The Ecology and Behavior of Aedes Atlanticus D. & K. and Other Species with Reference to Keystone Virus in the Houston Area, Texas1

Sampling Adults by Animal Bait Catches and by Animal-Baited Traps

“…The initial high biting rate was said to be caused by host movement, supporting the contention of Gillett (1972) that movement attracts diurnally active mosquitoes to their hosts. Roberts & Scanlon (1975), however, failed to observe any obvious depletion effect with nocturnal species such as Culex salinarius and Aedes fulvus. An initial high catch was also reported in Aedes aegypti in catches performed both outdoors and in huts in Kenya (Teesdale, 1955).…”

“…But because different species exhibit very different catch curves when collected from the same hosts at the same time, then clearly there must also be different intrinsic behaviours in addition to environmental stimuli affecting their sequence of arrival at bait. Roberts & Scanlon (1975) observed a depletion effect in their series of 15-min catches, that is high initial catches of Aedes atlanticus, Aedes tormentor and Psorophora ferox during the first 5 min followed by a decline during the next 10 min. The initial high biting rate was said to be caused by host movement, supporting the contention of Gillett (1972) that movement attracts diurnally active mosquitoes to their hosts.…”

“…Several workers have reported a burst of biting activity during the first 15-20 min in daytime bait catches followed by a decline in numbers (Germain et al, 1973;Mogi & Yamamura, 1981;Nishimura, 1982;Roberts & Scanlon, 1975;Service, 1969aService, , 1971bWellington, 1974), but McCrae et al (1976) working on Anopheles implexus in Uganda undertook the best analyses of this type of behaviour. They pointed out that during passive (opportunistic) biting by mosquitoes formerly resting amongst vegetation, there would be two principal categories; namely a static component (s) representing mosquitoes already present within the host's area of attraction, and a component of arrivals (a) flying into the host's attractant area after the bait had arrived.…”

“…In Texas in 14-hr human bait collections one person exposed his bare legs and arms to mosquitoes while the rest of his body was protected by mosquito netting, heavy clothing and boots. Collections were made for only 15-min periods each hour (Roberts & Scanlon, 1975). The biting behaviour of Anopheles darlingi in Brazil was investigated by having two human baits collecting together for 30 min every hour throughout the night in a house, while at the same time a similar collection was performed outside 20 m away.…”

“…Shirt sleeves or trouser legs may be rolled up or shirts removed, but frequently there is no need to expose bare skin to attract mosquitoes. In fact, it is sometimes advantageous to wear 'protective' clothing (Roberts & Scanlon, 1975). If the weather is not too hot, an anorak, or similar water-proof hooded coat, with hood pulled over the head can be worn by the collector who sits on the ground with outstretched legs.…”