Tenebrionid beetles in the shortgrass prairie: daily and seasonal patterns of activity and temperature

Abstract

ABSTRACT. 1. Patterns of daily and seasonal activity for seven species of tenebrionid beetles, genus Eleodes, were investigated in the shortgrass prairie of northeastern Colorado. The relationship between time of activity, body temperatures, and rates of water loss of the beetles was examined in the field and in laboratory experiments. 2. Common species were active from April until the end of October; however, asynchronous peaks of abundance occurred. 3. Beetles were diurnally active with peaks of daily activity occurring 2–4 h after sunrise and before sunset. Less than a 2 h shift in mean time of activity occurred between seasons. 4. Within species, body temperatures measured in the field closely corresponded to temperatures selected in an experimental thermal gradient; hence, species seemed to prefer particular body temperatures and were most active during times when those temperatures could be achieved. Body temperatures measured in the field approximated ambient temperatures measured in the vicinity of the beetle. 5. Significant differences among several species were found for times of daily activity and corresponding body temperatures. 6. Ability to resist water loss by evaporation was not correlated with daily or seasonal activity patterns.

A darkling beetle population in West Texas during the 1997–1998 El Niño

“…At the broader scale, we regularly detected a strong association of the beetles with habitat type, a result consistent with patterns of habitat use of E. extricata in Colorado (Stapp, 1997) and Wyoming (Parmenter et al, 1989a). Whicker & Tracy (1987) determined that the highest body temperatures of seven Eleodes spp. were maintained by E. extricata.…”

Environmental correlates of darkling beetle population size (Col. Tenebrionidae) on the Cañadas of Teide in Tenerife (Canary Islands)

“…A high vagility during the summer may occur because vagility is related to the environmental temperature (Nicolson et al, 1984;Whicker & Tracy, 1987;Parmenter et al, 1989). As found in previous studies (Baars, 1979a, b;Ericson, 1979;Crist & Wiens, 1995), a positive relationship between temperatures and population sizes was shown.…”

“…If there are density-dependent effects on the community structure of these generalist detritivores, difference in foraging efficiency may be important in separating species niches (Crawford, 1988). Although there is considerable evidence for spatial and temporal resource partitioning in desert darkling beetles (Whicker & Tracy, 1987;Aldryhim et al, 1992), there is no direct evidence that this is due to interspecific competition.…”

Thermal habitat and life history of two congeneric species of darkling beetles (Coleoptera: Tenebrionidae) on Tenerife (Canary Islands)

“…Furthermore, microhabitat selection may be substantially influenced by each species' preference and tolerance of field temperature regimes (Parmenter et al, 1989). Tenebrionids select microhabitats and activity times based on the thermal regimes rather than humidity (Hamilton, 1971;Whicker and Tracy, 1987;Parmenter et al, 1989;de los Santos et al, 2002b). Physiological and morphological adaptations affect their temperature relationships (Hamilton, 1973;Bartholomew et al, 1985).…”

“…Darkling beetle populations have adaptation syndromes to live in arid and semi-arid ecosystems and their life histories are linked to hot seasons in those areas with fluctuating climates (Brun, 1970;Knor, 1975;Allsopp, 1980a;de los Santos et al, 1988). Adult emergence, individual vagility, and population sizes are all related with the environmental temperature (Nicolson et al, 1984;Whicker and Tracy, 1987;Parmenter et al, 1989;Crist and Wiens, 1995;de los Santos et al, 2002a).…”