- Author: Kathy Keatley Garvey
Take the immature form (caterpillar) of the moth, Schizura concinna, family Notodontidae. We first spotted this caterpillar on our Western redbud tree (Cercis occidentalis) in September 2010.
It has a red hump. The common name: The redhumped caterpillar.
Art Shapiro, distinguished professor of evolution and ecology at UC Davis, told us that the red hump contains a defensive formic acid gland. "They hold their anal prolegs, which are not useful for walking, in the air and thrash their rear ends in unison when disturbed. This is the ONLY defoliator of redbud around here, and is very common. It also attacks walnut and a variety of other chemically-distinctive trees that other things don't eat, as a rule."
We wondered if these little thrashing visitors should concern us. "The damage is minor, and I strongly advise against spraying; hand-picking can be used if control is deemed necessary, but they feed so late in the season that there is no actual harm to the tree," he told us. "The moth is very nondescript. It holds its wings wrapped around the body cylindrically and looks remarkably like a cigarette butt, though it is probably 'imitating' a broken-off twig. Despite authoritative commentary to the contrary, they have two broods a year here but are usually seen in fall. The species is native on both coasts and oddly absent in most of the mid-continent."
We thought we might see redhumped caterpillars on our liquidambar (sweet gum) trees that we planted more than two decades ago. We never have.
What we did see this week is that the UC Statewide Integrated Pest Management Program (UC IPM) has revised its Pest Notes: Redhumped Caterpillar. A recent UC IPM blog described the caterpillar as a "familiar pest on fruit and nut trees such as plum, almond, cherry, and apple, as well as on ornamental trees like liquidambar and birch. It can reach high populations in California's Central Valley, sometimes defoliating entire trees."
The Pest Note, co-authored by entomologists Emily Symmes, UC IPM and UC Cooperative Extension, Sacramento Valley, and Steve Dreistadt, UC IPM, describes the pest, its life cycle, and the damage rendered. You can read about a variety of management techniques.
Ah, the redhumped caterpillar...
And if you're curious about common names and scientific names of insects, the Entomological Society of America (ESA) maintains a Common Name Database, "an essential reference for anyone who works with insects. It includes more than 2,000 common names and is searchable by common name, scientific name, author, order, family, genus, and species."
Have a suggestion for a common name? You can propose it on the ESA form. Names are reviewed by the Committee on the Common Names of Insects and voted on by the ESA Governing Board.
It's probably unlikely, however, that redhumped caterpillar, will undergo a name change any time soon. That red hump is so descriptive!
- Author: Kathy Keatley Garvey
Once upon a time, there was a redhumped caterpillar gorging on the leaves of a redbud tree.
For three days, the hungry caterpillar gobbled the leaves, like an insect version of Pac-Man. It snipped, shredded and skeletonized the leaves and then went for more.
On the fourth day, it lay motionless, entangled in a spider web.
On the fifth day, the lifeless redhumped caterpillar (Schizura concinna) came back to "life," in the form of Argentine ants gorging on its carcass.
Life and death in the garden...
- Author: Kathy Keatley Garvey
There's a whole lot of crunchin' going on.
The redhumped caterpillar has discovered our redbud tree, which it considers an "all-you-can" buffet.
Now this is a voracious eater on the same scale of a fellow named Joey "Jaws" Chestnut.
Seconds? Yes, please.
Thirds? Of course.
Fourths? Definitely.
Well, say "when!"
Win.
Distinguished by a bright red head and an equally bright red hump behind its head (Joey has neither, by the way), the caterpillar is yellow with red and white stripes. It's about an inch and a half long and can defoliate or skeletonize a leaf faster than you can say "The redhumped caterpillar is a Schizura concinna in the family Notodontidae." (Or “Joey Chestnut ate 54 dogs and buns on July 4, 2010 and took home the Mustard Belt.”)
The redhumped caterpillar is quite fond of redbud leaves but it also takes a liking to liquidambar, walnut and plum leaves, to mention a few.
Noted butterfly expert Arthur Shapiro, professor of evolution and ecology at UC Davis and the person behind "Art's Butterfly World," took one look at my trio of happy campers...er...caterpillars and commented:
"As you can see, they are gregarious and warningly colored. The red hump contains a defensive formic acid gland. They hold their anal prolegs, which are not useful for walking, in the air and thrash their rear ends in unison when disturbed. This is the ONLY defoliator of redbud around here, and is very common."
Shapiro says it also "attacks walnut and a variety of other chemically distinctive trees that other things don't eat, as a rule. The damage is minor, and I strongly advise against spraying; hand-picking can be used if control is deemed necessary, but they feed so late in the season that there is no actual harm to the tree."
No, no harm. Just some skeletonized leaves and leaf stubs.
What's the adult look like?
"The moth is very nondescript," he says. "It holds its wings wrapped around the body cylindrically and looks remarkably like a cigarette butt, though it is probably 'imitating' a broken-off twig. Despite authoritative commentary to the contrary, they have two broods a year here but are usually seen in fall. The species is native on both coasts and oddly absent in most of the mid-continent."
It will be awhile before we see the adults, which are grayish-brownish.
Shapiro says the insects "pupate in litter or slightly below the soil surface and won't hatch until June or so, if true to form."
Meanwhile, it's OTL, followed by OTD and OTB (out-to-lunch, dinner and breakfast).
It's already won the Redbud Belt.
