Genus Ephialtini
I found this small female wasp tapping its way along the stems of a dying sunflower on Antelope Island. From what
I understand, they tap with their antennae to feel the vibrations of insects that have burrowed in the plant. When
they locate an insect, they begin drilling through the stem so they can lay an egg. © Carol Davis, 10-30-2012
The long dark stinger-like structure at the end of the abdomen is a sheath that holds the thinner ovipositor, or egg-laying
apparatus. Wikipedia has some very interesting information on the ovipositor. © Carol Davis 10-30-2012
The wasp has begun inserting the ovipositor into the stem in order to lay her eggs in the host insect.
I love the way the ovipositor fits right against the abdomen in this photo. When the egg hatches inside the
burrowed host, the wasp larvae will feed off the insect. After pupation, the adult wasp will chew its way
out of the stem. I took this short movie (3 MB mpg) of the tapping and drilling process (if a small window
opens up, I would suggest enlarging it to view the video). © Carol Davis 10-30-2012
Here she is probing deeper into the stem to finish laying the egg, I suppose. This whole process was amazing to
watch because I knew absolutely nothing about it. I've noticed that in the Fall the wasps seem to congregate around
the largest sunflowers plants, maybe because there are so many burrowing insects in the them. To learn more about
the process of ovipositon, there's really good article here at Zip Code Zoo. Thanks to Bugguide for helping
identify this beautiful wasp to genus. © Carol Davis 10-30-2012
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