Bat aggregation mediates the functional structure of ant assemblages

Abstract

In the Guianese rainforest, we examined the impact of the presence of guano in and around a bat roosting site (a cave). We used ant communities as an indicator to evaluate this impact because they occupy a central place in the functioning of tropical rainforest ecosystems and they play different roles in the food web as they can be herbivores, generalists, scavengers or predators. The ant species richness around the cave did not differ from a control sample situated 500m away. Yet, the comparison of functional groups resulted in significantly greater numbers of detritivorous fungus-growing and predatory ant colonies around the cave compared to the control, the contrary being true for nectar and honeydew feeders. The role of bats, through their guano, was shown using stable isotope analyses as we noted significantly greater δ(15)N values for the ant species captured in and around the cave compared to controls.

Bat droppings collection by ants in epigean environments

“…Of the over 130 ant species found in caves, a minority are troglobiont species that can feed on guano (Tinaut Ranera, 2023), whereas the vast majority are trogloxene species that make intermittent use of caves to hunt other invertebrates (Pape, 2016). Therefore, subterranean guano deposits do not influence the species richness of ants frequenting caves (Dáttilo et al, 2012;Dejean et al, 2015), but they do influence functional diversity of their communities (Dejean et al, 2015). This ecological relationship between ants and bat guano, however, remains understudied in non-hypogean environments where bat droppings are present.…”