Effect of dragonfly nymph presence and conspecific larvae density on oviposition response of the invasive Asian Tiger Mosquito (Aedes albopictus)

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Kimberlie Yeoman (Creator)
The University of North Carolina at Greensboro (UNCG )
Web Site: http://library.uncg.edu/
Gideon Wasserberg

Abstract: Oviposition site selection is a critical fitness enhancing decision for container breeding insects. Predators have typically been shown to repel gravid females whereas conspecifics have been shown to be attractive at low-intermediate densities but repellent at high densities resulting in hump-shaped relations. The interaction of these two factors has, unfortunately, rarely been studied. In this study, I addressed this question by testing the effect of dragonfly nymphs as larval predators, conspecifics, and their combination on the oviposition response of Aedes albopictus mosquitoes. I expected a negative effect of predators, a hump-shaped effect of conspecifics, and a rightward shift in the peak of the hump in the presence of larval predators. I used three levels (0, 1, 3) of caged Odonata (dragonfly) nymphs and a range of predetermined conspecific larvae numbers (0, 10, 50, 100, 300, 500). I used two experimental designs: (1) Six 3-by-6 oviposition traps grids each containing all 18 predator-by-larvae combinations; (2) Three transects containing 12 pairs of oviposition traps with both cups containing a similar number of larvae, but one containing a given level (0, 1, 3) of caged nymphs. In the latter, I also cultured a sample of the water medium to evaluate bacterial concentration. Hump-shaped relations of egg number with conspecifics was observed at the grid design for the one nymph level and for the transect design at nymph level zero. The effect predator level on oviposition response was either non-significant or, unexpectedly positive. Due to increased larval mortality in the predator cups, I could not evaluate the third hypothesis concerning the combined effect of conspecifics and predators. Bacterial concentration was negatively associated with number of eggs laid. The absence or positive effect of dragonfly nymphs on Ae. albopictus oviposition response is encouraging in terms of its usage as a biocontrol agent for container breeding mosquitoes which in combination with low-intermediate levels of conspecifics could be attractive to gravid female mosquitoes. Their offspring, in turn, will be decimated by the control agent.

Additional Information

Language: English
Date: 2014
Aedes albopictus, Attractive Predator Effect, Dragonfly, Mosquito, Odonata, Oviposition
Aedes albopictus $x Eggs
Aedes albopictus $x Reproduction
Aedes albopictus $x Behavior
Aedes albopictus $x Effect of predation on
Allee effect

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