Gossamer Tapestry

Reflections on conservation, butterflies, and ecology in the nation's heartland

Monday, April 06, 2009

Carrion - It's What's for Dinner

Deer carcass remains. Note the relatively intact hoof in the lower midsection.

Last fall and winter, FC posted a whole series of photos documenting the decomposition of a dead deer. Things work a bit differently here up in the Arctic wastelands of Illinois. A deer that died over the winter got covered by snow. The cold temperatures meant that decay by both bacterial and insect processes was slowed. The coyotes definitely got in on the decomposition event, but they are far less relentless than the bugs (both insect and microbial). The result was that parts of the carcass became somewhat freeze dried over the winter.
I've been watching this carcass over the past couple of weeks as it has emerged from the snow.

Carrion beetle crawling over the deer hoof

On Saturday, we had very nice weather and Leon and I were out at the Fen. Even though the temperatures were only in the low 50s, carrion-feeding insects were in evidence around the deer remains. Blowflies in the genus Calliphora are often the first insects to arrive at a carcass. They become active very early in the spring. There were only two that were present at this carcass. Blowflies seem to prefer a carcass that it in the very early stages of decomposition. They lay their eggs in the tissues that are still soft- eyes and other mucosal tissue- and the result is often a large and very active mass of writhing maggots. That will not happen with this deer- the decomposition is too far along.

A large blowfly (probably genus Calliphora) at the carcass

A much smaller blowfly. I'm not much of a dipterist, so I'm not sure
whether these two flies are the same species or not.

I was very surprised to see not one but two species of carrion beetles (Silphidae) at the carcass, in some numbers. These beetles tend to show up somewhat later in the decay process. My surprise was that they were out this early. It's yet another sign of spring: the trees are budding, the flowers are blooming, the carrion is decaying.

Carrion beetle (Oiceoptoma inaequale)

Carrion beetle (Oiceoptoma noveboracense)

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At 11:03, Blogger Kirk said...

Some of my favorite beetles! I once watched the progress of a moose carcass, such a fascinating process. Never before have I seen such a load of flies.
I used to work at a fish hatchery, and taking the dead fish back to the mort bin was always interesting. We always had a nice collection of beetles

At 11:51, Anonymous jimbo said...

How does a mama carrion beetle find a carcass to lay her eggs in? Are they generally hanging around waiting for a carcass to drop, or can they smell a carcass like a buzzard and go towards it?

At 12:31, Blogger Doug Taron said...

Kirk- Sounds like you saw the moose carcass during warmer weather. The results of a lot of fly activity can be very dramatic, especially on something as large as a moose.

I have found fish to be very optent attractors of carrion beetles. A couple of years ago I was camping near the Illinois River. Somebody had forgotten a stringer of fish in the bushes up above the river. It was covered with hundreds of Nicrophorus beetles.

Jimbo- Odor is a powerful attractant to most of these insects. Some of the volatile (and smelly) chemical compounds that are characteristic of decaying carcasses have colorful names like cadaverine and putresceine.

At 12:42, Blogger Floridacracker said...

Our carrion beetles are prettier than yours.

At 14:53, Anonymous Mark H said...

WHEW! DOUG - you are the only guy I know who would be educating me about deer carrion, and I mean it in a good way. I KNEW what happened basically, but not the finer details of winter kill. Inneresting.........really. Now what to do with that MOLE that popped up dead in the back yard. If Mac weren't here, I'd wait for a coyote to get it.

At 16:38, Blogger Doug Taron said...

FC- I'm not so sure. You should have the all-black one in Florida. The prettier carrion beetles might include
Necrophila americana with a prominent yellow pronotum and the various species of Nicrophorus that are larger with lots of prominent red markings. We have plenty of both of them up here- just not at this carcass.

Mark- If the coyotes didn't get it, I'm sure that some of these guys would show up for it.

At 23:32, Blogger Ur-spo said...

only you could make decompensation interesting

At 04:22, Blogger Kathiesbirds said...

The details in these photos are amazing! Nice depth of field! Only your could celebrate spring with decomposing carcasses and insects!

At 05:55, Blogger cedrorum said...

Great post. We have finally begun to see some flying things here as well. Our winter was actually a winter this year. I haven't seen a mosquito in months. I'm sure that is about to change. It has been nice while it lasted though as the last 3 winters were so mild they never really left and were here year round. Ah, Chiggerex here we come.

At 07:00, Blogger Kirk said...

I found my moose in May, right before green-up. In 2 weeks it went from whole carcass to hide and bone, then a bear came across it. One thing you learn real quick is to keep your mouth closed. The bear also ran off with the skull.

At 14:55, Blogger rodger said...

I see very few decomposing carcasses around here thanks to all the scavengers. Mostly birds.

I do remember the smell of a certain deer hit by a car a few years back. The progress of bloat due to gasses was fascinating until it burst. I stick to skunks please.

Carrion on my wayward son! (sorry, I had to)

At 18:21, Blogger Dave Coulter said...

Erm....yum? I saw a coyote today in my travels...probably hunting for a similar morsel!

At 18:37, Blogger Chilmarkgirl said...

Sorry Doug-am having trouble with this post

At 01:47, Blogger Bug Eric said...

Gotta love how this post is followed by a recipe for rice pilaf! LOL! Sh-h-h-h, don't tell the carrion bugs, they will want it as a side dish:-)

At 14:01, Blogger Doug Taron said...

Spo- Decompensation? I think we should consider that for the AIG execs.

Kathie- Well, it is part of spring. Just not the part that first comes to most folks' minds.

Kirk >The bear also ran off with the skull.
I hate it when that happens.

Rodger- I need to find a way to get ahold of the pictures of our decomposing pig exhibit so I can blog about it. I remember the bloat stage well. Ooh, Kansas.

Dave- The coyotes have definitely paid a visit to this carcass.

CG- You're losing your edge. Remember when we used to talk about work at dinner, thinking nothing of it. Finally Dad would get totally grossed out and say "will you two knock it off."

Eric- I bet they could be baited with rancid pilaf.

At 19:21, Blogger Chilmarkgirl said...

Sorry for losing my edge- I guess decompossed animal parts do that for me- I know what a loser...:-)

At 22:08, Blogger Homer said...

I watched a moose disappear in Grand Tetons Park. Saw it moments after it went through a windshield of a speeding truck. Two weeks later only the largest bones were left. Coyotes and other animals probably got most of it.

At 08:37, Blogger Gallicissa said...

Interesting post, Doug. I enjoyed learning the chemical compound terminology of those foul smells, cadaverine and putresceine. I will read the compounds of cheap perfumes carefully next time.

BTW, blowflies look very good at extreme close ups, I have realized.


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