Amazing naughty fly!

Dear All

Many greetings – just back in access from a week of fieldwork at Suyian in Laikipia, north of Mt Kenya…

I have been looking at the ant-acacias up here, called Whistling Thorns. The name is especially apt at this time of year as the dry wind sweeps across the plains and plays plaintive music in the hollow thorns that the ants live in.

The Whistling Thorns sing in the dry season
The Whistling Thorns sing in the dry season

While collecting ants and scale insects (more on these fascinating creatures soon), I found myself sheltering from the hot sun and watching the comings and goings of ants on the trees. As it has been really dry, I didn’t expect to see much, but as always Mother Nature had a surprise in store…

The ants were walking up and down the stems and branches. The ants on this tree were Cocktail Ants, and they travel down to the ground to hunt and forage from the tree.

Cocktail Ant walking down a branch
Cocktail Ant walking down a branch

As I watched the ants coming and going, I noticed that one of them was moving in short hops and dancing around at one spot on the trunk. A closer look revealed the most incredible interaction taking place. First of all the errant ant was no ant at all, but a devious little fly that had perched on the trunk of the tree among the ants. It would sidle up to an ant and engage in begging behaviour that included tapping the ants on the head. The hapless ants then proceeded to regurgitate food for the fly. I watched it doing this over and over again (and on other trees later on too).

Fly coaxing ants to feed it!
Fly coaxing ants to feed it!

Ants do share food between each other, so it is this sharing behaviour that the fly is exploiting. While the ants fed the fly, I noticed that it gently rubbed their antennae with its own short stubby antennae to keep them mollified.

Naughty fly tricking another ant
Naughty fly tricking another ant

After tricking about ten ants, the fly then retreated to a shady spot to rest for a much-needed post prandial nap!

Satiated fly resting on the tree's trunk
Satiated fly resting on the tree's trunk

More from the wonderful world of bugs soon. Thanks to everyone for the kind comments!

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