Evidence of Pollinators Foraging on Centipedegrass Inflorescences

SIMPLE SUMMARY: Turfgrasses are generally considered devoid of pollinators, as turfgrasses are often described as being only wind-pollinated. Centipede grass is a popular turfgrass grown in the southeastern USA. Centipede grass produces a large number of inflorescences from August to October each year. In a recent study, honeybees were found to collect pollen from centipede grass. However, it is not clear whether other pollinators are attracted to centipede grass inflorescences and actively forage them. Thus, the aim of the current study was to document the pollinators that foraged on centipede grass inflorescences. Pollinators visiting centipede grass were sampled using (1) a sweep net when actively foraging on an inflorescence; (2) blue, white and yellow pan traps; and (3) malaise or flight-intercept traps. Sweat-, bumble- and honeybees were captured while actively foraging on the centipede grass inflorescences. In the pan and flight-intercept traps, more sweat-bees were collected than honey- or bumblebees. We also captured hoverflies in the samples. The adult hoverflies consumed pollen during flower visits. This research is a first step toward developing bee-friendly lawns. The data also imply that proper caution should be exercised to preserve bee habitat and encourage bee foraging. ABSTRACT: Turfgrasses are commonly used for lawns and as recreational surfaces in the USA. Because grasses are largely wind-pollinated, it was thought that pollinators would not forage on turfgrasses. Centipede grass (Eremochloa ophiuroides (Munro) Hack) is a warm-season turfgrass widely used in the southeastern USA. Centipede grass produces spike-like inflorescences from August to October, and little is known about whether pollinators utilize those inflorescences as pollen resources. Thus, the objective of the current study was to identify the pollinators foraging on centipede grass inflorescences. Pollinator samples were collected by (1) sweeping the insects actively foraging on centipede grass inflorescence for 30 min, (2) deploying pan traps for 24 h and (3) deploying malaise traps for 7 d. In the sweep samples, Lasioglossum spp., Bombus spp., Apis spp., Melissodes spp. and Augochlorella spp. were collected from centipede grass inflorescences. Syrphid flies were also collected in the sweep samples. The pan and malaise traps collected mostly Lasioglossum spp. The results imply that there is a critical need to conserve bee habitats and adopt nondisruptive lawn practices. Additionally, this new knowledge lays the foundation for future research to enhance our understanding of bee and syrphid behavior and the selection of host traits for improving bee foraging.