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タイトル山口市におけるツヅレサセコオロギVelarifictorus micadoとナツノツヅレサセコオロギV.grylloide(s Orthoptera: Gryllidae)の生活史
タイトル別表記Life history of Velarifictorus micado and V. grylloides(Orthoptera: Gryllidae) in Yamaguchi city, Japan
作成者新井, 哲夫
岡田, 麻美
作成者ヨミアライ, テツオ
オカダ, アサミ
作成者別表記Arai, Tetsuo
Okada, Asami
著者キーワードVelarifictorus micado
V. grylloides
Life history
Egg size
Egg period
Nymphal development
Yamaguchi City
内容記述(抄録等)In Japanese Islands, one kind of field cricket, Velarifictorus micado, is distributed from Hokkaido to Yakushima and Tanegashima in Kagoshima Prefecture, and the other one, V. grylloides is from west of Chiba Prefecture on Honshu to the Nansei Islands. Both species have a similar morphology and a univoltine life cycle in the area north than Kyushu. However, they differ in that V. micado overwinter as eggs, emerging as adults from early/mid-August to October, whereas V. grylloides have non-diapause eggs, instead overwintering as nymphs and emerging as adults in June and July. The species can be interbred in laboratory setting; successful development of F1 and F2 offspring has reported. Adults of V. micado was collected on mid-June, 2007 and V. grylloides was on late-August, 2007 in Yamaguchi City’s Hirano area (34.2 degree north latitude, 131.5 east longitude, elevation about 64m), where they are sympatric. The two species were cross-bred in the lab, and their life cycles were examined and compared in terms of F1 egg size, incubation period, wing phenotype, and nymphal development. Eggs of V. micado♀×V. micado♂(a) were longer in both the major and minor axis then eggs of V. grylloides♀×V. grylloides♂(b), while eggs of V. micado♀×V. grylloides♂(c) had a longer major axis than eggs of V. grylloides♀×V. micado♂(d). All four crosses had a shorter incubation period at higher temperatures. (a) had a longer incubation period than did (b), (c), and (d) at all temperatures. The females in crosses (b) and (d) both lay non-daipause eggs and eggs of (d), whose male parents belong to a diapause species, had a longer incubation period than eggs of (b), whose a non-diapause species. Both of (a) and (b) have a long- and short-winged phenotype. Long wing incidence was influenced by photoperiod ― lower for short day-lengths and higher for longer day-lengths in both (a) and (b) ― but consistently higher in (a). In (d), the long wing phenotype was roughly as prevalent as in (b) on days with photoperiods shorter than 13L: 11D (approx. 25%), and comparable to its incidence in (a) on long-light days of more than 14L: 10D(>95%). Nymphal development was influenced by the photoperiod. Development was accelerated on short days and delayed on long days for (a); the opposite trend was observed for (b). Regardless of photoperiod, nymphs of (a) developed more quickly than nymphs of (b). Nymphal developmental period length for females of (d) was intermediate between those for females of (a) and (b); however, males of (d) took even longer to develop than their (b) counterparts. Nymphal developmental period did not greatly differ between the sexes in both (a) and (b); in (d), however, females developed much more quickly than males regardless of photoperiod length. Although, V. micado and V. grylloides are technically sympatric, adults generally do not inhabit an area at the same time. They can be crossbred in the laboratory to produce F1 and F2 that develop normally. Theoretically, hybrid descendants could exist in the wild if males and females of the two species emerged at the same time. However, even if the unmated females of V. micado which emerged early in the wild and the males of V. grylloides which survived to late are crossing, few viable offspring of (c) would be produced. Also, it is unthinking that females of V. grylloides emerging from early June to mid/late July do not mate until mid/late August when males of V. micado appear, so that the appearance of (d) is impossible. Therefore interbreeding between these species seems not to occur in nature; although they inhabit the same areas, their respective times as adults in them hardly overlap.
出版者ヨミヤマグチ ケンリツ ダイガク
ファイル03.gen_ARAI.pdf ( 4.6MB ) 公開日 2019-03-29