Shelly Todd E
Department of Biology, University of California, 90024, Los Angeles, CA, USA.
Oecologia. 1985 Aug;67(1):57-70. doi: 10.1007/BF00378452.
Data regarding seasonal abundance, microhabitat preference, and diet were collected over 3 field seasons for adults of 15 robber fly species on Barro Colorado Island, Panama. The species comprised 2 distinct "thermal guilds"; light-seeking (hereafter LS) species foraged in sunlit areas, while shade-seeking (SS) species foraged only in deep shade. All species were rare during the dry season. During the rainy months, most SS species had flight periods of 2-3 months, and no temporal segregation was apparent. In contrast, most LS species had flight periods of only 4-6 weeks, and a distinct sequence of occurrence was evident during 2 years of censusing. Most SS and LS species displayed a pronounced specificity for perches of a particular substrate type. However, the ranges of perching heights utilized varied considerably among species. Dietary comparisons revealed that mean and maximum prey sizes increased with increasing robber fly size, while minimum prey sizes were constant. Robber fly species <20 mg fed primarily upon nematocerous Diptera, whereas larger species generally fed upon a wide variety of prey types. For each thermal guild, the actual mean overlap for a particular niche dimension was compared to mean overlaps generated by randomly assigning species to thermal guilds. No significant differences from the random null hypothesis were found for the SS guild. However, niche complementarity between dietary and spatial overlaps and dietary overlap was apparent among the 5 large LS species.
在巴拿马的巴罗科罗拉多岛，我们在三个野外季节收集了15种盗蝇成虫的季节性丰度、微生境偏好和饮食数据。这些物种包括两个不同的“热类群”；喜光（以下简称LS）物种在阳光充足的区域觅食，而喜阴（SS）物种只在深荫处觅食。所有物种在旱季都很稀少。在雨季，大多数SS物种的飞行期为2至3个月，没有明显的时间隔离。相比之下，大多数LS物种的飞行期只有4至6周，在两年的普查中出现了明显的顺序。大多数SS和LS物种对特定底物类型的栖息地表现出明显的特异性。然而，不同物种利用的栖息高度范围差异很大。饮食比较表明，猎物的平均大小和最大大小随着盗蝇体型的增加而增加，而最小猎物大小则保持不变。体重小于20毫克的盗蝇物种主要以长角双翅目昆虫为食，而体型较大的物种通常以多种猎物为食。对于每个热类群，将特定生态位维度的实际平均重叠与通过随机将物种分配到热类群而产生的平均重叠进行比较。在SS类群中，未发现与随机零假设存在显著差异。然而，在5种大型LS物种中，饮食重叠与空间重叠之间的生态位互补以及饮食重叠是明显的。
