Bombus (Cullumanobombus) fraternus (Smith)

Tripodi, Amber D. & Szalanski, Allen L., 2015, The bumble bees (Hymenoptera: Apidae: Bombus) of Arkansas, fifty years later, Journal of Melittology 2015 (50), pp. 1-17 : 11

Bombus (Cullumanobombus) fraternus (Smith)

‘Southern Plains Bumble Bee’

In their museum survey, Chandler & McCoy (1965) noted B. fraternus as “widespread”, and it was recorded in as many counties as B. griseocollis ( Fig. 3). Bombus fraternus remains widely distributed across Arkansas, and its occurrence has remained stable between the historic (36%) and contemporary periods (33%, Fig. 3). Although B. fraternus appears to have a wide geographic distribution, it is relatively less abundant than its congeners ( Colla et al., 2012; Grixti et al., 2009). There are some indications that B. fraternus may be declining and the International Union for Conservation of Nature has classified the species as endangered ( Hatfield et al., 2014), but its relative rarity makes it difficult to be certain of its status. Throughout its range, B. fraternus has declined in relative abundance and in geographic persistence, but its relative abundance over all museum records was only 0.32% ( Colla et al., 2012). Similarly, an Illinois study designated B. fraternus as declining after finding that it was absent from the southern region of the state where it was formerly present, but its relative abundance ranged from 0.2–1.9% over all studied records spanning 1900 to 2007 ( Grixti et al., 2009).

GLOSSA LENGTH: Short (4.69 ± 0.37 mm).

ADULT ACTIVE PERIOD: Late season with a long active period (92 days). Majority: early July through early October; Earliest: April 6; Latest: October 3.

PREFERRED PLANTS: Passiflora incarnata Linnaeus (purple passionflower, Passifloraceae ), S. integrifolium (wholeleaf rosinweed, Asteraceae ), Solidago Linnaeus (goldenrod, Asteraceae ), Liatris pycnostachya Michx. (prairie blazing star, Asteraceae ), Silphium Linnaeus (rosinweed, Asteraceae ), Bidens aristosa (Michx.) Britt. (bearded beggarticks, Asteraceae ), Cephalanthus occidentalis Linnaeus (common buttonbush, Rubiaceae ), Solidago altissima Linnaeus ( Canada goldenrod, Asteraceae ), Verbesina virginica Linnaeus (white crownbeard, Asteraceae ).