Advanced Imaging Techniques II: Using a Compound Microscope for Photographing Point-Mount Specimens

American Entomologist • Winter 2008 Parasitic Hymenoptera offer a particular challenge to scientific photography in this age of digital technology. This group is not only hyper-diverse, but ecologically one of the most important insect lineages for regulating the population densities of other arthropod species. In agriculture, this group is also responsible for the most successful cases of biological control of pestiferous insect species. One particular hallmark of this group, however, is their unusually small size (typically 0.5–5 mm adult size). Couple this with their projected worldwide diversity (225,000 named species, an estimated 15 million species on Earth; Gauld and Bolton 1988, Grissell 1999), and one quickly realizes many species remain to be described. The small size of parasitic Hymenoptera makes them not only difficult to examine, but quite often impossible to photograph adequately using standard equipment. This has reinforced the taxonomic impediment facing research into the systematics of the group. Hand-drawn illustrations and scanning electron micrographs (SEM) previously were the standard methods for describing characters in the literature. These methods are neither substandard nor outdated, but they can be time-consuming and cost-prohibitive. We have developed a technique for photographing these minute insects under very high magnification without the use of SEM. Our technique is advantageous over SEM for several reasons: destructive sputter-coating is unnecessary; the specimen need not be exposed to the rigors of low vacuum; color information is retained; and the technique is cost-effective, often using “surplus” equipment. Electronic dissemination, whether using species pages or e-journals, allows an unprecedented amount of visual information to be coupled with species descriptions, revisions, or morphologybased phylogenetic research. We believe that our work into imaging minute insects such as microhymenoptera will help put a backbone into “spineless taxonomy” (Wheeler 2007).