@article{buczkowski_silverman_2006, title={Geographical variation in Argentine ant aggression behaviour mediated by environmentally derived nestmate recognition cues}, volume={71}, ISSN={["0003-3472"]}, DOI={10.1016/j.anbehav.2005.04.012}, abstractNote={Social insects use a complex of recognition cues when discriminating nestmates from non-nestmate conspecifics. In the Argentine ant, Linepithema humile, recognition cues can be derived from exogenous sources, and L. humile acquires prey-derived hydrocarbons that are used in nestmate discrimination. We studied Argentine ant population-level distinctions in response to external recognition cues. Ants belonging to a California population were strongly affected by the imposition of prey-derived hydrocarbons, with spatially isolated colony fragments that had been fed different cockroach prey (Blattella germanica or Supella longipalpa) showing high and injurious intracolony aggression when reunited. In contrast, colonies of Argentine ants from the southeastern U.S. showed only moderate and noninjurious aggression when subjected to the same treatment. Field-collected colonies of L. humile had hydrocarbons in the range of those provided by S. longipalpa, and colonies from the southeastern U.S. had significantly higher initial levels of Supella-shared hydrocarbons. When fed cockroaches, Argentine ants from both regions acquired additional amounts of Supella- and Blattella-specific hydrocarbons, with a significant increase in levels of Blattella-specific hydrocarbons. Therefore, diet partitioning produced a greater change in the proportion of prey hydrocarbons in the California than in the southeastern U.S. populations, which may be responsible for the altered behaviour observed in the California population. Identifying factors underlying geographical variation in cue expression and/or perception may bring us closer to elucidating the selective forces driving nestmate recognition systems.}, journal={ANIMAL BEHAVIOUR}, author={Buczkowski, G and Silverman, J}, year={2006}, month={Feb}, pages={327–335} }
 @article{buczkowski_kumar_suib_silverman_2005, title={Diet-related modification of cuticular hydrocarbon profiles of the Argentine ant, Linepithema humile, diminishes intercolony aggression}, volume={31}, ISSN={["1573-1561"]}, DOI={10.1007/s10886-005-3547-7}, abstractNote={Territorial boundaries between conspecific social insect colonies are maintained through a highly developed nestmate recognition system modulated by heritable and, in some instances, nonheritable cues. Argentine ants, Linepithema humile, use both genetic and environmentally derived cues to discriminate nestmates from nonnestmates. We explored the possibility that intraspecific aggression in the Argentine ant might diminish when colonies shared a common diet. After segregating recently field-collected colony pairs into high or moderate aggression categories, we examined the effect of one of three diets: two hydrocarbon-rich insect prey, Blattella germanica and Supella longipalpa, and an artificial (insect-free) diet, on the magnitude of aggression loss. Aggression diminished between colony pairs that were initially moderately aggressive. However, initially highly aggressive colony pairs maintained high levels of injurious aggression throughout the study, independent of diet type. Each diet altered the cuticular hydrocarbon profile by contributing unique, diet-specific cues. We suggest that acquisition of common exogenous nestmate recognition cues from shared food sources may diminish aggression and promote fusion in neighboring colonies of the Argentine ant.}, number={4}, journal={JOURNAL OF CHEMICAL ECOLOGY}, author={Buczkowski, G and Kumar, R and Suib, SL and Silverman, J}, year={2005}, month={Apr}, pages={829–843} }
 @article{buczkowski_vargo_silverman_2004, title={The diminutive supercolony: the Argentine ants of the southeastern United States}, volume={13}, ISSN={["1365-294X"]}, DOI={10.1111/j.1365-294X.2004.02261.x}, abstractNote={Abstract Native to Argentina and Brazil, the Argentine ant ( Linepithema humile ) is an invasive species that has become established on six continents and many oceanic islands. In several parts of its introduced range, including the western United States, southern Europe and Chile, the Argentine ant is unicolonial, forming extensive supercolonies. We examined population genetic structure and intercolony aggression in two regions of the introduced range of this species in the United States: California and the southeastern United States. Our results show that the southeastern L. humile population has high genotypic variability and strong intercolony aggression relative to the California population. In the California population, intercolony aggression was absent and 23 alleles were found across seven polymorphic microsatellite loci. However, in the Southeast, aggression between colonies was high and 47 alleles were present across the same seven loci in an equal number of colonies. We suggest that distinctly different colonization patterns for California and the Southeast may be responsible for the striking disparity in the genetic diversity of introduced populations. Southeastern colonies may have descended from multiple, independent introductions from the native range, undergoing a bottleneck at each introduction. In contrast, the California supercolony may have originated from one or more colonies inhabiting the southeastern United States, thus experiencing a double bottleneck. The differences in present‐day distribution patterns between California and the Southeast may be due to the combined effect of two factors: lower winter temperatures in the Southeast and/or competition with another successful and widely distributed ant invader, the fire ant Solenopsis invicta .}, number={8}, journal={MOLECULAR ECOLOGY}, author={Buczkowski, G and Vargo, EL and Silverman, J}, year={2004}, month={Aug}, pages={2235–2242} }
 @article{roulston_buczkowski_silverman_2003, title={Nestmate discrimination in ants: effect of bioassay on aggressive behavior}, volume={50}, ISSN={["1420-9098"]}, DOI={10.1007/s00040-003-0624-1}, number={2}, journal={INSECTES SOCIAUX}, author={Roulston, TH and Buczkowski, G and Silverman, J}, year={2003}, pages={151–159} }
 @article{buczkowski_schal_2001, title={Emetophagy: Fipronil-induced regurgitation of bait and its dissemination from German cockroach adults to nymphs}, volume={71}, ISSN={["1095-9939"]}, DOI={10.1006/pest.2001.2572}, abstractNote={Blattella germanica (L.) (Dictyoptera: Blattellidae) that were fed fipronil bait produced liquid excretions that were toxic to conspecifics. We have used a combination of analytical and behavioral assays to localize the source, to elucidate the time course, and to evaluate the role of these excretions in facilitation of secondary kill. Fipronil excretion coincided with the onset of the paralytic symptoms, and most of the excreted fipronil (79%) was eliminated during the first 12 h after ingestion of the bait. More than 74% of the total radioactivity excreted in 48 h from [14C]fipronil-fed females was recovered from their oral region, and time-lapse video analysis showed that first instars were highly attracted to these excretions. Moreover, first instars preferentially contacted the oral region of dying females and imbibed the liquid exudates. Emetophagy, the ingestion of insecticide-induced regurgitate, may constitute an important mechanism by which fast-acting, emetogenic insecticides are disseminated within cockroach populations.}, number={3}, journal={PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY}, author={Buczkowski, G and Schal, C}, year={2001}, month={Nov}, pages={147–155} }
 @article{buczkowski_kopanic_schal_2001, title={Transfer of ingested insecticides among cockroaches: Effects of active ingredient, bait formulation, and assay procedures}, volume={94}, ISSN={["0022-0493"]}, DOI={10.1603/0022-0493-94.5.1229}, abstractNote={Foraging cockroaches ingest insecticide baits, translocate them, and can cause mortality in untreated cockroaches that contact the foragers or ingest their excretions. Translocation of eight ingested baits by adult male Blattella germanica (L.) was examined in relation to the type of the active ingredient, formulation, and foraging area. Ingested boric acid, chlorpyrifos, fipronil, and hydramethylnon that were excreted by adults in small dishes killed 100% of first instars within 10 d and >50% of second instars within 14 d. Residues from these ingested baits were also highly effective on nymphs in larger arenas and killed 16-100% of the adults. However, when the baits and dead cockroaches were removed from the large arenas and replaced with new cockroaches, only residues of the slow-acting hydramethylnon killed most of the nymphs and adults, whereas residues of fast acting insecticides (chlorpyrifos and fipronil) killed fewer nymphs and adults. Excretions from cockroaches that ingested abamectin baits failed to cause significant mortality in cockroaches that contacted the residues. These results suggest that hydramethylnon is highly effective in these assays because cockroaches that feed on the bait have ample time to return to their shelter and defecate insecticide-laden feces. The relatively high concentration of hydramethylnon in the bait (2.15%) and its apparent stability in the digestive tract and feces probably contribute to the efficacy of hydramethylnon. To control for differences among baits in inert ingredients and the amount of active ingredient, we compared 1% chlorpyrifos with 1% hydramethylnon in identical baits. Again, hydramethylnon residues provided greater secondary kill, but the results highlighted the importance of the inert ingredients. We conclude that, in the absence of cannibalism and necrophagy, translocation of baits and secondary kill are most effective with slow acting insecticides in palatable baits that can traverse the digestive tract and be deposited within and around the cockroach aggregation.}, number={5}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Buczkowski, G and Kopanic, RJ and Schal, C}, year={2001}, month={Oct}, pages={1229–1236} }