First Ceanothus Caterpillar Ecdyses into Third instar

Our oldest second instar Ceanothus caterpillar (Hyalophora euryalus) has ecdysed into third instar.

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When we checked on our Ceanothus caterpillars at around 5:30 PM today, neither of the two caterpillars that had entered apolysis yesterday had molted, but they looked extremely close as seen above. The cuticle looked more swollen than before and the head capsule looked looser as well. We were starting to think they would molt over the night , but at around 9:20 or so the older of the two in apolysis ecdysed. We caught it mid-act and quickly took plently of time lapse photos compiled below with the time labeled. When it just finished molting at 9:36 PM, the tubercles were all sort of squashed at wet looking, but by 2:13 AM, they were firm and erect, including the hairs at the tips. 

There are a lot of changes from second to third instar, primarily in color. The body is now a yellowish green on the lateral sides and blue on the dorsal side. The dorsal tubercles are now all orange and the lateral ones are light blue. This differs from the third instar Cecropias which are green all around (no blue dorsal strip) and have red and yellow dorsal tubercles. The third instar Ceanothus caterpillar has also lost its black markings on each segment as well, giving the body a much smoother look compared to the third instar Cecropias that still have the markings. Actually, if you think about it, the third instar Ceanothus resembles the fourth instar Cecropia quite a bit which is also blue on the dorsal side and lacks the black markings. Another interesting difference between the third instar Ceanothus and the third instar Cecropia caterpillars is the body and tubercle shape difference. The Ceanothus body shape has more of a squarish cross section rather than a circular one, which is especially well defined at the thorax where the four large dorsal tubercles are. Viewed laterally, there is even a slight angle were the large dorsal thoracic tubercles are. The Ceanothus tubercles are also much slimmer and longer, especially the large dorsal thoracic ones as well s the large middorsal one on A9.

In order to see some of the differences and similarities between the species, below are side by side dorsal and lateral view photos of a recently molted third instar Cecropia, third instar Ceanothus, and fourth instar Cecropia caterpillar. 

Today marks the end of second instar for the oldest caterpillar that lasted for approximately 5 days and 8 hours from 6/23-6/28. First instar for the oldest Ceanothus caterpillar lasted for approximately 5 days and 2 hours from 6/18-6/23. 

Count: L3: 1; L2+: 8; L2: 11; dead: 3 (1 missing, 2 disease); suspected sick: 1

- Alan