Monday, June 8, 2009

Caterpillar Predators and Diseases

While raising caterpillars I have learned a lot about the importance of predators. Without them we would have millions of diseased butterflies flying around. In nature only the fastest and healthiest caterpillars make it to adults. I think only 2 or 3% of butterfly eggs laid survive to adulthood.

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I have had Monarch butterflies lay hundreds of eggs in my garden, but have not found one caterpillar make it to a butterfly. With so many wasps attracted to my milkweeds they quickly spot the caterpillars for lunch. I’ve found small monarch hiding in my parsley and other bushy plants, but somehow the wasps manage to find them.

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This lizard stays around my garden in wait of a tasty caterpillar.

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The best solution for avoiding these predators is to keep the caterpillars protected in an enclosure. If you want to purchase a smaller size cage to raise caterpillars the best place is http://www.butterfliesetc.com/buy-butterfly-caterpillars/caterpillar-rearing-containers. Small netted containers sell for as low as $10 dollars. I have had great success with using enclosures. Out of 70 eggs about 60 emerged as healthy butterflies. Around ten percent died from a disease called OE.

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 Ophryocystis elektroscirrha (OE) is a small parasite that infects only monarch and queen butterflies. A female butterfly with OE can transfer an OE spore to its eggs. When the egg has an OE spore on it, it will ingest it when eating the egg shell. The only way to destroy the parasite is to clean the eggs with a bleach solution. To learn more about OE and how to clean eggs go to http://www.butterflyfunfacts.com/oe.php.

Right now I am trying to learn more about OE. I selected four of my monarchs that appeared to be OE free. I kept them in my pavilion ( with nectar and fruit to drink ) until they laid eggs on my milkweeds. Now that the eggs have hatched I am watching the caterpillars to see if they get OE or if they all stay healthy. If the caterpillars have OE they will start to develop dirt like spots on their bodies when older.

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Posted by at 11:55 AM

7 comments:

  1. Stephen HarrisJul 21, 2010 08:19 AM
    Yesterday I kept watch of an adult monarch caterpillar in my garden. It wasn't eating the milkweed leaves any more and seemed to be searching for a place to make its coccoon. I even left objects close by so it could hang on, but it just kept wandering and searching. At 5:30 pm I checked on the caterpillar and it was fine. Around 6:15 I was in for a big disappointment. I found the caterpillar severely injured, suffering and dying. I blamed it on some bird, but a wasp came, landed and seemed to drink from the struggling caterpillar still alive! How terrible. I don't know why God alows such cruelty. I wanted to observe the cocoon, the hatching and the happiness of bringing another beautiful monarch butterfly into the world.
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  2. Thanks! This is certainly helpful. Looks like our caterpillars all became victims to either wasps or the lizards. More new plants look like they are coming up so maybe we'll achieve balance next year. We just started to watch them this year.
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  3. I am in WI and wondering if anyone else felt there was a very small number of Monarchs this year and they arrived very late. I now have three chrysalis and hopefully two eggs. Starting with the egg will be a new experience for me. I have managed two generations of Painted Ladies (maybe the third on the way) Time will tell. It is all soooo interesting. betty
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  4. I'm in Michigan and have been rearing a handful of monarch each summer for the last 5 years. Last year south of Detroit was a good year for monarchs in my yard.

    This was an odd year so far. After the Joplin tornado I noticed a monarch in JUNE. It was a chilly month. I've never seen one that early here and felt awful for it because most of the plants they like in our area weren't even near blooming.

    To add insult to injury I've finally witnessed an incomplete shed death and possibly OE for the 1st time.

    Also seems to be an inordinate amount of pests stalking the plants.

    I'm heading off to see how to disinfect my rearing enclosure and consider another method.
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  5. Idea for creating your own caterpillar rearing container or sleeve. Buy a roll of fiberglass screen, used to replace your screen door/windows. Actual size screen depends on your needs. To make a sleeve cut the screen using household scissors, the length should be doubled, then fold in half and fold/staple the sides using a regular stapler. Put the sleeve over the branch and tie the bottom for easy release. As for a screened container you can use staking sticks to create a frame then wrap it with the screen, staple the ends on the side, and tie the top. I did the screened container for the smaller host plants such as the Milkweeds and the sleeves for the bigger host plants such as the Popcorn Cassia..
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  6. I'm in the Sierra Foothills and yesterday had the same experience that Stephen Harris had. As I was checking on one of the few Monarch caterpillars we had this year, a large black wasp with orange markings on its back landed on the caterpillar and stung it repeatedly until the caterpillar shriveled and died. I figured that was the same fate our other caterpillars met, so now the remaining one is inside.
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  7. I have many Monarch caterpillars on my milkweed as I do every year. They seem to get killed by some tick looking thing. It's body is a little smaller than an unpopped popcorn kernel. What is that?
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