The bumble bees (Hymenoptera: Apidae: Bombus) of Arkansas, fifty years later Author Tripodi, Amber D. Department of Entomology, University of Arkansas, Fayetteville, Arkansas 72701, USA (aszalan @ uark. edu). & Current address: USDA-ARS, Pollinating Insects Research Unit, Logan, Utah 84322, USA (amber. tripodi @ ars. usda. gov). Author Szalanski, Allen L. Department of Entomology, University of Arkansas, Fayetteville, Arkansas 72701, USA (aszalan @ uark. edu). text Journal of Melittology 2015 2015-06-01 2015 50 1 17 http://dx.doi.org/10.17161/jom.v0i50.4834 journal article 10.17161/jom.v0i50.4834 2325-4467 Bombus ( Thoracobombus ) pensylvanicus (De Geer) ‘American Bumble Bee’ Bombus pensylvanicus [as B . americanorum (Fabricius) ] was listed as the “most widespread and common species” in the state in Chandler & McCoy’s (1965) study. Its statewide occurrence is much reduced today, although it remains widespread ( Fig. 1 ). The contemporary occurrence of B . pensylvanicus (50%) is about one-third lower than its historic occurrence (82%, Fig. 3 ). Only a single record occurred in the period between our sampling intervals: Faulkner Co., September 6, 1976 . This state-level pattern reflects what has also been observed throughout the range of B . pensylvanicus , and many sources consider B . pensylvanicus to be a declining species ( Cameron et al ., 2011 ; Colla & Packer, 2008 ; Colla et al ., 2012 ; Grixti et al ., 2009 ). Although there are indications of a range-wide decline of B . pensylvanicus , it is likely that not all areas are reflecting the same shifts in abundance or occurrence. For example, B . pensylvanicus was abundant in the extreme south and western portions of its range ( Louisiana , Oklahoma , and Texas ) in recent surveys, although it was absent from much of the northern and eastern areas in which it was expected to occur ( Cameron et al ., 2011 ). Similarly, B . pensylvanicus was absent from the northern region of Illinois in recent surveys, although it was known from northern Illinois in historical records ( Grixti et al ., 2009 ). With contemporary records occurring throughout the state and in each ecoregion, we found no geographic pattern in the occurrences of B . pensylvanicus within Arkansas . This heterogeneity among regional studies highlights the utility of localized studies in determining the conservation status of species of interest. GLOSSA LENGTH: Long (6.41 ± 0.58 mm ). ADULT ACTIVE PERIOD: Late season with a long active period (82 days). Majority: late June through mid-September; Earliest: May 13; Latest: October 16. PREFERRED PLANTS: Baptisia alba (wild white indigo, Fabaceae ), Vernonia Schreb. (ironweed, Asteraceae ), T . canadense ( Canada germander, Lamiaceae ), M . fistulosa (wild bergamot, Lamiaceae ), A . esculentus (okra, Malvaceae ), Solanum carolinense Linnaeus (Carolina horsenettle, Solanaceae ), Cirsium discolor (Muhl. ex Willd.) Spreng. (field thistle, Asteraceae ), S . azurea (azure blue sage, Lamiaceae ), S . integrifolium (wholeleaf rosinweed, Asteraceae ), V . villosa (winter vetch, Fabaceae ).