Monarch Butterfly Migration News

Monarch Butterflies

Waiting for Adults
May 10, 2017 by Elizabeth Howard

While we continue to wait for the next generation, let's salute the monarch larvae. Most of the world's monarchs are in this stage right now.

"I have only seen a couple of single monarchs this spring but I found a caterpillar on my butterfly weed." Beth Rice of Chattanooga, Tennessee on May 7, 2017

Never Fewer Butterflies
Right now, the number of adult butterflies is at its lowest; at no other time of year are there so few adult monarchs.

With so few butterflies, the migration has come to a standstill. Look at the animated migration map and see how little things have changed. We're still waiting for the surge of 1st generation butterflies and this week was the slowest of the season. There were still people reporting faded-winged butterflies, which means that some of the monarchs from Mexico are still around.

New Generation Coming
People are reporting larvae — lots and lots of larvae. Eating and growing, today's monarch caterpillars will soon be northbound butterflies.

No to Neonicotinoids
Journey North participant Karen VanHeest wrote with concern about plants being sold to butterfly gardeners that contain neonicotinoids, a class of systemic pesticides that are harmful to monarchs and other pollinators. The flowers are toxic, and so is the plant material that's eaten by monarch larvae and other herbivores. Watch out for neonicotinoids — and other pesticides — in any garden products that you purchase. If you're not sure, don't buy it. Read more:

Xerces Society: Neonicotinoids in Your Garden
Monarch Joint Venture: Insecticides and Monarchs
Xerces Society: Neonicotinoids and Bees

Old Generation Persists
Kevin Ford

New Generation Coming
Warren Bielenberg

warning tag to butterfly gardeners that plants treated with neonicotenoids

No to Neonicotinoids!

What do monarch butterfly larvae do?

Monarch caterpillars grow through five stages as a larva. Each stage is called an instar. The smallest stage is the 1st instar. As the larva grows it goes through the 2nd, 3rd, 4th and 5th instars. After that, the larva becomes a chrysalis.

Grow Monarch caterpillars grow through five stages as a larva. Each stage is called an instar. The smallest stage is the 1st instar. As the larva grows it goes through the 2nd, 3rd, 4th and 5th instars. After that, the larva becomes a chrysalis.

This monarch larva just shed its exoskeleton and is now eating the remaining portion, called the exuvia. A monarch must shed its exoskeleton to make room for growth. The process of shedding is called molting and happens between each instar. The most likely reason for eating the exuvia is to recycle the nurtients it contains, especially hard-to-get nutrients like nitrogen.

Molt This monarch larva just shed its exoskeleton and is now eating the remaining portion, called the exuvia. A monarch must shed its exoskeleton to make room for growth. The process of shedding is called molting and happens between each instar. The most likely reason for eating the exuvia is to recycle the nutrients it contains, especially hard-to-get nutrients like nitrogen.

Monarch caterpillars have tiny, oval-shaped holes on the sides of their bodies. =Dr. Karen Oberhauser explains what they are and how they work:"Monarchs 'breathe' through tiny openings on the sides of the abdomen and thorax called spiracles. The spiracles are in their cuticle, like our skin. I put quotes around the word 'breathe' because this is very different than the kind of breathing you do. Monarchs don't have lungs. The air goes into their spiracles and through a whole series of tubes in the body called trachea. The trachea carry oxygen throughout the monarch's body."

Breathe Monarch caterpillars have tiny, oval-shaped holes on the sides of their bodies. =Dr. Karen Oberhauser explains what they are and how they work:"Monarchs 'breathe' through tiny openings on the sides of the abdomen and thorax called spiracles. The spiracles are in their cuticle, like our skin. I put quotes around the word 'breathe' because this is very different than the kind of breathing you do. Monarchs don't have lungs. The air goes into their spiracles and through a whole series of tubes in the body called trachea. The trachea carry oxygen throughout the monarch's body."

Monarch larvae have two different kinds of legs, true and false. Like all insects, the caterpillars have six true legs. They are attached to the thorax. The false legs, or prolegs, are attached to the abdomen and are only present during the caterpillar stage. False legs have pads at the ends with sticky hooks called crochets. When you hold a caterpillar, you can feel the grip of the crochets. Crawling along a paper-thin leaf, or eating while hanging upside down, monarch caterpillars defy gravity.

Walk and Grip Monarch larvae have two different kinds of legs, true and false. Like all insects, the caterpillars have six true legs. They are attached to the thorax. The false legs, or prolegs, are attached to the abdomen and are only present during the caterpillar stage. False legs have pads at the ends with sticky hooks called crochets. When you hold a caterpillar, you can feel the grip of the crochets. Crawling along a paper-thin leaf, or eating while hanging upside down, monarch caterpillars defy gravity.

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Driving Question

What do monarch larvae do? Research to learn about the larva stage of the monarch life cycle.

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Spring Migration 2017


Report all monarchs you see — adults, eggs, larvae.

What to Report	Adults report \| map \| list	Eggs report \| map \| list

Larvae report \| map \| list	Milkweed report \| map \| list	Other Observations report \| map \| list

Next May 18, 2017