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Return to Life Cycle Studies of Lower Rio Grande Valley Butterflies
Trying to raise a Great Southern
White - Ascia monuste butterfly, from eclosure through emergence, has been the most
frustrating experience I have ever suffered through in my years of raising many other caterpillars. I am the ALL-TIME KILLER of Great Southern White caterpillars, and I
promise all future Great Southern White cats that I will not touch them, breathe on them, and maybe not even look too closely
at them. Yes, I am the first to say, "they're just bugs!", but cleaning equipment, bringing in new food, taking
photos, keeping notes, and often staying up late or staying home just to catch a photo opp is a lot of effort. Before raising the three caterpillars that I could follow and choose which one to
use in this life cycle study, I had started well over a dozen studies, beginnning with well over a hundred eggs and caterpillars,
just to come to failure. That's less than a 3% success rate! I considered whether or not temperature
or humidity variations made a difference, but the humidity here in the upper Lower Rio Grande Valley (LRGV) is almost always
stable; and, since the eggs are laid in late summer, the temperatures are always well above 95F during the day and in the
80's at night. Whenever I am raising any kind of caterpillars indoors (which is the norm), the thermostat is kept at
80F in the daytime and 78F at night (thank goodness for ceiling fans, and you do get used to it). The plants in the yard never have any kind of chemicals put on them. The City mosquito
control folks cut their sprayers off, when their trucks come within several yards of our house. We seldom even have
mosquito control trucks driving by, anyway, and this year they never came by the house. I totally discount that chemicals
could be a problem, especially since none of the other caterpillar species in the yard were showing problems. I tried
completely netting the Clammyweeds in the yard, to see if I could rear the caterpillars outdoors in their normal environment,
and that did not work. I even began to question whether or not Clammyweed - Polanisia
dodecandra was a proper caterpillar food host for them. The only explanation that I can come up with is that they must
be using mustards and saltworts that are found more abundantly 50 miles to our east and north. I cannot ever remember
finding the caterpillars on Clammyweeds, even though I often see the Great Southern Whites tagging the Clammyweeds. Finally, after all the slaughter going on I was able to complete a full life cycle study.
Great Southern Whites - Ascia monuste
are very common in the LRGV, and it seems there always are these large, whitish butterflies, with their turquoise-tipped
antennae, flying around. Their host plant or caterpillar food plant is a caper, Clammyweed - Polanisia dodecandra, which is a commonly occurring plant in the LRGV. As we have often seen, on August 12, 2013, I photographed a Great Southern White - Ascia monuste laying eggs in our yard on Clammyweed - Polanisia dodecandra.
I collected the leaf and brought it indoors to begin a month-long life history study of this butterfly. One of the most
interesting discoveries that I found was that when the caterpillar goes from one instar into another, it literally crawls
out of the old exoskeleton leaving a completely intact exuviae. In all the other caterpillar species that I have watched,
the exuviae is gathered up into a wad and cast off from the rear of the caterpillar. I parallelled this study shown,
with another female and male caterpillar. Since I did not capture this female emerging from the chrysalis, I used photos
from the second female's emergence, which I was lucky to capture, in this photo essay. Enjoy.
All photos on this site are by Jan Dauphin and are copyright protected
and may not be used or published elsewhere without the permission of Jan Dauphin
Clammyweed - Polanisia dodecandra ssp riograndensis, is a commonly found plant in the LRGV. A member of the family Capparaceae, this plant
grows to about 2ft. tall. It gives off a sticky substance when touched and its crushed leaves are unpleasantly smelly.
Butterflies love it. We only allow one in the yard, because it produces a tremendous amount of seeds, that can spread
everywhere. This caper is the caterpillar food plant of the Great Southern White - Ascia
monuste butterfly.
Great
Southern White - Ascia monuste are commonly found in the LRGV, seen mostly in the
Fall. The female is more brownish, ventrally, than the male, is generally larger, and has a dark spot on the dorsal
forewing. Males are white above, lacking the dark spot. Both sexes have dark edging to the dorsal side of the
wings, and both have the distinctive turquoise-tipped antennae.
Female laying eggs on Clammyweed
on 8/12/13.
8/12/13,
Day-1. Eggs laid and brought inside to start this study.
8/17/13,
Day-5 from when the eggs were laid, Day-1 as a caterpillar.
8/18/13, Day-6 from when the
eggs were laid, Day-2 as a caterpillar. The caterpillar is 3mm long.
8/20/13, Day-8 from when the eggs were laid,
Day-4 as a caterpillar. The caterpillar is 5mm long.
8/22/13, Day-10 from when the eggs were laid,
Day-6 as a caterpillar. The caterpillar is 6mm long.
8/24/13, Day-12 from when the eggs were laid,
Day-8 as a caterpillar. The caterpillar is 9mm long.
8/26/13, Day-14 from when the eggs were laid,
Day-10 as a caterpillar. The caterpillar is 14mm long.
8/28/13, Day-16 from when the eggs were laid,
Day-12 as a caterpillar. The caterpillar is 20mm long.
Exuviae or the exoskeleton
left as the caterpillar went into a new instar. The caterpillar breaks out and crawls from the head end (top of photo),
not splitting the top, back or sides of the exuviae. It does not turn the exuviae inside-out, like a snake does when
shedding its skin. This was a total surprise.
8/30/13, Day-18 from when the eggs were laid,
Day-14 as a caterpillar. The caterpillar is 33mm long.
8/30/13 at 1433hrs. Exuviae
left when caterpillar went into a new instar.
9/1/13, Day-20 from when the eggs were laid,
Day-16 as a caterpillar. The caterpillar is 36mm long.
9/3/13 at 1600hrs., Day-22 from when the eggs were laid,
Day-18 as a caterpillar. The caterpillar has not eaten since 9/1 and has made a girdle. The
caterpillar has shrunk to 15mm long.
9/3/13 at 1900hrs., Day-22 from when the eggs were laid,
Day-18 as a caterpillar, Day-1 as a chrysalis.
9/3/13 at 2000hrs., Day-22 from when the eggs were laid,
Day-18 as a caterpillar, Day-1 as a chrysalis.
9/3/13 at 2100hrs., Day-22 from when the eggs were laid,
Day-18 as a caterpillar, Day-1 as a chrysalis.
9/11/13 at 0622hrs., Day-30 from when the eggs were laid,
Day-26 as a caterpillar, Day-9 as a chrysalis. The dorsal side of the forewing is what is showing.
Notice the spot in the wing. The spot means this is a female.
9/11/13 at 0726hrs., Day-30 from when the eggs were laid,
Day-26 as a caterpillar, Day-9 as a chrysalis.
9/11/13 at 1106hrs., Day-30 from when the eggs were laid,
Day-26 as a caterpillar, Day-9 as a chrysalis.
The following 13 photographs,
showing the butterfly emerging, were taken from a second female that began emerging two days later on 9/13/13. I missed
being able to photograph my above butterfly as she emerged from the chrysalis.
9/13/13 at 1150hrs.
9/13/13 at 1150hrs. + ~9secs.
9/13/13 at 1150hrs. + ~18secs.
9/13/13 at 1150hrs. + ~27secs.
9/13/13 at 1150hrs. + ~36secs.
9/13/13 at 1150hrs. + ~48secs.
9/13/13 at 1150hrs. + ~54secs.
9/13/13 at 1151hrs.
9/13/13 at 1152hrs.
9/13/13 at 1152.5hrs.
9/13/13 at 1153hrs.
9/13/13 at 1153.5hrs.
9/13/13 at 1155hrs.
Now, we switch back to the orginal female that we were
studying.
9/11/2013 at 1205hrs.,
Day-30 from when the eggs were laid, Day-26 as a caterpillar, Day-9 as a chrysalis. The female has filled and dried
her wings and is ready to be released.
9/11/2013 at 1205hrs., Day-30
from when the eggs were laid, Day-26 as a caterpillar, Day-9 as a chrysalis. I took the butterfly outside and placed
her on the same plant that the egg was laid. Finis
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