Download high resolution image here.
Pityococcus rugulosus lifecycle
7f. Adult female crawler
8f. Nesting female (this set)
9. Dead host trees
Several
adult female crawlers were collected on 29MAR2015 from a
Pinus edulis (pinyon) tree on Embudito Trl. (No. 192) at 6983 ft elevation in the
Sandia Crest 7.5’ quadrangle,
Sandia Mountains, Bernalillo Co., NM. They were collected by beating the terminal branches with a stick with a collection pail underneath. The one pictured above is shown as imaged on 02APR2015 after having laid an egg mass in captivity. The abdomen does not burst open to release the eggs, as it does with
Matsucoccus acalyptus. Instead, the eggs oviposit one at a time from a posterior orifice, forming a weakly bound chain similar to sausage links, as shown in the
2'nd image.
I located two natural nesting sites for such egg masses the following year. The rest of the images are of two clusters of egg masses, each oviposited within the web of a single
Pococera sp. caterpillar. The
3'th through
6'th images are of Web 1, collected and imaged on 24APR2016. Silk webbing, caterpillar frass, and needles were removed from a small area of the web structure to reveal several
P. rugulosus nesting females with their egg masses. The host caterpillar was retrieved live from this nest. Its images are
posted for identification. The
7'th through
9'th images are of Web 2, collected and imaged on 01MAY2016. This nest was left undisturbed. Egg masses can be seen partially hidden within, and one is unconcealed. This web too had a single live caterpillar therein.
P. rugulosus females apparently have a preference for ovipositing egg masses within such caterpillar webs. No webs without egg masses and no egg masses without associated webs were found despite extensive searching. The webbing and frass provide protection and concealment from predators for the females, as it does for the caterpillar. It is possible the relationship is mutually beneficial. That is, the caterpillar may benefit from the sticky wax fiber covered egg masses blocking smaller insects (such as parasitic wasps) that might otherwise be able to penetrate the silk webbing.
This image is from a
CombineZP processed stack of 128 images with a 22.6 µm step taken with a
Mitutoyo M Plan APO 5×/0.14 ∞/0 mm microscope objective + Nikon 135 mm F2.8 AIS telephoto lens + Nikon D300 camera (magnification 3.375×; technique described
here).
The main pages for each linked image set documenting a stage of development for this species are linked here:
