Social interactions between an inquiline ant, Ectatomma parasiticum, and its host, Ectatomma tuberculatum (Formicidae, Ectatomminae)

Abstract

Inquilines, workerless social parasites, frequently show advanced adaptations to their parasitic life style that indicate a long co-evolutionary history with their host. Ectatomma parasiticum, the first inquiline described in the poneromorph group, usurps established colonies of E. tuberculatum and produces only sexuals. In laboratory colonies, parasites were specifically attacked by the host workers, showing a failure in their social integration. Social interactions were frequent between parasites and their hosts, especially antennation, interpreted as attempts to promote colonial odor transfer. Inquilines destroyed eggs laid by the other queens (67 out of 209 eggs laid), including conspecific parasites, which is unusual. Such partial integration into the host colony and potential parasite virulence argue for a recent evolution of social parasitism in E. tuberculatum.

Juvenile hormone downregulates vitellogenin production in Ectatomma tuberculatum (Hymenoptera: Formicidae) sterile workers

“…JH activates ion channels in ovarian follicular cells, increasing the intercellular space as a result of changes in the architecture of the actin filaments (Ronnau et al, 2015) and facilitating vitellogenin to reach the surface of oocytes, where it is endocytosed Tufail and Takeda, 2009). In this way, the reduction of the circulating vitellogenin in the haemolymph in JH-treated ants may be associated with the uptake of vitellogenin for growing oocytes, since all workers used in the experiment have developing trophic eggs (Hora et al, 2001(Hora et al, , 2007. On the contrary, in S. invicta, the JH peak occurs in queens during the oviposition period (Brent and Vargo, 2003), but in this fire ant, worker are always sterile.…”

“…Ectatomma tuberculatum (Olivier 1792) (Ectatomminae) makes small colonies of up to 400 workers with one or many morphologically differentiated queens (Hora et al, 2001;Hora et al, 2005). The workers are morphologically identical, and the tasks they perform within the colony vary according to age (Champalbert and Lachaud, 1990;Fénéron et al, 1996;Hora et al, 2001). The workers of E. tuberculatum also have active ovaries and produce non-reproductive trophic eggs (Fénéron and Billen, 1996;Hora et al, 2007).…”

“…The workers of E. tuberculatum also have active ovaries and produce non-reproductive trophic eggs (Fénéron and Billen, 1996;Hora et al, 2007). Furthermore, they are not able to mate because their spermathecae are not functional (Hora et al, 2001). In this ant, vitellogenin is associated with age polyethism in workers (Azevedo et al, 2011).…”

As formigas poneromorfas do Brasil

“…O par de espécies E. parasiticum / E. tuberculatum constitui um caso particular de variação morfológica desde que a inusitada E. parasiticum foi inicialmente descrita como uma microgine de E. tuberculatum por Hora et al (2001). No entanto, um estudo comportamental das interações sociais entre rainhas grandes e pequenas, juntamente com operárias da mesma colônia, deixou claro que as rainhas pequenas eram, de fato, parasitas sociais, uma forma inquilina caracterizada por…”

Ants and Their Parasites 2013

“…Until now, only one case of inquilinism has been reported within the poneromorph ants [24], involving a facultative polygynous population of the common Neotropical ectatommine ant Ectatomma tuberculatum and miniature queens of the sibling species E. parasiticum. R. Fénéron and colleagues provide an upto-date survey of the biological, genetical, and behavioral data accumulated since the first discovery of E. parasiticum, fourteen years ago [25], and try to shed light on the evolutionary history of the parasitic relationships between both species. The phylogenetical proximity between both species, along with the fact that the parasite queens are clearly discriminated from conspecifics by the host workers and, apparently, are not well integrated into the host colony, suggest a recent sympatric speciation from the host.…”