The relative effects of two components of mountain environmental heterogeneity, altitude (1500, 1700 and 2000 m a.s.l.) and habitat (pastures, coniferous forests, wet meadows, scrub and anthropogenic woods) on the diversity of dung beetles in an Italian alpine valley were determined. The additive gamma diversity analysis indicated that differences among habitats (ßH) were always smaller than those among altitudes (ßA), irrespective of the measures used; it also showed that the contribution of ßA to γ-diversity was higher than expected by chance for all the measures of species diversity used, whereas the contribution of ßH was significantly higher in the case of one measure only. Generalized linear models confirmed that altitude was the most important factor associated with local diversity, with all the diversity parameters considered progressively and significantly increasing with increasing altitude. Indicator species analyses revealed that dung beetle altitudinal and habitat diversity patterns depended on local choice of species, with preferences for altitudinal levels being more numerous and apparent than those for habitats. Despite the minor effect of habitat differences, comparing a three-habitat with a single-habitat scenario it was possible to demonstrate that greater habitat heterogeneity is associated with a significantly greater diversity of dung beetles. This study suggests that preservation of local environmental heterogeneity by means of traditional pastoral activities should be encouraged as a means of conserving the diversity of dung beetle species in the Alps. and Matteo NEGRO, Claudia PALESTRINI, Maria Teresa GIRAUDO, Antonio ROLANDO.
Circellium bacchus is a flightless telecoprid (ball-rolling) dung beetle, endemic to the afrotropical region, where it is found in a few restricted populations in the eastern Cape of South Africa. Its apterous condition and large size (mass ranges from 6 to 12 g) are considered to be adaptations to a semi-arid habitat. This beetle is active in the sun for long periods, walking between widely scattered dung pats, thus is under selection pressure to reduce water loss.
C. bacchus has eight spiracles on each side of the body. The metathoracic spiracle and six abdominal spiracles open into the subelytral cavity, which is closed. The mesothoracic spiracle is the largest and most exposed, occurring ventrally in the membrane connecting the prothorax and mesothorax.
When at rest a cyclic form of respiration, known as discontinuous gas exchange cycle, is used by C. bacchus, releasing a burst of carbon dioxide approximately once an hour when the spiracles open for about 33 minutes. Flow-through respirometry was used to measure water loss from the thorax (being the head, prothorax and mesothorax) and elytral case (containing the metathorax and abdomen) separately. The total water loss of C. bacchus could be divided up as 65% cuticular water loss from the thorax, 35% cuticular water loss from the elytral case, 4% respiratory water loss from the thorax and no measurable respiratory water loss from the elytral case. 1.51 µg of water is lost for every µl of CO2 emitted during respiration in the thorax. Thus, the main avenue for both respiration and respiratory water loss is via the mesothoracic spiracles, suggesting that the primary function of the subelytral cavity is not to reduce respiratory water loss.
Two new species of Copris Geoffroy, 1762 are described and illustrated: Copris (subgenus incertae sedis) caobangensis sp. n. from Caobang Province (northern Vietnam) and Copris (Copris) sonensis sp. n. from Thanhhoa Province (central Vietnam). Copris (Copris) szechouanicus Balthasar, 1958 is recorded in Vietnam for the first time and data on the morphology, distribution and ecology of this species are given. An updated species list and an identification key for the Copris species so far known from Vietnam are presented along with detailed photographs of the poorly known species., Van Bac Bui, Kenneth Dumack, Michael Bonkowski., and Obsahuje bibliografii