New Insight Into the Evolutionary Arms Race Between Spider Egg Sac Pseudoparasitoids and Active Maternal Care by the Spiders

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  New Insight Into the Evolutionary Arms Race Between Spider Egg Sac Pseudoparasitoids and Active Maternal Care by the Spiders ABSTRACT Pseudoparasitoids can lead to high mortality in spider egg sacs, and in some cases, they reduce the reproductive success of a spider female to zero. On the other hand, a species that develops within the spider's egg sac uses a limited resource derived from a single egg sac for its larval development. Therefore, the most crucial behaviour that increases the fitness of free-living pseudoparasitoid females is choosing the best host for their offspring. We analysed various points of the counter-adaptations of the spider egg sac pseudoparasitoid and spiders exhibiting active maternal care, utilising the ichneumonid  Hidryta fusiventris  (Thomson, 1873) and the wolf spider  Pardosa lugubris  (Walckenaer, 1802). We showed that the oviposition decision of  H. fusiventris  is based on the spider's egg sac size and that the fema...

Sex Pheromones From Linyphia triangularis (Araneae: Linyphiidae) and Aphidoletes aphidimyza (Diptera: Cecidomyiidae) Are Promising Attractants for Aphidoletes aphidimyza (Diptera: Cecidomyiidae)

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Sex Pheromones From Linyphia triangularis (Araneae: Linyphiidae) and Aphidoletes aphidimyza (Diptera: Cecidomyiidae) Are Promising Attractants for Aphidoletes aphidimyza (Diptera: Cecidomyiidae)

ABSTRACT

Although Aphidoletes aphidimyza (Rondani) is a predator of aphids, its biocontrol efficacy depends largely on oviposition behaviour. Previous studies have shown that spider webs can attract A. aphidimyza and enhance its oviposition. It has been hypothesized that sex pheromones from spider webs and A. aphidimyza itself may affect its mating and oviposition, but this remains unconfirmed. In our study, we selected (2R,7S)-diacetoxytridecane (sex pheromone of A. aphidimyza), (R)-3-hydroxybutyric acid (sex pheromone of Linyphia triangularis (Clerck)), and a mixture of these pheromones (at a 10:1 concentration ratio) to investigate their overall response on A. aphidimyza in terms of electroantennogram, behaviour, fecundity, attraction, and aphid control. Our results indicated that these pheromones elicited antennal responses in A. aphidimyza. Specifically, (2R,7S)-diacetoxytridecane significantly attracted males, while (R)-3-hydroxybutyric acid significantly attracted females; their mixture attracted both sexes. These compounds did not affect oviposition and lifespan of A. aphidimyza. The pheromone mixture attracted significantly more A. aphidimyza than the control group. The number of aphids in the mixture group began to decline 1 day earlier than that in the control group and ultimately achieved a 100% control effect against aphids in a greenhouse. Our findings provide evidence for further exploration of the relationship between L. triangularis and A. aphidimyza. The studied pheromone blend shows potential as an attractant for A. aphidimyza, which could enhance aphid biological control in greenhouses.

Yang, S., Yu, X., Wang, K., Yang, M., Zhu, X., Wu, H., Guan, H., Huang, C., & Yang, X. Sex Pheromones From Linyphia triangularis (Araneae: Linyphiidae) and Aphidoletes aphidimyza (Diptera: Cecidomyiidae) Are Promising Attractants for Aphidoletes aphidimyza (Diptera: Cecidomyiidae). Journal of Applied Entomology. https://doi.org/10.1111/jen.70086