Impact of Sex, Age, and Mating Status on Flight Behavior of the Navel Orangeworm
Commodity Protection and Quality
2013 Annual Report
1a.Objectives (from AD-416):
1. Develop methods and baseline data for flight mill experiments with navel orangeworm
2. Compare the flight activity of unmated adults by sex and age
3. Examine impact of mating on the age-specific flight capacity of males and females
1b.Approach (from AD-416):
Using a 32-channel electronically monitored flight mill system, flight capacity of unmated and mated navel orangeworm adults will be assessed at four ages covering most of the reproductive life of this species. The longest single flight and total flight will be compared 1, 3, 5 and 7 days post eclosion. Since the median is usually the most suitable statistic for this type of data, analysis will be performed using the Kruskal-Wallis one-way analysis of variance. Two-way comparisons of sex or mating status within age group will be performed using the Wilcoxon rank sums test.
This research supports objective 2G (Determine the flight capacity of the navel orangeworm) in the parent project. The navel orangeworm Amyelois transitella (Walker) (Lepidoptera: Pyralidae) is the principal pest of California almonds and pistachios. The dispersal ability of this moth is thought to be important to its ability to inhabit orchards and infest marketable nuts. A flight mill study was conducted, examining the flight capacity of unmated female and male navel orangeworm adults 1, 2, 3, 5, and 7 days post eclosion. Females were stronger fliers than males. There was also a qualitative difference between the sexes in flight: unmated females had the most separate flights per night at 2-3 days post-harvest, whereas unmated males had the fewest flights per night at 2 days post-harvest. Compared to previous studies, unmated navel orangeworm adults exhibited flight capacity intermediate between that of tortricid orchard pest moths (e.g., codling moth and oriental fruit moth), and that of noctuids (armyworm and cutworm species). The median longest single flight was >2 km for 7-day old moths, and >4.5 km for younger moths. These findings provide improved guidance for the use and interpretation of pheromone monitoring traps used to guide treatment decisions.