Caveney Stanley, Scholtz Clarke H, McIntyre Peter
Department of Zoology, University of Western Ontario, N6A 5B7, London, Ontario, Canada.
Department of Entomology, University of Pretoria, 0002, Pretoria, South Africa.
Oecologia. 1995 Sep;103(4):444-452. doi: 10.1007/BF00328682.
Different species of African dung beetles emerge from the soil at characteristic times of the day to fly and colonize the freshly-deposited dung of mammalian herbivores. Onitine dung beetles in their natural habitat displayed one of five distinctive daily flight behaviours: dusk crepuscular (Onitis alexis Klug, O. caffer Boheman, O. fulgidus Klug, O. tortuosus Houston, O. vanderkelleni Lansberge, O. westermanni Lansberge); dusk/dawn crepuscular (O. pecuarius Lansberge and O. viridulus Boheman); dusk/dawn crepuscular and nocturnal (O. aygulus (Fabricius), O. mendax Gillet, O. uncinatus Klug); late afternoon-dusk and dawn-early morning [Heteronitis castelnaui (Harold)]; or diurnal flight activity [O. belial (Fabricius), O. ion (Olivier)]. These diagnostic daily flight behaviours span a light intensity range of over 6 orders of magnitude and have been retained in selected species introduced into Australia. Ambient light intensity appears to be the primary determinant of the daily flight period in onitine dung beetles. Because the dung of mobile herbivores is rapidly exploited by onitine species for feeding and breeding purposes, different flight behaviours result in a spatial and temporal partitioning of species in the local dung beetle community. The timing of flight may contribute to, or lead to avoidance of, competition between species which may ultimately affect colonization success. Many onitines show a strong preference for dung of specific herbivores, which may further reduce interspecific competition. All crepuscular-nocturnal species examined raised their thoracic temperatures endothermically to between 35°C and 40°C before the onset of flight. In O. aygulus the thoracic temperature excess was as large as 19.3°C. The thermal threshold below which the frequency of flight onsets drops off rapidly is about 12°C for O. aygulus and 17°C for O. alexis and O. pecuarius. Radiant loss of body heat during cool nights and dawns may explain why smaller species (<0.4 g body weight), in particular, are adapted behaviourally so that they fly only during the day or early dusk.
不同种类的非洲蜣螂在一天中的特定时间从土壤中钻出，飞行并在哺乳动物食草动物新排出的粪便上定居。在其自然栖息地中，奥尼廷蜣螂表现出五种独特的日常飞行行为之一：黄昏晨昏性（亚历克西斯奥尼廷蜣螂、卡弗奥尼廷蜣螂、闪亮奥尼廷蜣螂、曲折奥尼廷蜣螂、范德凯伦奥尼廷蜣螂、韦斯特曼奥尼廷蜣螂）；黄昏/黎明晨昏性（佩卡里奥尼廷蜣螂和翠绿奥尼廷蜣螂）；黄昏/黎明晨昏性和夜行性（艾古卢斯奥尼廷蜣螂、蒙达斯奥尼廷蜣螂、钩状奥尼廷蜣螂）；下午晚些时候至黄昏以及黎明至清晨[卡斯特尔诺异奥尼廷蜣螂（哈罗德）]；或日间飞行活动[贝利亚尔奥尼廷蜣螂、伊昂奥尼廷蜣螂（奥利维尔）]。这些具有诊断性的日常飞行行为跨越了超过6个数量级的光照强度范围，并且在引入澳大利亚的选定物种中得以保留。环境光照强度似乎是奥尼廷蜣螂日常飞行时段的主要决定因素。由于移动食草动物的粪便会被奥尼廷蜣螂物种迅速用于觅食和繁殖目的，不同的飞行行为导致了当地蜣螂群落中物种在空间和时间上的划分。飞行时间可能有助于或导致避免物种间的竞争，这最终可能影响定居成功。许多奥尼廷蜣螂对特定食草动物的粪便表现出强烈偏好，这可能进一步减少种间竞争。所有被研究的晨昏性 - 夜行性物种在飞行开始前都会通过吸热将胸温提高到35°C至40°C之间。在艾古卢斯奥尼廷蜣螂中，胸温升高幅度高达19.3°C。对于艾古卢斯奥尼廷蜣螂，飞行开始频率迅速下降的热阈值约为12°C，而对于亚历克西斯奥尼廷蜣螂和佩卡里奥尼廷蜣螂则为17°C。在凉爽的夜晚和黎明期间身体热量的辐射损失可能解释了为什么特别是较小的物种（体重<0.4克）在行为上进行了适应性调整，使得它们只在白天或黄昏早期飞行。
