Tobacco Hornworms & Brachonid Wasps
Tobacco Hornworms, Manduca sexta (often found feeding on tomato plants and confused with Tomato Hornworms, Manduca quinquemaculata) are often the target of a species of Brachonid wasp that parasitizes beetle, moth, fly and sawfly larvae. The adult wasp lays her eggs inside the hornworm with her long ovipositor. The eggs hatch and the wasp larvae feed on the caterpillar. Eventually the wasp larvae emerge and form white pupa cases on the skin of the dying hornworm larva, inside of which they transform into winged adults. Braconid wasps are extremely good at locating hornworms, even when there are very few to find. Because they parasitize hornworm, cabbage worm, aphid and gypsy moth larvae, Braconid wasps are considered important biological control agents. If you want to discourage Tobacco Hornworms in your tomato patch, allow the wasps to complete their metamorphosis – this accomplishes both the demise of the hornworm, as well as an increased population of Braconid wasps.
This entry was posted on August 11, 2012 by Mary Holland. It was filed under Adaptations, Arthropods, August, Hymenoptera, Insect Signs, Insects, Invertebrates, Metamorphosis, Moths, Pupae and was tagged with insects, Manduca quinquemaculata, Manduca sexta, Metamorphosis, Parasitoids, Tobacco Hornworms, Tomato Hornworms.


Hi Mary, Do you have a photo of the Brachonid wasp to post?
August 11, 2012 at 9:58 pm
Unfortunately, I don’t, Libby. There are over 1,000 species of Brachonid wasps! I would love to photograph the one that parasitizes Tobacco Hornworms, but have never caught one in the act. The one thing all of these wasps seem to have in common is a very long ovipositor. You can find images of this family of wasps at http://www.google.com/search?q=braconid+wasp+image&hl=en&rls=com.microsoft:en-us:IE-Address&prmd=imvns&tbm=isch&tbo=u&source=univ&sa=X&ei=w94mUO-mFuPk6QG_qYGoAg&ved=0CEIQsAQ&biw=1920&bih=923 .
August 11, 2012 at 10:40 pm
That is extremely gross and extremely cool! And I’m always delighted to learn about a new helpful garden insect. Thanks!
August 11, 2012 at 10:19 pm