Comparative studies on the evolutionary patterns of microhabitats and morphology in Passalidae based on the phylogenetic analysis

金龟甲科是鞘翅目，属于金龟甲总科，大多数种类分布在潮湿的热带地区。它们的亚社会行为在昆虫学文献中经常被引用。人们还知道，在成虫的身体形状上，passalid甲虫对它们的微栖息地表现出一些形态上的适应。为了了解成虫体型与微生境的关系，我们对8属50余种雀鸟进行了成虫体型测量和微生境野外观察。鞘翅长/体长和鞘翅宽/体长的比例在所有被测物种中都非常一致，而体厚在属和种之间都有很大差异。研究发现，较扁平的物种生活在原木树皮下，而前胫较扁平、较宽的物种生活在类似碎屑的微生境中。对于东方3种passalid属、Aceraius属、Macrolinus属和Ophrygonius属，各调查属的边材/热材居民比树皮下居民的体型更凸。从目前的结果可以推断，在每个属中，体厚的进化变化至少发生过一次，与微生境的变化有关。

Passalidae are the family of Coleoptera, belonging to the superfamily Scarabaeoidea, and most species occur in the humid tropics. The subsocial behavior of them has often been cited in the entomological literature. It has also been known that passalid beetles show some morphological adaptations in the adult body shape to their microhabitats. In order to know the relationship between adult body shape and microhabitats, we made measurements of the adult body shape and field observations on the microhabitats for about fifty species belonging to eight genera of the Passalidae. The proportions of (elytra length)/(body length) and (elytra width)/(body length) are remarkably uniform among all the apecies examined, whereas body thickness greatly varies both among genera and apecies. We found that flatter species are living under the bark of logs and the species with flattened and widened front tibiae living in the detritus-like microhabitats.For the Oriental 3 passalid genera, Aceraius, Macrolinus and Ophrygonius, it was revealed that sapwood/heatwood inhabitants are more convex in body shape than underbark inhabitants in each examined genus. It was duduced from the present results that evolutionary change of body thickness had occurred at least once associatedwith that of microhabitat within each genus.