Guidelines on sampling intensity of bees (Hymenoptera: Apoidea: Apiformes)

Abstract

Changes in bee fauna, such as the disappearance of certain species or increasing abundance of others, are very important. The common belief that pollinating insects are facing problems also prompts detailed studies of the bee fauna in order to track on-going changes. Assessment of the state of bee communities in particular ecosystems or ecosystem complexes within a landscape, tracing the course of trends in fauna and also predicting their future structures resulting from current changes, are only possible if sampling is carried out at an appropriate frequency, so that representative materials are obtained. The aim of the present study was to determine what sampling intensity during the growing season would enable the collection of representative materials to evaluate species diversity of bees in a study area. Repeated bee sampling at monthly intervals throughout the period of activity of bees resulted in the identification of 73 bee species, corresponding to 51.4 % of the estimated number of bee species in the study area. When samples were obtained twice a month, 93 bee species were captured, accounting for 65.5 % of the estimated number of bee species. When sampling took place nearly four times a month, 108 bee species were captured, making up 76 % of the estimated number of bee species; the materials obtained at this sampling rate may be regarded as representative. The importance of accounting for the phenology of a given animal group during a sampling effort is also emphasised.

Diversity and abundance of solitary and primitively eusocial bees in an urban centre: a case study from Northampton (England)

“…The order of site visits was randomised to ensure that all sites would receive roughly equal morning and afternoon sampling. High frequency surveys throughout the season are particularly important to record rare species and species that are active over a short period (Magurran and McGill 2011;Banaszak et al 2014). The 15 days of observation (hand net plus pan traps) was combined to make a single sampling unit for analysis.…”

Different sampling intervals for bowl trapping survey of Aculeata (Hymenoptera) in a semidecidual seasonal forest fragment

“…We understand that the no difference on observed richness can be attributed to the sampling insufficiency. The twice-amonth proportion of observed and estimated number of species (60%) is lower than the 65% obtained by Banaszak et al (2014) but the percentage of the once-a-month subsets (39%) can be considered very low and therefore non representative of the community. The same overall pattern described here for aculeates was observed for bees, the most common group within the samples.…”

“…Studies on bowl trap methodology have focused in different colour preferences (e.g., ABRAHAMCZYK et al, 2010;HENEBERG & BOGUSH, 2014;MOREIRA et al, 2016), and only one study compared diversity and richness under different sampling intervals. Banaszak et al (2014) found more bee species using weekly sampling intervals during the flowering season in Poland, ensuring the collection of about 75% of estimated species number. However, studies in tropical regions with a more continuous and extended plant blooming pattern are completely lacking.…”

An expert-assisted citizen science program involving agricultural high schools provides national patterns on bee species assemblages

“…2.25 ± 0.35) and their location in the school. Participants were asked to make, under suitable weather conditions (minimum of 15 °C, low wind, no rain), one 24-h capture session each month from March to October, in order to obtain an overall assessment of the bee assemblage composition over the whole flying season (Banaszak et al 2014). In practice, some participants could not carry out the required number of sessions or others made more than one session in a month.…”