High-flying ladybugs are taking over everything


It’s hard to picture the humble, adorable ladybug flying more than a kilometre over our heads, moving faster than Usain Bolt in a sprint. Nevertheless, radar evidence collected by Jason Chapman shows the bugs flying with this unexpected dexterity.

Lori Lawson Handley has been studying the harlequin ladybug since she first arrived at the United Kingdom’s University of Hull in 2007. The ladybug is very good at dominating environments in both North America and the U.K.

“It is extremely difficult to follow [ladybugs] in the field,” Handley explains.

Researchers had no idea just how well ladybugs fly. Up until now, flight up to a couple of meters was considered long distance flight for the critters. When the radar data shows ladybugs flying a kilometre in the air, it’s safe to say that two meters is nothing.

“We had no idea the ladybirds were travelling as high as this, but many other insects use high altitudes for migration too, so it wasn’t that surprising.”

Alright, so if that’s not actually very surprising, what is?

Well, that they aren’t flying where aphids are.

As anyone who’s tended a garden knows, ladybugs are great aphid killers. The best, in fact. And aphids are great threats to crops worldwide. It’s no surprise, then, that farmers have introduced aphid-hunting ladybugs in all manner of farmland.

Between flying and hitching rides on humans, ladybugs spread quickly once introduced, often wreaking havoc on native insect populations. Their simultaneous usefulness for crops and danger to ecosystems make them a very interesting topic for study.

It turns out temperature is the main trigger for ladybug migration. The warmer it is, the more they travel. Aphid populations hardly even enter the equation.

“Although speculative, this could mean that increasing global temperatures could trigger more dispersal,” according to Handley. “Rising temperatures could facilitate their spread.”

That’s fairly unfortunate news, since it means ladybugs aren’t following the food, but are entering ecosystems they could cripple by knocking out the natives.

It’s a bug-eat-bug world out there, and understanding that means a lot to farmers and scientists alike.
For any UK readers out there, you can help the cause by spotting ladybugs for science through the UK Ladybird Survey! It’s a hard job, but you can do it. I believe in you.

[PLoS ONE][image via das_miller/Flickr]

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