Stenodynerus krombeini

Identification Atlas of the Vespidae (Hymenoptera, Aculeata) of the northeastern Nearctic region
CJAI 05, February 19, 2008
doi: 10.3752/cjai.2008.05

Matthias Buck, Stephen A. Marshall, and David K.B. Cheung

Department of Environmental Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1

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59. Stenodynerus krombeini Bohart, 1953
Figs B7.39, 41, 43, 68; C59.1–4.

Species recognition. This species is strikingly similar to Parancistrocerus pedestris. The reduction of pits in the basal groove of tergum 2 (below overhang of tergum 1) has progressed so far in S. krombeini that it hardly differs from species of Parancistrocerus. In Parancistrocerus the dorsobasal lamella of tergum 2, which forms the roof of the acarinarium and is firmly appressed to the overhang of tergum 1, is longer than in Stenodynerus where the same space does not serve as an acarinarium. Further differences between terga 2 of S. krombeini and P. pedestris are mentioned in the key.

Variation. Fore wing length 5.0–6.5 mm (♂♂), 6.5–7.0 mm (♀♀). Variation otherwise not studied.

Distribution. The distribution of S. krombeini is insufficiently known, probably due to confusion with Parancistrocerus pedestris. Krombein (1979) lists S. krombeini only from the type locality in NC. We have seen specimens from nine states: MA, North Falmouth (1 ♂, CNCI), Wellfleet (1 ♀, AMNH); VA, Falls Church (2 ♂♂, AMNH); TN, Great Smoky Mts Natl. Pk., Indian Gap, 5200 ft (1 ♂, CNCI), Highlands (1 ♂ 1 ♀, CNCI); NC Raleigh (1 ♂, DEBU), Singletary Lake St. Pk. (2 ♂♂, DEBU); SC, Georgetown Co., Hobcaw Barony (1 ♂ 1 ♀, DEBU); GA, Reed-Bingham St. Pk (1 ♂, AMNH); FL, Gainesville (1 ♂, CNCI), Palatka (1 ♀, AMNH); MS, 3 mi N Wesson (1 ♀, CNCI); TX Fredericksburg (1 ♀, CNCI). Floridian specimens have the yellow markings suffused with orange (male) or red (female), tergum 1 is predominantly red, and the apical margin of tergum 2 is less thickened than in specimens from other areas.

Biology. Nests in borings in wood and makes nest partitions and closing plugs of firmly agglutinated sand. Prey are caterpillars of Gelechiidae and Tortricidae (Olethreutinae) (Krombein 1967, 1979).

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