Pterocolus ovatus (Fabricius)

Young, Julia Janicki Daniel K., 2021, Survey of the Attelabidae of Wisconsin (Coleoptera: Curculionoidea), Insecta Mundi 2021 (891), pp. 1-61 : 26-27

Pterocolus ovatus (Fabricius)

( Fig. 29–30 )

Diagnosis. Pterocolus ovatus can be easily recognized by the metallic blue-green to blue-black integument, by the distinct lateral carina on the pronotum with the prothoracic pleuron strongly excavated beneath it, by the antennae inserted close to the eyes, and by the elytra that are individually rounded apically.

Description. Length 2.8–3.2 mm. Body bright metallic blue or green; antennae, rostrum, and legs somewhat darker. Vestiture consisting of inconspicuous, fine setae. Head densely punctured on vertex. Rostral length about 0.7× pronotal length, constricted at antennal insertion, diverging to broad apex; surface shining, with 2 longitudinal rows of close punctures near lateral margin, area between rows very finely, sparsely punctured. Frons much narrower than dorsal tip of rostrum. Pronotal width about 1.3× length, widest at junction of elytral humeral angles; disc strongly convex, with dense, evenly spaced punctures, each bearing 1 short, recumbent hair-like seta; interpuncture spaces shining, smooth, much narrower than diameter of puncture. Elytral width 1.2× length; striae moderately impressed, with moderate, deeply impressed punctures; interstriae about 2.0× strial width, shining, smooth, with 1 irregular row of medium-sized punctures, each bearing 1 recumbent, fine seta. Visible abdominal tergites with large, strong, dense punctures.

Natural history. Pterocolus ovatus , the thief weevil, is an obligate egg-predator and nidus-kleptoparasite of Homeolabus analis ( Hall and Buss, 2007) . It may also use Synolabus bipustulatus as host ( Vogt 1992). It is found throughout the range of H. analis ( Vogt 1992) , except for southern Florida ( Anderson 1992), as well as eastern and southwestern United States where other leaf-roller hosts such as S. bipustulatus are found ( Vogt 1992). In

Wisconsin, two individuals of H. analis and a P.ovatus were observed on the same oak scrub on different leaves (personal observation, JJ).

Phenology. In Wisconsin, adults have been collected from June to September.

Collecting methods. The 16 Wisconsin specimens examined during this study from seven counties represent a new state record (Appendix 1). This species is most readily collected by beating oak ( Quercus spp. ), and by hand collecting from oak leaves.

Distribution. United States. AL, AR, AZ, CT, DC, FL, GA, IA, IL, IN, KS, LA, MA, MD, ME, MI, MN, MO, NC, NJ, NY, OH, OK, PA, RI, SC, TN, TX, VA, WI. Canada. Country only.

Wisconsin county records. Dane, Dodge, Grant, Monroe, Sauk, Trempealeau, Waukesha.

Figures

Figures 29–30. Pterocolus ovatus (Fabricius). 29) Habitus, dorsal view. 30) Habitus, lateral view.