Abstract Detail

Symbioses: Plant, Animal, and Microbe Interactions

Haelewaters, Danny [1], Shapiro-Ilan, David I. [2], Cottrell, Ted E. [2].

Will dual fungal infections increase Harmonia axyridis mortality in natural populations?

Reviewing the effects of parasites, pathogens, and parasitoids of Harmonia axyridis (Coleoptera: Coccinellidae) shows that they have only limited potential for controlling population dynamics of their host. Hesperomyces virescens (Ascomycota: Laboulbeniales) and Beauveria bassiana (Ascomycota: Hypocreales) have some negative effects on lady beetles; when acting alone they only have limited potential for controlling populations of invasive lady beetles. Independent studies show that natural enemies are starting to use H. axyridis as a new host, but no study has focused on the effects of infections of more than one pathogen on H. axyridis. We decided to examine mortality of native and invasive lady beetles co-infected with H. virescens and B. bassiana. Laboratory assays reveal that H. virescens-infected lady beetles are more susceptible to B. bassiana. We hypothesize that high thallus densities of H. virescens on H. axyridis weaken the host's defenses, thereby making the lady beetle more susceptible to infection by other natural enemies. Considering the results of our assays, we can ask how H. virescens affects survival against other pathogens that previously had little impact on H. axyridis. Given the abundance of both H. virescens and B. bassiana in the environment, we predict that invasive populations of H. axyridis will be naturally regulated.

1 - Harvard University, Organismic and Evolutionary Biology, Farlow Herbarium, 22 Divinity Avenue, Cambridge, MA, 02138, USA
2 - U.S. Department of Agriculture, Agricultural Research Service, Southeastern Fruit & Tree Nut Research Laboratory, 21 Dunbar Road, Byron, GA, 31008, USA

Keywords:
symbiosis
Laboulbeniales
lady beetle
invasive species
Hesperomyces virescens
Beauveria bassiana
Fungi.

Presentation Type: Oral Paper:Papers for Topics
Session: 36
Location: Salon 5/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 9:30 AM
Number: 36007
Abstract ID:79
Candidate for Awards:None