Gray Hairstreak (Strymon melinus) Life History

 
       Female ovipositing (laying eggs), 3-31-09


              freshly laid egg, 3-31-09               leaf has grown and egg is exposed, 4-3-09


Young caterpillar bored hole in pod.... and recently eclosed caterpillar, 4-5-09


4-6-09, caterpillar is eating and growing      4-9-09, damage to green seeds evident  


4-13-09, now truly green                               4-16-09, facial view      


4-16-09, last instar


4-18-09, beginning to form pupa


4-19-09, note waste expelled just before final molt


                  4-20-09, fresh pupa                    4-21-09, pupa takes on normal color


4-29-09, fresh Gray Hairstreak

On March 31, 2009, the female Gray Hairstreak pictured at the right was seen laying eggs on Tuberous Sida, Rhynchosida physocalyx. I monitored the egg, and when it appeared ready to eclose I clipped off the top of the plant and put it in a small, sealed container to minimize drying. The caterpillar emerged 5 days after the egg was laid.

Jan Dauphin has beautifully documented here how a Silver-banded hairstreak (C. simaethis) caterpillar will bore a hole and crawl into the balloon pod of its host plant. This caterpillar, when young, exhibited similar behavior. The Sida pods are not actually sealed, so when I provided fresh food I opened the pod and placed the young caterpillar on the seeds. As it matured, I simply placed it on the fresh food. I never found any leaf damage; this caterpillar seemed to almost exclusively eat the unripe seeds of the food plant.

Gray Hairstreaks are well known to feed on a wide variety of host plants. Even so, in gathering fresh pods, I found another caterpillar and evidence of at least 2 more. This suggests that Tuberous Sida is frequently used by Gray Hairstreaks in this area (Starr County, TX). The second caterpillar I found gave me the opportunity to answer the question, Can a Gray Haistreak caterpillar turn pink? The answer may be seen here.

I took the pupa to school with me on the day it would eclose. My students were disappointed to miss the emergence. However, they enjoyed seeing how frustrating butterfly photography can be. When the butterfly appeared ready to fly, we set its container on the window ledge. The hairstreak did not fly off as expected, but eventually spread its wings about half-way. I decided to take a photo of the dorsal. It waited until I opened the window for the picture, and then it took off. The class had a good laugh at my expense!

The caterpillar of this study emerged from its pupa on 4-29-09. The journey from egg to adult took 30 days.