Thesis
Studies of dung-dwelling insects in cattle-grazing regions of the Columbia Basin, Washington State
Washington State University
Master of Science (MS), Washington State University
2008
Handle:
https://hdl.handle.net/2376/102193
Abstract
Dung is an important resource for microbes, nematodes, insects and annelids. The study presented here focused on the dung-dwelling insects of pasture ecosystems. The pattern of succession and manipulation of dung results in exploitation and resource utilization by many organisms. The activities of dung insects cause the degradation of dung and the cycling of nutrients back into the environment, which is crucial for soil fertility and forage growth in a pasture environment. However, the presence of flies, beetles and wasps have been reported to be affected negatively by the presence of veterinary parasiticides (VPs), thus disrupting succession and dung degradation. VPs are commonly used in the Pacific Northwest (PNW) region of the U.S. and worldwide to control parasites of livestock. Studies were conducted over a two-year period in the Columbia Basin region of Washington, U.S. to examine the succession of insects in cattle dung and the effects of pour-on formulations of ivermectin and doramectin on those insects. The succession study examined the dung-dwelling insects emerging over three-day intervals from artificial pats placed in three microhabitats (natural grassland, non-irrigated pasture and irrigated pasture) in which cattle graze. The results for Experiment 1 (2007) revealed no differences in insect emergence through time, while Experiment 2 (2008) showed that significantly more Diptera emerged from dung on day 2 than 3 or 4. Numbers of flies emerging was greatest in natural grassland for both experiments, while numbers of beetles emerging was lowest in the natural grassland. VP experiments were examined the insects emerging from artificial pats from cattle treated with ivermectin, doramectin or no VPs. The results of these experiments varied between years with reduced emergence from dung treated with VPs for the Diptera (Experiment 3: 2008), lower emergence rates from control dung for Hymenoptera (Experiment 2: 2007), and no reductions in Coleoptera emergence in either experiment. This study suggests that VPs negatively affected dung-dwelling insects but varied by organism as well as from year to year in Washington State in the summer. These studies highlight the importance of characterizing the ecology of the dung insect community in the PNW region of the U.S.
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Details
- Title
- Studies of dung-dwelling insects in cattle-grazing regions of the Columbia Basin, Washington State
- Creators
- Daniel Robert Skoczylas
- Contributors
- Laura Lavine (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Entomology, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525199201842
- Language
- English
- Resource Type
- Thesis