Mexican Silverspot Life History
Mexican Silverspot (Dione Moneta) Life History


Egg, 1-1-11

Egg, 3 days later (1-4-11 )
            

Caterpillar has just emerged, 1-7-11
     

Day-old caterpillar, 1-8-11

1-11-11
     

Two-day old caterpillars: Mexican Silverspot (left); Gulf Fritillary (right); 1-9-11
     

1-18-11
     

1-25-11
     

On 2-1-11, in front of and now twice the size of the Gulf Fritillary caterpillar
     

2-9-11
     

A different Mexican Silverspot caterpillar, light form, 1-24-08
     

Study caterpillar, fully-grown, 2-16-11
     

Ready to pupate, 2-17-11

Chrysalis, 2-18-11
     

Fresh adult female Mexican Silverspot, ventral, 3-1-11
     

Fresh adult female Mexican Silverspot, dorsal, 3-1-11
 

Mexican Silverspots exhibit unusual behavior for tropical butterflies: they are most commonly found in south Texas in cool December, and they are often laying eggs at that time. This makes the caterpillars vulnerable to bad weather that, even if it doesn't kill the caterpillar, may ruin the host plant.

This egg of this study was deposited on Corky-stem passionflower, Passiflora suberosa. It probably was left a day or two before the first picture was taken: fresh eggs are normally a solid yellow. The photos show that the egg gradually darkened as it matured. In the pictures it can also be seen that the egg was not placed on the vine, but on the remains of a previously hatched egg, probably from a Gulf Fritillary. This is the second time I have found this to happen.

A second egg I found on the same vine eventually proved to be from a Gulf Fritillary. Both caterpillars emerged about the same time, giving good opportunity for comparisons. The caterpillars were raised together. As can be seen from the picture dated 1-9-11, the young Gulf Fritillary caterpillar had a greenish hue, while the Mexican Silverspot caterpillar was more uniformly yellow-orange. Both caterpillars has white spots, but those on the Mexican Silverspot were much more noticeable. The Mexican Silverspot caterpillar grew more rapidly; by 2-1-11 (see picture), it was twice as large as the Gulf Fritillary caterpillar. It pupated a week sooner.

The caterpillar emerged about a week after the egg was deposited. During January we had a freeze that killed the host vine; fortunately, I was able to save enough cuttings to feed the caterpillars. Outside, both would surely have perished. (The room the caterpillars were raised in was unheated, but insulated well enough to protect the caterpillars.)


Dark form Mexican Silverspot
caterpillar face

There are two major variations in the coloration of Mexican Silverspot caterpillars. The caterpillar of this study turned out to be the darker, yellow-and-black form. For comparison, a picture of a light-form caterpillar is included after the 2-9-11 picture. The life history of that caterpillar can be found here.

The caterpillar pupated 42 days after it emerged from the egg. This is a long maturation period for our area, but not surprising given the cool winter temperatures. The adult eclosed 11 days later.

Mexican Silverspot Page