Environmental Entomology (1988) 17, 280-286

Robert R. Parmenter and James A. MacMahon (1988)
Factors limiting populations of arid-land darkling beetles (Coleoptera: Tenebrionidae): Predation by rodents
Environmental Entomology 17 (2), 280-286
Abstract: The role of rodent predation as a limiting factor in the abundance of six species of darkling beetles (Tenebrionidae) was examined in a sagebrush-steppe ecosystem (Kernmerer, Wyo.). Rodent predators were identified in feeding experiments using captive rodents and darkling beetles. Grasshopper mice (Onychomys) and deer mice (Peromyscus) successfully captured and consumed Eleodes extricatus Say. Ground squirrels (Spermophilus) and pocket mice (Perognathus) initially fed upon E. extricatus but developed an aversion to them after several exposures. Subsequent experiments demonstrated that the chemical aerosol produced by E. extricatus as an antipredator defense was effective in providing escape time during deer mouse attacks but not during grasshopper mouse attacks. A replicated field experiment, employing 10 rodent exposures (15 by 15 m) and 10 control plots, showed that the removal of rodent predators resulted in population increases in five of the six species of darkling beetles (Coniontis ovalis, E. extricatus, E. pimelioides, E. rileyi, and Helops difficilis). The total population of beetles exhibited a 63% increase in abundance following rodent removal. Based on 1986 field density measurements of rodents (8/ha) and beetles (4,931 /ha), an average daily consumption of fewer than two beetles per rodent was calculated to be sufficient to produce the observed differences in darkling beetle populations on the site. Therefore, it is concluded that rodent predation functioned as a significant limiting factor on darkling beetle populations in the sagebrush-steppe study area.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
Peromyscus (genus - predators)
Spermophilus (genus - predators)