Oviposition response of container-mosquitoes Aedes albopictus and A. aegypti to larval presence and resource availability in urban cemeteries of Tampa, FL

Female container-dwelling Aedes oviposit near the water-line of containers. Females often have choices among multiple containers and may discriminate when making oviposition decisions. Resource availability (i.e., bacteria) and competitor presence influence such decisions in many species. Invasive Aedes albopictus and its resident competitor A. aegypti respond to such characteristics when ovipositing in the laboratory, but their behavior in nature is not well known. We designed several experiments to determine whether similar behaviors occur in the wild.

In summer 2009 the oviposition responses of wild A. albopictus and A. aegypti females to larval presence and resource quantity were tested in three Tampa, FL cemeteries. Treatments were 14 combinations of larval abundances (A. albopictus: A. aegypti; 0:0, 10:10, 20:0, 0:20, 20:20, 40:0, 0:40) and two resource levels (senescent live oak, Quercus virginiana, 0.25 g, 0.5 g). No response to larval abundances was observed although more A. aegypti eggs were laid in high-resource containers (p=0.0369).

In summer 2010 additional experiments isolated the oviposition response to resource type and larval presence. In the first, four detritus resource types (deciduous, coniferous, grass, or insect) were tested at high or low levels. In the second, we used 50 or 100 larvae of either A. albopictus or A. aegypti to condition water for 24 hours, before placing oviposition samplers (larvae removed) in the field. Both experiments were within one week of each other in a single cemetery in randomized block design. The oviposition response of Aedes was analyzed by ANOVA.