predation rate is basic to any investigation of prey-predator interaction and a major component in the selection of predators for biological control. the predation rate of variegated lady beetle, hippodamia variegata (goze), fed on different densities (20, 40, 60, 80 and 100) of third instar nymphs of cotton aphid, aphis gossypii glover, was studied under laboratory conditions (25 ± 1 °c, 65 ± ...

The relationship between the insect development rate and temperature was established very early and represents an important ecological variable for modeling the population dynamics of insects. The accurate determination of thermal constant values and the lower and upper developmental thresholds of Hyadaphis foeniculi (Passerini) (Hemiptera: Aphididae) on fennel (Foeniculum vulgare Miller (Apial...

1. Optimal foraging theory assumes that a predator preys selectively to maximize fitness gain. The associated model assesses predator’s fitness gain by estimating prey profitability in terms of appropriate foraging costs and benefits. While model developing, unsuccessful foraging was included in the model because it is inevitable and costly for a predator. However, it has rarely been taken into...

(1) Intraguild predation (IGP) can occur among aphidophagous predators thus reducing their effectiveness in controlling crop pests. Among ladybirds, Coccinella septempunctata L. and Hippodamia variegata Goeze are the most effective predators upon Aphis gossypii Glov., which is an economically important pest of melon. Understanding their likelihood to engage in reciprocal predation is a key poin...

Intraguild predation (IGP) is common in food web when two natural enemies share the same resources and prey. It may affect the success or failure of a biological control attempt. The role of intraguild predation by Geocoris ochropterus Fieber (Heteroptera: Geocoridae) on Trichogramma chilonis Ishii (Hymenoptera: Trichogrammatidae) developed on eggs of Helicoverpa armigera (Hubner) (Lepidoptera:...

The nutritive value of two cereal aphid species, Schizaphis graminum and Rhopalosiphum padi, for Hippodamia convergens development was compared as pureand mixed-species diets and as suboptimum and ad libitum quantities. Comparisons were based on the following daily aphid quantities and combinations: 4 mg R. padi, 4 mg S. graminum, 3:1 mg mixture of R. padi and S. graminum, 2:2 mg mixture of R. ...

Predators play a key role in shaping natural ecosystems, and understanding the factors that influence a predator's kill rate is central to predicting predator-prey dynamics. While prey density has a well-established effect on predation, it is increasingly apparent that predator density also can critically influence predator kill rates. The effects of both prey and predator density on the functi...