|Ceutorhynchus subpubescens |
This species is found in association with Descurainia sophia (L.) Webb but is far less common than its host plant.
The overwintering adults emerge in late April to mid May; oviposition occurs from late May into early June; and newly emerged adults appear in July (Dosdall et al. 2007).
Adults are oblong with a tapering thorax and head. The body color is brownish-black with fine brown scales above and wider gray scales below. The funicle (antennal segments between the scape and the clubbed) is seven segmented with segments one and two being longer than segments three and four united. The beak is slender cylindrical and half the body length. The tarsal claws as well as the hind femora are toothed. Length 3.2 mm. These above details are adapted from LeConte (1876).
Final instar larva can be separated from the sympatric C. obstrictus and C. neglectus based on several characters. The head capsule of C. subpubescens is as long as it s wide and has a mean width of 0.64 mm. There are three setae on the dorsal and ventral aspects of the epicranium. Finally, the stipes has five setae while the mala has three ventral and 6 dorsal setae. The above description is adapted from Dosdall et al. (2007).
According to Dosdall et al. (2007), adults overwinter in shelterbelts before emerging in the spring. Eggs are laid in the stems of D. sophia. All three larval instars feed within the stem on the pith tissue. The mature larvae bore exit holes below stem or leaf axils. The development time between egg and third instar larva is 35 to 45 days. Pupation occurs just below the soil surface in tiny earthen cocoons. Pupal development times ranged from 16.5 to 22 days. Adults are then oligophagous on various plants of the mustard family.
This species occurs in low density across its range (Dosdall et al. 2007).
Oviposition and larval feeding are only known on the introduced weed Descurainia sophia. Reproduction is also speculated on native Descurainia. Adults are oligophagous on brassicaceous plants and prefer to feed on Brassica napus L., Brassica rapa L., and Brassica juncea (L.) Czern. (Adapted from Dosdall et al. 2007).
This weevil has a western Nearctic distribution stretching from the Yukon and the North West Territories to California and New Mexico (Anderson 1997; Dosdall et al. 2007).
|species page author||Blake, A. J.||2007 |