Oviposition Dynamics of Two Released Species of Toxorhynchites (Diptera: Culicidae) and Potential Prey Species1

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Abstract
Releases of 122 Toxorhynchites brevipalpis and 106 Toxorhynchites rutilus were made in a 4.6-ha oak-maple woodlot in northern Indiana to examine the spatial distribution of Toxorhynchites oviposition in relation to prey oviposition preferences. Oviposition was monitored at 25 sites with ovitraps suspended at 0.6, 3.0, and 6.1 m. Six weekly collections yielded 137,917 eggs of Aedes triseriatus and Aedes hendersoni and all 75 traps received eggs. Over a 28-day period, 1370 Tx. brevipalpis and 785 Tx. rutilus eggs were recovered. Toxorhynchites brevipalpis eggs were collected in 88% (66/75) of the traps and Tx. rutilus eggs were collected in 91% (68/75). Toxorhynchites eggs of 1 or both species were found in all traps. The Tx. brevipalpis mosquitoes deposited over ½ of their eggs in the 0.6-m traps, whereas the 3.0-m trap received the most Tx. rutilus eggs. Eggs of both Toxorhynchites species and the potential prey species were spatially aggregated within the woodlot. The spatial differences in oviposition between the 2 species of Toxorhynchites enhanced the degree of overlap in oviposition between the predators and the potential prey population.