Busy little caterpillar, eat, eat, eat...

As a prequel to the previous post of the monarch chrysalis and the butterfly's first flight, I thought it would be nice to look closely at a monarch larva. I was able to use my macro lens to get a closeup of a monarch caterpillar (5th instar) chomping its way through a milkweed leaf. It gives you a good idea of how fast a larva can devour a leaf, and just how much it eats (practically nonstop) to be able to grow so quickly and move through 5 instars...

Monarch Larva Eating Milkweed (5th Instar) from Kelly Riccetti on Vimeo.

When the larva is ready to molt, it becomes very still and latches itself to a leaf with silk it produces from a spinneret located on its lower lip. The head capsule is the first to molt, and the cuticle (outer skin) then splits down the back. Below you can see the caterpillar just after it escaped from its cuticle (the grey mass behind it). It has now moved into its fifth instar. You can tell which instar a monarch larva is in by the size and shape of its tentacles. To learn more about monarch larva and instars, click here for a pdf version of "A Field Guide to Monarch Caterpillars (Danaus plexippus)," by Karen Oberhauser and Krista Kuda, or here for the monarch life cycle on the University of Minnesota's website. 

Our monarch caterpillar has just molted into its 5th instar. You can see the thin, crumbled cuticle behind it. 

In the following video, you can see the very end of the caterpillar shedding its skin. The quality isn't great, because I took it with a cell phone instead of my camera, but you get the idea... 

Monarch caterpillar shedding its cuticle (outer layer of skin) from Kelly Riccetti on Vimeo.

Where is its head?

At first it's a little hard to tell the front end from the back end of a monarch caterpillar. Both ends have black fleshy tentacles that resemble antennae, but when you look a little closer, it's easy to tell the difference. First look at the tentacles. The front pair are much longer than the back pair. The front tentacles function as sense organs similar to antennae, but the back pair are thought to be defensive to confuse predators on which end is the head. Second, look at the legs. Three pairs of jointed "true legs" are in the front. Five pairs of "false legs" (prolegs) are attached to the abdomen all the way to its rear. 

The monarch caterpillar's larger tentacles are near its head. Three pairs of jointed true legs are on the thorax near the head as well. In the photo above, the head is on the right (you can't see the third set of true legs).

What's the difference between true legs and prolegs?

Caterpillars have three pairs of true legs attached to the thorax. These legs are segmented and often have a claw on the end. They help the caterpillar hold its food. If you look closely in the photo below, you can see the tiny claws at the tips of the true legs on the monarch caterpillar. True legs transform into the legs of the adult insect during metamorphosis. Caterpillars also have prolegs attached to the abdominal segments, but the number of pairs varies among species (monarch caterpillars always have five pairs). Prolegs are stumpy, cylindrical, and unsegmented. They also have microscopic hooks at their tips that work like suction cups to help the caterpillar cling to stems and leaves. The prolegs dissolve during metamorphosis.

In this close-up you can see why monarch tentacles are always described as "fleshy." They are not segmented like an adult insect's antennae, they are fleshy. You can also see a close-up of the three segmented true legs on the thorax.

Cuteness! A monarch caterpillar was underneath the leaf munching away, then another crawled over the top and started to eat as well. When the two "met in the middle," they touched heads, looking a little smoochy-smoochy. The caterpillar underneath shook its head and moved to the other side of the midrib of the leaf. No time for that...must eat more milkweed leaves!

Milkweed beetle--possibly the cutest bug ever?

In our backyard we have milkweed bugs and milkweed beetles that live on our milkweed plants. Milkweed bugs are cool (click here for photos from a previous post), but Milkweed beetles are cute...and I'm talking puppy dog cute! Look at those long, droopy antenna and the sad, half-mast eyes. If they don't melt your heart, nothing will...

A Red Milkweed Beetle hides in common milkweed buds in our backyard.

Milkweed beetles are in the longhorn beetle family, which accounts for those long droopy "puppy-dog ears." And the half-mast eyes? They are an adaptation where the socket of the antenna actually bisects the compound eye, creating an upper and lower eye. The bug is often called a four-eyed beetle, and both the genus and species of its scientific name (Tetraopes tetrophthalmus) means four eyes.

Old four-eyes! If you look above the antenna, you'll see a black spot that is actually the top half of the eye.

...and if all of that doesn't get you, they sing, literally, but it's more like a soft squeak. The first time I heard it was in June of 2011 at Shawnee State Park. Jenny Richards, who is the naturalist there, picked one up for Matty and me and let us listen. Amazing! The little beetle definitely made soft squeaky sounds. I didn't hear the fellow in my backyard singing. He was tucked in the flower and hiding out, so I didn't bother him.

This is the milkweed beetle Jenny picked up and got singing for Matty and me. I took this photo back in June 2011 at Shawnee State Park in the butterfly garden just outside the nature center.

...but just so we don't think this fellow is a little ball of fluff, look at those mouth parts. Milkweed beetles chew through leaves at the tip, cutting the veins "upstream" so not as much of the gluey, white latex gets on them. If the beetle does get latex on its mouthparts, it rubs its face against the leaf right away to remove the gooey mess, otherwise, the latex will glue its mouth shut. Yikes!

Although cute, the milkweed beetle has a nice set of chompers!

In early summer, females lay eggs at the base of the plant's stem, sometimes inserting them in the stem, or even on nearby grass. When the larvae (grubs) hatch out, they crawl down to find the roots, either by burrowing through the soil or through the outer layer of the stem. They live in the soil and feed on the roots through fall and then overwinter in the roots. They pupate in spring in little chambers they dig in the soil. It takes about a month for them to emerge as adults.

The milkweed beetles you see on your plant in early summer lived in the roots of the plant as grubs during the winter.

Milkweed plants are toxic, and since the beetles eat the leaves, buds and flowers, they are toxic as well, which makes them taste bad, so predators leave the very bright and noticeable insects alone (just like the monarch butterfly who also eats the leaves as a caterpillar). No need for camouflage for these critters. The bright orange and red color is a warning to predators to shy away.

...see you later, "Fido!"

References
For more information on the Red Milkweed Beetle, click here for an article by the Bug Lady at the University of Wisconsin.

For a quick look at insects that live on milkweeds, click here for a post by Restoring the Landscape with Native Plants.

Large Milkweed Bugs (Oncopeltus fasciatus) at Fort Ancient

A few weeks ago I spent a little time hiking through the meadow by the Mound Trail at Fort Ancient. The grasses were brown and dry, and what was left of summer's bounty crackled and rattled with each breeze that worked itself through the tumble of spent flower heads and stalks. Autumn had drained the green from the landscape, and even the yellows had faded from the fields, but oranges and reds were still around to be found on the dry and cracked Common Milkweed plants...

An adult Large Milkweed Bug (Oncopeltus fasciatus) is surrounded by all five of its instars. The adult is at the top. It is the largest and has usable wings. Instars are nymphs, or immature versions of the bug. Instars differ in size, color and pattern. They also lack usable wings.

Large Milkweed bugs molt five times (nymphal instars) before they become adults. During these stages the nymphs look similar to the adults; however, if you look closely you can see each instar has its own color (from deep red to orange) and pattern. During the middle instars black wing pads start to form, but the wings are not usable until the fifth instar molts into an adult.

...also unique to the adult is the flame-red pattern on its face between its eyes...

...the adult Large Milkweed bug has a striking pattern of orange and black on its wings. Here you can see the veins that carry the hemolymph through the wings. On the final molt, the adult Milkweed bug pumps hemolymph through these veins to unfurl the wings. To see an adult who failed to open his wings, click here.

...a fifth instar almost looks like an adult, but lacks the defined face pattern, usable wings, and the eyes are much less "buggy!" Look to the right for a glimpse at an adult's eye.

One adult and several fifth instars mass together to form a color warning on an old Common Milkweed pod.

Since Large Milkweed bugs eat Common Milkweed sap, which contains toxic alkaloids, they do not taste good. A young bird only has to taste this bug once or twice to learn to avoid orange and black bugs! Large groupings of this color combination warn birds away. You may already know of another orange and black insect that has the same type of protection--the Monarch butterfly. Just like the Large Milkweed bug, Monarch butterfly caterpillars feed on Common Milkweed plants and concentrate the alkaloids in their tissue. When the caterpillars metamorphose into Monarch butterflies, they are toxic and also taste bad.

Another tidbit...I read on this site (click here) of an easy way to distinguish between a male and female milkweed bug--the female Milkweed bug has one black strip and two back dots on her abdomen, while a male has two thick black strips. I didn't know that before and never flipped one over to look. Next time I see one I'll take a peak.

...close-up of two later instars.

...close-up of an adult Milkweed bug--love the face tattoo.

This guy is not going to be hanging around much longer. These bugs migrate! Just like the Monarchs, they head south for the winter. Shorter days in autumn trigger diapause in the adults, which shuts down the reproductive system (source: "Migration: the biology of life on the move," by Hugh Dingle, page 139, click here to read more.). Shutting down the reproductive system saves energy and allows the Large Milkweed bugs and Monarch butterflies to migrate south for the winter. The same adult Milkweed bugs that overwintered in the south then migrate back north in the spring to lay the eggs of the next generation.

If you want to learn more about the Common Milkweed plant and all the insects that feed on it, check out this post by Marcia Bonta. I stumbled across it a few weeks ago and thought it would fit in here. For more photos of Large Milkweed Bugs, click here for an earlier post.

Large Milkweed Bugs (Oncopeltus fasciatus)

Saturday I went on a very exciting field trip with the Cincinnati Birding Club to Caesar Creek State Park in Warren County, Ohio. We saw some fabulous birds and the weather was perfect, but while searching for birds, I saw these Large Milkweed bugs...and they were close and immobile, and photographed infinitely better than the Common Loons, Hooded Mergansers....and American Bald Eagles I saw along the way (more on those pretties later)!

Large Milkweed Bugs on a Common Milkweed pod. One adult is at the top (he has wings), two fifth instars are at the bottom (they are nymphs, or immature versions of the Large Milkweed bugs--notice that they don't have usable wings yet.)

Milkweed bugs molt five times (nymphal instars) before they become adults. During these stages, the nymphs look similar to the adults except their color pattern is a little different and they do not have fully developed wings (during the middle instars black wing pads start to form, but they can not use their wings until they are adults--a great way to keep the kids at home and safe until they grow up).

Close-up of a middle instar. You can see the black wing pads. He's definitely not flying anywhere with those things! Eggs hatch in about a week if the temp is 75 degrees F or above. The bug goes through the five molts to become an adult in about a month! The adult then lives for about a month.

Three adult Large Milkweed Bugs and two instars.

At the tip of the Milkweed pod a group of adults are massing together to form a color warning to birds and other predators.

This behavior is thought to amplify the Milkweed bug's ability to broadcast a color warning. Since Milkweed bugs eat milkweed, which is toxic, they do not taste good. A young bird will think twice before downing another orange and black bug the second time it comes across one...and a great big mass of orange and black is a big warning to stay away! This is the same sort of protection Monarch butterflies receive because as caterpillars they too feed on Common Milkweed. Click here for an older post explaining how Pipevine Swallowtail butterflies and Monarch butterflies receive the same protection (and for a look at how beautiful Common Milkweed is as a flower in the summer).

I love how delicate their legs look against the silk of the milkweed seeds.

What do we have here? At first I thought it was a different bug, but if you look closely, you can see it's an adult with abnormally developed wings. For some reason they have shriveled and dried up. Perhaps on his final molt he was not able to pump hemolymph (bug blood) through the veins in his wings to unfurl them. I don't know...

Another view of our adult Milkweed bug's shriveled wings.

You can see how different the Large Milkweed bug looks without wings to cover his body.

For more information on Large Milkweed bugs, click here.

For photos of all the instars of Large Milkweed bugs, click here.

Orange on orange...

Just a quick little post...deep in the meadow, this sprig of Butterfly Weed was pushing through the grass. Neon orange in a sea of lime green, the colors shout summer! The Great Spangled Fritillary perched on top was taking it all in stride, sipping nectar from the blossoms, unaware of his own beauty.

I learned from my "Wildflowers of Ohio Field Guide" by Stan Tekiela, that Butterfly Weed (Asclepias tuberosa) is in the Milkweed family. It is found in meadows and prairies, and along roadsides blazing in the hot sun. It is a true milkweed, but it does not have milky sap. If broken, the stem and leaves ooze clear sap. "Tuberosa" refers to its large tap root, which makes it very difficult (if not impossible) to transplant. Sowing seeds is better. I just bought a Butterfly Weed plant from the local nursery. It was the last one they had and was flowerless and bedraggled. I hope it can come back. If not. I'm going to sow seeds next year. It is a host plant for Gray Hairstreak and Monarch butterfly caterpillars. Yeah!

Pipevine Swallowtail Nectaring on Common Milkweed

Birding Hocking Hills in Southeastern Ohio
...continued from the Catbird post.
While watching a Gray Catbird on the Creekside Meadows trail in Clear Creek Metro Park, I saw this beautiful butterfly off in the distance. I kept my eye on him hoping he would come in a little closer. He came in a little, but mostly kept his distance, constantly moving from blossom to blossom and seeming wary.

A stunning Pipevine Swallowtail sips nectar from a

Common Milkweed blossom. I've got to plant this native

wildflower in my garden! I saw several species of

butterflies nectaring from its fragrant flowers. I also

saw Ruby-throated Hummingbirds and Hummingbird

Clearwing Moths sipping nectar from it.

To us, the blue and orange against black is extraordinarily beautiful, but to a bird, the color combination says “Look, but don’t eat!” While it's a caterpillar, the Pipevine Swallowtail stores toxins in its body from its pipevine host plant, making him unpalatable to birds. Because of this, birds usually leave him alone. In Ohio, five other butterflies have evolved the same color pattern. By mimicking the color combination of the Pipevine Swallowtail, these other species gain protection from predators.

Common Milkweed is the host plant for Monarchs.

Female Monarchs lay just one egg per plant under

a leaf. Monarch caterpillars ingest and store toxins

from the Common Milkweed plant just as Pipevine

caterpillars do from pipevine plants. Birds soon

learn to leave Monarchs alone too.

Zebra Swallowtails love nectaring on Common Milkweed also. When I was at Strouds Run, a gorgeous Zebra Swallowtail hung around for quite a while, going over each blossom carefully.

A Zebra Swallowtail at Strouds Run State Park in Athens, Ohio

Birding in Athens, Ohio and Hocking Hills

...continued from the Road Trip! post.

Today I made it to Strouds Run State Park. It's not far at all from my hotel and seemed a great place to start. It was very pretty. Most notable were the butterflies, blackberries and Catbirds!

A Zebra Swallowtail butterfly...I know this because I bought

"Butterflies of Ohio" by Jaret C. Daniels at the Wayne National

Forest Visitor's Center. It's about time I start learning the

names of these incredibly beautiful and beneficial creatures!

A Silver Spotted Skipper. You can't see his orange

splotch. It's hidden behind that spiky blade of grass.

I think this is a Great Spangled Fritillary. Look at his

tattered wings. He has seen better days. I wonder what

happened to him? Maybe a bird tried to nip at him...

or he overwintered and his wings are just worn.

In Cincy, I see Catbirds every year, but not that many of them, but at Strouds Run State Park, I saw twelve...and every one was near, on, or eating blackberries! In three different spots in the park, I saw batches of blackberries and found Catbirds. Unfortunately, they said "No photographs today, please. We are eating blackberries and have no time for posing."

Wherever I saw a stand of blackberries,

I saw several Catbirds standing around...

Yum...I would too!

What in the world is this???

Check out this photo. I took it on the Hocking River Bike Trail. In the bottom-right corner, you can see a very blurry Acadian Flycatcher looking down (another non-posing bird), but what creeps me out is on the left side on the trunk of the tree. It looks like a big gelatinous pink wormy thing. I didn't see this when I took the photo...I only noticed it when I was cropped down the photo of the Acadian Flycatcher. I have five photos and they all have this on them, in the same spot. Is it some sort of fungus...or some sort of alien wormy thing? I hope someone out there knows! It's sort of weird...

Do you see the blurry flycatcher at the bottom right?

Now...look to the left. Do you see that pink, segmented,

wormy thing? It's pretty big and extends all the way up

the side of the tree for 3 or 4 feet (maybe more...that's

all my photo shows). It's that glistening bumpy stuff.

Here's a shot of just that end piece. See the segments?

I guess it's some sort of fungus, but it looks like it could

uncurl and reach out and grab that flycatcher! :-)