What’s that in my spinach?

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A speck on the spinach leaf…

One morning as I was preparing my lunch before school, I noticed something attached to a spinach leaf. It looked like a small tan rounded egg of some sort. Closer inspection revealed something very funny–an aphid mummy! These are the hollowed out exoskeletons of aphids, created by the larva of a parasite that had devoured the aphid’s internal organs. I was familiar with aphid mummies, having seen them many a time on aphid-infested plants outdoors, but to find one on a piece of spinach from the market was worth a good laugh. I tossed it in a vial and headed off to school.

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Aphid mummy on spinach. The only locality information I have is from the packaging, which simply stated “Product of USA”. So this aphid and its associated parasite could be from almost anywhere in the country.

Later that day I decided to get a few shots of the aphid mummy. As I was photographing it I noticed that there was no hole in it, and there was a suspicious-looking dark area inside. What if, despite all odds, there was still life inside? I decided to keep it on the off chance that the parasite might still be inside. Turns out I didn’t have long to wait. The very next day I was excited to spot a 2-mm long wasp walking around in the container. As expected, the aphid mummy now had a large circular hole cut in it where the wasp had emerged. I photographed the wasp and posted it to BugGuide, where Ross Hill quickly determined it as a member of the subfamily Aphidiinae (Hymenoptera: Braconidae), which specialize in parasitizing aphids.

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The resulting aphidiine wasp.

Never doubt that insects are all around us, even in your food!

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A Mantid and its Tormentor

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Omomantis zebrata

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Lifting the wing reveals the wasp hiding inside.

A few nights ago in Chitengo Camp, I caught a beautiful praying mantid Omomantis zebrata. A gorgeous species normally found in bushes and trees in savanna habitats, it is also attracted to lights. I photographed him, and then decided to lift up his wings to check for any coloration, as many mantids and grasshoppers have wild colors on their hind wings. I opened up his wings and was at first disappointed; they were mostly clear, with a slight pinkish tinge. But then I noticed a small dark object hunched in a fold of the right wing. It clearly was not a part of the mantid, and closer examination showed it to be a female parasitoid wasp in the family Torymidae! This animal parasitizes the egg cases (oothecae) of mantids. Many have developed elaborate ways of locating these oothecae, and this individual was a hitchhiker. When the mantid found a mate, the wasp would have jumped ship to the female mantid, and then parasitized the female mantid’s eggs as she laid them. A pretty sorry state of affairs for the mantid, but a very clever method of reproduction for the wasp, and also a reminder to always take a second look at everything.

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Torymid wasp, parasitoid of mantid oothecae.