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Born Pregnant: Aphids Invade with an Onslaught of Clones

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Female aphids are the matriarchs of a successful family operation — taking over your garden. But don’t lose hope; these pests have some serious predators and creepy parasites looking to take them down.

Additional Resources

  • Entomologist Ian Grettenberger studies agricultural pests at UC Davis.
  • Jhalendra Rijal is an integrative pest management advisor with UC Cooperative Extension in Modesto, Calif.
  • Information about garden and landscape pests like aphids comes from the UC Statewide Integrated Pest Management Program (UC IPM).


Got a plant? There’s probably an aphid for that.

They’re a nightmare for anyone growing veggies.

There are thousands of types, with all kinds of looks.

And they seem to pop up overnight.


Before you know it they’re everywhere.


They pierce leaves and stems with their stylet, and suck out sugary sap, leaving the plant yellow and wilted.

While they’re not particularly fast or well-armored … aphids are highly skilled at one thing.

Making babies.

Most of the time they give birth to live young instead of laying eggs.

That’s different from most other insects.

Aw. She’s got her mother’s eyes.

An aphid mom can push out five or six nymphs a day, sometimes more.

And she doesn’t need to find a mate to do it.

Most of the time, aphids just clone themselves.

You can see the eyes of her clones growing inside her.

And here’s the really wild part …

Her babies are born already pregnant.

In a week or two, they’ll start giving birth to clones of their own.

That’s why it only takes a single aphid to infest your greenhouse or garden.

When the buffet starts getting crowded and it looks like their food might run out, aphids switch gears.

They produce a different kind of clone.

See those light gray shoulder pads on the one on the right?

They unfurl into wings.

Yup, winged clones called alates.

They look different, but they’re still genetically identical to their mothers.

When they’re ready, the alates take to the air to search out new plants to colonize.

A gathering this big attracts some hungry party crashers.

Like this ladybug.

So some aphids strike a deal … with ants.

The ants treat aphids like dairy cows, looking after them and guarding them from predators.

When these ranchers are thirsty, they tap on the aphids with their antennae.

But instead of milk, these ant ranchers are looking for a tall drink of sweet aphid honeydew.

That’s the sugary waste that comes out of an aphid’s uh, backside.

So is there anything that can stop these aggravating … endlessly self-replicating pests?

Some growers use oils or insecticides.

Others sic even more predators on them, like lacewing larvae.

Or even unleash parasites like these wasps.

The female wasp uses her sharp ovipositor to inject an egg into the slow-moving aphids.

When the wasp egg inside hatches, the larva eats and eats, hollowing out its host and turning it into a little mummy.

When it’s ready, the adult wasp chews its way out to start the cycle again.

These tiny mummies are a gruesome sight.

But they’re one that lets gardeners breathe a sigh of relief.

Hi Deep Peeps, It’s Laura.

Did your charming image of ladybugs just get shattered?

Not to worry, they still have a softer side.

Every winter they gather by the thousands in a big ol’ cuddle puddle.

Thanks, and see you soon.

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