Data from: Predator-prey Interactions of Terrestrial Invertebrates are Determined by Predator Body Size and Species Identity

Predator-prey interactions shape ecosystem and can help maintain
biodiversity. However, for many of the earth’s most biodiverse and
abundant organisms, including terrestrial arthropods, these interactions
are difficult or impossible to observe directly with traditional
approaches. Based on previous theory, it is likely that predator-prey
interactions for these organisms are shaped by a combination of predator
traits, including body size and species-specific hunting strategies. In
this study, we combined diet DNA metabarcoding data of 173 individual
invertebrate predators from nine species (a total of 305 predator-prey
interactions) with an extensive community body size dataset of a
well-described invertebrate community to explore how predator traits and
identity shape interactions. We found that 1) mean size of prey families
in the field usually scaled with predator size, with species-specific
variation to a general size scaling relationship (exceptions likely
indicating scavenging or feeding on smaller life stages). We also found
that 2) although predator hunting traits, including web and venom use, are
thought to shape predator-prey interaction outcomes, predator identity
more strongly influenced our indirect measure of the relative size of
predators and prey (predator:prey size ratios) than either of these
hunting traits. Our findings indicate that predator body size and species
identity are important in shaping trophic interactions in invertebrate
food webs and could help predict how anthropogenic biodiversity change
will influence terrestrial invertebrates, the earth’s most diverse animal
taxonomic group.

捕食者-猎物相互作用塑造生态系统，并有助于维持生物多样性。然而，对于地球上许多生物多样性最高、数量最多的生物（包括陆生节肢动物）而言，使用传统方法直接观察这些相互作用往往困难重重，甚至无法实现。基于先前的理论，这类生物的捕食者-猎物相互作用很可能由捕食者的多种性状共同决定，包括体型大小和物种特异性的捕猎策略。本研究中，我们将9个物种的173只无脊椎动物捕食者（invertebrate predators）的饮食DNA宏条形码（diet DNA metabarcoding）数据（共记录305组捕食者-猎物相互作用），与一个描述详尽的无脊椎动物群落的大规模群落体型数据集相结合，旨在探究捕食者性状及物种身份如何塑造这些相互作用。研究发现：1）野外环境中猎物科的平均体型通常与捕食者体型呈比例关系，但这一普遍体型比例关系存在物种特异性差异（例外情况可能表明捕食者存在食腐行为或取食猎物的幼体阶段）；2）尽管捕食者的捕猎性状（包括结网和毒液使用）被认为会影响捕食者-猎物相互作用的结果，但相较于这两种捕猎性状，捕食者的物种身份对捕食者与猎物相对体型（捕食者:猎物体型比）的间接测量值具有更强的影响。本研究结果表明，捕食者体型大小和物种身份在塑造无脊椎动物食物网的营养相互作用中具有重要意义，且有助于预测人为因素导致的生物多样性变化将如何影响陆生无脊椎动物——这一地球上物种多样性最高的动物类群。