Flower resource and land management drives hoverfly communities and bee abundance in seminatural and agricultural grasslands

Abstract

Pollination is a key ecosystem service, and appropriate management, particularly in agricultural systems, is essential to maintain a diversity of pollinator guilds. However, management recommendations frequently focus on maintaining plant communities, with the assumption that associated invertebrate populations will be sustained. We tested whether plant community, flower resources, and soil moisture would influence hoverfly (Syrphidae) abundance and species richness in floristically‐rich seminatural and floristically impoverished agricultural grassland communities in Wales (U.K.) and compared these to two Hymenoptera genera, Bombus, and Lasioglossum. Interactions between environmental variables were tested using generalized linear modeling, and hoverfly community composition examined using canonical correspondence analysis. There was no difference in hoverfly abundance, species richness, or bee abundance, between grassland types. There was a positive association between hoverfly abundance, species richness, and flower abundance in unimproved grasslands. However, this was not evident in agriculturally improved grassland, possibly reflecting intrinsically low flower resource in these habitats, or the presence of plant species with low or relatively inaccessible nectar resources. There was no association between soil moisture content and hoverfly abundance or species richness. Hoverfly community composition was influenced by agricultural improvement and the amount of flower resource. Hoverfly species with semiaquatic larvae were associated with both seminatural and agricultural wet grasslands, possibly because of localized larval habitat. Despite the absence of differences in hoverfly abundance and species richness, distinct hoverfly communities are associated with marshy grasslands, agriculturally improved marshy grasslands, and unimproved dry grasslands, but not with improved dry grasslands. Grassland plant community cannot be used as a proxy for pollinator community. Management of grasslands should aim to maximize the pollinator feeding resource, as well as maintain plant communities. Retaining waterlogged ground may enhance the number of hoverflies with semiaquatic larvae.

The yellow specialist: droneflyEristalis tenaxprefers different yellow colours for landing and proboscis extension

“…Field studies found that many flies predominantly visit flowers of distinct colour hues (Kugler, 1950;Kay, 1976;de Buck, 1990;Proctor et al, 1996;Goldblatt et al, 2001;Kastinger and Weber, 2001;Manning and Goldblatt, 1997;Willmer, 2011) or are caught in pan traps of distinct colour hues (Ssymank and Krause, 2007;Vrdoljak and Samways, 2012;Lunau, 2014;Lucas et al, 2017). Colour preference tests under controlled conditions using artificial flowers have been done with the hoverfly E. tenax.…”

The effects of landscape structure and crop management on insect community and associated ecosystem services and disservices within coffee plantation

“…Therefore, we expected that flower flies would depend on forest cover to find a high diversity of larval micro habitats; however, alpha diversity did not respond as expected. Similar results were obtained by Lucas et al (2017), where the diversity of the plant community had no significant influence on the diversity or abundance of flower fly communities. The absence of effects of landscape variables on flower fly alpha diversity may be related to the fact that adult flower flies do not collect pollen and nectar for their offspring but for their own resources of carbohydrates, lipids and proteins (in contrast to wasps and bees that need to return to their nests repeatedly for foraging) and can move linearly into the landscape (Kleijn & van Langevelde 2006;Jauker et al 2009).…”

“…As vespas e diversas espécies de sirfídeos são importantes agentes de controle biológico de insetos praga em diversas culturas agrícolas . Abelhas e sirfídeos são importantes polinizadores em ambos os ecossistemas naturais e agrícolas (ALLEN-WARDELL et al 1998;POTTS et al 2016;INOUYE et al 2015;LUCAS et al 2017;OLLERTON 2017). Além disso, vespas, abelhas e sirfídeos são considerados bioindicadores confiáveis para avaliar a perda de biodiversidade e o sucesso de projetos de conservação (TSCHARNTKE et al, 1998;KLEIN et al, 2002a;RICARTE et al, ;GRAVENA, 1988;.…”

“…We used wasps (Insecta: Hymenoptera: Vespidae), bees (Insecta: Hymenoptera: Apoidea) and flower flies (Insecta: Diptera: Syrphidae) as a model of different groups of beneficial insects. Bees, wasps and flower flies provide important pollination services in natural and agroecosystems (Allen-Wardell et al 1998;Potts et al 2016;Inouye et al 2015;Ollerton 2017;Lucas et al 2017Lucas et al , 2018 including coffee plantations (Roubik 2002;De Marco & Coelho 2004;Klein et al 2003Klein et al , 2008. Moreover, bees, wasps and flower flies have been used as bioindicators to assess the loss of biodiversity and the efficiency of restoration and conservation policies Ricarte et al 2011;Sommaggio & Burgio 2014), and many wasp and flower fly species are important agents of biological control of pests in several agroecosystems Schmidt et al 2004;Nelson et al 2012;Eckberg et al 2015).…”

Come to the dark side! The role of functional traits in shaping dark diversity patterns of south‐eastern European hoverflies

“…Hoverflies (Diptera: Syrphidae) play important roles in providing vital ecosystem services such as pollination (Ssymank & Kearns, 2009;Petanidou et al, 2011;Jauker et al, 2012), waste decomposition (Gilbert, 1985), and biological control (White et al, 1995;Blaauw & Isaacs, 2012;Day et al, 2015). Recent studies have shown that hoverflies can serve as valuable model organisms in studies of climate change (Kaloveloni et al, 2015;Radenković et al, 2017;Miličić et al, 2018), urbanisation (Bates et al, 2011;Verboven et al, 2014), landscape structure (Power et al, 2016) or land use (Aguirre-Gutiérrez et al, 2015;Földesi et al, 2016;Lucas et al, 2017).…”