Explanation of Names
New Latin, from Greek anisos
(ανισος) unequal + ous, ot-
(ους, ωτ-) ear (1)
. This likely refers to the fleshy appendages of the caterpillars.
Tuskes et al
, pp. 69-80, (2)
has a detailed treatment of this genus. He has photos of adults and larvae of most species. Paraphrasing the generic discussion here:
is closely related to genus Anisota
, and has white spot on wing like it. Male Anisota
are day-flying. Partly transparent wing and white spot of males is thought to be mimicry of Hymenoptera. Females are mostly nocturnal, occasionally oviposit in late afternoon. Eggs are laid in clusters of 15-150. Hostplants are oaks, including Chinkapin Oak
), and formerly, Chestnut Oak
), or sometimes chestnut (Castanea
) or hazelnut (Corylus
There has been a lot of taxonomic shuffling in this genus. Tuskes et al sort it out this way, lumping many species into two groups as follows. Those marked with an "*" are of uncertain taxonomic status, and may be subspecies, members of clines, etc. However, Tuskes gives them full species accounts.
1-stigma group. Caterpillars of this group (1) are orange/pink-striped, with silvery dots (in stigma, manitobensis), variable in consularis. Sometimes striping is almost not there in A. stigma, and spines are branched (?).
i. A. stigma (Spiny Oakworm). Eastern North America. Males fly at night so found at lights. Most, or all, other Anisota males not typically found at lights. Mating in A. stigma typically occurs at night, but can occur during the day. One broad flight, begins June in north, July-August in southeast, August-September in Texas.
If you find a male at a light, it is probably A. stigma.
ii. A. manitobensis
*. Isolated northern species, Manitoba and Minnesota (see image of male [top] and female at CBIF
iii. A. consularis. Southeastern US, coastal Louisiana, Mississippi, Alabama, Georgia, South Carolina, most of Florida. Adult appearance quite variable, but usually has dots on wings. One flight per year, July to early September.
2-senatoria group. Caterpillars in this group are black with yellow and/or orange stripes.
Due to taxonomic uncerainty, they are treated as one species group.
i. A. senatoria. Eastern US, absent from deep south and northern areas. Adults are very orange, have black wing spots. Hyaline area on wings of male more extensive in north. One flight, late June to mid-July. Caterpillars have orange stripe in addition to yellow stripes.
ii. A. finlaysoni
*. Isolated northern species, south-central Ontario and Quebec. Similar to senatoria
(see image of male [top] and female at CBIF
iii. A. peigleri*. Mountains Virginia, Kentucky, Tennessee, Piedmont North Carolina, South Carolina Georgia, into central Florida. Adults similar to A. senatoria. One flight: mid-July to late August. Males don't have much hyaline area on wings. Caterpillars have no orange stripe, just yellow stripes. May be clinal variant of A. senatoria.
3-Two species belong to no group:
i. A. virginiensis (Pink-striped oakworm). Caterpillar pink striped, similar to stigma group, but easily identified.
Eastern North America, except south Florida. Adult males have pronounced hyaline area on forewing, no black spotting. Females have no black spotting on wings, and purplish margin of wings, obvious on forewing in living specimen.
One flight in north (early to mid-June). Two flights in mid-range: late July-early September. Some pupa overwinter until spring. Three flights possible in south. Some sources list Anisota pellucida
--this is a junior synonym of virginiensis
Both adults and caterpillars of A. virginiensis are distinctive in appearance. Apparently the only species with a spring flight.
ii. A. oslari. Isolated southwestern species, New Mexico and Arizona. Caterpillar orange with black dots.
Summary of widespread species of eastern US:
1. A. stigma, (see also consularis in deep south, Florida). Caterpillar spiny with silvery spots. Has spring flight in addition to summer. Males found at lights.
2. A. senatoria (see also peigleri in mid-south, esp. piedmont). Caterpillar dark with yellow/orange stripes.
3. A. virginiensis: adults fairly distinctive with purple-margined wings and no black spots. Caterpillar has pink stripes.
Eastern North America; one species in southwest.
Deciduous forests and woodlands with oaks
Adults typically fly mid to late summer (July-August). At least one species has a spring flight.
Larvae feed on leaves of oak.
Adults do not feed.
In most species, males fly during the day, seek out females, and mate in daylight. Female oviposits at night.
Covell, pp. 47-48, plate 8 (3)