based on a single database search, we found 238 carabid species interacting with 395 other species, including plants (72), fungi (53), animals (286), and 7 other Eucaryota. Of the 817 described interactions, in 235 cases, carabids were prey, mostly for birds and mammals. Hosting ectoparasites was the second most frequent relationship, with 144 connections. Most of these connections were to Laboulbeniales fungi. Further, detailed searches on carabid – fungus relationshipsyielded over 700 different interactions. Carabids were listed to consume 88 other taxa, including many plants; an additional 200 records refer to seed predation by ground beetles, mostly from the Zabrini and Harpalini tribes. The specificity of seed dispersal, and therefore assessing the extent plant species depend on carabids was not possiblefrom this database. Carabids also visit flowers and even pollinate them in 12 cases. Amara, Harpalus and Cicindela genera had the most records of interactions with other species. Although this list of interactions between Carabidae and other taxa is incomplete, it shows that many other organisms can depend on ground beetles, and some (mostly fungi) have specific relationship with them. The apparent information gaps on symbiotic and competitive interactions, and the geographical bias towards Europe and North America open doors for further research in these areas.