Starr County Butterflies
Ceraunus Blue egg on Tropical Neptunia
6-1-09, egg on Bundleflower
6-4-09, recently eclosed; barely visible
5 hours after left photo; baby can move!
6-6-09, has been feeding on leaves
6-8-09, resting
6-11-09
6-12-09, mature caterpillar
2:51 p.m., 6-14-09
4:37 p.m., 6-14-09
6-18-09, 6:00 pm., eyes visible
6-19-09, 9:00 a.m.
6-20-09, 8:22 a.m., chrysalis clear
6-20-09, 8:57, space between chrysalis and butterfly
Fresh Ceraunus Blue, 6-20-09; emerged about 9:00 a.m.
The carpetgrass lawns at Roma High School, where I teach, have a fair number of interesting "weeds" growing in them. One area has a thriving population of Swanflower, the native host used by Pipevine Swallowtails. A nearby wall is covered with their chrysalises; some fresh, some empty. Another weed, which I have not seen growing elsewhere in this area, is the sensitive plant called Tropical Neptunia or Yellow Puff (Neptunia pubescens). I wandered outside at lunchtime one day in May, and soon found myself watching a Ceraunus Blue laying her eggs on one of these plants. The eggs were generally tucked into joints where the stem branched, as is indicated by the first picture (dated 5-27).
I collected a branch with 2 eggs from the Neptunia at school. However, the plant did not keep well when cut, and the eggs never eclosed. In the meanwhile, I found a young caterpillar on the Neptunia and brought it home to raise. I soon had several caterpillars, not intentionally but because they were both abundant and also very difficult to spot when I was gathering fresh cuttings for the first caterpillar! The larvae clearly preferred flowers and flower buds, but also ate leaves and even the stems of the plant.
A few days after finding the blues were using Neptunia, in my yard I noticed an egg on the small flower buds of Bundleflower (Desmanthus virgatus). This egg proved also to be from a Ceraunus Blue, and the caterpillar that emerged is featured in the photos to the right. I was examining the plant because it somewhat resembled Neptunia. Similarity of looks is certainly no predictor of host-plant compatibility, but it did work out that way in this case.
Bundleflower is widespread in this area, perhaps because it tolerates dry conditions well. It also was present in the Roma High School lawn, but the Neptunia seemed to get much heavier use. Also, when both host plants were offered to a few caterpillars, they moved from Bundleflower to Neptunia but not vice versa.
It was easy to predict when the adults would emerge: the eyes would become visible through the chrysalis a day or two before eclosion. Throughout the intervening time, more detail of the butterfly would gradually be revealed. Unfortunately, although I tried to carefully monitor this butterfly, it emerged while I was elsewhere for ten minutes.
This species is one of the fastest-maturing that I have raised. This particular caterpillar pupated ten days after it eclosed. The adult emerged from the chrysalis 6 days later.