Hunger games: The joys of aphid-lady beetle IPM

This weekend, as I cleaned up the spent blooms of my bearded iris (Iris germanica), I noticed that one of the leaves was absolutely covered in aphids. I don’t like to use pesticides if I can avoid it, and bearded iris don’t need them. But aphids enjoying my iris will soon find my roses, my tomatoes, and other edibles–and I really don’t want to use pesticides on anything I’m going to eat.

I noticed a ladybug (or more correctly, lady beetle; I think this is Coccinella septempunctata, or seven-spotted lady beetle) on the ground. I gently picked her up and held her to the iris leaf. I hoped she would make like a high school football team at an all-you-can-eat crab legs buffet.

Lady beetle preparing to feast on aphids on Iris germanica.

Lady beetle preparing to feast on aphids on Iris germanica.

Unlike teenage Homo sapiens, lady beetles apparently aren’t a gluttonous species (though hungry adults can apparently eat up to several hundred aphids per day). But they’re no dummies, either, and know to eat when they are presented with easy prey.

I watched with delight as the aphids, acknowledging her presence, migrated down the leaf towards the ground. They’re slow creatures but can move when faced with imminent threat. As the faster aphids began moving away from the ladybug, the ladybug overtook one of their witless chums.

Lady beetle approaching her prey on a twigWatching a ladybug tear into an aphid is as thrilling as any David Attenborough-narrated documentary on life on the African savanna.  She (not that all lady beetles are female; they’re not) seized that aphid and crushed it in her jaws. In just a few seconds, she had eaten the aphid alive.

I didn’t have my camera at the time, so I raced into the house to grab it. Perhaps she had already feasted on other aphids in the garden, because by the time I came back, although I tried to coax her into eating more, she seemed to be full. So she settled down on the leaf to digest her dinner.

Ladybug content post-meal

No, thank you; I’m full. The lady beetle had eaten her fill by the time I came back.

Want to see the horror show for yourself? Here’s a video showing something similar to what I saw.

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