Pecan Nut Casebearer (Lepidoptera: Pyralidae): Seasonal Activity and Mating Frequency in Central Texas

Abstract

Seasonal activity and mating frequency of the pecan nut casebearer, Acrobasis nuxvorella Neunzig, were studied in three central-Texas orchards from 1976 through 1981. Moths were collected from blacklight traps throughout each season (May through November), and females were periodically examined for spermatophores. Comparisons were made between orchards, generations, years, and male-female ratios to determine how these factors influenced mating frequency and moth activity. The size of moth populations varied with orchards, but the generation cycles and mating frequencies were similar for all orchards. Mating frequencies were similar for different generations but were significantly different between years. The typical mating frequency of a generation began with the first moths captured being virgin or mated once; as the generation progressed, females with an additional spermatophore were encountered about every 2 to 4 days until near the end of the generation, when a few moths were found that had mated 5 to 10 times. Approximately 95% of the moths mated 0 to 4 times; about 50% of all females mated once. Because all generations of female nut casebearer moths were found to be multiple mated, this may preclude any anticipated sterile-male release program designed to eradicate this insect.