Skip to main content
ARS Home » Southeast Area » Byron, Georgia » Fruit and Tree Nut Research » Research » Publications at this Location » Publication #369336

Research Project: New Tools for Managing Key Pests of Pecan and Peach

Location: Fruit and Tree Nut Research

Title: Mortality of native and invasive ladybirds co-infected by ectoparasitic and entomopathogenic fungi

Author
item HAELEWATERS, DANNY - Harvard University
item HILLER, THOMAS - University Of South Bohemia
item Kemp, Emily
item VAN WIELINK, PAUL - Brabant Nature Museum
item Shapiro Ilan, David
item AIME, M - Purdue University
item NEDYED, OLDRICH - University Of South Bohemia
item PFISTER, DONALD - Harvard University
item Cottrell, Ted

Submitted to: PeerJ
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/16/2020
Publication Date: N/A
Citation: N/A

Interpretive Summary: The multicolored Asian lady beetle is an invasive alien lady beetle in North America and Europe. Studies show that natural enemies in new habitats where it is now established are starting to use the multicolored Asian lady beetle as a new host. No studies have focused on the effects of simultaneous infections of natural enemies on the multicolored Asian lady beetle. We hypothesized that high densities of an ectoparasitic fungus attached to a lady beetle weaken the lady beetle’s defenses, thereby making it more susceptible to infection by other natural enemies. We examined mortality of the North American-native Olla v-nigrum and multicolored Asian lady beetle co-infected by the ectoparasitic fungus and an insect-killing fungus – Beauveria bassiana or Metarhizium anisopliae. Laboratory tests revealed that the native lady beetle O. v-nigrum infected with the ectoparasitic fungus are more susceptible to insect-killing fungi, but not so for the invasive multicolored Asian lady beetle. Considering our results, we can start asking how the ectoparasitic fungus affects survival against other pathogens that previously had little impact on the invasive lady beetle.

Technical Abstract: Harmonia axyridis is an invasive alien ladybird in North America and Europe. Studies show that natural enemies are starting to use H. axyridis as a new host. No studies have focused on the effects of simultaneous infections of natural enemies on H. axyridis. We hypothesized that high thallus densities of the ectoparasitic fungus Hesperomyces virescens on a ladybird weaken the host’s defenses, thereby making it more susceptible to infection by other natural enemies. We examined mortality of the North American-native Olla v-nigrum and H. axyridis co-infected with H. virescens and an entomopathogenic fungus – Beauveria bassiana or Metarhizium anisopliae. Laboratory assays revealed that H. virescens-infected O. v-nigrum are more susceptible to entomopathogenic fungi, but not H. axyridis. Considering our results, we can start asking how H. virescens affects survival against other pathogens that previously had little impact on H. axyridis.