Digging Deeper into the Ecology of Subterranean Ants: Diversity and Niche Partitioning across Two Continents

Abstract

Soil fauna is generally understudied compared to above-ground arthropods, and ants are no exception. Here, we compared a primary and a secondary forest each on two continents using four different sampling methods. Winkler sampling, pitfalls, and four types of above- and below-ground baits (dead, crushed insects; melezitose; living termites; living mealworms/grasshoppers) were applied on four plots (4 × 4 grid points) on each site. Although less diverse than Winkler samples and pitfalls, subterranean baits provided a remarkable ant community. Our baiting system provided a large dataset to systematically quantify strata and dietary specialisation in tropical rainforest ants. Compared to above-ground baits, 10–28% of the species at subterranean baits were overall more common (or unique to) below ground, indicating a fauna that was truly specialised to this stratum. Species turnover was particularly high in the primary forests, both concerning above-ground and subterranean baits and between grid points within a site. This suggests that secondary forests are more impoverished, especially concerning their subterranean fauna. Although subterranean ants rarely displayed specific preferences for a bait type, they were in general more specialised than above-ground ants; this was true for entire communities, but also for the same species if they foraged in both strata.

Evolution and systematics of the Aculeata and kin (Hymenoptera), with emphasis on the ants (Formicoidea: †@@@idae fam. nov., Formicidae)

“…Although we did not specifically evaluate this hypothesis in our study because of uncertainty regarding the fossils, two previous works are available that have tested the pattern using ancestral state reconstruction across extant ants (Lucky et al ., 2013; Nelson et al ., 2018), which we will discuss in combination with the next hypotheses due to their continuity of explanation. Notably, Houadria & Menzel (2021) recently found that subterranean (hypogaeic) ants, even those which may forage above ground, were more specialized in their diet relative to epigaeic species.…”

Diversity, Biogeography and Community Ecology of Ants: Introduction to the Special Issue

“…Two papers in the Special Issue address the structure and dynamics of ant communities. The first [7] uses a wide range of sampling methods, incorporating diverse food resources along with sampling in different vertical strata, to examine niche partitioning in rainforest ant communities of French Guiana and Borneo. Many cryptobiotic species were recorded primarily or exclusively at subterranean baits, which supports findings from several recent studies (including [3]) that a diverse fauna of highly specialized hypogaeic species is characteristic of the tropics.…”