Warwick Gardens was awash with children from Bellenden Primary School last week, running around playing football, shouting and swinging from the swings and generally having a great time. Dolled up in orange high vis vests they virtually dazzled in the sunshine, like little daytime fireflies or mini construction workers having a playtime from mending the rail tracks. But they were not the only bright young things in the park – there were jewel wasps competing for the title of the brightest of bright young things.
If you look closely amongst the shrubs you might see a flash of metallic blue/green and red skittering around on the leaves. These are the ruby-tailed wasp Chrysis ignita. Whenever I see them they are running up and down stems, pausing occasionally to have a sniff using their downward-curving antennae to pick up the scent of their host insect. As a cuckoo wasp they are looking for mason bee nests. Once the female finds the nest she explores the entrance to make sure no one is home then sneaks inside and lays her eggs. With a hard body cuticle to protect from stings she is well-equipped to defend herself if she comes under attack from an angry host bee – she curls up into a ball. The eggs hatch into larvae, which eat the newborn host species. The larva complete their development inside the nest and the adults emerge the following spring.
Another jewel wasp to look out for is Hedychrum niemelai. Its the first time I have seen this beautiful shiny wasp in Warwick Gardens. They love to come out in bright sunshine to feast on the yarrow. The female lays her eggs in the nest of the digger wasp Cerceris arenaria – another first sighting for Warwick Gardens. If a host insect is nesting you can be sure to find its cuckoo!