Watch a newly-hatched caterpillar deal with danger

When they first hatch, monarch caterpillars are only about 2 millimeters long. For tiny critters, the world is a dangerous place.  Watch a freshly hatched caterpillar deal with two hazards...

What do monarchs and penguins have in common?

 

Think carefully... the clock is ticking...  make a guess before clicking on "Read more."

How to ensure that females lay eggs

I've described the entire breeding strategy and setup elsewhere.

But if you opened the honeymoon hotel and no eggs appeared, here are some tips.

Because non-reproductive butterflies begin to eclose about mid-August, the proportion of non-breeders increases.

It's confusing...  How can you spot the ones that can breed, vs the migratory ones? And for the recently eclosed butterflies that might be breeders, how do you know when they are ready to mate or lay?

How to avoid injuring butterflies in the breeding tent

When working with tiny critters, injuries can happen.  But you'd be surprised what the most common injury used to be in my breeding tent--before I learned how to prevent it.

Butterflies spend most time clinging to the wall and ceiling of a tent--and most tents have mosquito netting. The mesh cubes used by teachers to hold butterflies have similar material.

Butterflies have two huge claws on each foot--used for clinging to foliage.  These claws attach very firmly to netting.  When you pull butterflies off netting to transfer or feed them, this can exert s huge force on their legs and claws.

It's astonishing how much force.  When I was unaware of the danger, sometimes when I picked up a butterfly, a large object it was clinging to would come along as well.

Data needed from classrooms

Please provide feedback!  I'm trying to find out what works best for teachers.

I'm trying to understand what happens after teachers receive their eggs.  I've enjoyed meeting teachers when they pick up eggs, but I hear very little about what happens back at school.

My guess is that dealing with hatching and feeding very small caterpillars is the hardest part for teachers.  One school reported 27% losses by the time caterpillars were small (not tiny).  After that, very few losses.  Just an occasional accident, like a dropped chrysalid, or a butterfly that fell down during eclosure and became deformed.

Changes in behavor as caterpillars grow

Eggs are nearly always laid on the undersurface of a leaf.  This provides shelter from the sun--tiny eggs
in the sun on a hot day could quickly heat to lethal temperatures.  The downside also shelters an egg from rain drops--giant wrecking balls in comparison to tiny eggs.  And eggs under leaves are much less visible to visual predators like birds.

Given these clear advantages of being on the underside, I assumed the same was true for newly-hatched caterpillars.  So, imagine my astonishment when I checked a milkweed with just-hatched eggs, and discovered that most of the caterpillars were on the top of leaves. 

The fall migration has begun

During the last few days, I've seen more monarchs stopping to nectar on my Liatris flowers.

One observation today suggested these are representatives of the migratory generation:  A male and female were nectaring side by side, with absolutely no mating behaviors, including chasing or aggression.  They just ignored one another.

Clusters of migrating monarchs have been seen.  The Journey North website reported a "roost" of migrating monarchs at the north end of the Pheasant Branch Conservancy in Middleton, WI.  Over a hundred were estimated huddling on three oak branches.

See this excellent article by Dr. Karen Oberhauser and Jacob Swanson.