Almond moth oviposition patterns in continuous layers of peanuts

The spatial distribution of eggs laid over a 48-h period by individual female almond moths, Cadra cautella Walker (Lepidoptera: Pyralidae), was examined in bioassays where peanuts covered either the center quarter (quarter-coverage) or the whole (whole-coverage) of a 120-cm square arena gridded into 3 by 3-cm cells. The mean total of eggs laid in quarter-coverage bioassays was not significantly different from the mean in whole-coverage bioassays, i. e., neither food coverage limited oviposition. However, the maximum count of eggs laid in any cell was higher in whole- than in quarter-coverage bioassays, and eggs were more aggregated near edges of the arena in whole-coverage bioassays than near edges of the peanuts in quarter-coverage bioassays. In addition, eggs were aggregated near the release point where females initially encountered food cues. These results suggest that almond moth oviposition behavior in continuous areas of peanuts was similar to patterns observed previously for stored-product insect oviposition in small, scattered food patches. In both cases, females walked or flew between separate oviposition events where eggs were laid in small clumps or lines. Possible behaviors resulting in aggregations of eggs near edges of food, walls, boundaries, or entrances are discussed and implications for precision targeting of insects in food storage areas are considered.