I’ve Seen That Face Before
For a long time, we believed that only mammals and birds were capable of distinguishing between individuals, the very foundation of the capacity to develop personal relationships. This belief persisted until an enquiring scientist, with the help of some model aeroplane paints, began face-painting wasps. The species concerned was Polistes fuscatus, an American member of the family of paper wasps. Paper wasps build nests from chewed-up wood fibre, which look like a rosette of small larval cells. The nest hangs on a stalk, like an upside-down umbrella. Unlike regular stinging wasps, which also build nests from wood pulp, paper wasps’ nests do not have a protective envelope around the comb of larval cells.
This wasp lives in a strictly hierarchical society, where it’s crucial to know who’s the boss. Maybe that’s why they’re so good with faces. A wasp whose face had been painted in a way that altered her pattern of stripes met with an aggressive reception from her fellow inhabitants when she returned to the nest. They didn’t recognise her and were confused. As a control, the scientists also painted other wasps without altering their personal patterns. These wasps did not experience any reactions on their return to the nest.
Another fascinating point is that after a few hours of jostling, the other inhabitants of the nest got used to the face-painted wasp’s new look. The aggression diminished and everything went back to normal. The other wasps had learned that this was indeed the same old Waspella, despite her makeover. This implies that the wasps actually have the capacity to recognise and distinguish between individual members of their community by their detailed facial cues or ‘features’.
Honeybees take the whole business up a few notches: they can distinguish between human faces in the form of photographic portraits. What’s more, they can remember a face they’ve become familiar with for at least two days. It is doubtful whether the bees relate to what they are actually seeing. They seem to believe the portraits they are presented with are really funny flowers, with the darker areas of eyes and mouth representing recognisable patterns on ‘petals’ that are actually the outline of the portrayed face.
This is new and exciting information, which forces us to rethink how facial recognition actually works: after all, we’re saying that a creature whose brain is smaller than the letter ‘o’ in this book is able to achieve similar things to us humans, with our cauliflower-sized brainboxes. Greater understanding of these processes may be able to help people who suffer from face blindness (prosopagnosia), which is a neurological disorder characterised by the inability to recognise faces.
Perhaps this knowledge can also be used in surveillance – at airports, say. Not by installing a glass cage of buzzing bees to scrutinise us sternly as we go through customs (although that would be pretty cool!), rather by translating the principles that enable bees to recognise facial patterns into a logic that computers can follow. One hope is that this could lead to improved automatic facial recognition – of, say, wanted criminals – via surveillance cameras in crowded places.
What Shall We Call the Beetle? Names and Insect Groups
In an attempt to organise the hordes of tiny critters, we humans have split them into groups according to how closely related they are. It’s an ingenious system that starts with the kingdom, which is then divided into phylum and class, which are again divided into order, family and genus before we come to species.
Take the common wasp, for example. It is a species that belongs to the animal kingdom, the arthropod phylum, the insect class, the Hymenoptera order, the stinging wasp family, the Vespula genus and, finally, the common wasp species.
All species have a two-part Latin name, which is written in italics. The first part tells you which genus the species belongs to and the second additional part identifies the species. This system, introduced by Swedish naturalist Carl Linnaeus in the 1700s, makes it easier for biologists to be certain that they’re talking about the same species even when communicating across national borders and language barriers. The common wasp has been given the name of Vespula vulgaris. You can often grasp the meaning of the Latin names: for example, vulgaris means ‘common’ (and is also the origin of the word vulgar).
Sometimes, the Latin name may tell us something about the insect’s appearance, as with the Stenurella nigra beetle, where nigra describes the colour of this totally black species. Other times, the name may have been borrowed from mythology, as in the case of the beautiful peacock butterfly, Aglais io. Io was one of Zeus’s mistresses, who also lent her name to one of Jupiter’s moons.
With hundreds of thousands of insects to name, entomologists sometimes go a bit wild, calling species after their favourite artists, such as the Scaptia beyonceae horsefly (see here), or characters from much-loved films, like the Polemistus chewbacca, P. vaderi, and P. yoda wasps. Sometimes the species names contain a pun that you only discover when you say them out loud. Just try pronouncing the names of the bean-shaped beetle Gelae baen and Gelae fish, or the parasitic wasp Heerz lukenatcha and its relative Heerz tooya!
Orders for Order
There are around 30 different orders of insects in the world. Beetles, wasps and their relatives, butterflies and moths, flies and their relatives and true bugs are the five largest. Other orders include dragonflies, cockroaches, termites, Orthoptera (grasshoppers and crickets), caddisflies, stoneflies, mayflies, thrips, lice and fleas.
Let’s start with beetles (Coleoptera) – one of the largest orders of insects worldwide, despite tough competition from the wasp order, where improved knowledge is leading to a steady rise in the number of species. The hallmark of beetles is that their forewings are hard, forming a protective shell over their back. Beyond that, beetles are incredibly varied in appearance and lifestyle, and can be found on both land and water. There are more than 170 different beetle families, some of the largest being true weevils, scarab beetles, leaf beetles, ground beetles, rove beetles, longhorn beetles and jewel beetles. All in all, there are around 380,000 known beetle species worldwide.
The wasp order (Hymenoptera) consists of familiar insects such as ants, bees, bumblebees and stinging wasps, including many species that are social and live in colonies containing hordes of female workers and one or more queens. The order also encompasses many lesser-known sawflies and a huge number of parasitic wasp species. So far, we have identified more than 115,000 species in this order, but the number is rising steadily and this is probably the largest order of insects.
Butterflies and moths (of the Lepidoptera order) have wings covered in tiny scales arranged like roof tiles. There are more than 170,000 Lepidopteran species in the world, but many are small and unassuming. The best known are of course butterflies – comprising around 14,000 large, diurnal (as opposed to nocturnal) species that are often beautifully coloured and patterned. The nocturnal species are known as moths.
Flies, or Diptera, include not only species we commonly call flies, like blow flies and horseflies, but also mosquitoes, gnats and crane flies. Their Latin name derives from the fact that they have only two wings (di means two, ptera means wing), whereas insects normally have four, as mentioned earlier. In Dipterans, the hindwings have been repurposed as small, club-shaped gadgets that help them achieve balance in flight.
