Mites associated with egg masses of the viburnum leaf beetle Pyrrhalta viburni (Paykull) on Viburnum tinus L.

Authors: DESURMONT, GAYLORD - European Biological Control Laboratory (EBCL); KERDELLANT, ELVEN - European Biological Control Laboratory (EBCL); PFINGSTL, TOBIAS - Universitat Graz; KREITER, SERGE - Institut National De La Recherche Agronomique (INRA); AUGER, PHILIPPE - Institut National De La Recherche Agronomique (INRA); TIXIER, MARIE-STEPHANE - Institut National De La Recherche Agronomique (INRA)

Submitted to: Acarologia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/11/2019
Publication Date: 1/28/2019
Citation: Desurmont, G.A., Kerdellant, E., Pfingstl, T., Kreiter, S., Auger, P., Tixier, M. 2019. Mites associated with egg masses of the viburnum leaf beetle Pyrrhalta viburni (Paykull) on Viburnum tinus L.. Acarologia. 59(1):57-72. https://doi.org/10.24349/acarologia/20194311.
DOI: https://doi.org/10.24349/acarologia/20194311

Interpretive Summary: Mites may be used as biological control agents of invasive species of insects. Here we made an inventory of the mite species present on plants infested by the viburnum leaf beetle Pyrrhalta viburni, an invasive pest in North America. Results showed that a diverse fauna of mites can be found in the egg masses of P. viburni. These egg masses are laid in small cavities dug by the females in Viburnum twigs, and mites seem to find food and shelter within these cavities. These insect-mite interactions were previously not known. However, none of the mites identified seemed likely to pose a predation risk for P. viburni eggs, and further research would be needed to evaluate their potential as biological control agents.

Technical Abstract: The viburnum leaf beetle Pyrrhalta viburni (Coleoptera : Chrysomelidae) is a Eurasian chrysomelid that feeds on plants belonging to the genus Viburnum L. (Caprifoliaceae) and is invasive in North America. Females of P. viburni lay eggs in round cavities excavated in young Viburnum twigs that are covered with a frass-like secretion. Such egg masses can be damaged by wounding tissue produced by the twig after oviposition. Here we conducted an observational study in the southern part of France on V. tinus to document the mite fauna associated with P. viburni egg masses in natural areas. We then conducted a manipulative experiment to understand the seasonal patterns of mite infestation in V. tinus twigs. Results showed that a diverse range of mites can be found on V. tinus twigs, often inhabiting within P. viburni egg masses: a total of 10 mite species were found, including 5 predatory species and 5 phytophagous or detritivorous mites. Mites were more diverse and abundant on Viburnum twigs containing at least one intact egg mass compared to twigs with no egg masses or damaged egg masses, and mite abundance and diversity were positively correlated with the number of intact egg masses per twig. The number of detritivorous mites on the twigs was found to be higher nine months after oviposition than one and four months after oviposition. These findings show that P. viburni egg masses form a microhabitat favorable for the establishment of several mite species, which find food and shelter in these protected cavities. This unique association may have direct consequences on mite-mite and insect-mite interactions on Viburnum plants. The possibility that mite presence impacts the survivorship of P. viburni eggs remains to be explored.