Science Snapshot: One Insect’s Corpse Is Another’s Breakfast

Bees on the pavement surrounded by yellow flower petals

(Left) The two bees that were discovered on the pavement (Right) Close up on one of the bees

Sophie Klahr

On August 28, poet Sophie Klahr saw two dead bees on the pavement with scores of ants surrounding them with small yellow petals. She posted pictures of the tableau on Twitter, hoping the hive mind of social media entomologists could bring some clarity to the scene. The tweet soon went viral with thousands of replies pouring in, some more grounded in science than others.

One of the prevailing theories on Twitter was that the ants were responding to oleic acid, a compound that is released when bees and ants die. For such highly social creatures, having a dead comrade in the mix could leave the rest of the colony at risk of exposure to pathogens or parasites, so oleic acid signals the need to clear it away. Terry McGlynn, an entomologist at California State University, Dominguez Hills, spoke to The Scientist about the viral tweet and explains that if this is what was happening here, the ants wouldn’t be covering the bees up as they are in the picture. Rather, they’d clear them out of the way and move on. He also dismissed the anthropomorphic attempts to describe the scene as a funeral, which no insect species is known to do.

His interpretation of the scene hews more to something he’s seen many times and is common among fire ants (though he couldn’t identify the ants based on the tweeted pictures). The ants in the photo most likely came upon a dead insect to scavenge but couldn’t take the entire bee corpse back to their nest, so they covered it up to hide it from other opportunists.

“When fire ants encounter a big chunky piece of food that they can’t easily carry off, they cover it so that over the next several hours and days, the ants can selectively remove pieces of that animal as a prey item,” McGlynn tells The Scientist.

Many on Twitter did suppose that the ants were hiding a food source, but incorrectly assumed the flowers were chosen to mask the bee’s scent. Tristan Kubik, a graduate fellow at the University of Texas, tells The Scientist by email that the compounds behind the flowers’ smell are highly volatile and dissipate in the air quickly. 

So why did the ants use flower petals? Simply put, it’s what was available. According to Kubik, if the bees had fallen on soil, the ants would have used that to cover it up instead. 

“Because the bees are on pavement littered with petals, the ants are making the most of what’s around. The petals are perfectly usable material to try and physically hide these rich food sources,” Kubik writes.

Source: the-scientist.com

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