Data from: Impacts of an invasive ant species on roosting behaviour of an island endemic flying-fox

Introduced species can cause major disruptions to ecosystems, particularly
on islands. On Christmas Island, the invasive yellow crazy ant
(Anoplolepis gracilipes) has detrimental impacts on many animals ranging
from the iconic red crabs (Gecarcoidea natalis) to the Christmas Island
Thrush (Turdus poliocephalus erythropleurus). However, the full extent of
its effects on the island’s fauna is not yet known. In this study, we
investigated the impact of the yellow crazy ants on the island’s last
native mammal: the Christmas Island flying-fox (Pteropus natalis). This
species has been described as a keystone species, but has recently
experienced substantial population decline to the extent that it is now
listed as critically endangered. We examined the impacts of the yellow
crazy ants on the roosting behaviour of the Christmas Island flying-fox,
and on its local and island-wide distribution patterns. We showed that the
crazy ants increased behaviours in the flying-foxes that were associated
with avoidance of noxious stimuli, and decreased behaviours associated
with resting. Roost tree selection and roost site location were not
related to variation in the abundance of crazy ants on the island. Our
results indicate that the crazy ants interfere with the activity budgets
of the flying-foxes. However, the flying-foxes failed to relocate to
ant-free roost trees or roost sites when confronted with the noxious ant,
suggesting that the flying-foxes are either not sufficiently disturbed to
override strong cultural attachment to roosts, or, are behaving
maladaptively due to ecological naïveté.