A male Automeris iris on my blacklight sheet near Harshaw, Arizona early on the morning of 02 August 2003.
Automeris iris
A male Automeris iris on my blacklight sheet near Harshaw, Arizona early on the morning of 02 August 2003.
In progress...
Our experiences with Automeris iris, one of the more isolated of the six species of Automeris moths found in the USA. A. iris ranges only in a small part of southeast Arizona, from the Patagonia mountains west to the Pena Blanca area. It's home area is also that of Automeris patagoniensis and Automeris cecrops pamina. To me, it is the "trophy" Automeris of the region... pamina is usually very common, to the extent that we have seen thousands in a night. Automeris patagoniensis is usually considered the "real" trophy moth of the region, but it is significantly smaller than iris, and not as nicely marked... just my opinion. A. patagoniensis is held in special regard because it is the most recent addition to our Saturniid moths, being described just in the early nineties. Automeris iris is every bit as "rare" as patagoniensis also. I've never heard of anyone seeing more than a few iris in any one night of collecting, even in the prime flight season. The latest nomenclature for this moth comes from Lemaire, 2002, in which the subspecific name "hesselorum" has been dropped, and this moth is grouped with nominate iris.
The caterpillars began to shed into pupae on 30 September. Their behavior was a little surprising to me... Over the space of about a week, they all decided it was time to quit eating and pupate. They picked their spots on the bottom of the enclosure and laid around for several days, up to 7 or 8 days. A few of them spun a loose covering of golden silk that could almost be called a cocoon, but not really. Most either spun an open mat of silk and stayed on top of it, or simply laid on the ground wherever they felt comfortable. They almost appeared deceased... (reminded me of the old Monty Python bit with the guy in the pet store with the defunct parrot...) but they took on a shortened football shape as their internals started changing into the moth-to-be.
Conceived, created, edited, and published by Hunter and Joel. Kelly is the Creative Consultant.
On the night of 01 August, we were extremely lucky to see a female iris near Harshaw. We drove down to check a remote blacklight rig set up in the woods, and found a female iris sitting on the sheet. In fact I looked right over it at first. It was right on the edge of the sheet. Here was a great example that a simple 15 Watt black light tube can do a good job all on it's own! The female was in pretty good condition, so I put her in a large envelope instead of a paper lunch bag, so she wouldn't get more beat up. She didn't produce any ova for almost three days... I was beginning to think she was not going to produce any. Finally I saw a cluster of about 30 ova in the envelope. The next night she produced about 10 more. As shown below, they are typical Automeris ova... slightly enlongated with a dark micropyle on top of each egg. These were fairly small, smaller than the ova of either io neomexicana or zephyria.
As the ova matured, they took on a darker gray color, and the micropyle of each became black. The larvae hatched in about two weeks. They were kept in a small plastic container at a temperature of 75* to 80* F, just like all the other saturniid ova we got. Upon hatching, the larvae were very small, and solid orange in color, very much like the early instar larvae of io neomexicana.
Pictured is a group of second instar iris larvae
I was hoping the larvae would start out well on Red Oak leaves, like the other Automeris larvae we've reared, but these would not take it. The day after the larvae hatched and still had not eaten any oak, I supplied them with leaves of Desert Willow (Chilopsis linearis) and a species of Locust (Robinia sp.) that grows in a local park. Almost instantly, they started eating the Locust. I believe it is some sort of hybrid Robinia very similar to Honey Locust... It's a cultivated strain that is planted in many of the parks and lots around town. Now into their third instar, they appear to be doing well on it.
The leaves they are eating seem to stay pretty fresh, but must be changed about every other day, or they stop eating it. As with all rearing, the fresher the better for foliage.
Third instar iris caterpillar; slowly the base color of the larvae is changing from orange to yellow-green. In this instar the larvae's defenses have increased... Stinging spines typical of all Automeris cover their bodies in neat rows. They still like to stick together in groups of 10 to 15. The first picture below makes it obvious why... That's a LOT of venemous spines to deal with. Click on the small pictures below to see more photos of third instar larvae.
Fourth instar iris caterpillar photographed 14 September 2003. The entire brood seems to be coming along fine. They all are the same size and they all seem to shed into new instars within about 24 hours of each other. They have stopped hanging around in large groups and now travel around and eat in small groups of two, three or four. The lateral stripes vary a little among this brood... A few have the black over white over red like the caterpillar on the left, and some have the black over white with no red like the caterpillar on the right. The black stripe is present in all of the larvae. The typical Automeris venemous scoli are well developed now, as I found out today when changing out the food... I brushed the back of my finger against one that I didn't see. It was a fairly intense burning and stinging feel for about 10 minutes.
The ground color has changed distinctly to green. The larvae appear very similar to Automeris io neomexicana.
Hunter has named the foodplant we're using "Rattler Tree" because of the large seed pods it grew. They're dried out now and rattle when they're shaken. We're hoping the leaves stay fresh on the trees until the caterpillars are finished feeding.
Final instar iris caterpillar, photographed 27 September 2003. When moving around, the full size larvae are 65 - 70 mm in length; not quite as large as our Automeris io neomexicana were.
About half of the brood of 30 larvae are in their pre-pupal "wandering" phase. Some of them that left the foodplant and were wandering around with no interest in eating were put in a separate enclosure with twigs and leaf litter. A few have spun very loose, open cocoons and are ready to shed into pupae. Others have not spun anything more than a mat of silk and will apparently pupate without a cocoon. None have actually shed into pupae yet, but they have contracted into football shapes and are ready to. Click the small picture below for a large photo of the mature iris caterpillar.
© August - September 2003. All content © Hunter and Joel.