# Effect of Bactrocera minax (Diptera: Tephritidae) adult population density on its marginal distribution

## TL;DR

This study shows that Bactrocera minax fruit flies cluster near noncitrus trees in orange orchards when their population is low, but spread out evenly when their numbers are high.

## Contribution

The study reveals how Bactrocera minax distribution changes with population density, showing a shift from edge concentration to uniform spread.

## Key findings

- At low insect density (2% and 4% infestation), B. minax adults concentrate near noncitrus trees.
- At high insect density (20% infestation), B. minax adults are evenly distributed in the orchard.
- Trap catches near noncitrus trees decrease as infestation rates increase.

## Abstract

In order to explore the impact of insect density on the edge effect of Bactrocera minax (Diptera: Tephritidae) adult distribution in orange orchards, traps were set up in orchards with maggot infestation rates of 2%, 4%, and 20% to attract adults. The study compared differences in distribution between the side with noncitrus trees and the side farther away from them. The results showed that at lower insect densities (2% and 4% maggot infestation rates), the proportion of insect trap sites and the number of insects per trap on the side of the orchard adjacent to the trees were significantly higher than that on the side away from the noncitrus trees, additionally, the proportion of adults captured 10 to 20 m away from the side of noncitrus trees was also significantly higher than at other distances. However, at higher insect density (20% maggot infestation rates), there were no significant differences in the proportion of insect traps or the number of insects per trap between the adjacent and distant sides of the trees. Similarly, there were no significant differences in the proportion of adults captured at distances of 10, 20, 30, and 40 m away from the side of noncitrus trees in the orchard. In summary, at low insect density, B. minax adults exhibit a strong edge effect, concentrating on the side of the orchard with noncitrus trees, whereas at high insect density, they are evenly distributed throughout the orchard.