Climbing Up the Walls

Volucella pellucans

One of the larger hoverflies on the wing at this time of year is Volucella pellucans, a shiny syrphid with a strikingly distinctive half-black, half-white abdomen. Adults are common visitors to flowers such as bramble, various umbelliferous species and, as is the case in the individual pictured, other garden flowers such as privet. Females will lay eggs in wasps's nests with the resultant larvae living inside as scavengers (1).

"Foot" of Volucella pellucans

For its size (up to 15 mm), V. pellucans is quite agile upon lighting on a flower. This is due to a system of setose attachment pads on the pulvillus (located between the claws at the base of the tarsus). The setae create friction between the fly's leg and the surface. Due to its relatively large size, V. pellucans creates a greater frictional force than smaller hoverflies, but needs less acceleration to detach itself from the surface (2).

References:

1. Chinery, 2004. Collins Gem Insects p. 199
2. Gorb et al., 2001. The Journal of Experimental Biology 204 pp. 1421-1431