昆蟲.ニューシリーズ
Online ISSN : 2432-0269
Print ISSN : 1343-8794
6 巻, 1 号
選択された号の論文の21件中1~21を表示しています
  • 弘中 満太郎, 堀口 弘子, フィリッピ リサ, 野間口 真太郎, 藤條 純夫, 針山 孝彦
    原稿種別: 本文
    2003 年 6 巻 1 号 p. 1-8
    発行日: 2003/03/25
    公開日: 2018/09/21
    ジャーナル フリー
    The female of subsocial shield bug, Parastrachia japonensis (Heteroptera: Cydnidae) provides many drupes of the host tree for its nymphs. Our previous study revealed that female bug foraged tortuously until it had encountered a ripe drupe and the homing bug brought it back to its burrow directly. We here investigated the progressive change of her homing navigation comparing the several behavioural elements at the earlier and later periods during its provisioning season. The 'homing direction', the angles between the longitudinal axis of the bug dragging a drupe and the burrow direction, was measured and showed no apparent difference between the two periods. On the way to home, the bug suddenly stopped at the 'searching point' and changed its directional walking behaviour. The distance between the 'searching point' and its burrow was constant whole through the provisioning season. However, the 'homing speed' of the directional homing was slightly increased in the later homing. In addition, the 'searching time', the walking time from the 'searching point' to its burrow entrance, decreased in the later homing. These results indicate that the particular behavioural elements taking at the two different homing navigation stages in the P. japonensis are progressively changed during provisioning period.
  • 池田 綱介, 中筋 房夫
    原稿種別: 本文
    2003 年 6 巻 1 号 p. 9-18
    発行日: 2003/03/25
    公開日: 2018/09/21
    ジャーナル フリー
    The flight activity of Galerucella nipponensis, an herbivorous insect of the aquatic plant, Trapa japonica, was investigated using sticky traps in a pond from 1999 to 2001 in Okayama, Japan. Traps were placed above the water surface in a pond, and G.nipponensis adults were caught throughout the period. This suggested that the adults dispersed actively irrespective of season. Captured G.nipponensis adults had a bias toward females. Other insects were more abundant in early summer and autumn, but less so in midsummer. It has been reported that the density of G.nipponensis became extremely low due to predation by Gerris nepalensis in midsummer (Ikeda & Nakasuji, 2002). A positive correlation between the density of G.nipponensis on T.japonica and the abundance of the other insects caught was obtained in the early season, but such a relationship was not observed later in the season. The leaves of T.japonica extend horizontally on the water surface early in the season but grow vertically in the overgrown rosettes late in the season. G.nepalensis is capable of attacking the beetles in the former but not in the latter. It is possible that the abundance of alternative prey of G.nepalensis indirectly influenced seasonal changes in the density of G.nipponensis.
  • 安田 弘法
    原稿種別: 本文
    2003 年 6 巻 1 号 p. 26-
    発行日: 2003/03/25
    公開日: 2018/09/21
    ジャーナル フリー
  • 前藤 薫, 光後 圭枝, 小谷 英司, 宮田 弘明, 杉村 光俊
    原稿種別: 本文
    2003 年 6 巻 1 号 p. 27-41
    発行日: 2003/03/25
    公開日: 2018/09/21
    ジャーナル フリー
    We conducted a correspondence analysis (CA) of 88 species of Odonata (dragonflies) observed at 455 grid sites (ca. 0.5km×0.5km) in the Shimanto River basin and adjacent areas in Shikoku, Japan. Multiple regression analyses of the two main axes of the CA ordination on the geographical features (altitude, relief) and vegetation of grid sites indicated that the degree of relief and the areal proportion of paddy fields were the main determinants of the species distribution of Odonata. The species were classified into 5 groups by k-means clustering based on the coordinate axes. Groups I and II mostly consisted of lentic species inhabiting ponds, marshes and paddy fields of flat lands. Groups III and IV were composed of lentic species mainly inhabiting marshes and paddy fields and lotic species in slow streams. Group V consisted of lotic species inhabiting mountain streams and spring sources. Habitat requirements for the species appearing in the Red List of Kochi Prefecture are also discussed.
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