The march of the Kudzu Bug!
Megacopta cribraria (a.k.a. the Kudzu Bug; Fig. 1), a relative of the familiar, and more widespread, brown marmorated stink bug (Halyomorpha haly) is a relatively recent addition to the North American hemipteran (a group that includes stink bugs, aphids, planthoppers, and cicadas) fauna.
Native to Asia (including China, India, Japan, and others), this species was first recorded in the United States from Georgia in the fall of 2009 (Eger et al. 2010). It has since swiftly expanded its range in the eastern US where it has been reported from Alabama, Arkansas, Georgia, Kentucky, Louisiana, Maryland, Mississippi, North Carolina, South Carolina, Tennessee, and Virginia (distribution as of late 2014).
The beetle-like kudzu bug (Figs 1 and 3) is the sole member of the family Platispididae that is known to occur in the continental United States, and only the second species of this family to become established in the Western Hemisphere (Eger et al. 2010).
The most distinguishing characteristics of M. cribaria used to separate it from other North American stink bug (Pentatomoidea) groups are: 1) body size; 2) uniquely shaped scutellum, 3) number of tarsal segments; and 4) length of second antennal segment. Megacopta cribraria is a rather small species with individuals ranging between 3.5 and 6 mm (1/6 to 1/4 inch; Fig. 2). The enlarged scutellum (a hardened plate along the dorsal side of the thorax; Fig. 1) is truncated posteriorly covering the wings and most of the abdomen (other stink bugs usually have a much smaller, triangular-shaped scutellum). The tarsi (the tips of the legs furthest from the body) are two segmented (three segmented in other pentatomids, except Acanthosomatidae), and the second antennal segment is shorter than that of most other groups (Fig. 3).
In the US, the kudzu bug is a highly invasive species but it is rather unusual because of its mixed impact. While it seems to prefer kudzu (a highly invasive and damaging species itself), it is also a serious pest of leguminous crops, especially soybeans. Average soybean yield losses of over 20% have been recorded in untreated fields in South Carolina and Georgia (http://www.clemson.edu/extension/kudzubugs/), but losses could be much higher.
The bug is harmless to people but late in the season it often enters houses in large numbers in search of overwintering sites. Much like other stink bugs, when irritated the kudzu bug emits a mildly offensive-smelling liquid. This defensive compound can occasionally create a burning sensation and leave a red welt on the skin.
Institutions throughout the southeastern US have initiated research into means of dealing with the kudzu bug, and scientists are currently working on finding better ways of controlling this troublesome pest.
There’s an app for that!
Scientists now use technology to track the spread of the kudzu bug in the USA. The Southeast Early Detection Network (SEEDN) app includes many invasives that are currently being monitored in the southeastern United States. The app lets you submit invasive species observations directly from your iPhone or Android. You can download it from here and help researchers track down this unwanted invader.
To find more information about the kudzu bug visit http://www.kudzubug.org
J. E. Eger, Jr., L. M. Ames, D. R. Suiter, T. M. Jenkins, D. A. Rider, and S. E. Halbert. 2010. Occurrence of the Old World bug Megacopta cribraria (Fabricius) (Heteroptera: Plataspidae) in Georgia: a serious home invader and potential legume pest Insecta Mundi 0121: 1-11
“Kudzu Bug (Megacopta cribaria).” Developed by the University of Georgia, Center for invasive Species and Ecosystem Health. Available at: http://www.kudzubug.org. Accessed Jan 30 2015.
“Kudzu Bugs.” Cooperative Extension: Clemson University, South Carolina. Available at: http://www.clemson.edu/extension/kudzubugs/). Accessed Jan 30 2015.