Polythysana cinerascens pupae - ill or dry?

[Fernando]

Hi to everyone.

Well, I'm having trouble with my Polythysana cinerascens pupae. I went out for two weeks, and left them in a small container with some water in the bottom -but not in direct contact with the pupae- to keep the humidity.

When I came back, I noticed most of the pupae got or are getting red and hard, like if they dried. I don't know if it's an illness or they literally dried because of lack of humidity. What do you think? Please help, I don't want to lose all of them

Here are some pictures (click on them to see the larger version):





Here's a totally red pupa:



And here's one that's getting red:

[Fernando]

No one?

[evra]

I assume they are an earth-burrowing species? If so, my experience with Citheronia and Eacles is that it's best just to let them burrow and pupate in a 5 gal. bucket filled about 3/4 of the way with soil and just to leave them there. I keep the bucket outside in the shade in a flight cage with the rest of my cocoons. I generally have good success (80-90% survival, all of which emerge at the appropriate time during the following year), and it's always less work and less risk of trying to deal with the pupae.

[oehlkew]

Hi Evan and Fernando,
Polythysana species spin cocoons with an open mesh. Their flight season usually beings in late February, and that species might be quite accustomed, under natural conditions, to hot dry weather.
Perhpas they are still alive. I suggest Fernando pick a couple up and see if the abdomens are still pliant. He can also try tickling the abdomen between the segments with a fingername to see if he gets any movement.
If they still have good weight and are not totally stiff, they may still be alive. I suggest Fernando simulate the natural conditions as close as possible. If it is hot and dry outside, then they probably should not be stored in a humid environment. If you have a rainy season coming, then they probably should be
misted. I do not see how they could be dehydrated based on storage method. Maybe they acquired a late season virus and succombed to that, but again maybe they are still alive.
Always best to replicate natural conditions as much as possible.
Let us know whether or not the abdomens are pliant or are totally stiff. Let us know if you get any movement with the tickle technique??
if they were left exposed to direct sunlight in a closed container they may have cooked or been steamed. Generally not good to leave naked pupae or even cocoons exposed to direct summer sunlight. In most cases cocoons get some shade in the summer months. Chile is now having its summer, like mid August in the northern hemisphere.
Bill Oehlke

[Fernando]

Well, the "red" ones do not respond to tickling and are partially/totally stiff; the ones with regular color are still pliant and respond to tickling.

I always stored them in the shadows, never under direct sunlight. And yes, it is hot and dry out there, but the amount of water I put them with isn't enough to make the their environment too humid (besides, they are in an open container).

Taking into account all the previous, I guess it is an illness If so, I only hope it doesn't spread to the healthy ones (which I have already separated from the supposedly ill ones).

[oehlkew]

Fernando,
Good luck with the remaining live ones. Many viruses attack via the digestive tract with the larva injesting the virus during feeding. I think the ones you have that are alive, probably would still be okay, and some may emerge by the end of ths month or in March.
I believe they spin-up close to the ground, affixed to shrub stems, and they often incorporate some foliage/debris into the structure of the cocoon. Probably best to keep them warm and dry, as close to natural conditions as possible, until you get eclosions.
If you are moving into a rainier season, then it might be wise to mist them occasionally.
Their very porous cocoon probably protects them from overheating, and might allow for quick drainage if and when rains come.
You might experiment with the ones you think are dead, by soaking them in some air temperature water to see if they might rehydrate. It is a long shot, but it might work.
Let us know how you make out.

Why did you remove them from their cocoons?

Bill Oehlke

[Fernando]

Thanks for all the info and the advices, Bill. I'll follow them all.

As for your question, I removed them from their cocoons only for taking the pictures.

[enyas24]

It looks like they are dried, but i have seen the same thing before with some luna pupae.

The abdomen segments shred and were imobile while tickling . I had kept the humidity high but there was a heat spell. Never the less with very few loses most of them emerged but more than a year after.

It looks like the same happened here also. What Bill suggested seems reasonable and you get to see also if they float in the water. Slight changes in their weight may have occured but if they re not light enough there is still hope.

I would deffinately keep them just in case

ps: maybe it s just a defence strategy to slow down the metabolism into extremes , nature does wonders!!!

[Fernando]

Feb 15, 2011 10:24:32 GMT -8 enyas24 said:

It looks like they are dried, but i have seen the same thing before with some luna pupae.

The abdomen segments shred and were imobile while tickling . I had kept the humidity high but there was a heat spell. Never the less with very few loses most of them emerged but more than a year after.

It looks like the same happened here also. What Bill suggested seems reasonable and you get to see also if they float in the water. Slight changes in their weight may have occured but if they re not light enough there is still hope.

I would deffinately keep them just in case

ps: maybe it s just a defence strategy to slow down the metabolism into extremes , nature does wonders!!!

Hi Enyas!

I hope it is something like the last thing you mentioned. It would be very sad to lose them.