Flies earned this nickname (also called an order) when they ditched two of the four wings shared with their ancestral insects and instead developed the limbs into gyroscopic flight aids called “halteres”. Organs like these allow Diptera to perform excellent aerobatics, so along with their super-fast vison, I’m not surprised we can’t catch them.

They are an extremely successful group, with approximately 152,000 known species across 160 families in the world; even in Britain, there are 7,000 species!

That means there are more recorded species of flies in the UK that the current estimate of mammals globally.

Your living area is most likely very interesting to the fly, as they can taste with their feet land almost anywhere. Well also, if they did want to leave, they see in UV (Ultraviolet) which is refracted by the glass panes of your window making it pretty disorienting for a dipteran.

Flies are diverse and, in my eyes, rather beautiful.  Geometrically patterned hoverflies and the chrome iridescence of some soldier flies show this visually. Also, some species, are important as pollinators!

The hoverflies (Family: Syrphidae), prominent among the ‘non-bee pollinators’, are known to visit at least 72% of global food crops and 70% of animal-pollinated wildflowers.

In fact, many flies have other fascinating characteristics, for example - bee-flies evolved to mimic famous pollinators, the bumblebees, including a species I observed for the first time this year: the dark edged bee-fly (bombylius major).

The most common bee-fly of all, the dark edged bee-fly has a fluffy body like a bumblebee!

Their long, straw-like tongue (called a proboscis) is the optimal length to reach the nectar of certain flowers, such as primroses. It can also extend its mouthparts to reach into other flowers. Having pupated over winter, the dark edged bee-fly tends to emerge in March.

Like bees and other flies, adult bee-flies are great pollinators. They have an amazing ability to hover next to a flower, resting their legs as they feed on the nectar. You might not guess it but, like us, bee-flies have favourite colours. They aren't attracted to bright yellow or pink flowers and much prefer to feed from flowers that are purple, violet, blue or white.

Bee-flies are all parasitoids. Parasitoids are like parasites– that is, their larvae infect and then kill a single host animal. This distinguishes them from parasites, which live off a host but don’t usually kill them, and predators, which attack and consume many individuals of the same or different species.

Female dark-edged bee-flies float a few inches above mining bee nesting locations while they flick their eggs randomly on the ground. A few of these eggs will fall into or close by an active mining bee nest, almost entirely by accident.

Once that miracle has taken place, a bee-fly larva emerges from its egg and burrows inside the host bee's underground nest cell to wait for the bee larva to develop. The bee-fly larva attaches once the host bee larva is big enough and begins to drain the host's fluids. The lifecycle of the bee-fly is completed after the host bee larva is dead & digested! The larva pupates and spends the winter underground before emerging as a fully grown adult the following spring.

What an intricate life they live. Isn’t it wonderful that there’s still so much more to learn?

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