PARENT SESSION
Oral Session # 89: Insect Ecology II.
Presiding: R Sears
Friday, August 8. 8:30 AM to 12:00 PM, SITCC Meeting Room 101.
Competitive advantage and plasticity in growth and development in competing container mosquitoes.
Juliano, Steven*,1, Braks, Marieta2, Honorio, Nildimar3, Lounibos, L. Philip2, Laurenco-de-Oliveira, Ricardo3, 1 Illinois State University, Normal, IL, USA2 Florida Medical Entomology Laboratory, Vero Beach, FL, USA3 Instituto de Oswaldo Cruz, Rio de Janeiro, Rio de Janeiro, Brazil
ABSTRACT- A clear competitive advantage for one species over another species leads directly to questions about the mechanisms producing that advantage. For resource competition, greater feeding rate and greater efficiency are commonly postulated as mechanisms, but another way of realizing competitive advantage may be greater phenotypic plasticity, expressed as greater flexibility of size and development rate of one competitor, which may buffer a species against mortality effects of competition. Because of flexibility in one life history trait (e.g., size at maturity) impacts of competition on other life history traits more closely related to fitness (e.g., survivorship) may be reduced, giving a species an advantage in competition with other species that suffer mortality in competition. This hypothesis predicts that competitively superior species should: 1) suffer lower mortality when in competition; and 2) show a greater range of size or development time in response to a range of conditions than do competitively inferior species. We tested these predictions for competing larvae of two mosquitoes, the recently introduced invasive Aedes albopictus, and the long-established Aedes aegypti. In field experiments on two continents, A. albopictus has a clear advantage over A. aegypti. In the lab, although this advantage was dependent on conditions, when there was a strong advantage it usually fell to A. albopictus. This advantage is associated with greater survival to adulthood under the most severe conditions of inter- and intraspecific density. As predicted, in several independent studies, A. albopictus has significantly greater plasticity of body size and development time than does A. aegypti. This is true for both males and females, but is most evidence for female body mass. Thus, in this system, it appears that greater plasticity of size and development time are possible as mechanisms for the competitive advantage of A. albopictus over A. aegypti.
Key words: Interspecific competition, Aedes, Plasticity, Aquatic insects