A field test for competitive effects of Aedes albopictus on A. aegypti in South Florida: differences between sites of coexistence and exclusion?

Abstract

We tested whether interspecific competition from Aedes albopictus had measurable effects on A. aegypti at the typical numbers of larval mosquitoes found in cemetery vases in south Florida. We also tested whether the effect of interspecific competition from A. albopictus on A. aegypti differed between sites where A. aegypti either persists or went extinct following invasion by A. albopictus. Similar experiments manipulating numbers of A. albopictus in cemetery vases were conducted at three sites of A. aegypti persistence and three sites where A. aegypti was apparently extinct. The experiments were done using numbers of larvae that were determined by observed numbers of larvae for each site, and with resources (leaf detritus) that accumulated in experimental vases placed into each field site. In both the early rainy season (when number of mosquito larvae was low) and the late rainy season (when number of mosquito larvae was high), there was a significant effect of treatment on developmental progress of experimental A. aegypti. In the late rainy season, when numbers of larvae were high, there was also a significant effect of treatment on survivorship of A. aegypti. However, the competition treatment × site type (A. aegypti persists vs extinct) interaction was never significant, indicating that the competitive effect of A. albopictus on A. aegypti did not differ systematically between persistence versus extinction sites. Thus, although competition from A. albopictus is strong under field conditions at all sites, we find no evidence that variation in the impact of interspecific competition is associated with coexistence or exclusion. Interspecific competition among larvae is thus a viable explanation for exclusion or reduction of A. aegypti in south Florida, but variation in the persistence of A. aegypti following invasion does not seem to be primarily a product of variation in the conditions in the aquatic environments of cemetery vases.

Ovitrampas para Avaliação da Presença de Aedes aegypti (Linnaeus) e Aedes albopictus (Skuse) no Município de Vassouras, Estado do Rio de Janeiro

“…aegypti para os dois parâmetros (umidade relativa r s =0,268 e temperatura r s =0,208) em que não ficou evidenciado devido ao número baixo de imaturos obtidos após eclosão em laboratório, e recentemente comprovada a superioridade competitiva das larvas de Ae. albopictus (Juliano et al 2004).…”

Temperature and Dengue Virus Infection in Mosquitoes: Independent Effects on the Immature and Adult Stages

“…aegypti). [13][14][15][16][17] Temperature likely plays an important role in the distribution pattern of Ae. albopictus, which is by similar Northern isotherm limits of distribution in its native range in Asia and invaded range in North America.…”

The spatial distribution of Aedes aegypti and Aedes albopictus in a transition zone, Rio de Janeiro, Brazil

“…aegypti by Ae. albopictus in some areas 10,12 . In North America and Brazil, the introduction of Ae.…”