We have two polytunnels which we use for growing tomatoes and other fruit and vegetables, bumblebees and solitaries enter and leave through the doors and pollinate the flowers, sometimes they nest inside the tunnels. However at times the tunnels act like giant Malaise traps and insects find it difficult to find their way out, going up to the roof where in particularly hot weather they can desiccate and die. On cooler or more cloudy days they seem more able to come back down from the roof and find their way out or onto the flowers. I assume that once inside and finding it too hot they fly upwards seeking cooler air, but instead become trapped along with the very hot air against the ridge of the tunnel.

The insides of the tunnel became very hot over the bank holiday weekend and I rescued a large number of bees (and other insects) which were becoming overheated in the space above the doors. Some of these must have flown in though others were probably emerging from nests within the tunnel as both males and females were there. I released many straight away outside but some of each species I potted and rehydrated with damp tissue before taking photographs of those that would stay on a white background.

Andrena scotica female This is a common mining bee in the Spring, I have frequently seen them on apple blossom in our orchard.
Andrena cineraria female. This distinctive bee probably emerged from a nest in the tunnel as I released several.
Andrena lapponica female. This mining bee is a specialist on Bilberry, which is flowering in the wood near our garden.
Lasioglossum morio female. By far the smallest bee of the ones photographed, I have reproduced them all at roughly the same size. They nest in banks and are usually found on yellow flowers, dandelions especially in the Spring.
Bombus sylvestris queen. This bumblebee is a social parasite (cuckoo) of Bombus pratorum. This one had probably just come out of hibernation, and was looking for a nest to take over.
Nomada goodeniana female. Another cuckoo species, laying eggs in the nest of another bee species, in this case several including Andrena scotica.