This only species you could mistake V. zonaria with is V. inanis but there are a number of significant differences: Firstly, V. inanis is a fair bit smaller than V. zonaria, but we appreciate this is not a useful character unless you have seen both species! Second, the 2nd sternite is yellow not chestnut brown. Lastly, and this is the clincher, look at the second tergite on the underside. It black on V. zonaria and yellow in V. inanis (see pictures below).
Identification guide no. 2: Volucella hoverflies This installment will focus on identifying large and distinctive Volucella hoverflies (V. zonaria, V. inanis, V. pellucens,V. inflata and V. bombylans). All these species fly through summer (May to August). We’ll start with one of the most impressive: Volucella zonaria. Well basically it is unmistakable. If you think you have seen a large hornet (or a wasp on steroids), but it has two wings, then you have it. It is a very big insect, between 15.5-19.5mm. Have a look at the photograph below (on the left) for some diagnostics.
These are both distinctive hoverflies and V. zonaria is a relative newcomer to the country, only becoming established in the 1940s. The species was a southern speciality for many years but it is moving north (see this map). The adults are often seen feeding on nectar from flowers, like this specimen, which was feeding on flowers of a Lime tree. The larvae are scavengers and predators in nests of social wasps. V. inanis is a native species with a similar southern distribution (see map) and similar habits; the larvae are ectoparasites on larvae of social wasps. The next two species in the genus (pellucens and inflata) are easily distinguished by their dark wing bands and abdominal colours (i.e. only the second body segment is coloured and the rest are black). V. pellucens is by far the most common species of the genus and widely distributed across the UK (see map). You need to look up a lot to see these as they normally hover metres above ground in woodland glades. The adults are also partial to feeding on bramble flowers (Rubus spp.). It is very obvious in flight because the second abdominal tergite is white and sufficiently translucent to be very clear from below (see flight photograph). The larvae (like V. zonaria and V. inanis) are scavengers and predators on the floor of the nest cavity of social wasps.
The fourth species in the genus V. inflata, readily distinguished by its round body shape and colour, is the rarest species of the group. It is associated with mature broad-leafed woodland in the SE and Central England (see map). The larvae are linked to sap runs in deciduous trees. The last one in the group V. bombylans is an impressive bumblebee mimic in which the plumose antennae, long face and wing bands are a distinctive combination.
All photographs, unless otherwise indicated, were by Jon Sadler. The others are from the Wikipedia photograph pool and used under license.
V. bombylans occurs widely in the UK, especially in wooded areas (see map). Like many mimics it occurs in two forms which mimic white (see photograph) and red tailed bumblebees; the latter form is sometimes referred to as var. plumata. The larvae are associated with wasp nests.
If you are interested to find out more there is a fantastic key available from the British Entomological and Natural History Society: Stubbs, A.E. and Faulk, S.J. 2002. British Hoverflies: An illustrated identification guide. 2nd edition. This is how all keys should work - it is brilliant. There is also an active recording scheme to get involved with: http://www.hoverfly.org.uk/ Click here to download an PDF file of this guide.