Sampling For Emerald Ash Borer


Sampling for Emerald Ash Borer
Left: A stand holding an ash branch
Top Right: A volunteer peels bark
Bottom Right: A pupal chamber with an emerged adult is exposed.

Emerald Ash Borer larvae have cryptic habits.  They tunnel beneath the bark of ash trees leaving little outward signs other than small D-shaped exit holes. Larger populations cause much damage that leads to decline of the tree.  However, once a tree declines to a noticeable state, it is often too late to save the tree.  To better manage EAB, it is useful to know where populations are located before trees are severely damaged.

One way to sample for EAB is to collect branches from ash trees and peel away the bark to locate galleries, larvae, pupae or adults.  On my trip to Boulder, Colorado, colleagues were demonstrating the bark peel technique.   A branch to be sampled is placed in a stand and held in place with a chain.  The inspector uses a sharp adze to peel the bark and wood one thin layer at a time.  If a gallery is detected, the bark is peeled deeper to determine the direction of the gallery. The galleries are close to the surface, but when a larva is fully developed, it bores a tunnel deeper in the wood as a pupation site. In the case pictured above, many layers of wood had to be peeled to reach the pupation chamber. The chamber in the picture contains an adult EAB. Adults emerge within the chamber, but do not always exit immediately. This adult escaped a mid-May snowstorm by delaying its emergence.

The Emerald Ash Borer project in Boulder has sampled hundreds of trees and will sample hundreds more in an effort to map the population and know where to focus their effort.

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Go West Young Beetle

EAB gallery

Peeling the bark reveals a serpentine Emerald Ash Borer Gallery in a Dead Ash Tree on the University of Colorado, Boulder Campus

The Emerald Ash Borer has spread from its point of introduction in Michigan to the East Coast in less than 2 decades. It is now spreading west at a rapid rate. In Boulder, CO this month, I observed first hand the dead and dying ash trees, victims of Emerald Ash Borer. So far, Boulder is the only Colorado location to report Emerald Ash Borer. In spite of quarantine efforts it will probably soon spread.

Ash is not native to Colorado, but has been planted (over planted?) as a tree that tolerates parking lots and accompanying pollution reasonably well.  Emerald Ash Borer in Colorado affects urban and suburban areas.  Unlike Eastern North America where ash is common, EAB will have little effect on Colorado’s native forests.

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Don’t Move Emerald Ash Borer


Emerald Ash Borer Trapped in My Car

The ash trees in West Lafayette are in severe decline. All the ash trees along US 52, a major highway show severe ash borer damage. Today I parked my car under a damaged ash tree with my windows cracked while I shopped at a store. It was hot, and as I left, I turned on the AC and rolled up my windows. A few minutes later, I noticed an emerald ash borer on my driver’s side window. When I arrived home, I took its picture, then knocked the beetle into a plastic bag and froze it.

This makes me wonder about the effectiveness of quarantines in areas with heavy beetle infestation. How often do beetles travel by inadvertent hitchhiking even when no ash is moved? The pest is new and much of the public would not be able to identify it. The average person might flick a strange insect out their window without realizing the implications.

Quarantines for the Emerald Ash Borer have been mostly ineffective. Once a beetle is found in a new area, it spreads more quickly than predicted from natural migration. It is possible for beetles to land in or on a vehicle, travel a few or many miles and fly off. This does not involve the movement of ash, nursery stock or firewood. While the spread might be more rapid without quarantines, hitchhiking by the beetles could thwart the best planned quarantine.

It is hoped that quarantines will slow the spread of emerald ash borer to give more time for new solutions to be developed. It still makes sense to quarantine ash products to slow the spread of emerald ash borer. Perhaps new solutions can be developed before it becomes ubiquitous in North America. Inadvertent hitchhiking by the beetles may be adding to the rate of spread and decreasing the time for new solutions to be developed.

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Springtail Scales

Many Collembola (Springtails) are covered with scales, secretions of the epidermis that in some cases cover the body. The function of the scales is an open question. Functions may differ among springtails that have biological differences. Collembola taxonomists use the presence, shape and density of scales to distinguish some Collembola species. A note by Hawes and Greenslade* describes the diversity of scale morphology and density in a single Collembola species, Lepidophorella australis. They make an analogy between the diversity of shapes of Collembola scales and the shape of feathers on birds. This note is a caution to taxonomists that scale diversity must be considered carefully if used in identification.

Springtail Scales   Image: Hawes and Greenslade*

Springtail Scales

*TIMOTHY C. HAWES & PENELOPE GREENSLADE. 2015. A note on scale morphology in Collembola. Zootaxa 3925 (4): 594–596.

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Big Bugs In Columbus

Big Bugs

Big Bugs sculpture by artist, David Rogers

“Big Bugs” will appear at the Franklin Conservatory in Columbus, OH this summer. Conceived by artist David Rogers, Big Bugs are larger than life-sized sculptures made from found wood and other natural materials. Conceived in 1991 to celebrate insects and nature, Big Bugs have toured the US since 1994. Big Bugs has inspired interest in nature, gardens and insects, often appearing as an attractions at botanical gardens.

A complete gallery of Rogers’ work can be seen at .

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Orientation by Magnetic Dip

Monarch Butterfly

Monarch Butterfly

The earth has a magnetic field with the North and South magnetic poles as the axis of the magnet. The magnetic lines of force emanate from the South Pole and return to earth. The lines intersect the earth at -90 degrees at the magnetic South Pole and +90 degrees at the magnetic North Pole. The magnetic dip varies from -90 degrees to + 90 degrees at points in between the magnetic poles. Magnetic dip, first described by German scientist Georg Harmann in the mid 1500s, is an indication of latitude and can be used in navigation.

It can be shown experimentally that fall migrating monarchs can use magnetic dip to orient south. The monarch magnetic compass only functions in the presence of UV/blue light suggesting that the light-sensitive cryptochorme is needed. The details of magnetic navigation in Monarchs is sketchy, but may be important in guiding monarchs to their primary overwintering site in Mexico.

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Pondering the Life and Death of Insects

My favorite comic strip reminds me that most people have no compunction about killing insects. One of the topics I ask my students is whether it is acceptable to kill insects and whether it there should be restrictions on the type of research that can be done with insects. Are there advantages or disadvantages to having restrictions? When might restrictions be a good idea? Why do many people who “value life” place so little value on insect life? Interesting questions to ponder.


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