Movement Behavior of the Pine Needle Gall Midge (Diptera: Cecidomyiidae)

Abstract

The movement behavior of the pine needle gall midge (Thecodiplosis japonensis Uchida Et Inouye (Diptera: Cecidomyiidae)), an invasive species in China, was determined by using a tethered flight technique and digital videography in the laboratory. The flight distance, duration, and speed of females were compared at different ages (2–10 h) and ambient temperatures (17, 21, 26, and 30°C). Female flight distance and duration at 26°C were significantly greater than those at 17°C and 21°C. The age of T. japonensis did not significantly affect the three flight characteristics. For females at 2–10 h of age at 26°C and 70% RH, the maximum flight distance was 667.59 m; the longest flight time was 6,222.34 s; and the fastest flight speed was 0.44 m·s−1. For larvae wetted with water, the highest jump was 5.7 cm; the longest jump was 9.6 cm; and the greatest distance moved in 5 min was 27.13 cm, which showed that the active dispersal potential of larvae was very low.

Pest categorisation of Thecodiplosis japonensis

“…Flight has been studied in flight mills by Liu et al ( 2020 ); the females flew a maximum distance of 668 m. Liu et al ( 2020 ) also report that larvae are able to move by a succession of jumps; the longest jump covered 5.7 cm, and the longest distance recorded was 27 cm.…”

“…In nature, adults fly short distances (Kearby and Benjamin, 1964). Choi and Park (2012) report adult T. japonensis dispersing a maximum of 400 m whilst flight mill experiments measured adult females flying a maximum of 668 m at 26°C and 70% RH (Liu et al, 2020). Recall that adults live for 1 day.…”