Frequently Asked Questions
Where can I get milkweed plants?
Where can I find caterpillars to rear or adult butterflies to sample?
Why do I need to wear gloves and try and maintain sterile conditions?
The parasite spores are very small and easy to accidentally spread around. It's important to wear gloves to minimize the spread of spores from one sample to another. Always change gloves between handling different butterflies. One monarch may be infected, while another may not. It's important to try and keep a clean work area when handling and sampling the butterflies for parasites. Bleaching any containers, tools, and work surfaces the butterflies touched prevents cross-contamination of different samples and helps avoid touching a non-infected sample with infected spores from another. We suggest a 20% bleach solution be used between sampling individuals and also between different sampling periods.
Why are my caterpillars sick?
Larvae can die from many causes besides OE, including infection with bacteria, viruses, parasitoids, and temperature extremes.
• If you observe group deaths or individual caterpillars showing any of the following symptoms: vomiting, writhing, diarrhea, then it is likely they have been exposed to chemical poisoning. This can be a result of any pesticides used on the milkweed plants.
• If caterpillars are not eating, lethargic, and turn brown or black, then bacterial or viral infections are possible.
In any case where you observe caterpillar illness or death, immediately remove the affected individuals from the rearing containers, bleach the containers, and move remaining healthy individuals to new, clean containers with fresh plants.
Will sampling for parasites hurt a butterfly?
No. Monarchs are very sturdy and it is difficult for scales to be removed. It is important to apply enough pressure with the sticker on the abdomen to get a sufficient amount for a sample. You should see black coloration on the sticker when placed on the notecard.
What do I do with infected monarchs?
Read about this here.
Should I mail an empty chrysalis or part of a deceased butterfly to be sampled?
No. Unfortunately, we are only able to collect usable samples from the abdomens of monarchs so we cannot use other parts or the empty chrysalis to get an accurate estimate of the OE spores.
Should we send you tachinid fly pupa if they emerge from the chrysalis?
No, but you can send them to the Monarch Larva Monitoring Project
What does a pupa with OE look like?
Typical signs of OE infection in pupae include dark coloration that will initially show up on the abdomen and thorax areas, just underneath the cuticle (hard exterior of the pupa). These dark patches can be isolated as a few small spots, or may extend across all abdominal segments, thorax, and head. The signs of infection first appear about 3 days before adult butterflies emerge, before monarchs produce their own body pigment, and will progress each day. Often, these dark patches are distributed asymmetrically, whereas the monarch’s own pigment is symmetrical from the middle line of the abdomen.
What should I do if I've planted non-native tropical milkweed?
Because tropical milkweed continues to grow and bloom throughout the winter, it can reduce the need for monarchs to migrate. This lack of migration can result in increased OE prevalence in these resident populations. We suggest cutting back your tropical milkweed in the fall to mimic the "dying back" of native plants during this time. Or, you could remove these plants and replace them with native milkweed species. You can buy them online from Prairie Moon Nursery.