Starr County Butterflies
Egg mass, 5-15-10
Ready to eclose, 5-16-10
5-16-10, recently eclosed
5-18-10
5-22-10
5-24-10
A last-instar caterpillar, 5-27-10
Another last-instar caterpillar, 5-28-10
Chrysalis #1, 5-29-10
Chrysalis #2, 5-31-10
Fresh Bordered Patch, 6-2-10
Fall caterpillar in diapause, 3-10-10
A couple of days after leaving diapause, 4-6-10
Caterpillars now looking normal, 4-10-10
Bordered Patches are among the most commonly found butterflies in Starr County, Texas. They eat a wide variety of plants in the Asteraceae family, so there is almost always larval food available. The females deposit masses of eggs underneath the leaf of a host plant; I have not counted but it looks as though some of these masses easily exceed 100 eggs. The caterpillars feed communally in the early instars, often defoliating the original host plant. They then spread out and feed singly in the last instars.
The eggs of this study (from the spring of 2010) were found on a wild sunflower, probably Helianthus praecox. The mass was smaller than is typical, which allowed me to deal with a reasonable number of caterpillars. Still, most of the larvae were released before pupation.
The caterpillars took about two weeks to mature. This group had fairly consistent coloration: dark ground color with orange dorsal spotting. The caterpillars can vary from almost solid black to almost solid orange, but all will have the highly-figured stripe that runs the length of the body (see the photos from 5-27 and 5-28).
Two different chrysalises are shown to demonstrate that these also are highly variable, ranging from almost plain tan to white with strong black and orange markings.
Below the primary photo essay, I have included three pictures of caterpillars that went through diapause. On November 1, 2009, I found a large mass of first-instar caterpillars on an isolated Orange Zexmenia (Wedelia hispida). I visited the plant every day to observe the progress of the caterpillars "in the wild." In about two weeks they had defoliated the plant, and then the caterpillars simply disappeared. I could not find them on any suitable hosts nearby. Meanwhile, I had collected three caterpillars to raise. One did pupate in November (and emerge on December 3), but the other two went into diapause. I suspect this is what happened with the outside caterpillars.
I left the diapausal caterpillars alone until I began seeing Bordered Patch activity in the spring. Then I began offering fresh food. About the beginning of April the caterpillars began to move around and eat; they pupated and emerged at the end of the month. Thus, these Bordered Patches were in the larval form for nearly half a year.