Malpighian Tubule Primary Cells (Bug Waste Cleaners)

Cells lining tiny tubes

Insects like fruit flies, grasshoppers, and mosquitoes have Malpighian tubules (say "mal-PIG-ee-an"). They are long, skinny tubes that hang in the insect's blood. One end is closed. The other end opens into the gut.

A fruit fly has 4 of these tubes. The walls are made mostly of big, boxy primary cells. Each one is packed with mitochondria, the cell's power plants, because its job takes lots of energy.

Pump, flow, and flush

Primary cells clean the insect's blood, just like your kidneys clean yours.

• 1. Pump: The cells use energy to pump salts from the blood into the tube.
• 2. Flow: Water follows the salts in, and wastes come along too.
• 3. Flush: The liquid flows into the gut and leaves the body with the insect's poop.

Before it leaves, the gut takes back the water the insect still needs. That helps bugs in dry places save water.

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