Cattle herd inspections and fly trapping for the detection of the Old World screw-worm fly (Chrysomya bezziana)

AbstractSentinel cattle and a grid of swormlure-baited sticky traps were used to monitor a Malaysian population of the Old World screw-worm fly, Chrysomya bezziana Villeneuve. Observations were carried out on an isolated cattle station at monthly intervals during the period August 1996 to June 2000. The number of flies caught was unaffected by weather conditions at the time of trapping, but was positively correlated with the total rainfall and the average daily air temperature prevailing 15–28 days earlier, when trapped flies were still juveniles. Trap catches were biased in favour of females, but daily catch rates of both sexes increased significantly the longer traps were open, suggesting that efficacy was related to the differential volatility of the chemicals comprising swormlure. Oviposition on sentinel cattle occurred mostly in late afternoon or early evening but increased significantly as the wound aged. Oviposition rates were positively correlated with female catch rates, but the relationship was curvilinear, suggesting that fly populations may be subject to some form of density-dependent constraint. Consistent differences in oviposition rates on sentinel cattle at different localities on the cattle station suggested the existence of highly clumped, quasi-stationary populations. Differences in trap catches between traps located in pastoral areas and those sited in nearby oil palm or rubber plantations supported this interpretation of the data. These findings are discussed in relation to the use of the sterile insect technique for the control of screw-worm fly infestations.

Download Full-text

Genetic variation in the Old World screw-worm fly, Chrysomya bezziana (Diptera: Calliphoridae)

Bulletin of Entomological Research ◽

10.1017/s0007485300032053 ◽

1991 ◽

Vol 81 (4) ◽

pp. 491-496 ◽

Cited By ~ 10

Author(s):

K.L. Strong ◽

R.J. Mahon

Keyword(s):

Middle East ◽

Papua New Guinea ◽

Sibling Species ◽

New Guinea ◽

Electrophoretic Analysis ◽

Old World ◽

East Malaysia ◽

Australia Introduction ◽

Sterile Insect Release ◽

Chrysomya Bezziana

AbstractThe Old World screw-worm fly, Chrysomya bezziana Villeneuve, occurs in Africa, the Middle East, Malaysia, Indonesia and Papua New Guinea, but it is not found in Australia. Introduction into Australia from any of these source areas would threaten the viability of much of the grazing industry in the northern part of the continent. Proposed control by the sterile insect release method (SIRM) would be compromised by the existence of sibling species within C. bezziana. This study examines the degree of genetic differentiation throughout the extensive range of the fly to assess if the degree of geographic differentiation indicates the existence of sibling species and, allows identification of the source of any introduced flies. Electrophoretic analysis of 23 loci from samples collected in southern Africa, the Middle East, Malaysia, Indonesia, and Papua New Guinea revealed 11 polymorphic loci. Overall, populations show remarkably little divergence given the geographic distribution of sample sites. None of the populations sampled were fixed for alternative electromorphs. There is no evidence from this study for the presence of sibling species within C. bezziana.

Download Full-text