2012 Annual Report
1a.Objectives (from AD-416):
1. Determine under controlled laboratory conditions, the colony level effects of the distribution of excessive amounts of the fire ant pheromone on normal recruitment to food resources and in colony/colony competition.
2. Determine under semi-controlled field conditions whether or not a sustained release formulation of the fire ant recruitment orientation pheromone disrupts the fire ant’s ability to locate and recruit workers to food resources and for an extended period of time, thus impacting colony size and health.
1b.Approach (from AD-416):
1) Monogyne laboratory colonies will be derived from newly mated queens or from excavated colonies from the field. Colonies will be housed in large boxes that can be connected with bridges allowing contact between to different colonies. Treatments will be sustained release recruitment pheromone uniformly distributed on the foraging surface. Two colonies – one treated and the other a control will be bridged to a common foraging area. The dynamics of this competitive arrangement will be observed at least three times a day. The results will determine if the treatment confers a disadvantage, no advantage, or an advantage to the treated colony. Trailing events will be recorded and colony size (brood/workers/presence of a queen will be periodically monitored as measures of colony health.
2) Monogyne field sites will be selected and manipulated by eliminating surrounding colonies so that target colonies have a well defined territory. The sustained release formulation of the fire ant recruitment orientation pheromone will be evenly distributed over the target colony territory and challenged systematically and over time with baits to determine their recruitment capabilities. and the longevity of the sustained release formulation. Colony size will be monitored weekly using mound size and a population index measure. Brood production will be aslo measured weekly as a gage of queen productivity.
These results directly support and correspond to inhouse project objective 3: Characterize semiochemicals through investigation of pheromone biosynthesis and release; use these findings to develop novel biologically-based control and surveillance methods, including the detection and treatment of incipient or low level populations.
Laboratory studies were conducted to determine if aerosol application of fire ant trail pheromone to the foraging area will disrupt the ability of fire ants to bring back food to their colonies. Results determined that, at least on a small scale, this application method may be useful for the disruption of a normal fire ant food trail. In the future this research will be applied to controlled field situations. Trail disruption has been shown to be a useful tool in conjunction with toxic baits to control another difficult to control pest ant species (Argentine ant), thus development of this technique for fire ants will add to our integrated management tool box!