Showing papers on "Lucilia cuprina published in 1990"

The incidence of flystrike in sheep in relation to weather conditions, sheep husbandry, and the abundance of the Australian sheep blowfly, Lucilia cuprina (Wiedemann) (Diptera: Calliphoridae).

Abstract: The incidence of cutaneous myiases (flystrike) in sheep in the Southern Tablelands of New South Wales is examined in relation to the abundance of the Australian sheep blowfly, Lucilia cuprina (Wiedemann), and various management and environmental variables known to affect sheep susceptibility. Regression analysis showed that the incidence of flystrike increased with increases in the density and activity of gravid L. cuprina. Body strike was more predictable than crutch strike, and was positively correlated with monthly rainfall, cloud cover and the rate of pasture growth. Rainfall intensity was also important, with frequent, small falls of rain being more conducive to flystrike than occasional heavy showers. The combination of weather, pasture and fly effects accounted for 76% of the observed variance in body strike and 58% of that for crutch strike. Crutch strike appeared to replace body strike under dry conditions and also when fly densities were low (less than 0.5 gravid females h-1 trap-1), irrespective of weather conditions. The analysis of total strike suggested that rainfall determined overall levels of strike, whereas pasture conditions and cloud cover regulated type of strike.

Evidence for the Multiple Exotic Origin of Australian Populations of the Sheep Blowfly, Lucilia-Cuprina (Wiedemann) (Diptera, Calliphoridae)

Abstract: Some Lucilia cuprina populations in the eastern coastal areas of Australia are shown to be a blend of the two subspecies, Lucilia cuprina cuprina and L. cuprina dorsalis. The possible history of the introduction to Australia of these two subspecies, respectively from the Pacific and South Africa, is discussed. The hybrid nature of the Australian population makes it vital to take into consideration the genetic constitution of cultures before launching comparative studies.

Cloning and characterization of the white and topaz eye color genes from the sheep blowfly Lucilia cuprina.

Abstract: Clones carrying thewhite andtopaz eye color genes have been isolated from genomic DNA libraries of the blowflyLucilia cuprina using cloned DNA from the homologouswhite andscarlet genes. respectively, ofDrosophila melanogaster as probes. On the basis of hybridization studies using adjacent restriction fragments, homologous fragments were found to be colinear between the genes from the two species. The nucleotide sequence of a short region of thewhite gene ofL. cuprina has been determined, and the homology to the corresponding region ofD. melanogaster is 72%; at the derived amino acid level the homology is greater (84%) due to a marked difference in codon usage between the species. A major difference in genome organization between the two species is that whereas the DNA encompassing theD. melanogaster genes is free of repeated sequences. that encompassing theirL. cuprina counterparts contains substantial amounts of repeated sequences. This suggests that the genome ofL. cuprina is organized on the short period interspersion pattern. Repeated sequence DNA elements, which appear generally to be short (less than 1 kb) and which vary in repetitive frequency in the genome from greater than 104 copies to less than 102 copies, are found in at least two different locations in the clones carrying these genes. One type of repeat structure, found by sequencing, consists of tandemly repeating short sequences. Restriction site and restriction fragment length polymorphisms involving both thewhite andtopaz gene regions are found within and between populations ofL. cuprina.

Toxicity of three avermectins to insecticide susceptible and resistant larvae of lucilia cuprina (wiedemann) (diptera: calliphoridae)

Abstract: The toxicity of 3 avermectins–ivermectin, abamectin and 4-deoxy-4-epi (methyl amino) avermectin B1–to larvae of the sheep blowfly, Lucilia cuprina, was determined by in vitro bioassay. Mean LC50 values for the susceptible reference strain were between 0.0021 mg/L and 0.0028 mg/L for the 3 compounds. Similar values were obtained for 11 field populations. The organophosphorus/carbamate resistant strain had mean LC50 values between 0.0029 mg/L and 0.0067 mg/L. Despite this small difference between strains, the potency of the avermectins against both susceptible and OP/carbamate resistant larvae demonstrates their potential as insecticides for the control of flystrike.

Fitness and Asymmetry Modification as an Evolutionary Process A Study in the Australian Sheep Blowfly, Lucilia cuprina and Drosophila melanogaster

Abstract: Biologists have usually considered resistance to pesticides as an applied problem, albeit one of considerable importance. An ever increasing range of organisms have become resistant to chemical agents used in their control, adding to the costs of a number of industries (Georghiou, 1986). The future availability of effective new control agents is also a cause of concern (Metcalf, 1980; Hotson, 1985).

Dose response and selection for propetamphos resistance in field populations of lucilia cuprina (wiedemann) (diptera: calliphoridae)

Abstract: The toxicological response of field populations of Lucilia cuprina to propetamphos was correlated to that of diazinon suggesting that resistance to propetamphos is a direct consequence of existing diazinon resistance. However, the level of resistance to propetamphos was generally low in field strains despite diazinon resistance being close to fixation in wild populations. A laboratory selection of first instar larvae with propetamphos increased resistance more than 4-fold. Resistance also increased to diazinon (3.7x), chlorfenvinphos (6.3x) and coumaphos (4.8x).

Localization of the 5S RNA genes to arm 2R in polytene chromosomes of Lucilia cuprina (Diptera: Calliphoridae)

Abstract: The 5S RNA genes of Lucilia cuprina were mapped to section 15A in the short arm of chromosome 2 by in situ hybridization to pupal trichogen polytene cells. As in most eukaryotes the 5S genes are lo...

Protein acquisition and mating by females of the Australian sheep blowfly Lucilia cuprina in the field.

Abstract: Examen des ovaires permettant de determiner si la femelle L. cuprina liberee dans un champ s'est nourrie de proteine et si elle a ete inseminee

Susceptibility of mulesing wounds to oviposition and strike development by the Australian sheep blowfly Lucilia cuprina.

Abstract: The age and/or physical condition of mulesing wounds had a significant effect on both the oviposition response of L. cuprina and the ability of the wound to support a strike. Up to 48 h after mulesing, untreated wounds elicited a strong oviposition response in contrast with chemically treated wounds, although subsequent larval development was negligible. Seven to 9-day-old wounds, however, regardless of the wound treatment, were highly attractive oviposition sites, which subsequently developed into strikes; the D3 formulation of Defiance*S, however, significantly depressed strike development and shows promise as a mules wound treatment. A marked improvement in the wound healing 14 to 16 d after mulesing coincided with a significant decrease in oviposition. Only those sheep whose wound scabs remained broken, exposing pus and raw tissue, attracted oviposition; subsequent development of the eggs into strikes was negligible.

Gene and Genome Structure in Diptera: Comparative Molecular Analysis of an Eye Colour Gene in Three Species

Abstract: Drosophila melanogaster and Drosophila buzzatii belong to the same family (Drosophilidae) within Order Diptera but to different species groups, which are thought to have diverged about 50–60 MY ago; the sheep blowfly (Lucilia cuprina), however, belongs to a different family (Calliphoridae), which is thought to have diverged from Drosophilidae at least 100 MY ago (Beverley and Wilson, 1984). We have been analyzing the similarities and differences in gene and genome organization at the molecular level between these species using eye colour genes as our model system.