Nature on our doorsteps: Nomad Bees take advantage

Rosaleen Dwyer is the County Heritage Officer at South Dublin County Council – every week she gives us an insight into the natural heritage around us and the beautiful biodiversity of the plants and creatures.

Amongst the 77 different species of solitary bees in Ireland, some belong a group known as the Cuckoo Bees.

Like the Cuckoo bird, Cuckoo Bees also use the nests of others as a location in which to lay their own eggs.

One such Cuckoo Bee is the Nomad Bee. Its name reflects the fact that these bees are nomads, they wander around and do not build a nest of their own.

While their yellow and black stripes make them look like a wasp, they are in fact solitary bees.

Nomad Bees are kleptoparasites, meaning they steal the food of another species to provide food for their own young.

They typically focus on the nests of mining bees who dig tunnels in sandy soil where the females lay their eggs.

Before the mining bee seals off the tunnel, she will make several journeys back and forth to collect pollen from nearby plants.

She leaves this pollen in the tunnel, as food for the young larvae when they hatch from the eggs.

Nomad Bee females observe the female mining bees going back and forth.

This Gooden’s Nomad Bee is heading straight for the nesting tunnel of a mining bee

Whenever she sees a mining bee leave, the female Nomad sneaks in.

She quickly lays one or two eggs and then leaves before the mining bee returns.

When the mining bee has finally filled the tunnel with pollen, she seals it off and leaves the eggs to develop by themselves.

When the Nomad larvae hatch, they eat the eggs or any hatched larvae of the mining bee, and they feed on the store of pollen.

They continue to develop and mature for up to a year before emerging from the tunnel as new adults.

Like mining bee adults, Nomad bees also visit flowers to feed on pollen and nectar.

Unlike mining bees however which have special pollen-collecting hairs on their legs, Nomads bees are almost completely hairless because they have no need to collect pollen to feed their young.

Two species of Nomad Bees can be spotted between April and June, Gooden’s Nomad Bee and Marsham’s Nomad Bee.