Comparison of the Feeding Niche of Polyphagous Insectivores (Araneae) in a Texas Cotton Plantation: Estimates of Niche Breadth and Overlap
作者:
Martin Nyffeler,
Winfield L. Sterling,
期刊:
Environmental Entomology
(OUP Available online 1994)
卷期:
Volume 23,
issue 5
页码: 1294-1303
ISSN:0046-225X
年代: 1994
DOI:10.1093/ee/23.5.1294
出版商: Oxford University Press
关键词: insectivores;feeding niche;cotton
数据来源: OUP
摘要:
The feeding niches of 10 spider species that are polyphagous insectivores were compared by computing coefficients of niche breadth and niche overlap. The study is based on predation evidence from an insecticide-free cotton plantation in east Texas. All overlap values were<1.00 (range, 0.08–0.94), which indicates that each spider species has its own feeding niche in the cotton agroecosystem. Diet breadth, that is inversely related to feeding specialization, was computed for each species. The highest value was approximately five times higher than the minimum, which indicates considerable differences between species in feeding specialization. Diet breadth values indicate that large web weavers exhibited a less specialized feeding behavior (relatively broad feeding niche) compared with small web weavers (narrow feeding niche). Prey specialists in this study concentrated on either aphids or fire ants as a primary food source. The nonweb-building spiderOxyopes salticusHentz, which actively searches the cotton plant for prey (up to=6 mm maximum length), showed the highest diet breadth value (broad feeding niche) under the conditions of this experiment. This abundant species, which is considered a highly beneficial biocontrol agent of smaller cotton pests, shows high flexibility in its foraging patterns.
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