Asian lady beetle + microsporidia = Native lady beetle death!

As we've noted before in this blog, the decline of many native lady beetle species occurring in North America and other countries coincides with the presence of the Asian lady beetle, Harmonia axyridis. The mechanisms as to why this is the case have been unclear. Is Harmonia a more effective predator than natives? Is it merely eating the natives at a particular life stage (termed intraguild predation, and the topic of Chelsea's M.S. thesis)? Does it have a faster life cycle and therefore able to reproduce in higher numbers?

A new study published today in Science reports that H. axyridis may be such an effective invasive species due to microsporidia in its hemolymph. These microsporidia are safe for their hosts, but when native species (to Europe), such as Coccinella septempunctata, were injected with these microsporidia they died. In the field, this may mean that consumption of H. axyridis eggs is lethal to intraguild competitors.

C. septempunctata is also established in the U.S., and is a dominant competitor of our own native species. It will be interesting to see how these new findings will influence our understanding of American native lady beetle declines.

Harmonia axyridis (wikipedia) 

Report in Science (paywall): http://www.sciencemag.org/content/340/6134/862

Science Daily article: http://www.sciencedaily.com/releases/2013/05/130516142541.htm

Are you signed up for the Gardiner Lab Buckeye Lady Beetle Blitz training workshop?

Battling USDA's top-ranked invasive insect

Wikipedia.org
 credit: David R. Lance, USDA APHIS

The brown marmorated stink bug causes problems not only farmers and gardeners, but can be a problem for anyone who lives in a building at some point...so...everyone. This invader from Asia was accidentally introduced to the United States, and was first discovered on US soil in 1988. Theys aggregate to overwinter, and can find their way into homes. They don't bite, or spread disease, but they do leave behind a foul odor when disturbed. In addition to being a house pest they cause severe economic damage to fruit and vegetable crops.

Being ranked as the top "invasive insect of interest" by the USDA has lead to a large mass of research. Scientists from a laboratory in Beltsville, WI have identified an "aggregation pheromone" which could be used to trap the bugs and curb their population growth. The pheromone is released by the male bugs as they feed and it attracts adults and nymphs of both sexes. Other molecular research is being conducted as well to find out which genes could be targeted to control the pest.

Ohio State University also maintains a data collection program with a map where the stink bug has been detected in Ohio: Brown Marmorated Stink Bug Data

OSU FACT SHEET

Sources:
Combating USDA's Top-ranked insect
Penn State fact sheet
UofMaryland fact sheet