Portal de Periódicos da CAPES

Thermal ecology and behaviour of Physadesmia globosa (Coleoptera: Tenebrionidae) in the Namib Desert

1990; Elsevier BV; Volume: 19; Issue: 3 Linguagem: Inglês

10.1016/s0140-1963(18)30796-1

1095-922X

J. L. Cloudsley‐Thompson,

Neurobiology and Insect Physiology Research

Of 2850 Physadesmia globosa counted at the Desert Ecological Research Unit of Namibia, Gobabeb, 67% were found beneath a large Acacia erioloba and two large Euclea pseudebenus beside it; the remainder in the open or beneath smaller trees. There was no tendency for the beetles to be in the open more at times when air temperatures were lower than higher. Wind speed had no effect on activity. The insects buried themselves, or retreated beneath rocks and stones at night. Of 1914 beetles sexed, 63% were male, 37% female. Vision is much used in day to day activity. Although not a fog-basking species, P. globosa sucks moisture from damp sand. This may shed light on the evolutionary origin of fog-basking in other species. No significant difference was recorded between the body temperatures of beetles selected at random, and those of geckos, Rhoptrophis afer, captured on nearby rocks at the same time of day. A population of some 60,000 km−2 was calculated around a point in the Kuiseb River bed. It is suggested that diurnal activity in P. globosa may be related to the cold nights and the enhancement of metabolic activity. Conclusions based on field observations were confirmed in the laboratory by aktograph experiments on the diurnal rhythm of locomotory activity.