In arthropod community ecology, species richness studies tend to be prioritised over those investigating patterns of abundance. Consequently, the biotic and abiotic drivers of arboreal arthropod abundance are still relatively poorly known. In this cross-continental study, we employ a theoretical framework in order to examine patterns of covariance among herbivorous and predatory arthropod guilds. Leaf-chewing and leaf-mining herbivores, and predatory ants and spiders, were censused on ' 1000 trees in nine 0.1 ha forest plots. After controlling for tree size and season, we found no negative pairwise correlations between guild abundances per plot, suggestive of weak signals of both inter-guild competition and top-down regulation of herbivores by predators. Inter-guild interaction strengths did not vary with mean annual temperature, thus opposing the hypothesis that biotic interactions intensify towards the equator. We find evidence for the bottom-up limitation of arthropod abundances via resources and abiotic factors, rather than for competition and predation.
Bibliographical noteFunding Information:
This study was funded by the Czech Science Foundation (19‐8126X) and European Research Council (669609).
We thank the staff, interns, students, volunteers and local assistants of Smithsonian Conservation Biology Institute (USA); Ostrava University (CZE); and the New Guinea Binatang Research Centre (PNG). Namely, we thank Jaroslav Bla?ej, and Joe and Matthew Rhodes for allowing us to use their facilities or work on their property as well as for providing logistical support. We gratefully thank the communities of Wanang, Numba and Yawan for permission to use their land and for logistic support during the project. We also thank Katerina Sam for validation of temperature data.
© 2020 The Authors. Ecology Letters published by John Wiley & Sons Ltd.
- community ecology
- spatial interactions