Bees and Other Pollinators in Adjacent Old World Bluestem and Cotton Fields in the Texas High Plains

The rapid decline in water supply for irrigation in the Texas High Plains is encouraging some growers to convert a portion of their irrigated cropland including cotton (Gossypium hirsutum L.) to the production of water-frugal perennial forages such as ‘WW-B.Dahl’ old world bluestem [Bothriochloa bladhii (Retz) S.T. Blake, OWB]. WW-B.Dahl OWB is a persistent pasture grass, which has strong inhibitory effects on soil-dwelling ants (Hymenoptera: Formicidae); however, effects of OWB on pollinators in cotton-dominated agroecosystems are not clear. We characterized bees and other pollinators of OWB and an adjacent cotton monoculture at four sampling dates in fall of 2018 using the bee bowls. Fifteen families from four insect orders were recovered. Sweat bee (Hymenoptera: Halictidae) was the most abundant family composing 67% of the total individuals recovered. The next abundant family was hover flies (Diptera: Syrphidae), constituting 11% of the total numbers. Total number of pollinators was consistently greater in OWB than in cotton at all sampling dates. Despite the fact that insects are not needed for pollination, presence of fairly high numbers of bees and other pollinators in OWB and cotton suggests that both crops may be providing habitat and food resources for pollinators in semi-arid Texas High Plains.