Population biology of the saw-toothed grain beetle, Oryzaephilus surinamensis (Coleoptera: Silvanidae), in an experimental model of a fabric treatment

Abstract

The response of populations of the saw-toothed grain beetle, Oryzaephilus surinamensis (Linnaeus) (7022/1 strain), to insecticide treatments of different extent and standard concentration was studied over 16 weeks (no more than two generations) in experimental bins containing a wheat bulk and 16 kibbled wheat-filled refuges. Populations comprised initially low frequencies of resistant phenotypes, as would occur in natural populations where resistant alleles had newly arisen. The degree of control achieved was related to the extent of treatment. Distribution of adult beetles was greatly influenced by the effects of insecticide treatment superimposed on intrinsic microhabitat preferences. Live beetles were recovered from all bins, although numbers sampled from wheat bulks of treated bins were 1-6% of that of the untreated bin. More live beetles were sampled from wheat bulks than were recovered from all respective refuges, except in one treated bin. Live beetles were more numerous in refuges in corners and in those furthest from refuges on treated walls. Beetles were more likely to die in refuges in corners and lower down in the bins or in refuges on treated walls adjacent to untreated walls. Although treatments produced heavy mortality, the frequencies of resistant individuals did not increase significantly. This could either be because treatments were equally successful in eliminating homozygous susceptible and heterozygous individuals, or because selection in favour of resistant individuals was too weak to be detectable, especially if there were negative correlations between viability and fecundity. Significant genetic structuring of refuge subpopulations with respect to the resistance phenotypes was noted and appeared to be related to behavioural preferences for microhabitat.

Rearing method of Oryzaephilus surinamensis (L.) (Coleoptera, Silvanidae) on various wheat grain granulometry

“…Although the biology of O. surinamensis has been studied by many authors (Howe 1956(Howe , 1965Fleming 1988;Collins et al 1989;Jacob & Fleming 1989;Mason 1996), the rearing process to get good production of offspring is still a challenge because of the small size of the insect and its high mobility. Oryzaephilus surinamensis prefers cereal food than oil seeds to feed on (Sinha 1971;LeCato & McCray 1973;Nakajima et al 1996).…”

Selection for and against resistance to insecticides in the absence of insecticide: a case study of malathion resistance in the saw-toothed grain beetle,Oryzaephilus surinamensis(Coleoptera: Silvanidae)

“…The common reversion to susceptibility is not surprising as the strains were related and presumably shared the same major resistance locus, with alleles that were less fit in the absence of malathion. Laboratory and field selection may have qualitatively and quantitatively distinct consequences in this species (Mason, 1996;Mason et al, 1997), and the distinct history of insecticide exposure is reflected in the different estimates of initial frequency of resistant alleles of each strain.…”

“…This may explain the responses of the 8401, 8401sel and 8518B strains. In addition, the drift of resistance allele frequency in small populations can lead to differentiation that may be of local consequence to the control of pest populations (Mason, 1996;Mason et al, 1997). This type of investigation of intra-specific differences in the response to the cessation of insecticide treatment is generally applicable to other species.…”

Toxicity of Aromatic Plants and Their Constituents Against Coleopteran Stored Products Insect Pests

“…However, behavioral adaptations of target insects can play an important role in developing resistance to treated contact insecticides including hydroprene. Several studies using a strain of the sawtoothed grain beetle, O. surinamensis showed that the adults avoided surfaces or grains treated with permethrin and pirimiphos-methyl (Collins et al, 1988;Mason, 1996;Watson & Barson, 1996). Therefore, the highlighted problem, insect resistance, on conventional synthetic insecticides drove many researchers to study alternative methods including botanical insecticides from plants.…”