Ruby-tailed wasps get their common name from their ruby red coloured abdomen.
Latin name: Chrysis ruddii
Notable feature: Beautiful red, blue & green metallic colours.
Ruby-tailed Wasp (Chrysis ruddii) © Roger Key
There are a number of Ruby-tailed wasp species that look very similar and are difficult to tell apart. They’re all beautifully coloured, with red, blue, green and bronze metallic colours. These wasps are solitary, meaning they don’t live in large social nests.
Chrysis ignita is the species of the ruby-tailed wasps that can be found across the UK from April through to September.
Being barely 10mm in length, they can be difficult to spot. You can often see them running restlessly over walls and tree trunks, constantly using their downward-curving antennae to pick up the scent of their host insect. As a parasite they require another species for part of their life cycle, Chrysis ignita mainly parasitizes mason bees and other solitary bees.
Parasite on bees
Once a female ruby-tailed wasp finds the nest of its host insect, it explores the entrance to make sure no one is home. If it should encounter an angry resident, it is well equipped to defend itself; it has a very hard body cuticle which protects it from stings and the underside of the abdomen is concave so the wasp can curl up into a ball.
Laying eggs in a solitary bee nest
The wasp reverses into the hosts nest hole and lays its eggs next to the host eggs. The wasp eggs hatch into larvae, which eat the newborn host species. The unsuspecting adult host returns to seal its nest hole, never knowing that Chrysis ignita is inside! This is why this wasp is also known as a cuckoo wasp. The larva complete their development inside the nest and the adults emerge the following spring.
Some Ruby-tails are rare
Chrysis ignita is one of a number of very similar Ruby-tailed wasp species which are extremely hard to tell apart; Chrysura hirsuta and Chrysis fulgida are classified as Priority Species in the UK Biodiversity Action Plan. Buglife have been lucky enough to find the rare Ruby-tailed wasps at one of our brownfield project sites in Scunthorpe!