cryptoleamus montrouzieri is the most important natural enemy of pseudococcus citri. the effects of different temperatures and different densities of c. montrouzieri on predation rate, searching efficacy and mutual interference of the mentioned coccinellid feeding on the nymphs of p. citri was studied. hassel and varley model was applied for estimation of interference constant. according to the...

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 ± ...

two 60 day experiments on predation behavior of leeches were conducted concurrently. in the first, medicinal leeches, hirudo orientalis (utevsky and trontelj, 2005) were fed to satiation on bovine blood and subsequently transferred into two large opaque plastic containers of equal size but with differing temperatures, 6-7?c and 23-24?c, containing starved erpobdella octoculata (l.). at the high...

anthocoris nemoralis (f.) (hemiptera: anthocoridae) is one of the most prominent predators of the pear psylla, cacopsylla pyricola (forster) (hemiptera: psyllidae) and is considered as a biological control agent against this pest. in order to investigate the effects of plant varieties on predation of c. pyricola by a. nemoralis, the functional response of both the sexes of a. nemoralis to pear ...

Increased perceived predation risk can cause behavioral and physiological responses to reduce direct predation mortality, but these responses can also cause demographic costs through reduced reproductive output. Such indirect costs of predation risk have received increased attention in recent years, but the relative importance of direct vs. indirect predation costs to population growth (λ) acro...

Knowledge of dominant predators is necessary to identifY predation patterns and mitigate losses to nest predation, especially for endangered songbirds. We monitored songbird nests with timelapse infrared video cameras at Fort Hood Military Reservation, Texas, from 1997 to 2002 and 2005, and in Austin, Texas, during 2005, 2006, 2008, and 2009. Predation was the most common source of nest failure...

Recent theoretical and empirical work argues that growth rate can evolve and be optimized, rather than always being maximized. Chronically low resource availability is predicted to favour the evolution of slow growth, whereas attaining a size-refuge from mortality risk is predicted to favour the evolution of rapid growth. Guppies (Poecilia reticulata) evolve differences in behaviour, morphology...