# Flight Characteristics of Bactrocera dorsalis Associated with Long-Distance Migration

## TL;DR

This study investigates the flight behavior of Bactrocera dorsalis to understand its potential for long-distance migration, which is important for predicting its spread and managing agricultural risks.

## Contribution

The study provides new insights into the flight capabilities of Bactrocera dorsalis under different temperature conditions and over extended durations.

## Key findings

- B. dorsalis initiates flight around 10:00 and sunset.
- Flight activity stops at temperatures between 16.2 and 16.5 °C.
- Some individuals can sustain flight for over 7 hours.

## Abstract

Recently, individuals of the oriental fruit fly and its relatives (Bactrocera dorsalis com-plex)—previously eradicated in Japan—have occasionally been captured in surveillance traps in the Kyushu District of western Japan, suggesting possible overseas migration. Generally, however, this species is not considered capable of long-distance flight. This emerging situation in East Asia highlights the need to understand the species’ flight characteristics associated with long-distance migration, which is essential for developing a migration prediction model to provide early warnings of their arrival and ensure effective pest control. In this study, flight experiments were conducted using young first-generation adults originating from Taiwan. Outdoor observations revealed that B. dorsalis actively initiates flight around 10.00 and sunset. Flight mill experiments under varying temperature conditions indicated that flight activity ceased at temperatures between 16.2 and 16.5 °C. Furthermore, a 24-h flight test demonstrated that some individuals could sustain flight for over 7 h, suggesting a potential capacity for long-distance migration. These findings improve our understanding of B. dorsalis flight behavior and provide a basis for migration model development.

Recently, individuals of the oriental fruit fly and its relatives (Bactrocera dorsalis complex)—previously eradicated in Japan—have occasionally been captured in surveillance traps in the Kyushu District of western Japan, suggesting possible overseas migration. However, as this species generally is not considered capable of long-distance flight, its potential for overseas migration remains largely unexplored. Moreover, this emerging situation in East Asia poses an increasing risk to agricultural industries, highlighting the need to develop a migration prediction model to provide early warnings of their arrival, for which understanding the species’ flight characteristics is essential. In this study, flight experiments were conducted using young first-generation adults that emerged from larvae collected in Taiwan. Outdoor observations revealed that B. dorsalis actively initiates flight around 10:00 and sunset. Flight mill experiments under varying temperature conditions indicated that flight activity ceased at temperatures between 16.2 and 16.5 °C. Furthermore, a 24-h flight test demonstrated that some individuals were capable of sustaining flight for over 7 h, suggesting a potential capacity for long-distance migration. These findings contribute to the development of a migration flight model and enhance our understanding of the flight behavior associated with long-distance migration in B. dorsalis.