Print PageThe larvae of the Asian tiger mosquito (Aedes albopictus), a recent invader in North America, and the southern house mosquito (Culex quinquefasciatus) are common occupants of water-filled automobile tires in the southeastern United States. Although Ae. albopictus is known to be a superior resource competitor to several established species, the nature of interactions between larval Ae. albopictus and Cx. quinquefasciatus has not been studied. Our objective was to determine the nature of resource competition between Ae. albopictus and Cx. quinquefasciatus. Microcosms were established containing three levels of organic detritus (Quercus virginiana leaves and Drosophila melanogaster carcasses) and eight ratios of Ae. albopictus:Culex quinquefasciatus larvae. Microcosms were placed in an incubator at 27 °C for 45 days. Kruskal-Wallis tests were used to test for differences in survivorship (i.e., percentage of individuals of a species surviving to adulthood) among detritus levels and among larval density ratios. Multivariate analysis of variance (MANOVA) was used to test for effects of detritus level, larval density ratio, and a detritus x density interaction on development time (i.e., days to pupation) for both mosquito species.
Results/Conclusions
Culex quinquefasciatus survivorship differed significantly among detritus levels, with lower survivorship values observed at lower detritus levels; survivorship also differed significantly within detritus levels, with lower survivorship observed at higher larval densities. Culex quinquefasciatus survivorship was zero in all but one low detritus treatment. Aedes albopictus survivorship differed significantly among detritus levels, with highest survivorship observed at the intermediate detritus level; survivorship significantly differed among larval density ratios only within the lowest detritus level, with lower survivorship observed in higher densities. There was a significant detritus x density interaction for development time of both species. No discernable trends were noted for Cx. quinquefasciatus, as development time differed significantly both within and among detritus levels and larval density ratios. Aedes albopictus development time did not significantly differ within or between the intermediate and high detritus levels; significantly longer development times were observed at higher larval densities only within the low detritus level. We conclude that Ae. albopictus has a competitive advantage over Cx. quinquefasciatus, as Ae. albopictus survivorship and development time were unaffected at resource levels and larval densities at which those of Cx. quinquefasciatus were negatively affected. Future directions include incorporating adult body mass into statistical analyses for the current experiment. A follow-up experiment will investigate the effects of chemical pollutants on resource competition between these two species.
