Need help with high fatality rate

[Robert61]

Wednesday June 30: I had a nice day, collected 3 eggs off of sideyard Swamp MW at Waystation No.613 patch. I've noticed many eggs appear hatched but are transparent with slits in them, with much empty egg remains. A heavy toll appears to be eggs eaten, or maybe they weren’t fertilized and just dry out? In the afternoon, collected 9 eggs and collected 2 tiny cats along nearby bike trail. I'm hoping they will all make it. Currently, I've got 25 eggs, 12 tiny cats and 1 larger one. Here's the problem:
This year, so far, I've collected 104 eggs and 7 cats, and released 13 Monarch butterflies. I add up my current eggs and cats = 38 + already released Monarch butterflies = 13, which makes the potential Monarch butterflies reared and released = 51. Yes, 51 releases possible, but I collected 111 eggs and cats thus far; that's 60 fatalities! Most fatalities occur in the egg stage.

Do others have this high a fatality? Could the eggs I collect off the roadways unfertile? Are the eggs I put in the nursery eaten by predators? (I separate the 1st instars immediately). Could the newly hatched 1st instars be escaping the nursery, which has narrow air slits at the top?

Any tips on avoiding fatalities among eggs? Robert at CREATE A WILDLIFE-FRIENDLY YARD http://wildlifefriendlylawn.blogspot.com/

[Mona Miller]

Newly hatched instars will turn around and eat unhatched eggs. And, they will wonder. I don't know why. Perhaps they know that they need to move to another leaf to eat because of siblings.

Assasin bugs will pierce eggs and suck the young caterpillars right out of the eggs before they hatch.

[Robert61]

Thanks, Mona; I will take out the new hatchlings and put them in a separate cage so the eggs will have a "incubator" all by themselves. Bob
http://wildlifefriendlylawn.blogspot.com/

[dandjtaylor]

I find that most of my fatalities are first instars that wander away from their leaf and shrival up before they can make it back, I would estimate about 1-2%. Once they "get their first stripes", I have much better success rates for eggs collected in the yard. For eggs or cats from the wild, the mortality rate is higher due to OE and T-flies. Those I keep separate from my yard "kids".

[Robert61]

Yesterday I collected 9 eggs and two 1st instars around the city parks where they mow. I put the 2 instars into the nursery cage with other small cats. The 9 eggs were put into the incubator with 15 other eggs. Overnight, 4 eggs hatched and I found only 1 of them. But, 19 eggs were eaten! I guess I'll have to monitor the egg incubator every half hour or so to cut down on such huge losses. Thanks for the information. Robert http://wildlifefriendlylawn.blogspot.com/

[Monarch MaMa]

Perhaps it would help if you kept the leaves with eggs on them separated by an inch or so. I hardly ever find a newborn wandering off its leaf, mostly they travel to the underside probably to hide while they nibble & grow.

One way to keep the leaves from shriveling is to put it in an airtight container with a wet cotton ball or wadding of wet paper towel. The humidity keeps the leaves from curling up & the baby has something decent to eat when it gets out. The little cats really don't need all that much air & you'll want to check the eggs daily anyway.

[pjvanee]

I keep my egg-containing swamp milkweed leaves in shot glasses with water soaked cotton balls (to keep the babies from drowning) until they hatch, and then carefully transfer them to swamp milkeed sprigs that are kept fresh in the plastic florist tubes. The eggs are kept in a small plastic aquarium, and the small instars in another small plastic aquarium. Once they get big enough to defend themselves (aka able to run away fast enough) they go in my large 10 gallon glass aquariums with the bigger cats. They travel to the top and attach to the plastic top when ready to form their "J". All my aquariums have slits on the top, and I rarely (if ever) loose eggs or newly hatched 1st instars.

Check your egg incubator for a small sneaky spider! They can hide between the leaves and will eat many eggs and small instars in no time. Most times I am very tolerant of spiders, but when I find them nosing around my caterpillar aquariums...they get squished.

[Mona Miller]

Spiders don't like water. If you mist plants, you will often see spiders running for cover. Small spiders soon become large spiders. I often put on those non-latex gloves when wondering around watering in my tent so that I can take care of the spiders quickly. I also keep a fly swatter in there, too.

[Robert61]

Thank you all for the good ideas! I've looked for tiny spiders and found them, daily, in the aquarium. I like the idea of placing eggs in air tight containers. That would protect them from predators and from each other. I think Tupperware is about to gain a new market! Robert http://wildlifefriendlylawn.blogspot.com/

[Mona Miller]

Glad containers are cheaper and work just as well. You can sterilize them in the top of the dish washer.

http://www.glad.com/containers/gladware_containers.php
Glad information.