Emigrating together but not establishing together: A cockroach rides ants and leaves

Symbionts of ant colonies can hitchhike on winged ant reproductives (alates) during colony nuptial flights. Attaphila fungicola Wheeler, a miniature cockroach that lives in the nests of Texas leaf-cutter ants (Atta texana Buckley), hitchhikes on female alates (winged queens). Hitchhiking roaches are presumably vertically transmitted from leaf-cutter parent colony to daughter colony, remaining with female alates as they transition into foundresses (workerless queens); however, foundresses have limited resources and high mortality rates. Rather than remaining with foundresses likely to die (vertical transmission), roaches might abandon them during dispersal to infect higher quality later stages of colony development (female alate-vectored transmission). In field experiments, I find evidence for female alate-vectored transmission, and discover roaches use a second hitchhiking step, riding foraged plant material, to infect established colonies. This work reveals a novel relationship between host dispersal and symbiont transmission, and shows colony development can be an important selection pressure on transmission.

Methods
This data was collected in the field with direct observations recorded in field journals.  All observations are described in more detail in the Methods and Results section of the manuscript, "Emigrating together but not establishing together: A cockroach rides ants and leaves."