Effectiveness of pyramidal emergence traps for estimating production of Culex mosquitoes (Diptera:Culicidae)

The percentage of emergent mosquitoes (Culex spp.) collected, temporal dynamics of collection by pyramidal emergence traps, and the effect of a chemical deterrent (pest control strips) for terrestrial scavengers, which remove emergent mosquitoes from collection jars, on the number of emergent mosquitoes collected were studied in ponds in southern California. On average, 75.5% of emergent mosquitoes were collected in jars at the apex of 0.25-m emergence traps placed on the water surface. Recently emerged mosquitoes spent ,1 d in emergence traps before moving into the collection jars. Pest control strips (2.54 cm of Vaportape II: 10% 2,2-dichlorovinyl dimethyl phosphate), which have been used in collection jars during previous studies to deter foraging on newly emerged mosquito adults by Argentine ants (Linepithema humile Mayr), did not significantly reduce the number of adult mosquitoes in collection jars and did not delay the movement of adult mosquitoes into collection jars. The cumulative proportion of adult mosquito production sampled by the pyramidal emergence traps increased at a decreasing rate across time (proportion of total production = 20.314 + 1.021(1 2 e) where t is days of trapping). The proportion of adult mosquito production collected during 3to 5-d collection periods ranged between 0.37 and 0.55 during periods that Culex emergence was continuous from aquatic habitats.