@article {1548, title = {The role of the subelytral cavity in water loss in the flightless dung beetle, Circellium bacchus (Coleoptera : Scarabaeinae)}, journal = {European Journal Of Entomology}, volume = {99}, number = {2}, year = {2002}, note = {digital copy}, pages = {253-258}, abstract = {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 sub-elytral 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 mug of water is lost for every mul 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.}, keywords = {Circellium bacchus, desert tenebrionid beetles, discontinuous gas exchange cycle, Discontinuous gas-exchange, dung beetle, insects, patterns, physiology, respiration, Scarabaeidae, subelytral cavity, terrestrial, trait information, ventilation, water loss}, url = {://000177174200016 }, author = {Duncan, F. D.} } @article {1918, title = {Estimation of Dung Beetle Biomass (Coleoptera, Scarabaeoidea)}, journal = {European Journal of Entomology}, volume = {90}, number = {2}, year = {1993}, pages = {235-238}, url = {://A1993LL77500012}, author = {Lobo, J. M.} } @article {1775, title = {Dung feeding in hydrophilid, geotrupid and scarabaeid beetles: Examples of parallel evolution}, journal = {European Journal Of Entomology}, volume = {101}, number = {3}, year = {2004}, note = { digital disease ecology, parasite transmission, scarbaeinae, ecological function}, pages = {365-372}, abstract = {The maximum size of ingested ball-shaped particles was determined in three species of adult dung feeding beetle: Anoplotrupes (Geotrupes) stercorosus and Geotrupes spiniger (Geotrupidae, Geotrupinae) and Sphaeridium lunatum (Hydrophilidae, Sphaeridiinae). Maximum diameters were 40-65 mum, 60-75 mum and 16-19 mum in A. stercorosus, G. spiniger and S. lunatum, respectively, and it was concluded that these beetles feed in the same way as found in previous studies on coprophagous scarabaeids (Scarabaeinae and Aphodiinae). Coarse particles, mainly indigestible plant fragments, are rejected by an unknown filtering mechanism, and only very small particles are actually ingested. The two geotrupids, however, tolerate somewhat larger particles than do scarabaeines of similar size. This may reflect a lower degree of specialisation towards dung feeding in the geotrupids than in the scarabaeines. In several ways, the mouthparts of the coprophagous Scarabaeidae, Geotrupidae and Hydrophilidae show essentially the same morphological modifications that must be adaptations for dung feeding. For the hydrophilid (Sphaeridium), such modifications are described for the first time. They include asymmetric mandibular molars (right convex, left concave), fitting exactly into each other, with highly specialised surfaces that may concentrate the food prior to ingestion by squeezing fluid out of it. Other examples are the conjunctives (scarabaeids and geotrupids) or similar structures (the hydrophilid) and the large, hairy, pad-like distal lobes of the maxillar galeae. Provided that current views on the evolutionary history of these beetles are correct, dung feeding has arisen independently in the Scarabaeidae, Geotrupidae and Hydrophilidae. If so, the feeding on very small particles and the concomitant modifications of mouthparts in these three groups must be results of parallel evolution.}, keywords = {COLEOPTERA dung beetle, Dung beetles, evolution, feeding habits, Geotrupidae, HELMINTH EGGS, hydrophilidae, Mouthparts, particle feeding, Scarabaeidae}, isbn = {1210-5759}, url = {://000224407300003}, author = {Holter, P.} }