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!

Scruffy Chic...the must-have spring wardrobe choice for happenin' male goldfinches...

Yet another sign of spring--from the changing of the guard to the changing of the wardrobe...

Male American Goldfinches (Spinus tristis) everywhere have started undergoing their spring molts.

Before you know it Scruffy Chic will be out of style and Sleek Yellow will be in!

The molt goes on...

Birding at Voice of America (VOA) Park near Mason, OH

..continued from a post last week on a male Bobolink molting into his Basic non-breeding plumage at VOA Park.

I stopped by the park late friday afternoon to see how far along the male Bobolinks were in their molts. It had only been five days since I was last there, but boy had they changed!

He has lost almost 50% of his black

feathers. The change is fairly quick!

If you look closely, you can see he is losing

the pigment in his bill. It's mottled black now.

Check my other side...I'm quite handsome in

my "tortie-shell transition phase."

He will molt all of his feathers including flight and

tail feathers. He does not lose them all at once,

so he is never rendered completely flightless

Click here for a post earlier this summer showing a male Bobolink in full breeding plumage.

While walking through the mowed areas of the meadow, I heard three Henslow's Sparrows in the middle...and a single Henslow's Sparrow in the area closest to the little parking spot by the big tree. There were also five Willow Flycatchers hawking insects using the big tree as a base. If you want to learn more about the Henslow's Sparrows of VOA, head over to my friend's new blog, Everybody Funny. He surveyed VOA from 2001 to 2007 weekly and accumulated a lot of research on the Henslow's Sparrows nesting there.

Male Bobolink starting to molt into his non-breeding Basic plumage

Birding at Voice of America (VOA) Park near Mason, OH

...continued from the Henslow's Sparrow post.
Before fall migration coaxes Bobolinks south to their wintering grounds, male Bobolinks start molting into non-breeding Basic plumage. It’s almost like the males shed their formal “tuxedos” for more relaxed and casual traveling clothes. The following male Bobolink is just starting to molt into his Basic plumage. By the time he’s ready to fly south, he will more closely resemble the understated females.

Looking a little scruffy, this male Bobolink

has started molting into his Basic plumage.

He was singing just as sweetly, but maybe

not quite as often as earlier this summer.

He did a lot of calling instead.

In addition to their molt into non-breeding

plumage, male Bobolinks will lose the

dark pigmentation in their bills.

He looks like he's ready to fly south right now!

A female Bobolink perched on a sapling--her

warm caramels and browns are every bit

as appealing as the male's flashy summer

tuxedo. In the fall, the male Bobolink

takes on the female's casual colors.

Sitting in the fading light, the female was gorgeous.

I need to go back and capture her in full sunlight.

Click here for an older post showing a male Bobolink in complete breeding plumage.

I'm next, I'm next!

I looked out the family room window a few days ago and watched Little Chiggy waiting in line for a sunflower seed at the new feeder. He really is eyeing the other bird, and paused for several seconds until it left.

I'm next, I'm next, I'm next...my turn!

When I cropped the first photo down, I noticed how worn his little feathers were. I don't know how to tell if this is a juvenile who will have a small molt in the spring, but if he's an adult, he definitely is going to need to upgrade those feathers this summer!