Invasive Species Compendium

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Abstract

Wind-dependant spring migration of Chromatomyia horticola (Goureau) (Diptera: Agromyzidae) in Hokkaido, the northern island of Japan.

Abstract

Pupal periods of the garden pea leafminer Chromatomyia horticola (Goureau) were 12.6, 14.2 and 13.6 days under 12L-12D, 14L-10D and 16L-8D at a low temperature (15°C), respectively. In the samples of C. horticola mature larvae and/or puparia collected on wild plants and vegetables in Hokkaido, northern Japan, and Honshu, mid-Japan, the pre-emergence periods from the collecting date to emergence at room temperature did not exceed 30 days throughout the year, including autumn and winter. These results showed that C. horticola puparia did not show diapause even under low temperature with a short photoperiod. When puparia of C. horticola reared at a low temperature (15°C) under 12L-12D were stored at 0°C for various periods, the survival rates of puparia decreased in accordance with the storage period. The survival and successful emergence rates of puparia decreased to 10.5 and 0% in samples stored at 0°C for 75 days, respectively. These findings indicate that C. horticola puparia cannot survive more than 75 days under the snow. In the spring of 2004 and 2005, there was synchronicity among the first mass trapping days of C. horticola adults by yellow pan traps in 2 and 3 different localities in Hokkaido, respectively. In addition, the first mass trapping days between 2004 to 2007 synchronized with the occurrence of strong southern or southwestern winds in the 850 hPa low-level jet stream without exception. All of these findings supported the hypothesis that C. horticola could not hibernate in the northern part of Japan with snow periods lasting for more than 3 months. In such areas, C. horticola might migrate in spring on strong southern winds accompanied by lower pressure. This is the first recognized case of the long-distance migration of agromyzid flies.