International Union for the Study of Social Insects (IUSSI2018), August 5-10, 2018 in Guarujá, Brazil.

only days left!
Find us: Ft

The aminergic and olfactory underpinnings of self-exclusion by infected ants

Author(s):
Veronica M. Sinotte, Veronica M. Sinotte , Marc A. Seid , Matthew Barrett , Jacobus J. Boomsma , Line V. Ugelvig
Institution(s):
Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark; Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark ; Department of Biology, University of Scranton, Scranton, PA, USA ; Department of Biology, University of Scranton, Scranton, PA, USA ; Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark ; Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark
Social insects maintain a repertoire of prophylactic defenses to prevent pathogen uptake and subsequent infection. However, when these are ineffective, pathogenic infection induces defenses vital to inhibiting transmission, namely isolation of the sick individual. Self-exclusion is a recognized altruistic behavior expressed prior to death, yet little is known about the neurobiological changes correlated with infection that may prompt this drastic dissociation from the colony. Given that behavior in social insects, particularly ants, is largely coordinated by olfactory communication and regulated by neuromodulators, changes in olfaction and/or the underlying neurobiology may be expected during self-exclusion. Here, we examine self-exclusion behavior in leafcutter ants (Acromyrmex echinatior) infected with an entomopathogenic fungus (Metarhizium roberstii). We will test if the behavior of individuals at different stages of infection is correlated with pathogen loads and levels of the biogenic amines octopamine (OA), dopamine (DA), and serotonin (5-HT) of whole brains. Then, we will assess infection-induced changes in olfactory sensitivity to relevant pheromone and chemical cues. If we observe a relationship between biogenic amines, self-exclusion behavior, and olfactory sensitivity, we will secondarily confirm this with pharmaceutical manipulation. We expect that self-isolation behavior will be positively correlated with pathogen load and that DA and OA levels will decrease with pathogen load, mirroring known biogenic amine levels of waste-management workers. Further, we predict infection will reduce olfactory sensitivity, thus supporting social dissociation. Overall, neurobiological changes associated with pathogen-induced self-exclusion will provide key insights to a behavior essential to preventing disease outbreaks in social insect colonies.
Back