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

PeerJ

Emily A. Kemp¹  David I. Shapiro-Ilan¹  Ted E. Cottrell¹  M. Catherine Aime²  Oldřich Nedvěd³  Donald H. Pfister⁴  Danny Haelewaters⁴  Thomas Hiller⁵  Paul S. van Wielink⁶ 

[1] Agricultural Research Service, Southeastern Fruit and Tree Nut Research Laboratory, United States Department of Agriculture, Byron, GA, United States of America;Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, United States of America;Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic;Farlow Reference Library and Herbarium of Cryptogamic Botany, Harvard University, Cambridge, MA,United States of America;Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Ulm, Germany;Natuurmuseum Brabant, Tilburg, The Netherlands;

关键词: Coccinellidae;    Hesperomyces virescens;    Harmonia axyridis;    Invasive alien species;    Native species;    Enemy release hypothesis;   

DOI  :  10.7717/peerj.10110

来源: DOAJ

【 摘 要 】

Harmonia axyridis is an invasive alien ladybird in North America and Europe. Studies show that multiple natural enemies are using Ha. axyridis as a new host. However, thus far, no research has been undertaken to study the effects of simultaneous infection by multiple natural enemies on Ha. 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 Ha. axyridis co-infected with He. virescens and an entomopathogenic fungus—either Beauveria bassiana or Metarhizium brunneum. Laboratory assays revealed that He. virescens-infected O. v-nigrum individuals are more susceptible to entomopathogenic fungi, but Ha. axyridis does not suffer the same effects. This is in line with the enemy release hypothesis, which predicts that invasive alien species in new geographic areas experience reduced regulatory effects from natural enemies compared to native species. Considering our results, we can ask how He. virescens affects survival when confronted by other pathogens that previously had little impact on Ha. axyridis.

【 授权许可】

Unknown