Ecology of Three Sympatric Species of Parasitic Insects of the Genus Megarhyssa (Hymenoptera: Ichneumonidae)
Ecology of Three Sympatric Species of Parasitic Insects of the Genus Megarhyssa (Hymenoptera: Ichneumonidae)
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巨蝇属三种同域寄生昆虫生态学（膜翅目：姬蜂科）
DOI：
10.2307/1935265
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发表时间：
1965
期刊：
影响因子：
4.8
通讯作者：
Donald M. Davis
中科院分区：
文献类型：
--
作者：
H. Heatwole;Donald M. Davis
在密歇根州的山毛榉-枫树林中对三个物种：Megarhyssa atrata lineata、M. macrurus lunator 和 M. greenei greenei 进行了研究。它们都是昼夜活动的，具有相似的活动模式，只是雌性黑斑海龟在当天晚些时候比其他海龟保持更高程度的活动。高于 10 g/m2 的饱和度赤字会抑制活动，而正常的夏季白天温度则不会。雌性和雄性在春季的出现时间似乎没有显着差异，各物种的季节出现也没有差异，只是 M. Greenei 在秋季可能持续时间稍长一些。所有性别和所有物种的昆虫都倾向于反复返回同一根原木或树桩，但在不同地点之间的移动量有限。成虫在不活动期间栖息在山毛榉和枫叶的背面。由于此类场所的数量多于使用它们的个人，因此似乎不会发生对住所的竞争。成年人也不争夺食物。这三个物种的幼虫在生态上很大程度上是隔离的，因为它们寄生于宿主种群的不同部分。这取决于以下事实：(1) 成虫在木材深处选择寄主幼虫，以便产卵器以与木材表面成直角的方式完全插入木头表面，(2) 不同物种的产卵器长度不同，(3) 寄主幼虫在其幼虫期的大部分时间里，在木材中保持大约相同的深度。在给定的原木上存在物种的连续性，但没有达到在没有上述机制的情况下这三个物种将被生态隔离的程度。物种演替的顺序似乎取决于产卵器长度的差异。当一个物种入侵新的原木时，原木上的雌性通常会更加丰富；在衰退期，雄性的数量通常较多。成年人至少可以活27天。该地区的捕食者是强盗蝇，也许还有花栗鼠。在所检查的部分原木中，巨蜥寄生巨蜥的发生率为 26.7%。
Three species, Megarhyssa atrata lineata, M. macrurus lunator, and M. greenei greenei were studied in beech—maple forests in Michigan . All are diurnal with similar activity patterns except that female M. atrata maintain a high degree of activity later in the day than do the others. Saturation deficits above 10 g/m2 inhibit activity whereas normal summer daytime temperatures do not. There does not seem to be a significant difference between time of emergence of females and of males in the spring, nor are there differences in seasonal occurrence of the various species except that M. Greenei may persist slightly longer in the fall. Insects of both sexes and of all species tend to return repeatedly to the same log or stump with but a limited amount of movement between sites. Adults rest on the undersides of beech and maple leaves during inactive periods. Since there are more such places than individuals to use them, competition for shelter does not seem to occur. Neither do adults compete for food. The larvae of the three species are largely segregated ecologically in that they parasitize different segments of the host population. This depends on the facts that (1) the adults select a host larva at a depth in the wood so that complete insertion of the ovipositor at right angles to the surface of the wood will just reach it, (2) the ovipositors of the different species are of different lengths, and (3) the host larvae maintain themselves at about the same depth in the wood for most of their larval period. There is succession of species on a given log but not to the extent that the three species would be ecologically segregated without the above mechanism. The sequence of species in the succession seems to depend on differences in ovipositor length. Females are usually more abundant on logs when a species is invading a new log; males are usually more numerous in the declining phase. Adults can live at least 27 days. Predators in the area were robber flies and perhaps a chipmunk. Incidence of parasitism of Tremex by Megarhyssa was 26.7% in part of a log which was examined.