- Custom Microscope System Takes the 'Bugs' out of Insect Study
Ruth A. Mendonsa
Entomologists who track the behavior of insects have some pretty specific needs with regard to a microscopy system.
The head of a gypsy moth caterpillar can be seen clearly through the Zoom 70 system.
They must observe live insects in their natural environment, and frequently a flexible and economical solution to their requirements cannot be found in an "off-the-shelf" microscope system. The traditional camcorder with macro capabilities does not offer the long working distances required for behavioral research and magnification is limited. Poor depth of field is also a problem with conventional microscopes or combination video cameras and zoom lenses.
Terrence Fitzgerald, an entomologist in the department of biological sciences at the State University of New York at Cortland, was using a camcorder with macro capabilities to study insect behavior when Optem International of Fairport, N.Y., approached him with an offer that he try the company's Zoom 70 optical system in his work. Optem designs, develops and manufactures custom microscope-type optical systems for a variety of markets and applications. The company loaned Fitzgerald a system on a trial basis.
Because his old setup allowed only low magnification, a very short working distance and shallow depth of field, Fitzgerald found the Zoom 70's features invaluable: The 7:1 zoom ratio lets him increase or decrease magnification while maintaining focus; it allows variable working distances from 5 to 17 in. so he can observe the specimen without disturbing or removing it from its natural environment; and it is video-compatible so he can view the specimen on a monitor and record the images for future use. The Zoom 70 also provides the depth of field required for behavioral research and provides the space needed for a fiber optic illuminator. Fitzgerald was sold on the system.
He has most recently been investigating the biomechanics of the leaf-rolling behavior of caterpillars. The rollers are just a few millimeters in length, and he said that without the high magnification, depth of field and long working distances that this system provides, it would be impossible to study this behavior. Two other advantages, he said, are the utilization of a high-intensity fiber optic illumination system that does not heat the subjects and the ability to view the insects from any angle. He also combines the zoom lens system with a Javelin time-lapse videocassette recorder to make very detailed recordings and precise measurements of behavior.
Most recently, Fitzgerald and his student David Munson have been videotaping episodes of the behavior of aquatic and terrestrial insects for use as instructional material in his undergraduate entomology course. These detailed close-ups would be impossible to achieve without this system. Lucky students.
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