Natures wonders: male butterflies leave warning on ladies (Introduction)

by David Turell , Wednesday, January 20, 2021, 01:11 (1402 days ago) @ David Turell

Have sex and then leave a mark to warn off other males:

https://cosmosmagazine.com/nature/animals/butterfly-turn-off-flower-turn-on/?utm_source...

"A new study, led by Chris Jiggins of the University of Cambridge, UK, has found that male postman butterflies (Heliconius melpomene) make a chemical compound called ocimene in their genitals, which they leave on female butterflies to deter other males.

"Fascinatingly, and somewhat ironically, ocimene is also produced by some flowers to attract butterflies, so postman butterflies and flowers evolved the genes that produce the compound independently – for different, context-dependent purposes.

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“'Male butterflies use it to repulse competitors and flowers use the same smell to entice butterflies for pollination.”

"Postman butterflies can live as long as six months, and the females store sperm from a small number of sexual partners. They can then fertilise their eggs over many months from a single fling.

"'This smelly substance is no deterrent when on flowers, though.

“'The visual cues the butterflies get will be important – when the scent is detected in the presence of flowers it will be attractive, but when it is found on another butterfly it is repulsive to the males; context is key,” says Darragh.

"One potential explanation for this strange convergent evolution is that a single smell requires less scent receptors to recognise, but in combination with how something looks it can communicate a different scenario. This is somewhat like the aroma of garlic cooking in a pan as opposed to its smell on somebody’s breath.

“'The butterflies presumably adapted to detect [ocimene] and find flowers and they have then evolved to use it in this very different way,” says Jiggins. “The males want to pass their genes onto the next generation, and they don’t want the females to have babies with other fathers, so they use this scent to make them unsexy.'”

"While not all butterflies produce this anti-aphrodisiac, the male postman’s chemical-making capacity sheds interesting light on smell as a form of communication in insects."

Comment: Many male animals mark territories with their urine. This is similar. The so-called explanation three paragraphs above is just a wild guess guess. Why a repellent is an attractant seems strange. How much 'context' do butterflies appreciate. Maybe approaching a 'hot' female prospect who smells like a flower is just confusing to the male who wants sex, not a meal!