Factors Influencing Honeybee (Apis mellifera L.) Visits to Crepe Myrtle (Lagerstroemia sp.)

Abstract

Honeybees (Apis mellifera L.) are important pollinators and will selectively forage on crepe myrtle (CM) during the summer months. Unfortunately, CM pollen can become contaminated with pesticides used to control insects, especially crepe myrtle bark scale (Acanthococcus lagerstroemiae Kuwana). An experiment was conducted in July and August of 2019 and 2020 to compare honeybee visits to CM among four cultivars (‘Natchez', ‘Tuscarora', ‘Ebony Fire', and ‘Pocomoke') at an isolated location, and within a single cultivar series (Ebony) near other pollinator-friendly plants. ‘Natchez' had the most honeybee visits per tree, averaging 1.4 visits per 75 seconds per tree per day in 2019 and 1.2 visits per 75 seconds per tree per day in 2020, followed by ‘Tuscarora' with 0.8 and 0.4 honeybee visits per 75 seconds per tree per day, in 2019 and 2020, respectively. In 2020, there was a significant, moderate correlation (P< 0.001, r = 0.51) between bloom number and honeybee visits, with ‘Natchez' (158.9) and ‘Tuscarora' (148.2) having more average blooms per tree than ‘Ebony Fire' (35.6) and ‘Pocomoke' (35.7). Landscape environment and proximity to pollinator-friendly plants did not affect honeybee visits. CM are an important foraging resource for honeybees in the summer, and honeybees have a strong preference for cultivars with large, productive bloom clusters. Index words: pollinators, crepe myrtle bark scale, Acanthococcus lagerstroemiae, crepe myrtle Species used in this study: Crepe myrtle, Lagerstroemia indica L.; Lagerstroemia × faurei; Honeybee, Apis mellifera L.; American bumblebee, Bombus pensylvanicus De Geer.