Hoverfly (Diptera: Syrphidae) assemblage of an oak–hornbeam in the Merlino Wood Natural Reserve and implications for its conservation

Abstract

Merlino Wood is a typical oak–hornbeam forest in the Po Plain hydrographic region. It is one of the few remaining lowland forests in Northern Italy and is a Regional Natural Reserve and a Site of Community Interest (code IT1160010). This is the first survey on hoverflies in the study area and they act as bioindicators to assess habitat conservation. Sampling was performed with three Malaise traps and an entomological net. A total of 61 species of Syrphidae were recorded between March and October 2019. Three of the species observed are considered to be under threat in Europe, three species have been recorded for the first time in Piedmont and Heringia latitarsis (Egger, 1865) has been recorded for the first time in Northern Italy. The Syrph the Net analysis has been used to assess habitat conservation. It shows good preservation of xylosaprophagous species, while the conservation conditions of other larval trophic categories are poor.

Forest and grassland habitats support pollinator diversity more than wildflowers and sunflower monoculture

“…For instance, solitary wild bees thrive in forests within an agricultural matrix, specifically in the early stages of forest development rich in floral resources and nesting sites (Centrella et al, 2020;Hanula et al, 2015;Roberts et al, 2017;Rubene et al, 2015). On the other hand, saproxylic hoverflies depend on well-established forests and abundant sources of large, dead trees (Maritano, 2020;Reemer, 2005;Ricarte et al, 2009).…”

“…For instance, solitary wild bees thrive in forests within an agricultural matrix, specifically in the early stages of forest development rich in floral resources and nesting sites (Centrella et al, 2020; Hanula et al, 2015; Roberts et al, 2017; Rubene et al, 2015). On the other hand, saproxylic hoverflies depend on well‐established forests and abundant sources of large, dead trees (Maritano, 2020; Reemer, 2005; Ricarte et al, 2009). For instance, as large saprophagous hoverflies are closely associated with water during their development, greater species richness could be expected in areas with a greater number of riparian sites (Keil et al, 2008), while species with phytophagous larvae developing on the underground storage organs of plants can often be found in habitats with a higher proportion of agricultural land (Jovičić et al, 2017).…”