Walnut Grubs
One of the best parts about studying bugs is the Ewww Factor, and these little guys sure do work that angle. These are walnut grubs, and I have no idea what they turn into (but it’s probably a moth). This type of walnut is a black walnut, and walnuts fend off predators and competition alike by producing midly toxic husks and leaves. This combined with a thick canopy to block out sunlight is why it is often hard to grow grass under walnut trees.
Whatever these grubs are, they seem to be unfazed by the walnut’s poison; if anything they seemed to find it extra tasty. They squirmed and glistened the whole time they were photographed. Which just added to the Ewww Factor. (Awesome.)
Slowly getting the site back onto an even keel. It's nice to get back into the old posting rhythm.
Liz said,
September 27, 2007 @ 7:16 pm
It’s extra eewwwwy if you park your car under a walnut tree that’s infested with these grubs. The drip with the sap onto your car and then become glued to your car. It’s is especially disgusting if come to your car and they are still wiggling in the sappy glue. EEEEEEWWWW!!!!!
Henk said,
October 3, 2007 @ 3:22 pm
A little searching on google pictures suggest these may be Walnut husk fly maggots.
Link goes to the Ontario ministry agriculture, food and rural affairs. Pictures show
the same type of tiny transparent grubs.
Their transparency is fascinating actually. You can actually see their internal structure.
I guess they’re to small for a bigger closeup?
Wrote ‘he who lives far on the other side of the ocean and is not eating any walnuts this season’…
David Brady said,
October 3, 2007 @ 3:25 pm
I could have gotten a bit closer; my camera can focus with the lens just a millimeter or two from the objective. Focusing that tight is very sketchy at best, though, and a double-handheld like this (handheld camera, handheld subject) wasn’t feasible at the time.
Thanks, and welcome!
David Brady said,
October 3, 2007 @ 3:29 pm
Henk: Also, the maggots eat the husk only. They do not get into the nuts themselves. One site I saw today actually praised the maggots as part of the nut collection process, because their action makes it easier to remove the husks prior to cracking the nut and gleaning the meat.
Henk said,
October 4, 2007 @ 5:11 pm
Of course, only now do I realise which part of the nut/fruit is the “husk”, and how
the fly/maggot relates to that. It’s just not part of my daily vocab.
Keep it up…
singingnettle said,
October 13, 2007 @ 7:54 am
Hmm, I bet the toxin makes them unappetizing to predators who want to eat them. Like monarch caterpillars–no one wants that milkweed aftertaste.