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The year is coming to an end and the time to start making summaries has come. We asked the bumblebee experts and wildlife photographers who have introduced bumblebees in words and images this year what the recent spring and summer were like for bumblebees and what was particularly interesting.

 

Marika Mänd, EMÜ PKI Head of Plant Protection Department:

This summer was poorish for bumblebees. Precisely in the active growth period for bumblebee colonies there was much rain and the weather was chilly. It also prevented the development of the colonies so that they stayed smaller than usual. The smaller numbers of bumblebees also was striking on walking in nature. For instance, on summarising the monitoring data from bumblebees in agricultural landscapes and comparing to 2009 it turned out while we 5 years ago counted 180 specimens in the most bumblebee-rich areas, then they were less than a hundred this summer. Similarly, the number of species is smaller by a couple of species in the studied test areas. To a great extent it can be explained by the fact that if there are fewer bumblebees then rare species with small colonies simply may not happen to be encountered although they are likely to be very much present in the area.

 

It was sad that no Bombus  maculidorsis nor great yellow bumblebee (Bombus distinguendus) were seen. These two long-mouthed bumblebees of open landscapes are indicator species of environmentally-friendly agriculture. As an interesting species this year I saw the brown-banded carder bee (Bombus humilis) whose numbers seem to be rising.

 

Eneli Viik, PMK Agri-Environmental Monitoring Bureau Chief Specialist:

I saw very few bumblebees at my country house in Jõgevamaa. There were also few species: mainly only white-tailed bumblebees (Bombus lucorum), buff-tailed bumblebees (Bombus terrestris) and tree bumblebees (Bombus hypnorum). The white-tailed bumblebees made a nest above the garage door, in the wall under the eaves as in the previous year and you had to keep your eyes open when moving there so that they would not accidentally fly into your head.  The tree bumblebees too made a couple of nests in the house wall. More than once, but still seldom, I also saw red-tailed bumblebees (B. lapidarius), garden bumblebees (Bombus hortorum), early bumblebees (Bombus pratorum) and shrill carder bees (Bombus sylvarum). Given the very cold weather in June and the several weeks of heat wave in mid-summer which bumblebees don’t like much either, I would have presumed that in monitoring areas bumblebee numbers would be small too. Surprisingly this year even somewhat more bumblebees were encountered than in the previous year. 

 

Eha Kruus, EMÜ PKI Plant Protection Department scientist:

Despite its small size Estonia offers a surprising diversity, particularly with regard to extreme temperatures. Since my observation areas (Väike-Maarja, Rakvere - Vinni and Tamsalu, Järva-Jaani and the Jäneda - Tapa area) fall into the colder part of Estonia it affected the bumblebees significantly. The long cold period of June brought day maximum temperatures fluctuating around 10-15°C  and long rainfalls from June 12th until practically the end of the month. It was difficult to find days at all when to do the monitoring. In my home garden I noted that despite the promising abundance of bumblebees in early spring, flowers disappeared almost wholly during this period. After the flowering of apple trees, lilacs and late spring flowers, the pause lasted until calendulas started the summer flower cycle. This paucity of flowers may also have been the cause of a phenomenon that I wondered at in the end of June. Namely that when Umbelliferae generally are for two-wings and beetles to pollinate, then this year white-tailed bumblebees were foraging on ground elder that just had started flowering.

 

This year I noticed more of Bombus soroeensis than usual. I found fewer red-tailed bumblebees (B. lapidarius), and red-shanked bumblebees (B. ruderarius) I saw mainly only in spring in our garden. Two specimens that at the August monitoring had been classed visually as workers of black-red B. soroeensis turned out to be male cuckoo bumblebees (judged from the genitalia evidently B. norvegicus). In the course of the monitoring I tried to find rarer species in previous sites but the brown-banded bumblebee (B. humilis) and the great yellow bumblebee (B. distinguendus) as well as  B. confusus and  B. semenoviellus  remained not found. In contrast the short-haired bumblebee (B. subterraneus) occurred here and there throughout the season. Among the less common species it was also pleasing to see early bumblebees (B. pratorum).

 

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