Level-dependent effects of predation stress on prey development, lifespan and reproduction in mites

Older mothers produce smaller eggs without compromising offspring quality: a study of a thelytokous mite predator (Acari: Phytoseiidae)

Negative relationships between the parental age and offspring life history traits have been widely observed across diverse animal taxa. However, there is a lack of studies examining the influence of parental age on offspring performance using mites, particularly phytoseiid predators as subjects. This study explored the influence of maternal age on offspring life history traits in Amblyseius herbicolus (Chant) (Acari: Mesostigmata), a phytoseiid predatory mite reproducing through thelytokous parthenogenesis. We hypothesised that increased maternal age negatively impacts offspring traits, including developmental duration, body size, fecundity and lifespan. Amblyseius herbicolus was reared under controlled laboratory conditions, and the life history traits of offspring from mothers of varying ages were analysed using linear mixed-effect models. Our results showed that the increase in maternal age significantly reduced individual egg volume, but did not significantly affect offspring developmental duration, body size, fecundity or lifespan. These findings indicate that while older A. herbicolus females produced smaller eggs, the subsequent performance (i.e. body size, fecundity and lifespan) of offspring remained largely unaffected, suggesting possible compensatory mechanisms in the offspring or alternative maternal provisioning strategies. The results of this study offer useful insights into the reproductive strategies of phytoseiid predators and asexually reproducing species, enhancing our understanding of how maternal age affects offspring fitness. Further studies can examine how offspring of A. herbicolus from mothers of different ages perform under adverse environmental conditions.

The Impact of Predation Risks on the Development and Fecundity of Bactrocera dorsalis Hendel

Predators are dependent on the capture of prey to meet their energetic and nutritive requirements, which brings the risk of predation to prey. The predation risk is divided into consumptive and non-consumptive effects. Non-consumptive effects may manifest through altered growth and ontogenetic trajectories in prey species, a dynamic modulated by olfactory or other sensory cues from predators. Bactrocera dorsalis Hendel represents a major invasive threat to global horticulture. While earlier research was primarily centered on the consumptive interactions between B. dorsalis and its natural enemies, the potential consequences of non-consumptive interactions on the development of B. dorsalis have been overlooked. In this study, we investigated the impact of predation risk effects, induced by both visual exposure to the predatory mantis Hierodula patellifera Serville and its associated odor, on the life history traits of B. dorsalis. Female B. dorsalis demonstrated a reduced developmental time in the presence of a caged predator (H. patellifera) or predator odors, but showed significantly increased fecundity. Conversely, males displayed no significant change in developmental time. Additionally, neither the female nor male body weight at death was significantly influenced by the predation risk from the caged predator or predator odors. This study investigated the effects of predation risk on the development and reproduction of B. dorsalis, emphasizing the potential importance of odor risk in biological and pest control.

Predation stress experienced as immature mites extends their lifespan

The early-life experience is important in modulating the late-life performance of individuals. It has been predicted that there were trade-offs between early-life fitness and late-life success. Most of the studies on senescence have focused on the trade-offs between the reproduction and lifespan, and the influences of diet, mating, and other factors. Because the negative, non-consumptive effects of predators could also modulate the behaviour and underlying mechanisms of the prey, this study aimed to examine the different effects of predator-induced stress experienced in the early life compared with later life of the prey. The prey (Tyrophagus putrescentiae) was exposed to predation stress from the predator (Neoseiulus cucumeris) during different periods of its life (immature, oviposition period, and post-oviposition period). The results showed that the predation stress experienced during immature stages delayed development by 7.3% and prolonged lifespan by 9.7%, while predation stress experienced in the adult stage (both oviposition and post-oviposition periods) decreased lifespans of T. putrescentiae (by 24.8% and 28.7%, respectively). Predation stress experienced during immature stages also reduced female fecundity by 7.3%, whereas that experienced during the oviposition period reduced fecundity of the prey by 50.7%. This study demonstrated for the first time lifespan extension by exposure to predation stress when young and highlighted the importance of early-life experience to aging and lifespan.