Coexistence, Exclusion, or Neutrality? A Meta-Analysis of Competition between Aedes Albopictus and Resident Mosquitoes

Abstract

Competition experiments estimating the relative effects of inter- and intraspecific competition can help to resolve whether interspecific competition results in coexistence or exclusion. For mosquitoes, most such experiments have focused on invasiveAedes albopictusand its interactions with residentAedes.A meta-analysis of such experiments tested whether the effect of interspecific competition is greater than, less than, or equal to that of intraspecific competition, and whether competitive outcomes are dependent on food quality. ForA. albopictusandA. aegypti, there was significant context dependence, with interspecific competitive advantage forA. albopictuswith low food quality, and competitive equivalence with high food quality. Meta-analysis of survivorship yielded more significant effects than did estimated rate of increase. Competitive effects and competitive responses of each species yielded similar results. This meta-analysis suggests competitive exclusion ofA. aegyptibyA. albopictus, and is thus consistent with field sampling, qualitative reviews, and interpretations from individual publications. ForA. albopictusandA. triseriatus, most results indicated competitive equivalence and no context dependence, and are thus contrary to previous qualitative reviews and to interpretations from individual publications. For both pairs of species, published results suitable for meta-analysis remain scarce, and better experimental designs and improved analysis and reporting of statistical results are needed. Greater emphasis needs to be placed on estimating species' inter- and intraspecific competitive effects, rather than the more common, but theoretically less interesting, competitive responses. Experiments without low-density controls (i.e., replacement series) are inadequate for comparing competitive effects and responses.