Temnocerus perplexus (Blatchley)

Young, Julia Janicki Daniel K., 2021, Survey of the Attelabidae of Wisconsin (Coleoptera: Curculionoidea), Insecta Mundi 2021 (891), pp. 1-61 : 22-23

Temnocerus perplexus (Blatchley)

( Fig. 23–24 )

Diagnosis. Temnocerus perplexus can be recognized by the almost completely visible pygidium, by the rostrum that gradually widens from antennal insertion to apex, by the pronotum that is slightly longer than wide with dense, setigerous punctures, and by the large punctures on the head.

Description. Length of male 1.7–2.6 mm, of female 2.0– 2.7 mm. Integument black, shiny, with faint blue sheen or without bluish reflections; apex of rostrum, antennae and apex of legs somewhat paler. Head quadrate, slightly longer than wide, with round, evenly spaced, setiferous punctures; interpuncture spaces with dense, shining, minute granules. Rostral length 1.3× length of head + pronotum, in lateral view distinctly flattened apically; sides in dorsal view gradually widening from antennal insertion apically, narrower at apex than frons; distinctly arcuate and weakly flattened apically; punctures large. Antennae in male inserted just in front of basal 0.2 of rostrum, in female inserted near basal 0.2 of rostrum. Pronotum slightly longer than wide, slightly narrowed apically, widest behind middle; disc with round to irregularly shaped, dense setigerous punctures, interpuncture space with a few granules. Elytral length>2.0× width, width 2.0× pronotal width; striae not impressed, with deep, quadrate punctures; interstriae about 0.5× strial width, weakly convex, each interstria with 1 row of small, round, setiferous punctures. Pygidium almost completely visible, covered only at extreme base. Sexual dimorphism present in size and antennal insertion.

Natural history. According to Hamilton (1983b), both Auletobius cassandrae and Temnocerus perplexus have the same general distribution in eastern North America; they have been collected at both separate and common sites, and occur on the same host plant, sweetfern ( C. peregrina ). The females of both species oviposit in and then cut the terminal leaf primordia of sweet fern, which causes this tissue to fall to the ground and provide food and protection for the larva. Adults of both species feed on leaves of sweetfern, though in different manners. Temnocerus perplexus feeds by scraping off strips of the upper epidermis.

Some species of Temnocerus are “tip cutters”. Females of these species oviposit in young terminal plant growth; after oviposition they cut off the terminal part with their mandibles so the larvae can pupate in the ground after their development in the dead terminal tissues ( Hamilton 2010). Hamilton (1983a) reported the tip cutting behavior of T. perplexus on sweetfern ( Comptonia peregrina ) in the Midwest. The females in some other species of Temnocerus are known to oviposit in terminal buds or shoots without excising them ( Dieckman 1974; Hamilton 1994).

Phenology. This species is univoltine. In Wisconsin, adults have been collected in June.

Collecting methods. One Wisconsin specimen was examined during this study from Wood County.

Distribution. United States. CT, DC, GA, IA, IL, IN, KS, MA, ME, MI, NC, NH, NJ, NY, OH, PA, RI, WI. Canada. NB, ON, PE, PQ.

Wisconsin county records. This species was previously recorded from Oconto County ( O’Brien and Wibmer 1982; Downie and Arnett 1996). Oconto, Wood.

Tribe Auletini Desbrochers

Figures

Figures 23–24. Temnocerus perplexus (Blatchley). 23) Habitus, dorsal view. 24) Habitus, lateral view.