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  • Seth King

Insect Monitoring 2021

Our Framework partners were very busy in 2021 monitoring insects and pollinators. There was a particular focus on syrphids, bumblebees and butterflies and our farmers and scientists used a range of techniques including transects and pan traps. This year our scientists had to come up with new solutions to dealing with regional landscape and weather conditions and this ingenuity is reflected in this blog, taking a look at some of the highlights of this year’s insect and pollinator monitoring.

Some of the earliest pollinator monitoring occurring in our clusters this year came in Austria. Here, BOKU demonstrated two of the major monitoring techniques used across the clusters.

Transect walks

This was a method for butterfly-bumblebee monitoring. They counted all the individuals of butterflies and bumblebees along a 500 m transect walked with uniform pace several times during the favourable weather condition in May-August. Further, they divided each transect into 50 m sections and each section was represented by a single habitat type. During walking in transect, they filled the field form with the date, start time, finish time, average temperature, and average wind speed on the Beaufort scale. Butterfly individuals were identified to species level by collecting them in a glass box. In the case of bumblebees, samples were taken and caste (i.e. queen, worker, male) where noted.


This was a method for solitary bees (especially Halictidae) and syrphid monitoring. They made pan-traps with the set of three colours (white, UV blue, and UV yellow). Pan traps were made of plastic bowls painted with the UV reflected based on the recommendation of provided protocol. They used water and few drop of (unscented) liquid soap (to break surface tension) in each bowl so that insects land and drown inside it.

According to the recommended protocols "For a 1km grid-cell, it is recommended to place between 5 and 7 pan-trap sets". However, in our 500 m grid cell, they placed 3 pan-trap sets near to butterfly-monitoring transect. Pan-traps were left in place for 24h in suitable weather condition. Afterward, the samples were taken and stored in 70% ethanol for preservation and later identification. Also, they counted the flowers cover and average height of plants present within an area of 2m radius centered on each pan-trap station.

In Estonia, EMU completed pollinator and butterfly surveys (26 transects thrice). EMU prepared all traps needed for pan trapping and conducted three rounds of pan trapping (18 transects thrice). They also digitized survey data for butterfly and pollinators transects (26 transects 3 times per season). While in the Czech Republic, pollinator monitoring, i.e. pan traps and transects, was carried out twice, on August 21st and September 21st by an entomologist from CZU, hired to carry out this work. The entomologist followed the pollinator monitoring protocol provided by LIST. CZU also met with LIST to clarify uncertainties in the monitoring methodology and storage of insects. The same area, as for the birds, was sampled.

In our Italian cluster this year, transect walks were performed in June, July and September in all 12 quadrates. Pitfall traps were done only in June and September because in July the vegetation was dead, due to hot and dry weather conditions.

Instead in the transect walks, there was a total of 1056 pollinating insects among which wild bees, few honeybees, some bumble bees and few hoverflies. The dry and hot weather affected flower abundance and insect abundance. There were 1317 butterflies belonging to 48 species.

Finally, in a novel and exciting development, in October spider nests were set up together with the farmers in two olive groves. These nests are now monitored to see if they host spiders.


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