Tuesday, March 10, 2015

How an Entomologist Does Yard Work

The day this post was born was very different from the one that jump-started the whole thing. You may have seen my post on our Facebook page showing a ca. 25-30' eastern red cedar (Juniperus virginiana) that fell from a heavy coating of freezing rain a couple weeks ago:

Poor tree couldn't take it :(

It was not an ideal situation for our yard, and certainly not for the tree. But I couldn't deal with it due to on and off snow for two weeks.

THEN THE SUN EMERGED!!!! During a warm and sunny afternoon this past Sunday I (with a newly purchased chainsaw) was ready to tackle this tree.

STEP 1.
Trim the branches off and cut the trunk into manageable sections.

STEP 2.
Snip the small branches up into a waste can and yard bags.

STEP 3.
Start to see little flying insects glimmering in the sun over the pile of remaining branches. Also start to get excited - what are they? Go and get the insect net to sweep some critters under the ire of my wife who is attempting to do real work.

This net is not necessary for getting rid of a tree unless you are an entomologist.

STEP 4.
Sweep. Unsuccessfully, but then something! But I need a vial! Run into house to get a vial. See that they are beetles. Also see some flies including dark-winged fungus gnats (Sciaridae) and some kind of acalyptrate fly (perhaps Drosophilidae).

STEP 5.
Continue to "work" by cutting up the branches. Notice more and more beetles landing on the waste bag and pile of logs. Continue to collect (and work). Convince wife to go for a run so she doesn't roll her eyes right out of her head. After a little more collecting, vial is full to my satisfaction - so back to work.

I'm actually doing yard work - see the pruners in my hand? Oh and a vial full of beetles...

STEP 6.
Clean up time. But what's this? Roll over one of the logs to see a beautiful beetle sitting still. Run in to grab the camera. Take some photos and capture the beetle to identify. Back to work cleaning up.

This is no ladybug - it's a curious longhorn beetle, the cedar tree borer (Cerambycidae: Semanotus ligneus). Note the necklace of phoretic mites. [Size: 10 mm]

STEP 7.
Yard is done to our satisfaction for the day. Enjoy a beer and dinner.

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So what were the little flying beetles? When I saw the first specimen I though it may be a member of the very strange darkling beetle genus Rhipidandrus, but upon closer inspection I knew they were some kind of bark beetle. After keying them out they had a name: Phloeosinus dentatus (Curculionidae: Scolytinae), a species known to colonize various Cupressaceae including eastern red cedar.

Little beetles like this Phloeosinus dentatus always interest me. [Size: 2.5 mm]

I was somewhat surprised with the speed at which these beetles began to arrive. It was late afternoon and only took about 20 minutes of cutting before they smelled the distinct odor of cedar. About two dozen landed around the various piles of wood. These beetles, although having relatives that are detrimental to our trees and landscape, are important decomposers of trees and their activities help to begin the process of decay in forests. They are also monogamous and create nice galleries under bark in which they and their larvae live and feed.

And now for a couple more photos:

Cedar bark beetle (Curculionidae: Scolytinae: Phloeosinus dentatus)
Cedar longhorn beetle (Cerambycidae: Cerambycinae: Semanotus ligneus)