Effects of mummy consumption on fitness and oviposition site selection on Harmonia axyridis

Abstract

Intraguild predation (IGP) has been commonly reported between predators and parasitoids used as biological control agents as predators consuming parasitoids within their hosts. However, the effect of parasitoid–mummy consumption on the fitness of the predator and subsequent oviposition site selection have not been well studied. In our study, we conducted two laboratory experiments to examine the influence of Aphidius gifuensis Ashmead (Hymenoptera: Braconidae) mummies as prey on fitness and subsequently oviposition site selection of Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae). Results indicate that when H. axyridis was reared on A. gifuensis mummies only, its larval development was prolonged, and body weight of the 4th instar larvae and newly emerged adults, and fecundity decreased. Moreover, H. axyridis did not exhibit oviposition preference on plants infested with unparasitized aphids or aphids parasitized for shorter than 9 days. However, compared with plants with mummies (parasitized ≥9 days), H. axyridis laid more eggs on plants with unparasitized aphids. In contrast, H. axyridis previously fed with A. gifuensis mummies did not show a significant oviposition preference between plants with unparasitized aphids and those with mummies (parasitized ≥9 days). Overall, our results suggest that mummy consumption reduced the fitness of H. axyridis. Although H. axyridis avoided laying eggs on plants with A. gifuensis mummies, prior feeding experience on A. gifuensis mummies could alter the oviposition site preference. Thus, in biological control practice, prior feeding experience of H. axyridis should be carefully considered for reduction of IGP and increase of fitness of H. axyridis on A. gifuensis.

Consuming Parasitized Aphids Alters the Life History and Decreases Predation Rate of Aphid Predator

“…Development times for each stage and total immature stage of A. aphidimyza that fed on parasitized M. persicae were longer than those of predator larvae feeding on unparasitized M. persicae. Our results are consistent with studies of C. septempunctata, H. convergens, H. axyridis, and P. japonica that subsisted on mummified aphids, demonstrating that predators could slow their ontogenetic development [7,10,34]. Our study using A. aphidimyza revealed that its longevity, oviposition period, and fecundity were all significantly affected by its feeding on parasitized aphids.…”

“…Consumption of parasitized aphids and mummies could adversely affect the development, body size, survival, and behavior of aphid predators [6,7,10,34,35]. Our results showed that consumption of parasitized aphids did not influence the survival rates of immature A. aphidimyza individuals, but it did significantly delay their overall developmental time and also reduced the predator's longevity, fecundity and predation rates.…”

“…Little research has been conducted on the effects of parasitized aphid species on the reproduction parameters of their predators. When fed A. gifuensis mummies, aphid enemy H. axyridis females had a longer pre-oviposition period and did not lay eggs within 30 days of observation [10]. The number of eggs produced by Episyrphus balteatus females was affected by mummified aphids and the exuvia of mummies of Acyrthosiphon pisum, but the number of eggs laid by E. balteatus was nonetheless similar when the female fed with healthy aphids and parasitized aphids [36].…”

“…Predatory brown lacewing Micromus variegatus (Fabricius) and lady beetle Coccinella septempunctata L. prefers to consume parasitized aphids over unparasitized aphids [4,5]. However, the consumption of intraguild prey by the intraguild predator can also negatively affect the development, survival, and oviposition of such predators [6][7][8][9][10]. Conversely, under greenhouse conditions, the combination of M. variegatus and Aphidius ervi Haliday did not result in intraguild predator densities and shared prey compared with intraguild predator alone [4].…”

Effect of parasitized prey on prey consumption, survival, growth, and development of Coccinella septempunctata L. (Coleoptera: Coccinellidae) under laboratory conditions

“…This study also demonstrated that overall aphid mummies were a low-quality diet and longer developmental time was observed on mummified aphid diet. Yu et al (2020) reported that the larval developmental time of H. axyridis was significantly prolonged when fed with mummified prey.…”