365 Urban Species. #048: Sawtooth Grain Beetle

[urbpan]

photo by cottonmanifesto

Urban species #048: Sawtooth grain beetle Oryzaephilus surinamensis

The food grain of the world, grown and then stored and then shipped and then stored again, has its own particular fauna. No one can yet say where these creatures originated, since the mixing of the products of agriculture began so long ago--long before anyone thought to wonder about the origin of species. The scientific name of the sawtooth grain beetle contains the name of an South American country because the first scientific description of this beetle (by Linnaeus, in the 18th century) came from a Surinamese specimen. The beetle is found wherever grain is stored, and probably has been for centuries.

The sawtooth grain beetle is minute: the size of the letter "l"on your screen. The yellow boulder in the above photograph is a tiny fragment of cracked corn. The beetle is unable to feed on unbroken grain; the grain must be broken, processed, or already infested with another insect (the Indian meal moth, for example) in order for the beetle to make use of it. Its closest non-pest relatives live under the bark of trees. The sawtooth shares their flattened body shape, and can enter sealed grain bags and boxes easily. Fortunately they float, and can be easily skimmed off of the top of the water you put your rice in, or your cereal milk.

The sawtooth gets its name from the points on its middle segment. This feature is not visible to the naked eye, but can be seen in the microscope photograph under the cut:

Comments

[ankhanu.livejournal.com]

The reference to cracked corn is brilliant :)

I assume it's a Cucujid? Yeah, I could easily google that info myself, but... hey :P

[by-steph.livejournal.com]

Is your microscope an Intel Play QX3?

[urbpan.livejournal.com]

It's the microscope at my work: an ancient iron and glass affair--don't know the model number. I put my camera lens directly on the eyepiece.

I would love an inexpensive digital microscope, but they don't make a Mac-compatible one that I'm aware of.

[wulfsbane.livejournal.com]

Actually, there is - roundabout.

miXscope is an OSX program that works with several microsopes, including the QX3, QX3+, QX5, and Smithsonian USB microscopes - along with several more.

Check http://edhsw.com/mixscope/ for more details :)

[gigglingwizard.livejournal.com]

I think these things are what we had in our rice. They do float, as you say, but I wasn't sure that would adequately decontaminate the rice. Do they foul the grain with their droppings like mice and roaches do, or is this something that would rinse off easily? I don't know, so I just cooked the rice and fed it to my chickens, bugs and all--all 10 lbs. or so.

Also, why would they be in rice in the first place if they only eat cracked grains? Does the polishing process of white rice somehow process it enough for them?

[urbpan.livejournal.com]

In my reading about this animal, I havent found anything about contamination of the food it lives in. They are so small that I don't worry about it. Of course, chickens would appreciate insects in their grain!

Roaches give off a bad smell, and many people are allergic to them; more importantly, they don't just live in food--they'll track in contaminants from under the sink or wherever else they travel. Mice urinate on everything, and their urine smells awful; and they defecate kind of constantly too. Of course there are acceptable levels of rodent droppings in processed foods, legally speaking...

The first part of their scientific name means "rice lover," hinting that Linnaeus found them in rice. I'm guessing that, yes, some process that rice goes through damages it enough for the beetle to feed. I don't know if they were polishing rice in the 18th century, but they must have done something that allowed the beetles in. Modern rice (even the brown rice that I use) seems to have a lot of broken pieces in it--I imagine that it's processed roughly.