Love and a Regurgitated Gift

In the world of fruit flies, romance can take surprising forms. The species Drosophila subobscura has a peculiar courtship ritual: before mating, a male must win over the female by giving her a gift. But instead of flowers or chocolates, he offers her a tiny mouth-to-mouth meal of regurgitated food. Interestingly, their close cousin Drosophila melanogaster—the fruit fly most often used in laboratories—doesn’t do this at all.

So what makes one species a generous suitor while the other skips the gift exchange? Japanese researchers discovered that the difference comes down to a single gene, called FruitlessM (FruM), which helps wire male brains for courtship behavior. In D. subobscura, this gene switches on in a group of brain cells that regulate feeding. When FruM is missing, the cells don’t grow the connections they need, and the males fail to present their nuptial gift.

Even more intriguing, when scientists turned on FruM in the same brain cells of D. melanogaster, something remarkable happened: the cells sprouted new connections, and the males began regurgitating food more often—hinting at a hidden potential for gift-giving buried in their biology.

This research shows how a small genetic change can spark big differences in behavior between species. What looks like a simple act of food sharing is, in fact, the product of evolutionary history written deep in the wiring of the brain.

Previous thoughts on the same topic:
Climate Warning Signs Were There 130 Years Ago – If Only We Had Noticed
Preventing future fires in Hawaii is possible, but the question remains: Are animal activists and politicians prepared for the necessary measures?
Seeing sex developed novel cultures

Seeing sex developed novel cultures

In Sweden the local culture is breaking down as the number of immigrants from other cultures increases, but in Finland even a main media journalist Annamari Sipilä has noticed that all cultures may not be equally good. That turned clear to her, when a rapist recently asked the court to reduce his punishment by pleading to his cultural legacy. 

I have also noted other cultural oddities - at least to us westerns - during the last years. Women were forced to sex work by threatening with their cultural specialties including voodoo. In Iran 4200 girls under 14 years of age got married in year 2010, 716 of them under 10 years of age. And in India eight men raped a pregant goat. 

Thus, there are differences between the cultures. And that is why the scientific and technological revolution that changed the world took place in Europe instead of e.g. China, Near East or Africa. 

But how did the cultures appear? Are they typical only to people and perhaps most intelligent animals? Or could cultures develop even among insects?

This question was addressed in the research conducted by Etienne Danchin and colleagues. They analysed the effects of seeing sex on the common fruit flies´ sexual behavior and their offspring. In their report, Danchin et al. define cultures as a traditions, which have their roots in earlier generations and are inherited via social learning.

The research was also based on the knowledge that we tend to conform our behavior to that surrounding us. One extreme of this are children, who say that black is white when several robots claim that. Fortunately we adults are more clever, and only conform our behavior according to real people surrounding us.

But then to the research report itself.

In their first experiment Danchin and colleagues gave three days old virgin flies to watch a young female selecting a partner between two males colored either pink or green. After seeing the copulation, the virgin fly was allowed itself to make a choice between a pink and a green fruit fly. As a result, their selection was the same color as what they had just seen being selected by another female. In control, where the virgin had not seen any copulation, the colors did not make a difference.

In the second experiment the researchers made a similar experiment, but now the virgin was allowed to follow an elder female to select between pink and green colored males. And the result was the same as in the first experiment. That it, they selected a male with the same color as they had just seen being selected by the elder female. So the virgins learned equally well from elder flies and their peers.

In the third experiment the virgin flies followed five times a selection of the same colored fly, and were again allowed to make their own selection, but only after 24 hours. That is, after about three per cent of their lifetime. The same rule worked again, so the flies remembered what they had once seen.

In the fourth experiment, mutant flies - normally avoided in pairings - were offered to virgins as painted according to their favorite color. And the males were again selected according to the color instead of genetically determined outlook.

In the fifth experiment the researchers manipulated the ratio of colors shown to be selected by other virgin flies in their sphere of vision. Again when there was only one color selected in front of their eyes, they tended to make the same selection themselves. However, it was a big surprise that this rule held all the way to a frequency of 60 vs. 40 percent. 

And finally, the researchers made an experiment to determine whether the mode of behavior - that flies had learned as virgins - was also transmitted to their offspring. The answer was yes, and even over several generations. Therefore fruit flies developed a learned tradition somehow taught over several generations, and can thus be added to the list of animals with cultural behavior, where populations learn habits from previous generations. 

Taken together, the study by Danchin and others showed that as simple animals as fruit flies may have cultures that differ from each other. Therefore, also the roots of our own cultural behavior probably extends to our evolutionary prehistory; perhaps even to the time we had not yet climbed from ancient seas to the dry land.

Because this blog is considered a political one, it is also important to think what the above described research contributes to the question of equal value of all human cultures. However, as the purpose of this blog is not to provide prefabricated views, but to provoke its readers to think themselves, I am not going to give answers myself, but leave the question to be figured out by all my highly valued readers. 

The original thought published in Finnish:
Seksin katsominen synnytti uuden kulttuurin