Invasive Harlequin Ladybird Carries Biological Weapons Against Native Competitors

• Published in: Science (American Association for the Advancement of Science) Vol. 340; no. 6134; pp. 862 - 863
• Main Authors: Vilcinskas, Andreas, Stoecker, Kilian, Schmidtberg, Henrike, Röhrich, Christian R., Vogel, Heiko
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 17-05-2013; The American Association for the Advancement of Science
• Subjects: Animal, plant and microbial ecology; Animals; Applied ecology; Beetles; Biological and medical sciences; Biological control; Biological weapons; Coleoptera - parasitology; Coleoptera - physiology; Conservation, protection and management of environment and wildlife; Continents; Economic Impact; Eggs; Equivalence; Evolutionary biology; Fatal; Food Chain; Fundamental and applied biological sciences. Psychology; Hemocytes; Hemocytes - parasitology; Hemolymph; Hemolymph - parasitology; Insect larvae; Insects; Introduced Species; Microscopy; Microsporidia; Mortality; Nonnative species; Nosema - physiology; Nosema - ultrastructure; Parasites; Parks, reserves, wildlife conservation. Endangered species: population survey and restocking; Predation; Species; Spores; Spots; Entomopathogen; Biological invasion; Coccinella septempunctata; Coleoptera; Insecta; Parasite; Microsporidia; Fungi; Invasive species; Coccinellidae; Transmission from animal to animal; Arthropoda; Interspecific competition; Harmonia axyridis; Predator; Invertebrata; Environmental monitoring; Native species; Intraguild predation
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1234032

Invasive species that proliferate after colonizing new habitats have a negative environmental and economic impact. The reason why some species become successful invaders, whereas others, even closely related species, remain noninvasive is often unclear. The harlequin ladybird Harmonia axyridis, introduced for biological pest control, has become an invader that is outcompeting indigenous ladybird species in many countries. Here, we show that Harmonia carries abundant spores of obligate parasitic microsporidia closely related to Nosema thompsoni. These microsporidia, while not harming the carrier Harmonia, are lethal pathogens for the native ladybird Coccinella septempunctata. We propose that intraguild predation, representing a major selective force among competing ladybird species, causes the infection and ultimate death of native ladybirds when they feed on microsporidia-contaminated Harmonia eggs or larvae.