Predicting resistance and managing susceptibility to cyromazine in the Australian sheep blowfly Lucilia cuprina

1996 ◽  
Vol 36 (4) ◽  
pp. 413 ◽  
Author(s):  
YL Yen ◽  
P Batterham ◽  
B Gelder ◽  
JA McKenzie

Four cyromazine-resistant variants of Lucilia cuprina were selected after ethyl methanesulfonate mutagenesis and screening above the concentration of cyromazine lethal to susceptibles. Resistance is controlled by a single gene in each variant. Two resistance loci have been identified, one (Cyr 4) closely linked to the marker 'reduced eyes' on chromosome IV, the other (Cyr 5) closely linked to the 'stubby bristles' marker on chromosome V. Concentration-mortality line analysis shows resistance ratios are low (1.5-3x). One variant [Cyr 4(2)] is viable as a homozygote, the others are lethal [Cyr 4(1)] or, at best subvital [Cyr 5(1) and Cyr 5(2)]. Competition experiments between resistant heterozygotes and susceptibles show that resistance to cyromazine is selected for over a limited range of concentrations. The capacity of laboratory studies to predict likely resistance mechanisms before they evolve in the field is discussed. The use of genetic, toxicological and relative fitness data arising from these studies to devise the most effective strategies of insecticide usage while minimising the evolution of resistance is emphasised.

1998 ◽  
Vol 353 (1376) ◽  
pp. 1729-1734 ◽  
Author(s):  
J. A. McKenzie ◽  
P. Batterham

Strategies to manage resistance to a particular insecticide have usually been devised after resistance has evolved. If it were possible to predict likely resistance mechanisms to novel insecticides before they evolved in the field, it might be feasible to have programmes that manage susceptibility. With this approach in mind, single–gene variants of the Australian sheep blowfly, Lucilia cuprina , resistant to dieldrin, diazinon and malathion, were selected in the laboratory after mutagenesis of susceptible strains. The genetic and molecular bases of resistance in these variants were identical to those that had previously evolved in natural populations. Given this predictive capacity for known resistances, the approach was extended to anticipate possible mechanisms of resistance to cyromazine, an insecticide to which L. cuprina populations remain susceptible after almost 20 years of exposure. Analysis of the laboratory–generated resistant variants provides an explanation for this observation. The variants show low levels of resistance and a selective advantage over susceptibles for only a limited concentration range. These results are discussed in the context of the choice of insecticides for control purposes and of delivery strategies to minimize the evolution of resistance.


Genetics ◽  
1988 ◽  
Vol 120 (1) ◽  
pp. 213-220 ◽  
Author(s):  
J A McKenzie ◽  
G M Clarke

Abstract Genetic evidence suggests that the evolution of resistance to the insecticide diazinon in Lucilia cuprina initially produced an increase in asymmetry. At that time resistant flies were presumed to be at a selective disadvantage in the absence of diazinon. Subsequent evolution in natural populations selected modifiers to ameliorate these effects. The fitness and fluctuating asymmetry levels of resistant flies are currently similar to those of susceptibles. Previous genetic analyses have shown the fitness modifier to co-segregate with the region of chromosome III marked by the white eyes, w, locus, unlinked to the diazinon resistance locus, Rop-1, on chromosome IV. This study maps the asymmetry modifier to the same region, shows, as in the case of the fitness modifier, its effect to be dominant and presents data consistent with the fitness/asymmetry modifier being the same gene (gene complex). These results suggest changes in fluctuating asymmetry reflect changes in fitness.


2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Ying Yan ◽  
Maxwell J. Scott

Abstract Genetic approaches, including the sterile insect technique (SIT), have previously been considered for control of the Australian sheep blow fly Lucilia cuprina, a major pest of sheep. In an SIT program, females consume 50% of the diet but are ineffective as control agents and compete with females in the field for mating with sterile males, thereby decreasing the efficiency of the program. Consequently, transgenic sexing strains of L. cuprina were developed that produce 100% males when raised on diet that lacks tetracycline. However, as females die mostly at the pupal stage, rearing costs would not be significantly reduced. Here we report the development of transgenic embryonic sexing strains of L. cuprina. In these strains, the Lsbnk cellularization gene promoter drives high levels of expression of the tetracycline transactivator (tTA) in the early embryo. In the absence of tetracycline, tTA activates expression of the Lshid proapoptotic gene, leading to death of the embryo. Sex-specific RNA splicing of Lshid transcripts ensures that only female embryos die. Embryonic sexing strains were also made by combining the Lsbnk-tTA and tetO-Lshid components into a single gene construct, which will facilitate transfer of the technology to other major calliphorid livestock pests.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Kumar Saurabh Singh ◽  
Erick M. G. Cordeiro ◽  
Bartlomiej J. Troczka ◽  
Adam Pym ◽  
Joanna Mackisack ◽  
...  

AbstractThe aphid Myzus persicae is a destructive agricultural pest that displays an exceptional ability to develop resistance to both natural and synthetic insecticides. To investigate the evolution of resistance in this species we generated a chromosome-scale genome assembly and living panel of >110 fully sequenced globally sampled clonal lines. Our analyses reveal a remarkable diversity of resistance mutations segregating in global populations of M. persicae. We show that the emergence and spread of these mechanisms is influenced by host–plant associations, uncovering the widespread co‐option of a host-plant adaptation that also offers resistance against synthetic insecticides. We identify both the repeated evolution of independent resistance mutations at the same locus, and multiple instances of the evolution of novel resistance mechanisms against key insecticides. Our findings provide fundamental insights into the genomic responses of global insect populations to strong selective forces, and hold practical relevance for the control of pests and parasites.


1985 ◽  
Vol 38 (3) ◽  
pp. 275 ◽  
Author(s):  
GG Foster ◽  
WG Vogt ◽  
TL Woodburn

The results of progeny tests of males and females captured during two field trials of sex-linked translocation strains for genetic control of L. cuprina are presented. Males released as mature larvae survived to adulthood and mated with field females. However, the levels of genetic death introduced into the population were insufficient to suppress the native population. This was due partly to seasonal ineffectiveness of the release method, and partly to poor performance of the released males. On average, the mating competitiveness of the released males was only one-third that of field males, whereas their field-reared, translocation-bearing sons were fully competitive with native males.


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