Studies on the flight of black-flies (Diptera: Simuliidae). I. Flight performance ofSimulium ornatumMeigen

Abstract

The flight performance of Simulium ornatum Mg. s.l. was measured under laboratory conditions using a simple flight mill. Males and unmated females were flown and the duration, distance and average speed of flight were recorded for adults fed on water only, sucrose, blood & water, or blood & sucrose. On 91% of all test occasions sucrose-fed insects flew but 25% of those on water only did not fly. Feeding flies on 10% sucrose solution markedly improved both willingness to fly and flight performance, and under these conditions maximum duration, distance and average speed recorded were 4.9 h, 4-2 km and 2-84 km/h, respectively. The ratio of average to maximum speed was 0"631 for females and 0 -610 for males, with absolute maximum speeds of 3"19 and 2-99 km/h, respectively. Duration and distance flown were well-correlated, speed being the least variable aspect of flight performance measured. The distributions of flight duration and distance flown were skewed such that few insects made long flights. Mean flight performance at different ages was measured; unmated females appeared to retain a high level of willingness to fly throughout the age-range tested (up to 33 days). The longest recorded flight (5.3 h) was made by a female during an overnight experiment. The implications for long-range flight movements by simuliids are discussed.

Tethered flight of the potato moth, Phthorimaea operculella

“…The increased energy cost of reproductive development has been used to explain similar observations in other insect species (e.g. Dingle, 1966;Sharp et al, 1975;Cooter, 1982). Dispersal of mated females may best be undertaken before the first 3-4 days post-eclosion, because the increased wing loading (body weightiwing area) accompanying the production of eggs would lower flight performance after this time…”

“…Another possibility is that this is not an artefact of tethering but reflects a biological difference between first and later flights. The first flight of tethered Simulium ornatum (Cooter, 1982) and Rhyacionia buoliana (Green, 1962) were also found to be the longest of a series of flights, and Johnson (1969) recognized that the first flight may be important in regard to dispersal.…”

Effect of weather conditions on the flight activity of Nigerian blackflies (Diptera: Simuliidae)

“…Wind velocity has long been recognized as an important factor affecting flight. Laboratory studies have shown that the maximum flight speed of S.ornafum Meigen is 3 kmfh (Cooter, 1982) and 4 k d h for Xurcticum Malloch (Grace & Shipp, 1988). In the field, however.…”

Effects of age and mated status on flight potential of Helicoverpa armigera (Lepidoptera: Noctuidae)

“…The flight mills used were a modification of the system described by Cooter (1982Cooter ( , 1983, originally devised to study the flight performance of blackflies. The mill arm was lengthened to a radius of 23.9 cm and counterweighted at the end remote from the tethered insect to balance the greater weight of the moth.…”