Once introduced for biological pest control, Asian lady beetle Harmonia axyridis populations have been increasing uncontrollably in the US and Europe since the turn of the millennium. The species has been proliferating rapidly in Germany; conservationists fear that the Asian lady beetle will out-compete native beetle species.
Scientists from the University of Giessen and the Max Planck Institute for Chemical Ecology in Jena, Germany, have now found the reason why this animal is so successful. Apart from a strongly antibiotic substance − a compound called harmonine − and antimicrobial peptides, its body fluid, the hemolymph, contains microsporidia. These tiny fungus-like protozoa parasitize body cells and can cause immense harm to their host. The Asian lady beetle is obviously resistant to these parasites in its own body. However, transferred to native species, microsporidia can be lethal.
See on phys.org