Nature Notes May 2023

The garden is starting to fill up with insects now that the weather is warmer. Some, like the butterflies, are really beautiful, but some of the others are an acquired taste. Bee-flies like the one captured in flight here are seriously strange insects – although built like a bee, they have only two wings so they are clearly flies. The proboscis may look fearsome, but it is used exclusively to sip nectar from flowers. Why the legs are held in such an unusual position is anybody’s guess. They are not entirely innocuous as their young parasitise the offspring of miner bees that lay their eggs in nest tunnels dug in light soil. When the female Bee-fly locates such a nest, she flicks her eggs towards the entrance to the tunnel. After hatching, the larvae crawl into the tunnel and eat the bee larvae; they develop over the summer and spend the winter in the tunnel before emerging in the spring. There are two species found locally, the Dark-edged Bee-fly (shown above) and the Dotted Bee-fly which has several dots on each wing.

Shieldbugs are smart-looking insects in the adult stage, found in a variety of colours on your garden plants. However, the larvae are often rather misshapen as seen here in this early instar Dock Bug (unsurprisingly, they feed largely on Dock and related plants). It seems over-endowed with antennae and legs at this stage, but will soon develop into the usual shieldbug shape.

Larval insects often differ dramatically from the adult form and none more so than butterflies. The larval form, or caterpillar, is purely a feeding machine, without wings or proper legs. The larva of the Comma butterfly, however, does possess a fearsome array of spines. Although they are not usually harmful, the spines do produce a substance that can cause a rash in anyone prone to allergic reactions. The spines and false eyes along the side certainly do act as a deterrent to hungry birds. The caterpillars feed on a variety of plants and trees – the one shown here was cheerfully demolishing the leaves of my gooseberry bush.