Indirect effects in predator-prey interaction: development and predation rates by immature Neoseiulus cucumeris increased by odour from its prey (Tyrophagus putrescentiae)

Predator-prey interactions have long been of great interest to ecologists. Although the direct consumptive effects have received extensive research, indirect influences of odour derived from their conspecifics and prey on predators have largely been underestimated and overlooked. In this study, the indirect effects of predator-prey interactions were determined with predatory mites Neoseiulus cucumeris and its factitious prey Tyrophagus putrescentiae. The responses of immature N. cucumeris to mixed odour with their conspecifics and prey were determined in a laboratory experiment. Our results showed that the mixed odour with their conspecifics did not demonstrate any obvious influences on the survival rates, developmental periods, predation rates and activities of the predatory mites. Intriguingly, the predators prolonged their protonymphal stage and consumed more prey eggs when exposed to mixed odour with their prey. Our results indicated that the mixed odour with their conspecifics was weak and its influence was insignificant for this species, but the prey odour showed a signifcant influence on the growth and consumption rates of immature predators, which highlighted that the indirect influences of predator-prey interactions on the predator were substantial and cannot be neglected.