#beeblr

It’s Monday and here’s a bee: the Japanese Sweat Bee (Lasioglossum duplex), a bee species found in Japan, whose life cycle has been documented quite extensively. They’re a eusocial bee [1], meaning they live in cooperative groups [2]. I couldn’t find a picture specifically of a Japanese Sweat Bee, so the above is rather a picture of a Lasioglossum found in Japan.

Throughout the year, they undergo various phases. In the spring, females which overwintered from the previous year will emerge from the ground to start their own little underground nest with 5-7 brood cells, provisioning them with nectar and pollen and laying an egg inside, before closing them off. She stays with the nest [3] and, similar to other bees of their subfamily, the larvae will coat the inside of cell with excrement. If they manage to get to that point, they are almost certain to emerge successfully from the nest in the summer [1].

Mostly worker bees then hatch in the summer, who will go out and forage food while the queen bee lays another batch of eggs, the size of which can be very variable, from 3-41. After closing at the end of summer, the nest opens once again in the autumn [3]. This time, males will attempt to mate with the females. A lot of times this is unsuccessful, with 95% of male bees being shaken off by the females, though if they do mate, it takes less than 10 seconds [1]. The males then go off and die while females who have successfully mated bury themselves in the soil for the winter [3].

They generally overwinter close to their nest from the previous season, and bury themselves at depths of 30-40 cm, with around 10% of them dying [4], though the rest will then go on to try and establish their own nests in the spring as outlined above. The first nest (referred to as the solitary phase) is usually around 8-12 cm in the ground, while the post-summer nest (referred to as the eusocial phase) is deeper at around 10-20 cm [5]. Most nests don’t actually make it past the first phase, with only a quarter getting to the eusocial phase. Once they’ve made it there, 60% of those nests manage to produce mating females [3].