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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

 

40. Odynerus dilectus de Saussure, 1870
Figs A4.2; B2.8, 14, 16, 18, 36; C40.1–6.

Odynerus dilectus
Odynerus dilectus Odynerus dilectus Odynerus dilectus
Odynerus dilectus Odynerus dilectus Odynerus dilectus

Species recognition. Odynerus dilectus superficially resembles certain pale-marked species of Euodynerus and Ancistrocerus. The former differs from O. dilectus by the presence of a sharply defined and continuous pronotal carina (at most very vaguely indicated in O. dilectus), the latter by the presence of a transverse carina of tergum 2 (absent). The male of O. dilectus is highly distinctive by its deeply emarginate clypeal apex, deep emargination between second and third mandibular tooth, coiled apical four flagellomeres, ventrally depressed fore femur, two deep, ventral emarginations of mid femur, clavate mid tibia and sternum 2 with a low, sparsely punctate, median swelling. The female has widely separated cephalic foveae each of which is bordered by a fine carina posteriorly. The propodeum of O. dilectus is evenly rounded laterally without a clearly defined posterior concavity.

Variation. Fore wing length 6.0–8.0 mm (♂♂), 6.0–9.0 mm (♀♀). Female clypeus entirely black, very rarely with a pair of small lateral spots, in one specimen from NT connected by an evanescent, interrupted, crescent-shaped mark along dorsal margin. Narrow pale spot along inner orbit extending to from ventral margin of eye emargination to clypeus, sometimes interrupted at level of antenna or restricted to ventral margin of eye emargination. Interantennal spot transverse in male, usually medially divided and small in female. Pronotal band usually somewhat expanded posteriorly on each side, sometimes almost linear, almost always entire but medially divided in one female. Scutellum very variable, completely black to marked with a well-developed transverse, usually anteriorly emarginate, pale band, often with a pair of pale lateral spots or an irregularly interrupted band. Metanotum usually black, sometimes with a pair of lateral pale spots (very rarely almost coalescent); markings of scutellum and metanotum on average better developed in male than in female. Mesopleuron sometimes with a pale dorsal spot in male (rarely in female and then usually evanescent). Male tegula marked with pale posteriorly and usually anteriorly, rarely completely pale except hyaline spot; female tegula darker on average, never completely pale, in some specimens dark brown and lacking pale markings. Terga 1–(3)4 or 5 (female) or 1–(5)6 (male) with apical fasciae. Sternum 2 with interrupted or sometimes entire apical fascia, sternum 3 (and rarely 4) with pale apicolateral spots.

Distribution. Canada: AB (Krombein 1979) and YT (Finnamore 1997), newly recorded for NB, QC, ON, MB, SK, BC, NT. Northern and western U.S.: NY, MN, AK; WA and MT to CA and NM in Canadian life zone (Krombein 1979).

Biology. This species nests gregariously in the ground and constructs mud turrets over the nest entrance. The turrets are usually straight (curved in ca. 20% of cases), and vary in length from 1.2–3.0 cm. Each nest contains 3–7 cells. Prey are alfalfa and clover weevil larvae (Hypera postica (Gyll.), H. punctata F.; Curculionidae), exceptionally caterpillars (Bohart et al. 1982, Schaber 1985).

 

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Odynerus dilectus Odynerus dilectus