Estimates of population density and dispersal in the blowfly Lucilia sericata (Diptera: Calliphoridae)

To investigate the population density and dispersal of the sheep blowfly Lucilia sericata (Meigen) mark-release-recapture trials were carried out in lowland pastures in south west England. In three trials, 2142, 1351 and 451 fluorescent dust marked flies were released of which 4%, 14% and 10% were recaptured using a grid of sticky, odour-baited targets, placed between 8 m and 1000 m from the release point. There was no significant effect of wind direction on dispersal pattern and no apparent directional movement of the flies from the release point. Using the method described by Hawkes (1972) the mean distance travelled by all the flies on the first day of each of the three trials was calculated to be 108 m, 128 m and 137 m respectively. Using the method described by Fletcher (1974) the mean distances travelled were calculated to be 135 m (+/- 42), 118 m (+/- 27) and 183 m (+/- 61) on the first day of each of the three trials. respectively. The median distances travelled by the flies on the first day of each of the three trials were calculated to be 109 m, 130 m and 150 m, respectively. A Lincoln Index was used to estimate the population density of wild female L. sericata. The number of female flies was estimated to be zero in June, approximately one per hectare in July and six per hectare in August in 1994.