Snail-nesting bees


Snail-nesting mason bees (Osmia rufohirta) nest in empty snail shells. Inside they line them with leaf mastic, with which they also mark their exterior. Then they bring pollen and nectar into them, lay their eggs and close their nests with chewed up leaves and sand. Eventually they roll the shells into leafage and hide them well. Their efforts, however, can be in vain if their nests are discovered by the parasitic chrysidid wasp. While the nest's owner is away, the wasp enters the shell and lays its eggs in it. The larva that hatches from it feeds on nutrients gathered by the bee and, on top of it, kills its larva.


Snail-nesting mason bee (Osmia rufohirta) nests in an empty snail shell.

When returning from "pasture", it first of all enters the shell head first to disgorge the nectar.


In order to scrape the pollen cargo from the bottom part of its abdomen, it must enter the shell also with its backside first.

Chrysidid wasp Chrysura dichroa lays its eggs into the nests of snail-nesting mason bees.



Slovenian Museum of Natural History

                                Text and photographs by Andrej Gogala