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Causes and Consequences of Ladybug Washups in the Finger Lakes Region of New York State (Coleoptera: Coccinellidae)

Denemark, Eric, Losey, John E.
Entomologica americana 2010 v.116 no.1 pp. 78-88
Coccinellidae, animals, lakes, new species, surface water, testing, weather, Finger Lakes region, New York
We searched for and collected data on a phenomenon known as ladybug washups, in which large numbers of coccinellids aggregate on the shores of major bodies of water. Our field season lasted from 5/23/2008 until 8/12/2008 in the Finger Lakes Region of New York, United States. Ladybug diversity and survival at washups, as well as washup size and frequency were studied to help understand why these events occur. Lab tests were conducted to determine how long ladybugs can survive afloat. This information was used to estimate the duration of floating in the washups we observed. The frequency, composition, and duration of washups in the Finger Lakes support the hypothesis that a weather condition known as a lake breeze forces coccinellids to fall into the water. These animals subsequently arrive on shore in large numbers. This study adds three new species to the growing list of coccinellids affected by this phenomenon.