Biological studies of the date stone beetle,Coccotr ypes dactyliperda

Abstract

The date stone beetle,Coccotrypes dactyliperda F. (Coleoptera: Scolytidae), is a primary pest of green unripe dates. The adult beetle chews a characteristically round hole in the fruit, which results in the druit dropping 1 or 2 days later. Egglaying and entire development occur within galleries produced by the female in the date stone; males are unable to penetrate the stones. In laboratory cultures and in field-collected date stones, the beetle adult females were predominant (85-93%). Overwintering probably occurs in the adult stage within date stones of fruits which had dropped and were left on the ground. At 28°C the average egg incubation period was 5.9 days, larval duration 12–15 days, and pupal development 4.0 days. Development from egg to adult for females was significantly longer than for males (24.8vs. 22.1 days). Mated females produced males and females, whereas unmated females gave rise to males only. The mean number of progeny per mated female (30.4) was significantly higher than that recorded for unmated females (6.6), but the latter lived significantly longer (73.3vs. 62.9 days).