Diel activity, frequency and visit duration of pollinators in focal plants: in situ automatic camera monitoring and data processing

Abstract

Summary Data collection on interactions between organisms and their environment has traditionally been conducted by on‐site human observations, a time‐consuming enterprise that could explain the shortage of around‐the‐clock observations of free‐ranging wild animals. In this paper, I outline a time‐efficient procedure to collect data on flower‐visiting animals. The objectives were, first, to model diel activity rhythms by using cosine‐based mixed‐effects regression models (cosinor method) on data from an established automatic video monitoring system and, secondly, to test the use of a cheap off‐the‐shelf digital camera modified for automated monitoring of flower visitors. Two different model systems were studied: foraging bumblebees visiting focal white clovers, monitored around‐the‐clock (193 h) to model diel activity; and honeybees visiting thistles, monitored over a shorter period (5 h) to test the applicability and reliability of a new method for monitoring pollinators. The data were automatically entered and processed using R‐scripts after manual filtering of the images, obviating the need for manual data entry prior to analysis. For diel activity in bumblebees, the model that gave the best fit included the 24‐h fundamental period and one harmonic, a 12‐h period to modulate the signal, together with temperature. The bumblebees were exclusive diurnal, with activity starting about 5 h after sunrise, peaking sharply in the afternoon and ending about 1 h before sunset. In addition to time of day, activity also increased with temperature. The off‐the‐shelf digital camera, Canon PowerShot®, with motion detection script, was triggered by every flower‐visiting honeybee. In addition to recorded visitor frequency and visitor duration, it enabled high‐resolution images, which could be important for species identification. Automatic camera recording is advantageous for close‐up monitoring, compared with continuous video recording, because the latter demands more time and effort in reviewing the material. It could be used to study a range of different species such as pollinators, on‐plant behaviour of herbivorous animals, cavity dwellers or cavity breeders. Moreover, the procedures for automatic data entry, data processing and statistical analysis for modelling diel activity rhythms could have great relevance for researchers using other types of camera monitoring systems operating 24 h per day.

From dusk till dawn: camera traps reveal the diel patterns of flower feeding by hawkmoths

“…This study shows that commercially available PIR cameras are sensitive enough to record the behaviour of hawkmoths and even noctuid moths. Unlike cameras using video motion detection, which have previously been used to record insect behaviour (Steen, , ), the Bushnell PIR cameras are relatively inexpensive, commercially available, and can be left at remote sites for long periods as they do not require constant illumination of the subject for activation. The videos we obtained using PIR cameras not only give insights into diel rhythms of activity and other behaviours, but in most cases also enable identification of individual moth species and the location of pollen loads on the body (Video S1).…”

Vertical and temporal distribution of spotted‐wing drosophila (Drosophila suzukii) and pollinators within cultivated raspberries

“…The applied goal of this study was to identify a height within the crop and time of maximal D. suzukii activity and minimal pollinator activity. Collectively, wild and commercial pollinators were most active in the top of half of the crop and only during the day, which was temporally consistent with previous reports ).…”

The use of digital video recorders in pollination biology

“…Direct observation techniques have long been considered an effective sampling technique and they continue to be an effective tool in the monitoring of pollinator behaviour (e.g. In recent times, cameras and video recordings have been used in pollination biology (Bumrungsri et al, 2009;Steen & Thorsdatter Orvedal Aase, 2011;Lihoreau et al, 2012;Lortie et al, 2012;Nakase & Suetsugu, 2015;Steen, 2016) with the optimum technique dependent upon the type of flower visitor expected and the study plant morphology. However, this approach is highly labour-intensive and is also limited by observer bias (Westphal et al, 2008;Popic et al, 2013).…”

“…Kaiser-Bunbury et al, 2010;Hermansen et al, 2014;Gilpin et al, 2016). Steen (2016) demonstrated the applicability of automatic camera monitoring of pollinators, utilising a motion detection device in a small-scale (single inflorescence) survey. Digital video recording (DVR) has the potential to allow more efficient observation, with a single researcher able to conduct multiple simultaneous observations over a range of temporal and spatial scales.…”

“…Digital video recording (DVR) has the potential to allow more efficient observation, with a single researcher able to conduct multiple simultaneous observations over a range of temporal and spatial scales. In recent times, cameras and video recordings have been used in pollination biology (Bumrungsri et al, 2009;Steen & Thorsdatter Orvedal Aase, 2011;Lihoreau et al, 2012;Lortie et al, 2012;Nakase & Suetsugu, 2015;Steen, 2016) with the optimum technique dependent upon the type of flower visitor expected and the study plant morphology. Steen (2016) demonstrated the applicability of automatic camera monitoring of pollinators, utilising a motion detection device in a small-scale (single inflorescence) survey.…”