Search

The non‐consumptive effects of predator‐induced stress can influence a variety of life‐history traits. Many previous studies focused only on short‐term effects such as development and reproductive rates. Recent studies have showed that long‐term predation stress (given during the whole life of the prey) and short‐term predation stress (provided during the immature stage of the prey) could generate completely opposite results: the former could decrease lifespan, whereas the later could increase lifespan. However, it is still unclear whether the advantage is because of the short duration of exposure or the early stage of life during which exposure was exerted. Thus, in this study, the prey (Tyrophagus putrescentiae) was exposed to predation stress from the predator (Neoseiulus cucumeris) during different life stages (larva, protonymph, tritonymph, first 5 d of oviposition, the full lifespan or none of the above). The results showed that the predation stress supplied during larval and protonymphal stage delayed development, reduced fecundity and prolonged lifespan of the prey, while the stress given during tritonymphal stage only reduced lifespan slightly and the stress given during the first 5 d of oviposition did not change lifespan but reduced fecundity. This study indicated that the effects of predation stress are dependent on prey life stage and the predation stress experienced in the early life stages is important to lifespan modulation. [ABSTRACT FROM AUTHOR]

Simple Summary: Intraguild predation between the introduced enemy Neoseiulus barkeri (Hughes) and the native enemy Scolothrips takahashii (Priesner) frequently occurs when target prey is scarce. It is hypothesized that intraguild predation is an adaptative strategy for predators, ensuring the persistence of the intraguild predators during periods of prey scarcity. Therefore, we undertook a study to evaluate the effects of the intraguild prey on the survival, development and reproduction of intraguild predators in a reciprocal predator guild with N. barkeri and S. takahashii. Our results support the hypothesis, showing that intraguild prey enhanced the survival, development and oviposition of intraguild predators, further confirming the effectiveness of intraguild predation as an adaptative strategy. The predatory mites Neoseiulus barkeri (Hughes) and the predatory thrips Scolothrips takahashii (Priesner) are known as potential biocontrol agents for the two-spotted spider mite Tetranychus urticae (Koch). These two predator species occur simultaneously on crops in agricultural ecosystems and are proved to be involved in life-stage specific intraguild predation. The intraguild prey may play a role in securing the persistence of the intraguild predators during food shortage periods. To understand the potential of intraguild prey as food source for intraguild predators in the N. barkeri and S. takahashii guild at low T. urticae densities, the survival, development and reproduction of both predators was determined when fed on heterospecific predators. The choice tests were conducted to determine the preference of the intraguild predator between the intraguild prey and the shared prey. Results showed that 53.3% N. barkeri and 60% S. takahashii juveniles successfully developed when fed on heterospecific predators. Female intraguild predators of both species fed on intraguild prey survived and laid eggs throughout the experiment. In the choice test, both intraguild predator species preferred their extraguild prey T. urticae. This study suggested that intraguild prey served as an alternative prey for intraguild predators prolonged survival and ensured the reproduction of intraguild predators during food shortage, ultimately decreasing the need for the continual release of the predators. [ABSTRACT FROM AUTHOR]