キリギリス(Gampsocleis buergeri de Hann & G. micado Burr)(Orthoptera: Tettigoniidae)の卵休眠

Egg diapause of Gampsocleis buergeri de Hann and G. micado Burr (Orthoptera: Tettigoniidae)

Creators ARAI Tetsuo

The katydid, Gampsocleis buergeri(de Hann, 1843), which inhabit the Japanese archipelago, hatches around the beginning and middle of May. The adults emerge in July-August and lay either annual- or biennial-type eggs. Annual-type eggs overwinter in a state of final diapause and hatch in the spring, and there is only one generation per year. The biennial-type eggs, which hatch after overwintering twice, pass their first winter in a state of initial diapause and their second winter in a state of final diapause to produce one generation every two years. A single female can lay both annual-and biennial-type eggs. If eggs are incubated at 20℃, then they will produce biennial-type eggs. Interestingly, the period of dormancy can exceed two years and is independent of habitat. The percentage of annual-type eggs in katydids from Aomori Prefecture was very low at 0-20% of the total number of eggs laid. Conversely, the percentage of annual-type eggs in katydids ranging from Machida City (Tokyo metropolis) to Matsuyama City (Ehime Prefecture) was 65.5-90%. Under conditions similar to those in the natural environment in Hirosaki City(Aomori Prefecture), the percentage of annual-type eggs laid by katydids from Aomori Prefecture decreased at the beginning of August, when the day length was approximately 13.5 h, and the end of August in katydids from Tokyo, Kyoto and Matsuyama, when the day length was about 13 h. The percentage of annual-type eggs laid by katydids that emerged on the same day decreased at around the same time under near-natural and constant conditions (25℃, 16L:8D). The percentage of annual-type eggs in broods vary according to geography, likely in response to hereditary and environment factors

[ISSN]2189-4825