Antennal Proteome of the Solenopsis invicta (Hymenoptera: Formicidae): Caste Differences in Olfactory Receptors and Chemosensory Support Proteins

Little is known about the expression pattern of odorant and pheromone transporters, receptors, and deactivation enzymes in the antennae of ants carrying out different tasks. In order to begin filling in this information gap, we compared the proteomes of the antennae of workers and males of the red fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae). Male ants do not perform any colony work, and their only activity is to leave the nest on a mating flight. Previous studies showed that male ants express fewer types of odorant receptors than workers. Thus, we expected to find large differences between male and worker antennae for expression of receptors, transporters, and deactivators of signaling chemicals. We found that the abundance of receptors was consistent with the expected caste-specific signaling complexity, but the numbers of different antenna-specific transporters and deactivating enzymes in males and workers were similar. It is possible that some of these proteins have antenna-specific functions that are unrelated to chemosensory reception. Alternatively, the similar complexity could be a vestige of ant progenitors that had more behaviorally active males. As the reduced behavior of male ants evolved, the selection process may have favored a complex repertoire of transporters and deactivating enzymes alongside a limited repertoire of odorant receptors.

ECOLOGICAL RELEASE OF AN EXOTIC SPECIES UPON SUPPRESSION OF ITS INVASIVE PREDATOR

Ecological release allows a species to expand beyond its currently occupied niche upon removal of a limiting mechanism such as a predator or competitor. Unfortunately, these interactions between exotic and invasive organisms are relatively unknown. We examine how a small-scale, intensive Red Fire Ant (Solenopsis invicta) eradication program may influence the herpetological and formicid community on a 1.85 ha plot in northeast Texas. Red Fire Ant mounds were individually treated with a series of pesticides in 2005, with follow up treatments in 2006 and 2007. Populations of Red Fire Ants, other ant species, reptiles, and amphibians were monitored throughout the study. Other ant species showed signs of recovery after two years of Red Fire Ant suppression. Although reptile and amphibian diversity increased during the study, only populations of the Mediterranean Gecko (Hemidactylus turcicus) showed a dramatic response. The removal of Red Fire Ants provided this exotic Gecko with the opportunity to proliferate. The potential for these kinds of unexpected responses must be considered when removing introduced species from communities containing multiple exotic and potentially invasive organisms.