Ecology of Antricola ticks in a bat cave in north-eastern Brazil

Argasid ticks are a diverse group of acarines that parasitize numerous vertebrate hosts. Along with birds, bats serve as hosts for several argasid ticks, which are commonly found in bat caves. Argasid ticks have regained attention from tick taxonomists in recent decades, with a number of new species described in various zoogeographical regions. Nonetheless, studies on their ecology are still scarce. We conducted a 1-year longitudinal study to assess the presence of argasid ticks in a bat cave in the drylands of north-eastern Brazil and evaluate their possible response to abiotic factors. From July 2014 to June 2015, 490 ticks were collected (272 nymphs, 169 males and 49 females) in a cave chamber hosting a large colony of Pteronotus spp. bats, being relatively more frequent from July to December 2014. Adults were identified as Antricola guglielmonei, whereas nymphs were assigned to the genus Antricola. Almost all ticks (98%) were collected on the cave walls. Only 2% were on the ceiling and, surprisingly, no specimens were found on the floor and/or guano. Adults were usually clustered in the crevices and little mobile, whereas nymphs were dispersed and more active, moving over the walls or ceiling of the cave. Although present in most of the studied period, there was a significantly negative correlation between tick abundance and relatively humidity, and A. guglielmonei was more frequent during the dry season. Moreover, there was no evident correlation between the abundance of ticks and bats. Further long-term studies will be able to verify whether this pattern is repeated over time, and even whether other variables can influence the population dynamics of A. guglielmonei.