Thursday, July 8, 2010

Gulf Fritillary caterpillars, chrysalides, and emerging adults ...

I had a bunch of gulf fritillary caterpillars eating the leaves (of passionvine). I watched a couple get real big. I have yet to see any chrysalis around. I have a big frog and a million lizards so they may be eating them. However, I do have one adult Gulf Frittilary which buzzes around for a few minutes in the late afternoon. I never seen it land on anything though I have about 6 mature pentas and about 8'x3' (x 2' high) of lantanas. All the plants are very healthy and were purchased locally at a mom and pop nursery who also have millions of adult butterflies and caterpillars. They control the caterpillars by picking them off and therefore use no chemicals or BT.

My questions is: Do the Gulf Frittilaries LOVE a certain plant because the loner I have here seems to pass it up like an Eskimo passing up a store which sells ice.

A second concern is that I have had over 24 large "healthy" monarch caterpillars on my milkweeds at a time (and a lot more smaller ones still growing). Most have seemed to have vanished. About 5 or so reached chrysalis. Of those, none have made it to adulthood. One just came out this am and when I checked on it around 2pm it was flopping around on the ground like its wings were not fully mature. Its 615pm and its about dead. Another one made it out but was found inside the BBQ storage cabinet under the grill dried up. A third one never made it out and had maggots.

My question: Is this normal?

Many times Gulfs do stay near the vine when they pupate, but often they wander over 100 feet from the vine to pupate, often in hidden areas. Of course wasps (#1 enemy), frogs, lizards, birds, and other predators take a toll on butterfly numbers.

Males tend to hang around the plant but really don’t do much. They’re looking for females. Their instinct leads them to passionvine. Females tend to lay eggs next to the plant on anything (including people) including the plant itself. Many (if not most) Gulf Fritillary eggs are laid off the plant. 

Flopping around usually means that either it ate leaves late in caterpillar life that had insecticide with a colon esterase inhibitor or a spider, ants, or other such critter got it. It’s sad to see. Sometimes a deformed pupa or a disease such as OE (Ophryocystis electroskirrha) can cause deformed wings where the butterfly can’t fly. 

Maggots are very normal.  They cat the inside of the chrysalis - the developing butterfly. The maggots are normally chalcid wasps (although there are other critters like tachind flies that do the same thing). The little wasp lays eggs in a soft chrysalis. It’s all over in nature.

The good news is that all the above nasty things that happen to butterflies is the reason we still have butterflies in the world!

Our little critters have so much against them ..

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