A sticky situation: honeydew of the pear psylla disrupts feeding by its predator Orius sauteri

Abstract

Background Honeydew is valuable food source for predators that can build predator numbers and strengthen biological control. Honeydew excreted by hemipterans often supplements the diets of their predators and parasitoids. However, dense sticky honeydew also creates a difficult foraging environment, potentially limiting predator efficiency. Results We examined the benefits and costs of honeydew excreted by the pear psylla (Cacopsylla chinensis [Yang and Li]) for its key predator in much of Asia, the anthocorid bug Orius sauteri (Poppius). We found these predators spent more time foraging and laid more eggs in the presence of psyllid honeydew compared to the control. However, predators more often foraged among psylla without honeydew than those coated in honeydew. This suggests that while O. sauteri recognized honeydew as a useful cue to prey presence, the predators were more likely to attack pear psylla lacking the sugary excretion. In foraging trials, honeydew consistently reduced the number of psyllids killed by the predator, suggesting it limited O. sauteri mobility or reduced the nutritional value of psyllids as prey. We also found slowed development, reduced longevity, and reduced fecundity of O. sauteri reared on moth eggs (Sitotroga cerealella [Olivier]) coated in honeydew compared to those reared on moth eggs alone. Conclusion Altogether, our results suggest that psyllid honeydew could serve as a prey‐location and oviposition cue for O. sauteri. However, honeydew also limited predator foraging with the potential to limit biological control. More generally, honeydew might form an important type of defense for stationary feeders like psyllids. © 2019 Society of Chemical Industry

Assessment of the biocontrol potential of natural enemies against psyllid populations in a pear tree orchard during spring

“…Nymphs of pear psyllids usually cover their whole body with secreted honeydew, to regulate the osmotic stress caused during feeding 69 . This sticky honeydew serves as an arrestant and protects them against predation 70,71 . We believe that predators preyed mostly on adults; thus, the numerical response to the abundance of adult psyllids should not be dramatically different from the numerical response to the entire psyllid population.…”

Honeydew composition and its effect on life‐history parameters of hyperparasitoids

“…Another interesting finding is that the concentration of sorbitol was negatively correlated with longevity and fecundity, albeit non-significantly. Adverse effects of high concentrations of this carbohydrate were recently also reported in an anthocorid bug that uses psyllid honeydew as an alternative food source to herbivorous prey (Ge et al, 2019). Controlled experiments with pure carbohydrates or artificial honeydews of known composition are needed to further investigate the relationship between honeydew quality and hyperparasitoid life history.…”

Identification and characterization of soluble binding proteins associated with host foraging in the parasitoid wasp Diachasmimorpha longicaudata

“…However, soluble binding proteins (mainly for OBPs) are encoded by genes subjected to rapid evolution rates [82][83][84], and this should be considered in studies of these genes as potential targets associated with biological control. Moreover, this rapid evolution, in some species, results in clade expansions (mainly for OBPs), facilitating the development of species-specific strategies [85,86].…”