Carrion on

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Filed under Outdoor Notes

March 28, 2012

Dead things draw scavengers. Among the things that warm weather reveals—usually to the nose before the eyes—are the carcasses of those critters that did not survive the winter. That smell is unmistakable, foul, sweet, and somehow, alluring.  I am always drawn to track that odor of death to its source, to visit the scene.[1]

Or take pictures of.

So, in late March, on a warm day, I found myself turning slowly in a windless clearing, nose up, seeking the source of the scent of death warmed over.

It was—or had been—a deer. It was now a banquet. There were flies aplenty. There were also beetles, a type of carrion beetle I had never seen before, and they were busy.

The funny thing about a stinking carcass, it draws you, up to a point, and then it repels you. I was not committed to close examination, so I took some photos with a long lens and went home to see what I could learn.

Margined Carrion Beetles (Oiceoptoma noveboracense)

Margined Carrion Beetles (Oiceoptoma noveboracense) mating.

First, thanks to the marvelous website BugGuide, I learned that these were Margined Carrion Beetles (Oiceoptoma noveboracense). [2]

They are active in the spring, so I figured that they are former-frozen-food specialists. There is, however, some uncertainty over what they actually eat—rotting meat, fungus, maggots, or all of the above. I suspect it is all of the above, regardless: tough rations.

Margined Carrion Beetles (Oiceoptoma noveboracense). On White-tailed Deer carcass.

Margined Carrion Beetles (Oiceoptoma noveboracense) on White-tailed Deer carcass.

As I scanned through the photographs, I also found these little guys—Oiceoptoma larvae.

Carrion Beetle larvae (Oiceoptoma spp).

Carrion Beetle larvae (Oiceoptoma spp).

These were extremely active little insects, constantly exploring at a high rate of speed.

Carrion Beetle larvae (Oiceoptoma spp).

Carrion Beetle larva (Oiceoptoma spp).

I’m not sure what they were looking for. I saw a couple hitching rides with the adults.

Carrion Beetle with larvae

Carrion Beetle with larva

Obviously, the beetles had been getting busy for quite a while, for these larvae seemed fairly well along in their journey through life.

Now, why didn’t I just say they were Margined Carrion Beetle larvae?  Because I’m not quite sure; I also found this guy hanging out in a photograph.

Ridged Carrion Beetle (Oiceoptoma inaequale)

Ridged Carrion Beetle (Margined Carrion Beetle ). No orange on the pronotum (bit behind the head).

This is a Ridged Carrion Beetle (Oiceoptoma inaequale). According to Bugguide, the adults eat maggots. The larve feed on carrion. Apparently, the under side of the elytra is iridescent blue, which causes a “”disappearing effect as the beetle lands.”[3] I didn’t get to see that.

Now the small sample of photos I found on line show the larvae of the Margined Carrion Beetle to have a racing stripe right down the middle of its back, the larvae of the Ridged Carrion Beetle seems to lack the stripe. I’m not sure that is diagnostic; to my eye, none of these seem to have the racing stripe. While the other larvae I photographed seemed dark matte brown, this little guy was hanging out near the Ridged Carrion Beetle adult.  It seems shinier and more black. That said, I found it hiding out in the out-of-focus and under-exposed part of one of my photos–the color may only be an artefact of poor photography. It might also represent a different instar.

Oiceoptoma larva

Oiceoptoma larva

The members of the genus Oiceoptoma are Silphids in the sub-family Silphinae of the Carrion Beetle family (Silphidae). Here is what the folks at NC State have to say:

Silphids… are ecologically beneficial as decomposers and are important for maintaining ecosystem health and productivity.  For the most part, both larvae and adults feed on carrion. There are two subfamilies of Silphidae, the Nicrophorinae and Silphinae.  Members of the two subfamilies are attracted to carcasses at different stages of decay. Silphinae feed on carcasses in a more advanced stage of decay, while Nicrophorinae need mostly fresh carcasses for reproduction.  Most Nicrophorinae bury small carcasses and exhibit biparental care, but species of Silphinae lay eggs just beneath the surface of the soil near a larger carcass without burial. Many silphid species also have potential importance for forensic investigations, but post-mortem estimations are difficult due to the unresolved natural histories of many Silphinae species.[4]

By the way, the NC State article started with the line, “I like poetry, long walks on the beach, and poking dead things with a stick.”[5] I wish I had written that.

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  1. I used to think it was just me, but many folks who are connected to the out of doors have admitted to me that they are also drawn to check out the dead things they smell). At one time we were all scavengers; perhaps something from our atavistic hunter-gatherer experience impels us, just checking if there is anything left to eat or turn into tools or make into ornaments. ((Those cultures who have lived closer to the nutritional margin do not share our modern sensibilities. There is the infamous “stink flipper” of Western Alaska (rotten seal flippers), and certain of the Plains Indians were reported to eat the putrescent flesh of river-drowned buffalo with a spoon. See Edwin Thompson Denig, Five Indian tribes of the upper Missouri: Sioux, Arickaras, Assiniboines, Crees, and Crows. (University of Oklahoma Press, Norman, OK, 1961). pg. 46. []
  2. BugGuide, Info page:  Oiceoptoma noveboracense —Margined Carrieon Beetle, (page 6775), available online at http://bugguide.net/node/view/6775 [accessed 27 March 2012]. []
  3. BugGuide, Info page:  Oiceoptoma inaequale—Ridged Carrieon Beetle, (page 6746), available online at http://bugguide.net/node/view/6746 [accessed 27 March 2012]. The actual quote is attribute to Ratcliffe, Brett, The Carrion Beetles (Coleoptera: Silphidae) of Nebraska. University of Nebraska State Museum, 1996. []
  4. NC State University, Insect Museum. Insect of the week—number 22, 4 June 2010, available online at http://blog.insectmuseum.org/?tag=silphidae [accessed 27 March 2012].] []
  5. Ibid []

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One Response

  1. Gene Odato said:

    great stuff. thanks for sharing

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