Since there was an increasing awareness on the environmental problems caused by the abuse of the use of insecticides in controlling insect pests, it was argued that other alternative measures be considered such as the use of biological control agents. The predatory earwig, Euborelliaannulata is considered effective in controllingan important pestof corn such as the cornborerOstriniafurnacalis thus was mass-reared. To be able to maintain the quality control of insect mass-rearing, many studies were focused on quantitative genetic studies of the life history and behavioral traits. However, quantitative analysis of phenotypic characters of the reared insects are limited. In this study, the different morphological body characters (head, pronotum, prosternum and elytra) of E. annulata between reared and wild populations were quantitatively analysed using landmark-based geometric morphometrics and correlation analysis based on distances (CORIANDIS). These tools were considered very useful in determining variations in characters of many organisms thus was applied in the examination of character shapes in the predatory earwigs in culture and in the wild. Results of the stacked bar graph analysis showed that reared male and female populations show similarities of characters (in the head, pronotum, prosternum and elytra). Disparity of characters were observed between sexes of the wild populations. These variations among characters can explain the differences between the reared and the wild populations of the insect. Inbreeding must have affected the insects in culture as the morphological characters have become similar between sexes for those that were in culture suggesting that in cultured insects genetic variance can be reduced and that it will lead to increased homozygosity among individuals resulting to phenotypic homogeneity.
