Why is Harmonia axyridis the culprit in coccinellid biting incidents? An analysis of means, motive, and opportunity.

摘要: The tendency of aphidophagous coccinellids to bite humans is a subject that has seen very little study in the scientific community. With introduction adventive species, anecdotal reports biting lady beetles have greatly increased frequency and seemed warrant further investigation. Coccinellids three native species [ Coccinella novemnotata Herbst, trifasciata L., Adalia bipunctata (L.)] two most common introduced Harmonia axyridis (Pallas) septempunctata L.] were collected wild reared separately laboratory colonies. In caged trials, 40 individually marked single given either no source food or water aphids ad libitum exposed experimenter's hand forearm movement, frequency, severity with which they bit into skin recorded. All tested shown humans. Feeding treatment did not significant effect on propensity duration species. Large such as distinguished by lower than smaller except H. C. exhibited startling blood-feeding behavior yet clearly understood was heretofore undocumented this family beetles. trials affording A. adults choice between cotton wicks soaked cow blood water, both preferred blood, preferring much greater extent. Furthermore, survivorship hematophagic well monitoring survival weight change across individuals afforded following five treatments: 21 per day, 3 day addition only, only. low mortality only dead individuals, while same number bovine drop similar blood. This remarkable trend likely result oxidative stress other hardships involved feeding vertebrate Based level overwinter within building (the location greatest exposure humans) their lack adaption human tissue feeding, we predict currently rare should decline.