Malachite (Siproeta stelenes) Life History


Egg, 10-19-16

Recently hatched, 10-22-16
            

First instar, 10-23-16
            

Second instar, 10-26-16
     

Third instar, 10-27-16
     

Fourth instar, 10-31-16
     

Fifth instar, 11-07-16
     
Front and rear views of chrysalis, 11-9-16
     

Recently-emerged adult Malachite, ventral view, 11-18-16
     

Fresh adult Malachite, dorsal view, 11-20-16
 

I captured a female Malachite at bait, and placed her in my small greenhouse. Potted Green Shrimp Plant (Ruellia blechum) and Runyon's Violet Wild Petunia (Ruellia nudiflora) were offered as potential hosts. Green Shrimp Plant is used by a commercial breeder I know, while the Wild Petunia is one of the Malachite's reported hosts. It was over a week later that the first eggs appeared on the Green Shrimp plant. Interestingly, the first egg I found was empty even though it seemed to have an intact shell. Over a period of days the female placed a number of eggs on that plant, and then she moved on to place a few more on the Wild Petunia.

I brought in 3 eggs to observe; two hatched. The first and older caterpillar is the one pictured to the right. As can be seen from the picture taken on 10-26-16, this caterpillar had "horns" on its head in the second instar. The second caterpillar did not develop horns until its third instar. From that point on, the development of the caterpillars was the same, resulting in the younger one apparently having six instars compared to the older caterpillar's five. I found this puzzling, because in my experience, at least, caterpillars of the same species and especially the same brood generally have the same number of molts (unless they go into diapause or some similar stress produces an extra molt). While writing this in November, 2016, I looked for literature describing others' observations, but I did not find any detailing the typical number of instars that Malachite larvae have.


Face of Malachite

The caterpillars were challenging to photograph because they were so dark. Once the spines appeared, more red was added during each instar until they were entirely red in the last instar. They were brightest immediately after a molt (as in the case of the face pictured above), and then they gradually darkened as the caterpillar drew near to its next stage of development.

The egg of the study caterpillar was laid on October 19 or perhaps the previous day. The adult emerged from its chrysalis on November 18, so the journey from egg to adult took 30 days. Its emergence coincided with the arrival of a windy cold front, so I delayed release of the butterfly until November 20.

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