101 years old and still flying high as ever...

It has long been known, to those who research sexual behaviour of flies if not to you or me, that female fruit flies are more choosy than males, or, if you prefer, in the matter of mating, males are more indiscriminate than females.

Previous research with fruit flies has shown that if a female sees a girlfriend mating with a particular male, she is more likely to mate with that same male than to pick another whom she has not watched. 

This behaviour, in which the female copies the choice she saw another female making, is called “mate-copying” and new research shows that the same applies to males.

The researchers, from the University of Toulouse in France, began by randomly dusting females with green or pink powders after which “virgin naive observer males” were given the chance to see another male choosing between a pink and a green female. 

The observer males were then given the choice between two new females, one pink, the other green. 

The object of the exercise was to test the hypothesis that the males would be influenced by what they had seen and go for a girl who was the same colour as the one they had just seen mating. 

And in case the males had an innate preference for green or pink, they performed the same experiment on a group of male flies who had not first watched two other flies mating. 

In that case, their choice of female colour was random, but if they had watched the earlier mating, then they tended to go for the same colour as the previous male did. 

The researchers see this as clear evidence of mate-copying, but I thought I would check by asking a passing male fly. 

“I say,” I said, when I succeeded in trapping one inside an upside-down glass, “may I ask you a question or two about mate-choice?” 

“Oh not another researcher,” he sighed. 

“The last ones wanted to see whether we preferred pink women or green women. What on earth are these guys on? And what do you want now?” 

“Oh, were you part of that earlier experiment?” I asked. 

“It’s really lucky I caught you as I wanted to ask what your feelings were about it. Did you really show a preference for the colour of the girl you’d seen mating?” 

He blushed when I put the question. 

“Well if you think about it, you’ll see it stands to reason. It you’ve got to choose between pink girls and green girls for an amorous tryst and you’ve not seen flies of those colours before, it makes sense to go for the colour you’ve seen delivering the goods. 

“Call it colour prejudice if you like, but I was so taken aback by these gaudily coloured women that I just did what the chap in front of me had done.” 

Then his buzz dropped to a whisper as he said: “Actually I prefer bluebottles.” 

Deeply shocked, I lifted the glass and splattered him with a copy of the Daily Express and we left it at that.