The randomly amplified polymorphic DNA technique was used to trace the geographic origin of Liposcelis bostrychophila Badonnel populations in Australia from unknown geographic sources internationally. Haplotype (or clonal) diversity was high, with 474 unique haplotypes found from 616 individuals genotyped. Gene diversity estimates (0.10–0.28) and percent polymorphic loci (38.1–88.1%) were moderate to high for most populations. This resulted in genetic distance estimates that ranged from 0.04 to 0.26 and were significantly different for most pairwise population combinations. GST values for all populations were also moderate (0.04–0.54) and again were significantly different for most pairwise population comparisons. Analysis of molecular variance revealed that the majority of variation was apportioned among individuals within populations regardless of the level at which they were grouped. Gene flow (Nm) was mostly low for all pairwise populations comparisons with an average Nm = 1.8. A non-significant negative correlation between genetic distance and geographic distance was found for worldwide populations. In contrast, within Australian populations a significant positive correlation between genetic distance and geographic distance was detected. Genetic relationships explored using unweighted pair group method analysis and non-metric multidimensional scaling indicated a mixed pattern of genetic similarities among all populations. Multiple introductions, from a wide range of international source populations, have obscured the ability to accurately determine the geographic origin of L. bostrychophila in Australia.

A simple method for the insecticide bioassay of liposcelids is outlined. The contact toxicity of five organophosphorus insecticides (OPs) and two carbamate insecticides (CBMs) was ascertained for Liposcelis bostrychophila and L. entomophila. Liposcelis entomophila was more tolerant to all the insecticides tested than the other species. Malathion was the least toxic OPs to both species, while chlorpyrifos-methyl was the most toxic insecticide tested against L. bostrychophila. These findings are discussed in relation to the infestation of these liposcelids in rice storages.