Rain beetle
Pleocoma
Pleocoma is the only genus of the family Pleocomidae within the beetle suborder Polyphaga.
- 4.1 Notes and references
- 4.2 Literature
Features
Beetle
The beetles have a length of 16.5 to 29.0 mm ( males ) and 19.5 to 44.5 mm (females ). Your strong body has a wide - oval in outline and is strongly convex. Your back is hairless, the mounting side is densely covered with fine, long hair. The beetles are reddish brown to black, with different colored hair. The head is not excessively bent down, nor can it be confiscated. The sensors are elfgliedrig and have a four-to achtsegmentige lobe, similar to the Melolonthinae. The mandibles and maxillae are the regressed. The maxillary and labial palps are four members. The beetles are the only ones within the Scarabaeoidea, in which the indentations for the hips ( coxae ) of the front legs are open. The tracheae at first to eighth abdominal segment are functional and are located in the Pleuralmembranen. The genitalia of the male consist of a symmetrical triple lobe. The genital capsule is well developed. In females ( ovarioles ) are present per ovary 14 to 25 ovarioles, which otherwise occurs in any other family of Scarabaeoidea. Only the males are winged.
The Pleocoma have several unique, mainly primitive features, such as the indentations for the front hips, the large number of ovarioles of females and the extremely long-lived larvae. A few others might represent synapomorphies. The autapomorphies of Pleocoma include in the imagos: a Epipharynx from IMP - type, the lack of Prostheca and ligule, the open front hips on the wings of the dorso- proximal lobe of 2Ax is exceptionally small and basal extremely narrow, the subalare point which the tendon is grown, is extremely long and narrow, 2BP BMP is strongly convex and extremely narrow and more than 12 ovarioles in females who are also wingless. The autapomorphies larvae include a round, small flat " sense box " at the apical half of the last sensor element, the partly formed claws whose hair which is longer than the mouth itself, the significantly forwardly curved claws on the central and rear legs and the more than three larval stages.
Larvae
The body of the larvae is wide "C" -shaped. The third through seventh body segment is divided at the back in three or four lines. Simple eyes ( ocelli ) are missing. The sensors are tripartite and have no great sense stain. The mandibles are asymmetrical, have on the ventral side of an extension and there is no Stridulationsbereich. Galea and lacinia are clearly separated. The middle and rear legs are formed to the sound-generating organs. The hind legs are normal length and not shortened. The Tracheenöffnungen are sieve-like ( cribriform ).
Dissemination and lifestyle
The beetles are limited in their distribution to western North America from Washington to Baja California in Mexico.
The beetles are active early morning active during the cold season. The males fly actively during rains. The females they attract by pheromones. Mating takes place either on the ground or in the construction of the females for the larvae. Mated females return to their building and leave their eggs to mature for several months before they drop them spirally under construction. The adults have no functional mouthparts, even a digestive tract and accordingly take no food. The larvae live eight to twelve years and live as only within the superfamily more than three, namely nine larval stages. They develop in the soil and feed on roots. They are well adapted to digging in the ground.
Taxonomy and systematics
The genus Pleocoma was originally counted on the dung beetles ( Geotrupidae ). This taxon is closely related to the Bolboceratidae. There are 26 known species.