butterfly defects

[Beth]

We have raised monarchs for years in Wisconsin, but this year, five of our last butterflies have not been able to put their proboscis together. They were all males. One could not fly and seemed to have a more swollen abdomen. I didn't let any of them go because I knew they couldn't eat and I didn't know if they could spread it to other butterflies. What could have caused this? Is is contagious to the others because we have about 15 chrysallis and 7 caterpillars. We are so frustrated because we thought we were helping the population.

[Keith Petrosky]

I had a moth that could not roll up it's probascis. I checked on it the next day and it was perfectly fine and eating, mabye this is the case with your monarch?

[Jim]

I believe Beth is talking about the monarchs not being able to "zip" their proboscis together - something that they normally do soon after emergence. The proboscis is actually a paired structure that must be zipped together to form a tube through which the monarchs will feed. No zip = no tube = no drink...try cutting a straw lengthwise and see if you can still enjoy your favorite beverage



This defect is not unheard of and it is most often associated with diseased or parasitized individuals. I would recommend a thorough cleaning/disinfecting of your rearing equipment with a 10% bleach solution. You should also consider isolating your larvae which will help reduce the spread of disease.

Hope this helps!

FYI - additional information about the monarch proboscis is available at

http://www.monarchwatch.org/update/2002/0910.html#6

[Keith Petrosky]

I know what she meant. I hope if it's possible her butterflys recover.

[Beth]

We were happy to see a perfect monarch hatch yesterday. Since we've had problems, I agree with the suggestion to isolate them. We usually keep stems of milkweed in water with 4 to 6 caterpillars but I can see how one who was sick could spread it to the others. Thanks for the advice.

[Megathymus ursus]

Beth, I suspect your butterflies had a viral infection. A swollen abdomen can be a symptom of polyhedrosis virus in adults.