insects Communication Evidence of Pollinators Foraging on Centipedegrass Inflorescences Shimat V. Joseph 1,* , Karen Harris-Shultz 2 and David Jespersen 3 1 Department of Entomology, University of Georgia, Griffin, GA 30223, USA 2 Crop Genetics and Breeding Research Unit, USDA-ARS, Tifton, GA 31793, USA; [email protected] 3 Department of Crop and Soil Science, University of Georgia, Griffin, GA 30223, USA; [email protected] * Correspondence: [email protected]; Tel.: +1-770-228-7312 Received: 19 October 2020; Accepted: 10 November 2020; Published: 13 November 2020 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. Keywords: Eremochloa ophiuroides; Lasioglossum; sweat bee; Bombus; bumble bee; turfgrass; spikelet 1. Introduction Pollinators utilize floral resources available to them in green spaces [1–5]. The incidence and abundance of pollinators are driven by available floral resource communities in the landscape [6–9]. Insects 2020, 11, 795; doi:10.3390/insects11110795 www.mdpi.com/journal/insects InsectsInsects2020, 202011, 795, 11, x 2 of 8 2 of 8 1. Introduction However,Pollinators lawns in theutilize USA floral are typicallyresources maintainedavailable to them aiming in forgreen agreen spaces monoculture [1–5]. The incidence free of weedsand or otherabundance flowering of plants. pollinatorsTurfgrasses are driven are by regularly available trimmedfloral resource and communities mowed at regular in the landscape intervals. [6–9]. In public and residentialHowever, lawns lawns, in the patches USA are of typically flowering maintained weeds, aiming such asfor cloversa green monoculture or dandelions, free areof weeds common, and theseor other weeds flowering often provideplants. Turfgrasses supplemental are nectarregularly and trimmed pollen for and foraging mowed beesat regular [4]. A intervals. diverse group In of pollinatorspublic and have residential been documented lawns, patches to occur of flowering in urban weeds, and suburbansuch as clovers lawns or indandelions, southern are Connecticut common, [10], Newand York these [11 ],weeds Massachusetts often provide [4], supplemental and Georgia nectar [12]. an Ind addition,pollen for ground-nestingforaging bees [4]. beesA diverse construct group nests in theof patches pollinators of exposedhave been bare documented soil along to theoccur edges in urban of some and suburban lawns [13 lawns]. in southern Connecticut [10], New York [11], Massachusetts [4], and Georgia [12]. In addition, ground-nesting bees construct Turfgrass is an integral and inseparable element of the southeastern USA. It provides an essential nests in the patches of exposed bare soil along the edges of some lawns [13]. green cover,Turfgrass enhancing is an theintegral aesthetics and inseparable and property elemen valuet of ofthe landscapes. southeastern InUSA. Georgia, It provides the turfgrass an industryessential is valued green atcover, 7.8 billionenhancing USD the in aesthetics 2010 [14 ].an Amongd property warm-season value of land turfgrasses,scapes. In Georgia,centipedegrass the (Eremochloaturfgrass ophiuroides industry is(Munro) valued Hack)at 7.8 billion is one USD of the in major 2010 [14]. species Among found warm-season in managed turfgrasses, landscapes in the southeasterncentipedegrass USA, (Eremochloa as it requiresophiuroides minimal (Munro) managementHack) is one of andthe major fertilization species found [15]. in A managed recent study showedlandscapes that a diverse in the southeastern group of bee USA, genera, as it mainly requiresLasioglossum minimal managementspp., transit and in fertilization centipede grass[15]. A lawns in Georgiarecent study [12]. Centipedeshowed that grassa diverse typically group of produces bee genera, spike-like mainly Lasioglossum inflorescences spp., (raceme)transit in centipede beginning in Augustgrass in lawns the southeastern in Georgia [12]. USA. Centipede The structures grass typically of grass produces flowers spike-like (spikelets) inflorescences include a(raceme) gynoecium, androecium,beginning lodicules, in August palea,in the southeastern and lemma USA. [16]. The The structures gynoecium of grass and androeciumflowers (spikelets) of flowers include appear a gynoecium, androecium, lodicules, palea, and lemma [16]. The gynoecium and androecium of from raceme (Figure1) and support wind pollination. However, the European honeybee, Apis mellifera flowers appear from raceme (Figure 1) and support wind pollination. However, the European Linnaeus,honeybee, has beenApis mellifera found toLinnaeus, forage has on thebeen inflorescences found to forage of on centipede the inflorescences grass [17 of]. centipede Of note, grass when the honeybees[17]. Of traveled note, when from the inflorescencehoneybees traveled to inflorescence, from inflorescence they to generated inflorescence, biotic they winds generated that moved biotic the pollenwinds significant that moved distances, the pollen although significant the exact distances, distance although the pollen the exact travelled distance by the biotic pollen wind travelled is not clear. A previousby biotic survey wind is found not clear. a diverse A previous group survey of bees found in unmoweda diverse group lawns of bees when in unmowed centipede lawns grass when produced inflorescencescentipede grass [12], withproducedLasioglossum inflorescencesbeing [12], the with most Lasioglossum abundant being bee genera. the most To abundant develop bee a bee-friendlygenera. centipedeTo develop grass a lawn, bee-friendly it is critical centipede to document grass lawn, the it direct is critical foraging to document activity the of direct bees onforaging the inflorescences activity of centipedeof bees on grass. the inflorescences Thus, the objectives of centipede of the grass. current Thus, study the objectives were to determine of the current (1) thestudy diverse were groupsto of pollinatorsdetermine that(1) the directly diverse visit groups or forage of pollinators on the inflorescencesthat directly visit of or centipede forage on grass the inflorescences and (2) the relativeof centipede grass and (2) the relative abundances of pollinators foraging on centipede grass using abundances of pollinators foraging on centipede grass using various trapping devices. various trapping devices. FigureFigure 1. Spike-like 1. Spike-like inflorescences inflorescences of of centipede centipede grassgrass emerged emerged 12 12 d dafter after mowing mowing in a inresidential a residential lawn lawn in Pike County, GA, USA, during September 2020. The androecium (stamens) (purple anthers and in Pike County, GA, USA, during September 2020. The androecium (stamens) (purple anthers and white filament) containing pollen (indicated by orange arrows) and gynoecium (carpel) (white stigma, and style), which receive pollen (indicated by red arrows) are shown in the figure. Photo credit: Shimat Joseph. Insects 2020, 11, 795 3 of 8 2. Materials and Methods 2.1. Study Sites This study was