02063nas a2200289   4500008004100000245006600041210006500107260000800172300001200180490000800192520129100200653001801491653001301509653001201522653003401534653001501568653002101583653001701604653001701621653002301638100001401661700001401675700001801689700001601707700001601723856003401739       2003                        eng d00aVisual cues used by ball-rolling dung beetles for orientation0 aVisual cues used by ballrolling dung beetles for orientation  cJun  a411-4180 v1893 aBall rolling by dung beetles is considered to be a derived behaviour that evolved under pressure for space, and from competitors at the dung pat. Straight-line orientation away from the pat using a celestial cue should be the most successful rolling strategy to move dung to an unknown burial site. We tested this hypothesis in the field and the laboratory by presenting five species of ball-rolling beetles with different orientation tasks, involving reaction to obstacles as well as to reflected sunlight and artificial light sources. Beetles were found to consistently orientate along a chosen route, usually in the direction of the sun. Beetles rolling dung balls successfully negotiated barriers and returned to the original path as did beetles falling from ramps, or rotated about a fixed point while rolling a ball. The sun was found to be the main orientation cue, which could be substituted by reflected or artificial light. However, beetles reoriented themselves less accurately in response to lights in the laboratory, than they did to the reflected sun in the field. It is probable that phototactic orientation using the sun, which is widespread amongst arthropods, has been incorporated in the straight-line foraging behaviour that has evolved in ball-rolling dung beetles.10acelestial cue10aforaging10ainsects10akheper nigroaeneus coleoptera10anavigation10apath integration10aScarabaeidae10aScarabaeinae10avisual orientation1 aByrne, M.1 aDacke, M.1 aNordstrom, P.1 aScholtz, C.1 aWarrant, E.  u<Go to ISI>://00018401560000202643nas a2200301   4500008004100000245013000041210006900171300001200240490000700252520172600259653002301985653003102008653003702039653003102076653001602107653001202123653001302135653001502148653001602163653001702179653002202196653001602218653002202234653001602256653001502272100001902287856003502306       2002                        eng d00aThe role of the subelytral cavity in water loss in the flightless dung beetle, Circellium bacchus (Coleoptera : Scarabaeinae)0 arole of the subelytral cavity in water loss in the flightless du  a253-2580 v993 aCircellium 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.10aCircellium bacchus10adesert tenebrionid beetles10adiscontinuous gas exchange cycle10aDiscontinuous gas-exchange10adung beetle10ainsects10apatterns10aphysiology10arespiration10aScarabaeidae10asubelytral cavity10aterrestrial10atrait information10aventilation10awater loss1 aDuncan, F., D.  u<Go to ISI>://000177174200016 