Title: Ectoparasitic mite and fungus on Harmonia axyridis Author
Submitted to: IOBC/WPRS Bulletin (Abstract for Conference Proceedings)
Publication Type: Abstract Only
Publication Acceptance Date: April 15, 2010
Publication Date: November 16, 2010
Citation: Riddick, E.W. 2010. Ectoparasitic mite and fungus on Harmonia axyridis. IOBC/WPRS Bulletin (Abstract for Conference Proceedings). Vol. 58. Technical Abstract: Ectoparasitic mites (Acarina: Podapolipidae) and ectoparasitic fungi (Laboulbeniales: Laboulbeniaceae) occur on ladybirds (Coleoptera: Coccinellidae) throughout the world (Riddick et al., 2009). This study documents the interaction of a coccinellid-specific mite Coccipolipus hippodamiae (McDaniel & Morrill) and fungus Hesperomyces virescens Thaxter in Harmonia axyridis (Pallas) overwintering aggregations (Riddick, 2009). The objectives of this research were to (1) determine the prevalence and intensity of both parasites and (2) estimate the effect of parasitism on winter survival of the host. The prevalence of mite and fungus in host aggregations ranged from 3.2 to 17.4% and 3.6 to 43.5%, respectively, in winter aggregations in five different locations in Mississippi, southeastern USA, from 2007-2009. The mite colonized the subelytral space of male and female H. axyridis. Mite intensity was greatest on fungus-infected beetles, especially females. Fungus intensity was greatest on the abdomen of H. axyridis males that harbored mites than those that did not. H. axyridis adults (particularly males) infected with the mite and fungus or the fungus alone had lower survival rates, under simulated winter conditions, than those not infected with any parasites. This research documents the parasitic mite C. hippodamiae infecting H. axyridis under natural field conditions for the first time anywhere in the world (Riddick, 2009). Maybe a suite of natural enemies could assist in curbing H. axyridis populations in targeted locations. There is a need to identify effective methods of managing H. axyridis to diminish its negative impacts in some urban and agricultural landscapes worldwide (Kenis et al., 2008).