Dryinidae

Virla, Eduardo G., Moya-Raygoza, Gustavo & Guglielmino, Adalgisa, 2023, A review of the biology of the pincer wasps (Hymenoptera: Dryinidae), Austral Entomology 62 (3), pp. 274-299 : 290

Dryinidae interactions with Auchenorrhyncha hosts and plant pathogenic virus and mollicutes

As previously stated, Dryinidae larvae develop on/in nymphs and adults of Auchenorrhyncha. Many of these host species belong to planthoppers ( Delphacidae ) and leafhoppers ( Cicadellidae ) that can carry and transmit viruses and mollicutes (phytoplasmas and spiroplasmas), causing important diseases in several crops such as maize, barley, wheat, rice and oats ( Nault 1994, 1997; Trivellone 2019; Trivellone & Dietrich 2021; Weintraub & Beanland 2006; Wilson & Weintraub 2007). These viruses and mollicutes are vectorised to plants via a persistentpropagative mechanism in which the pathogens replicate within the nymphs and adults of Auchenorrhyncha ( Nault 1997). This means that once the virus or mollicute is acquired by the vectors, they remain infected all their lives, and if dryinids parasitise them, their larvae must grow and interact with the pathogen.

Increasing evidence indicates that viruses and mollicutes can influence host plant phenotypes and the behaviour of insect vectors to facilitate their spread. In the interaction between viruses, mollicutes and host plants, pathogens manipulate plant signals that in turn influence the orientation, feeding and dispersal behaviour of vectors. In this way, pathogens ensure that they can colonise other plants and thus spread the disease ( Mauck et al. 2018). The ‘adaptive host manipulation hypothesis’ highlights the fitness benefits of manipulation as a strategy and proposes that pathogens/parasites can evolve to control features of their host’ s phenotype and so maintain or improve their transmission rates ( Poulin 2010). Interactions among viruses and mollicutes with their vectors, Delphacidae and Cicadellidae , have been broadly investigated. However, little is known about how plant pathogens and vectors interact with parasitoids (like dryinids) in nymphs and adults. Studies related to aphid vectors (Sternorrhyncha) found that infected insects carrying a plant pathogen experienced great vulnerability to the parasitoid Aphidius colemani (Dalman) (Hym.: Braconidae ) ( de Oliveira et al. 2014). In a study related to dryinid parasitoids, it was found that when the Gonatopodine Gonatopus bartletti and the Spiroplasma kunkelii coexisted within Dalbulus maidis (De Long & Wolcott) ( Cicadellidae ), the development of the dryinid was not affected by the spiroplasma ( Moya-Raygoza et al. 2006).