The Bees among Us: Modelling Occupancy of Solitary Bees

Abstract

Occupancy modelling has received increasing attention as a tool for differentiating between true absence and non-detection in biodiversity data. This is thought to be particularly useful when a species of interest is spread out over a large area and sampling is constrained. We used occupancy modelling to estimate the probability of three phylogenetically independent pairs of native—introduced species [Megachile campanulae (Robertson)—Megachile rotundata (Fab.), Megachile pugnata Say—Megachile centuncularis (L.), Osmia pumila Cresson—Osmia caerulescens (L.)] (Apoidea: Megachilidae) being present when repeated sampling did not always find them. Our study occurred along a gradient of urbanization and used nest boxes (bee hotels) set up over three consecutive years. Occupancy modelling discovered different patterns to those obtained by species detection and abundance-based data alone. For example, it predicted that the species that was ranked 4th in terms of detection actually had the greatest occupancy among all six species. The native M. pugnata had decreased occupancy with increasing building footprint and a similar but not significant pattern was found for the native O. pumila. Two introduced bees (M. rotundata and M. centuncularis), and one native (M. campanulae) had modelled occupancy values that increased with increasing urbanization. Occupancy probability differed among urban green space types for three of six bee species, with values for two native species (M. campanulae and O. pumila) being highest in home gardens and that for the exotic O. caerulescens being highest in community gardens. The combination of occupancy modelling with analysis of habitat variables as an augmentation to detection and abundance-based sampling is suggested to be the best way to ensure that urban habitat management results in the desired outcomes.

Effects of urban greenspace configuration and native vegetation on bee and wasp reproduction

“…Our data set contained a high proportion of zeros (approximately 67%) and was zero‐inflated, according to a likelihood ratio test comparing zero‐inflated model fit with a negative binomial base distribution (Bolker, 2021). Zero‐inflation is a common occurrence in ecological count data (Martin et al., 2005; Sileshi et al., 2009; Zuur et al., 2009), and we expected false absences of bees in traps to result from species’ varying preference for natural nesting substrate over artificial trap nests (Everaars et al., 2011; MacIvor & Packer, 2016). The overdisp_fun function (Bolker, 2021) showed our data were overdispersed.…”

The Impact of Different Biotopes and Management Practices on the Burden of Parasites in Artificial Nests of Osmia spp. (Megachilidae) Bees

“…Osmia rufa L.) and Osmia cornuta L. These bee species live in similar environments but differ in phenology and time of emergence in the spring. These species are being increasingly used for pollination services in agricultural and natural environments [1,2]. Osmia bicornis is polylactic and collects pollen from a very broad spectrum of plants, while O. cornuta prefers Rosaceae, especially fruit trees.…”

“…They emerge early in spring and so they are important in pear plantations which bloom early [4]. Additionally, these bees forage readily among different trees and rows within the orchard, which is particularly important for self-incompatible fruit cultivars that require cross fertilization [2][3][4]. Because they are also common in non-agricultural environments, these bees are important for the preservation of natural landscapes.…”

“…Because they are also common in non-agricultural environments, these bees are important for the preservation of natural landscapes. Therefore, these bees have been introduced in urban areas as an environmental accompaniment [2,5].…”

Reproduction and Accompanying Fauna of Red Mason Bee Osmia rufa L. (syn. Osmia bicornis L.) in Areas with Different Levels of Urbanization

“…The red mason bee (Osmia rufa L.), one of the most common early spring species in Poland with broad food preferences (Ruszkowski & Biliński, 1986;Teper, 2007), readily occupies artificial nests and forms aggregations (Giejdasz & Wilkaniec, 2003) to pollinate many agricultural and horticultural crops (Biliński & Teper, 2004Fliszkiewicz et al, 2011). Osmia rufa was recently introduced as an environmental complement (Everaars et al, 2011;MacIvor & Packer, 2016) and is used as a bioindicator (Szentgyörgyi et al, 2017). An important factor influencing the health and number of red masons is the accompanying fauna, including nest parasites.…”