|Noel McFarland and David Wagner|
|Caterpillars and provisions ready for over-night shipping across the US|
This year we had an impressive outbreak of Tent-Caterpillars of the genus Malacosoma on Mount Lemmon in the Catalina Mts. One of my collecting trips in mid May was mostly devoted to these guys.
|Western Tent Caterpillars Malacosoma californicum on aspen, left, Sonoran Tent Caterpillar, Malacosoma tigris, on Silverleaf Oak, right|
Of the oak feeders, I only found early instar caterpillars in very rudimentary nests, all the larger caterpillars were by themselves. I learned later that this solitary life style is typical for the species.
The oak feeders spin flocculent cocoons under and between oak leaves to pupate.
The caterpillars on Cherry, Aspen, and Willows at Marshall Gulch are probably M. californicum, the Western Tent Caterpillar. The final word (from Dave Wagner) on these ids will come when the adult moths hatch. He confirmed it later.
|Western Tent Caterpillar nest on Cherry|
On Mt Lemmon I also found big gatherings of the aspen feeders resting out in the open on tree trunks and fence posts.
One of the caterpillars spun its cocoon on the way home from the mountain - anchoring it to a plastic bag instead of leaves of the food plant. Note the infusion with a yellowish powder, typical for some Malacosoma species.
|Pupa and adult tachinid flies in the genera Exorista and Lespesia that hatched from Malacosoma pupae|
Although several of my Malacosoma caterpillars eventually wove their silky cocoons and pupated inside, I have not yet seen any adult moths. Instead, I soon found a big hole in each cocoon, and next to it a smaller pupa in the barrel shape characteristic for a dipteran (fly) cocoon. Over the last few days several adult Tachinid Flies of different genera, but no adult moths, eclosed. I hope David has more luck with the caterpillars I sent him. Parasitism of caterpillars is common. As a child in Germany I wanted to raise our beautiful Peacock Butterfly, Inachis io. Instead I got a whole row of little wasp cocoons (Ichneumonid) attached to an empty, hollowed out caterpillar skin.. The experience shocked me so much that I didn't try to raise any more caterpillars until I had to do it in a developmental physiology course during my biology studies. We worked with wax moths and repeated Kopec's ligation experiments - so again, I was deprived of any inspiringly beautiful results.
But - the limited success of this generation of tent caterpillars will probably save some aspen trees on Mt Lemmon from death by defoliation next year. And I am sure Nature will strike a balance in a way that will eventually allow me to see an adult Tent Caterpillar Moth.
June 17, 2012
A moth eclosed from a pupa that I collected from Gambel's Oak at Summerhaven, behind the Community Center
David Wagner answered in three consecutive e mails::