The Spotted Blister Beetle Iron-Cross Blister Beetle

Blister Beetle Basics W. Eugene Hall1, Naomi Pier1 and Peter C. Ellsworth2 University of Arizona, 1Assistants in Extension & 2IPM Specialist Blister beetles (family Meloidae) are found throughout Arizona. These beetles contain a defensive chemical (cantharidin) that may be harmful to humans and other animals. Blister beetles are often times confused with other similar looking beetles that do not produce cantharidin. Blister beetles are found in many different sizes and colors. However, they all share the characteristic feature of a broad head that is wider than the thorax (“neck”). This, combined with broader elytra (wing covers), creates a distinct “neck-like” appearance (Fig. 1 & 2). They also have just 4 1 segments in their hind tarsi (Fig. 1). Blister beetles may be 2 confused with checkered beetles, soldier beetles, darkling beetles, 3 4 Figureground 8G. Adult beetles blister beetle, and Zonitis others atripennis beetles. (Fig.Figure 8H 2. –Adult6). blister beetle, Zonitis sayi. (Whitney

(WhitneySandya Cranshaw, Colorado State University, Bugwood.org) Cranshaw, Colorado State University, Bugwood.org) BODY SOFT 4 TARSI IN Blister Beetle NOT Blister Beetles OR LEATHERY HINDLEG Athigiman Figure 1. Examples of two blister beetle species (Epicauta pardalis, left; Tegrodera aloga, right) with the characteristic narrow thorax (“neck”) , NMSU, Circular 536 indicated by arrows. Blister beetles have soft, leathery bodies. Other Resources: Hall, WE, LM Brown, N Pier, PC Ellsworth. 2019. Blister Beetles in Food? U. Arizona. https://cals.arizona.edu/crops/cotton/files/BBinFood.pdf Figure 2. Left to right, Epicauta blister beetle, tamarisk leaf beetle, Pierce, JB. 2014. Blister Beetles in Alfalfa. Circular 536. New Mexico State University. https://aces.nmsu.edu/pubs/_circulars/CR536/ Figuresouthern 9. Many insectscorn can rootworm, have a similar appearance and caterpillar and be confused with hunter blister beetles. (from Shown Pierce here are (left2014). to right) Epicauta sp., a common blister beetle in New Mexico; tamarisk leaf beetle; southern corn rootworm; and caterpillar hunter beetle. Illustrations are not drawn to scale. (Illustrations courtesy of Sandya Athigiman. Used with permission.) Soldier Beetles Checkered Beetles

BIOLOGY (F. Cantharidae) emergence depends on temperature. Adults feed on (F. Cleridae) Blister beetle eggs are usually laid in the soil during plant materials, particularly flowers and foliage of such summer.Soldier Te first-stage beetles larvae areof many similar species of Epito- plants as alfalfa,Darkling carelessweed (pigweed/amaranth), Beetles Ground Beetles Checkered beetles have a thorax cauta are active, long-legged insects (called triungulin puncturevine (goathead), peanuts, soybeans, and many (F. Carabidae) larvae)blister that forage beetles for grasshopper in that eggs. Youngtheir larvae other species(F. of plants, Tenebrionidae both wild and domestic.) with a similar “neck-like” of other blister beetles lurk in flowers. Tere they hitch ridesbodies on visiting are bees andsoft are carriedor leathery, back to nests where Like blister beetles, Ground beetles also appearance as in blister beetles, they can feed on bee eggs and stored food. DISTRIBUTION butWhether they they feedare on flattergrasshopper in egg shape pods or infest Tere aredarkling more than 300 beetles blister beetle have species 4in -the have a thorax (“neck”) however, checkered beetles can bee nests, older blister beetle larvae become increasingly continental United States. New Mexico has at least 28 sedentarythan as blister they molt andbeetles. mature (Figure Their 10). T ey species segmentedin eight genera; some hind that are tarsi, found in but alfalfa that is wider than the be easily distinguished by the overwinter as mature larvae, pupate in spring, and usu- in New Mexico are shown in Figures 8A through 8H. allythorax emerge as adult(“neck”) beetles in early is summer.wider Some blistera thorax beetle species (“neck”) are gregarious, that congregat is - head and will oftentimes cylindrical nature of their thorax In New Mexico, adult blister beetles usually emerge ing in large numbers, especially near field margins. fromthan the soil the about head mid-May and and begintends to search to for Livestockwider poisoning than cases arethe probably head, a result and of bal - have ridged forewings and from the bristly hairs foodextend and mates. over Dates are the diffi cultbase to predict of thebecause ing partsthey of these have swarms hard,into alfalfa shell hay. It -islike unlikely (elytra) and hard, shell- covering the entirety of their head (Fig. 3). hard body (Fig. 6). ˆÀVՏ>ÀÊxÎÈÊUÊÊ*>}iÊxbodies (Fig. 4). like bodies (Fig. 5). Mike Quinn, Quinn, Mike TexasEnto.net

Fig. 3 Fig. 4 Fig. 5 Fig. 6 5/2019 Material based upon work supported in part by the U.S. Department of Agriculture National Institute of Food and Agriculture (USDA-NIFA) under the Crop Protection and Pest Management, Extension Implementation Program, award number 2017-70006-27145. Any findings, recommendations, services, or organizations that are mentioned, shown, or indirectly implied in this publication do not imply endorsement by the University of Arizona or the USDA. A PDF of this publication is available on-line at: https://cals.arizona.edu/crops/cotton/files/BBid.pdf.