Great Smoky Mountains National Park

Is there any question why these are called the Smoky Mountains?

Last week I attended the Entomological Society of America (ESA) meetings in Knoxville, Tennessee. It was my first ESA attendance in more than ten years, so I took full advantage of the opportunity by speaking at the insect macrophotography symposium, presenting a poster on my soybean insect research, and enjoying face-to-face conversations with an extraordinary number of colleagues—some of whom I had not seen since my last ESA meeting and many more for which this was my first opportunity to meet them in person. I admit to having grown a little complacent in recent years about the importance of regular personal contact in cultivating these relationships—my attendance at this year’s ESA reminded me of that fact, and I’ve renewed my commitment to make ESA attendance a priority in the coming years.

Of course, no meeting should be all work and no play, and for me the chance to sample the local natural or cultural history is an added benefit of meeting attendance. This year’s destination for such was a no-brainer—located less than an hour’s drive from Knoxville, Great Smoky Mountains National Park is the largest federally protected area east of the Mississippi River. Straddling some of the highest peaks of one of the world’s oldest mountain ranges, the park has been designated an International Biosphere Reserve by the United Nations due to its rich biota.

One afternoon is not nearly enough time to even scratch the surface of the park’s 800 square miles, but it’s enough to get a taste of the diverse habitats they encompass and whet the appetite for further exploration. Highly recommended for those short on time is Clingman’s Dome—the park’s highest point at 6,643 ft. An observation tower allows spectacular vistas (provided the day has good visibility) of the surrounding mountains and the evergreen forests that cloak them. Unfortunately, the view has been marred in recent years by the accidental introduction of an exotic woolly adelgid (a relative of aphids) from Europe and its subsequent establishment on the forest’s Frazier firs. Dead trunks rise from the forest like tombstones—ghostly reminders of what has been lost. The starkness of the high elevation forest contrasts with the lush mixed hemlock forest that dominates the park’s lower elevations, and the 2.4-mile Alum Creek Trail provides an intimate experience with this rich forest and its thick understory of native rhododendron. I hope the following slide show imparts some essence of the experience, and larger versions of each photo can be seen by clicking on the thumbnails in the gallery that follows.

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Arch Rock

View south from Clingman’s Dome

View east from Clingman’s Dome

View east from Clingman’s Dome

View south from Clingman’s Dome

View north from Clingman’s Dome Overlook Tower

Rhododendrons line Alum Creek

Snow melt rushes through Alum Creek

Small rapids are common in the upper reaches of Alum Creek

Foot bridge over Alum Creek

Arch Rock

Arch Rock

Copyright © Ted C. MacRae 2012

Life at 8X—Bandedwinged Whitefly

Trialeurodes abutiloneus (bandedwinged whitefly) | Obion Co., Tennessee

The world of minute insects can seem strange and even bizarre when compared to our relatively giant perspective. To the unaided human eye, this bandedwinged whitefly (Trialeurodes abutiloneus), measuring only 1 mm in length, looks like nothing more than a fleck of dandruff. Through a Canon MP-E 65mm 1–5X macro lens with 68 mm of extension tube (resulting in 8X magnification), however, we see an almost moth-like insect with a decidedly adorable “face” negotiating the “trichome forest” of a soybean leaf under-side.

A more conventional 2X view of a whitefly infestation on the underside of a leaf

Whiteflies (order Hemiptera, family Aleyrodidae) are tiny insects (more related to aphids than true flies) that colonize a variety of host plants, often building to extraordinary numbers and densities while sucking juices from the leaves. The bandwinged whiteflies in these photos were seen in a soybean field in northwestern Tennessee this summer and can be easily identified as this species due to the transverse, zig-zag bands on the forewings (Malumphy et al. 2010). In the photo above numerous eggs can also be seen distributed over the leaf surface—a sign that this population is about to explode given the numbers of eggs present.

Zooming in to 8X allows the zig-zag wing pattern to be seen easily.

Whiteflies are an occasional pest of soybean in the U.S., but yield reduction has been documented only in the southeastern U.S. by another species, Bemisia tabaci (sweet potato whitefly). Whiteflies are also occasionally seen on soybeans in the Midwest by B. tabaci or yet another species, Trialeurodes vaporarium (greenhouse whitefly); however, yield impacts in this area are rare. Trialeurodes abutiloneus is occasionally reported from soybean, but this species is actually more commonly encountered on sweet potato and malvaceous crops such as cotton and hibiscus (Clower et al. 1973). There was a lot of cotton growing in the area of this soybean field, so perhaps this infestation was a result of spillover from that crop.

Piercing/sucking mouthparts are inserted into the leaf for feeding.

“Adorable” and “cute” are not words that I’ve ever associated with whiteflies, but these ultra-closeup photographs give them a personality that I’ve not seen before. For an even more astounding view of the face of a greenhouse whitefly, see this incredible 16X photograph by Huub de Waard. Taken with the same lens as these—though I suspect with a 2X converter rather than extension tubes, it shows an amazing level of sharpness compared to the admittedly soft photos in this post. The larger aperture used (f/6.3) may also be a better choice than the small f/13 aperture I used in an attempt to preserve as much depth of field as possible but with which diffraction is likely significantly greater. Stay tuned as I do some more testing…

A cute couple!

REFERENCE:

Clower, D. F. & C. M. Watve. 1973. The bandedwinged whitefly as a pest of cotton, pp. 90–91. Proceedings of Beltwide Cotton Production and Research Conference, 11–12 January, Phoenix, Arizona. Cotton Council of America, Memphis, TN.

Malumphy, C., A. MacLeod & D. Eyre. 2010. Banded-winged whitefly Trialeurodes abutiloneus. Plant Pest Factsheet, The Food and Environment Research Agency (Fera), 4 pp.

Copyright © Ted C. MacRae 2012