Showing papers by "David Wool published in 1982"

Malathion resistance in Tribolium strains and their hybrids: inheritance patterns and possible enzymatic mechanisms (Coleoptera, Tenebrionidae).

Abstract: (1) The genetics of malathion resistance in two strains of the flour beetle, Tribolium castaneum, was investigated. In CTC-12, resistance is polygenic, while in Kano, it is due to a dominant allele at a single autosomal locus. Reciprocal hybrids with the susceptible control strains bb and pp showed an overdominant response in particular when Kano was the male parent in the original cross. (2) Three possible genetic mechanisms to explain these results are discussed. The model which best explains the genetic results, particularly the difference between the reciprocal crosses, assumes a modifier resistance allele on the Y chromosome. (3) The levels of activity of total esterases, carboxylesterases, mixed-function oxidases, epoxide hydrase, and glutathione transferase in the parent strains and their hybrids were measured quantitatively. Although total esterase activity may not be relevant for the breakdown of malathion, it was inhibited by the pesticide. The activity of the microsomal enzymes was high in CTC-12, low in bb, and intermediate in the hybrids, while carboxylesterases were very active in Kano as well as in the hybrids with bb and low in the latter. These patterns agree with the genetics of resistance in the two strains. A higher level of GSH transferase in the Kano x bb hybrids than in Kano seems to indicate a possible biochemical mechanism for their overdominant resistance.

Dynamics and genetics of mating behavior in Tribolium castaneum (Coleoptera: Tenebrionidae).

Abstract: Three aspects of mating behavior—time to mating, repetitiveness, and mate selection—were investigated in six genetic strains of the flour beetleTribolium castaneum and their hybrids. The data were compared with predictions from theoretical models. Time to mating was found to be heritable and characteristic of a strain. In homotypic strain combinations the duration of mating was longer than in heterotypic combinations. In repeated matings the male mating rate declined with time. In a multiple-choice experiment there was a tendency for positive assortative mating; this did not occur in female-choice or male-choice tests. Keeping beetles of two strains together prior to the experiment removed this tendency. Males almost exclusively preferred virgin to fertilized females when given a choice. The data fitted Taylor's [(1975).Behav. Genet. 5:381–393] model better than Kence and Bryant's [(1978).Am. Nat. 112:1047–1062] model. The absence of assortative mating when males (and females) of two strains were held together can be explained by the pheromone-saturation model of Averhoff and Richardson [(1974).Behav. Genet. 4:207–225] but not by Bryant's [(1979).Behav. Genet. 9:249–256] alternative.

Critical examination of postulated cladistic relationships among species of flour beetles (genus Tribolium, Tenebrionidae, Coleoptera).

Abstract: Cytological considerations have led to the hypothesis that Tribolium confusum (CF) evolved from an ancestor similar to T. castaneum (CS) by translocation of an autosome to the X chromsome, and that T. destructor (DEST) was derived from CF. T. brevicornis (BREV) is regarded as the most primitive on morphological grounds. Electrophoretic analyses of 19 strains of CS, 7 of CF, and 1 each of DEST and BREV do not support this postulated evolutionary pathway. CF and CS are much more similar to BREV than they are to each other. (Comparisons of morphological mutations in CS and CF also indicate that the two species are not similar genetically.) DEST and CF are very dissimilar electrophoretically. It is likely that the species evolved independently from an ancestral stock which may be represented by BREV. Recognition of gene homology in different species is the keystone for all attempts at constructing genetically meaningful evolutionary pathways. The difficulties involved in doing so are pointed out.