Mosquito Larvae: How to Identify Wrigglers in Standing Water

Tiny wriggling creatures in a bucket, plant saucer or water tank are very likely mosquito larvae. Finding them is actually good news: it means you have found a breeding site, and you can remove it before the larvae turn into biting adults.

This guide explains how to recognise larvae and what to do.

The short answer

Mosquito larvae, often called wrigglers, are small, slender, worm-like creatures, usually a few millimetres to about a centimetre long, that hang at the water surface, breathing through a tube or surface, and wriggle with a jerky S-shaped motion when disturbed, diving down and returning. They are found in standing water, from large tanks to bottle caps. When you find them, empty and scrub the container, cover or remove it, or treat water that cannot be emptied. Larvae turn into pupae and then adult mosquitoes in about a week in warm weather.

What they look like

• Thin, worm-like bodies with a distinct head and a segmented tail end.
• Colour varies from pale to brownish or greyish.
• Many species hang head-down from the surface, with a breathing tube at the tail end near the surface. Some, such as Anopheles, lie flat just under the surface.
• They move with a jerky, wriggling motion and dive when disturbed.

Larvae versus other creatures

1. Pupae: Comma-shaped, with a bulbous head, also hang at the surface. They are the next stage.
2. Bloodworms and other midge larvae: Often reddish and stay near the bottom.
3. Other worms and tiny water creatures: Do not hang at the surface in the same way.

Where to look

• Buckets, drums, tanks and sumps.
• Plant saucers, vases and water-grown plants.
• Coolers, AC trays and fridge trays.
• Discarded containers, tyres, coconut shells and bottle caps.
• Blocked drains, gutters and puddles.
• Ponds, fountains and unused pools.
• Rainwater collected on terraces and tarpaulins.

How to check

1. Look at the water surface in good light, using a torch in dark containers.
2. Stay still for a moment and watch for wriggling when the water is disturbed.
3. Use a white dish or ladle to scoop a sample and see them better.

What to do when you find them

• Empty and scrub: Tip the water onto dry ground or into a drain, and scrub the sides, since eggs stick to surfaces.
• Cover or remove: Cover containers tightly or turn them upside down, and remove what you do not need.
• Treat water you cannot empty: Ask a professional about safe larvicide, or larvae-eating fish where appropriate. Do not add insecticides to drinking water.
• Check again: Look again after several days.

Why it matters

Larvae mean adult mosquitoes in about a week. Dealing with larvae is the most effective way to cut mosquito numbers, including disease-carrying species.

When to call a professional

If you find larvae in tanks, drains or places you cannot clear, a professional can treat them safely.

Frequently asked questions

How long do larvae take to become mosquitoes?

Often about a week in warm weather.

Can larvae live in clean water?

Yes. Some species prefer clean water, others dirtier.

Do larvae bite?

No. Only adult females bite.

Can I flush them away?

Empty into a drain or onto dry ground, and clean the container.

This guide is part of IPest's complete resource on mosquito control. For identification help, prevention and treatment options, see our full mosquito control guide for Bangalore.