Allopeas myrmekophilos (Gastropoda, Pulmonata), the first myrmecophilous mollusc living in colonies of the ponerine army ant Leptogenys distinguenda (Formicidae, Ponerinae)

Abstract

Allopeas myrmekophilos was regularly found in colonies of the ponerine army ant Leptogenys distinguenda. The gastropods always remained inside the bivouacs of their hosts, where they were able to move around undisturbed by the ants. During emigrations A. myrmekophilos was always carried by workers in a manner identical to brood or prey items. A regularly, actively secreted substance was responsible for attracting the ants. This foamy substance was usually produced only during contact with workers of L. distinguenda and had no effect on other ponerine ants. In feeding experiments A. myrmekophilos fed very well on fresh meat, which is regularly available in the bivouacs of the strictly carnivorous L. distinguenda. This study reveals a high degree of adaptation of A. myrmekophilos to L. distinguenda colonies, thereby meeting the definition of myrmecophily. Consequently, A. myrmekophilos is the first mollusc observed to be a true ant guest.