Leaf Cutter Bees - pac-man of the insect world
Carrying out some late summer pruning of the wisteria this week I came across several leaves with semi circular ‘bites’ removed by the Pac-man of the insect world. These were classic tell-tale signs of leaf cutting bees. Meticulously cut out, the half-moon portions of leaf are transferred to a nesting site, usually a hole in a rotting log or hollow plant stems, where they are rolled together to form the most perfect ‘cigar’, the home for a new developing bee larva.
There are seven species of these solitary bees in the UK but the two most commonly encountered are the Patchwork leafcutter bee (Megachile centuncularis) and Willoughby’s leafcutter bee (Megachile willughbiella).
Harmless to humans, and apart from some casual leaf removal, harmless to the garden, they are just another piece to a jigsaw that completes the biodiversity of our gardens. We’d certainly never resort to ridding our garden of them. Efforts can easily be made to encourage them into the garden by providing suitable nesting sites. Bundles of hollow stems can be bunched together or a block of wood can be drilled with a range of holes up to 10mm in diameter. Placed about 1.5 metres above ground level and on a sunny south facing wall they should soon attract inquisitive females. Ready made ‘hotels’ can be purchased where the nesting chambers can be revealed and inspected by the removal of a side panel. It's important to clean out and replace these nests every few years to prevent the build up of parasites and any fungal pathogens.
