Nature's weird cheats
By Taylor Wildlife, Oct 2 2018 10:51AM
Without wanting to state the obvious - wasps and bees can sting. And although it might feel like they're just out to ruin summer picnics, these stings are intended to work as a defence against predators. Wasps and many bees are boldly striped with colours that act as a warning to predators: don't try to eat me or i'll sting you! Many insect-eating birds and mammals learn to leave these insects along and opt for a less hazardous food option instead.
These warning colours are so effective that even non-stinging insects with similar colour patterns often spared and hence it becomes advantageous to sport a black-and-yellow uniform even if you are not in possession of a stinging apparatus. The evolutionary selection of non-dangerous animals look dangerous is called Batesian mimicry. Many insect groups evolved to mimic wasps and bees independently of each other, including many longhorn beetles, hoverflies, and clearwing moths. This evolutionary selection of non-dangerous animals to look like dangerous animals is called Batesian mimicry. On our survey sites we observe many species which display Batesian mimicry, and we'll discuss two of those before.
Bog hoverfly (Sericomyia silentis)
The larvae of the bog hoverfly develop in bog pools that are too acidic for many other insects. In order to obtain enough oxygen in this still and oxygen-poor water water, the larvae possess a long straw-like tube at the end of their abdomen with which they manage to obtain oxygen from the water surface. The adult flies are commonly seen feeding on flowers on the moors in late summer and have yellow and black bands over their body, similar to the markings wasps have. They can, however, be disguished from wasps (along with other wasp-mimicking flies) by looking at the following traits:
(1) Wasps and bees have two pairs of wings, but flies only have one set of wings.
(2) Stinging wasps and bees have a narrow 'wasp waist'. Flies do not have this.
(3) Wasps and bees have biting jaws, whereas flies have an enlarged proboscis with a labellum attached. The labellum is comparable to a large tongue which they use in feeding.
Bumblebee hoverfly (Volucella bombylans)
Like the previous species, the bumblebee hoverfly mimics a more dangerous species, and actually goes one step further than the bog hoverfly. The larvae of these hoverflies live on organic debris on the inside of bumblebee nests. This species also has different colour varieties, which look like different bumblebee species. There are yellow and black striped flies with white-haired bums which resemble buff-tailed bumblebees (Bombus terrestris), and black and orange flies that look like red-tailed bumblebees (Bombus lapidarius).
So have a good look next time you're out and about, and don't feel the need to run away from these harmless cheats!