Field Guide to Common Western Grasshoppers: Names and Species
by Robert E. Pfadt
Scientific and Common Names
Grasshoppers have been collected, studied, and named from all but the most frigid regions of the earth. More than 10,000 species have been classified and given scientific names. These are binomials, a method of naming used by the Swedish biologist, Carolus Linnaeus (1707-78) in his book, Systema Naturae. The method proved so successful that other biologists promptly adopted it. The tenth edition of Systema Naturae (1758) has been designated as the official beginning for zoological nomenclature. This classic book contains an account of the widely distributed North American grasshopper, Dissosteira carolina (Linnaeus).
In addition to the scientific name, species of grasshoppers may have good common names. Some are approved by the Entomological Society of America, such as the Carolina grasshopper for D. carolina. Nevertheless, in searching the literature and in communicating information on species of grasshoppers, the scientific name has an unrivaled advantage. All of the known species have scientific names while only a small fraction have generally accepted common names.
The scientific name of a species consists of two parts. The first is the name of the genus, a taxonomic category containing a group of closely related species. The second part is the specific epithet or species name. For example, Dissosteira is the name of the grasshopper genus that contains four species; carolina is the specific epithet of one of the four species. The two words together, Dissosteira carolina, comprise the scientific name of the Carolina grasshopper. After the two words the name of the describer, Linnaeus, provides extra information. Linnaeus' name is in parenthesis, which means that originally Linnaeus had placed this species in a different genus (Gryllus) and another taxonomist later revised the scientific name by placing the species in a new or different genus. A describer who has assigned a newly described species to an established genus is not named in parentheses, for example Melanoplus confusus Scudder.
The scientific name is always italicized. After it has been written in full once, it is usually abbreviated by using the initial of the genus, followed by the full spelling of the epithet, and the dropping of the describer's name, hence D. carolina. The first letter of the genus name is always capitalized and the first letter of the specific epithet is always lower case. The genus name may be used alone when referring to the genus only or to all of the species making up the genus such as Dissosteira or Melanoplus.
How do taxonomists choose a scientific name for a species new to science? Rules of Latin grammar must be followed but otherwise there is much latitude in selecting a name. If the new species can be assigned to a valid genus, a specific epithet not already in use within the genus is chosen. The name may describe a character of the grasshopper or locate the region or state where it was collected. Or it may honor a friend or a renowned scientist. For example, in a taxonomic study published in 1897, Samuel Scudder named a new species Melanoplus bruneri in honor of professor Lawrence Bruner, a pioneer grasshopper specialist at the University of Nebraska, Lincoln. To be a valid scientific name, the author must publish the description and name of a new species in a journal article, bulletin, or book.
As a finishing touch in establishing the authenticity of a new species, the describer chooses a particular specimen as the type or holotype. In the taxonomy of grasshoppers, the type selected by the author is an adult male from which the original description and illustrations were made. A female specimen is also chosen for description and illustration and is specified as the allotype. The author uses other specimens, termed material, for comparison with the types, often describing slight differences in size and color. These may be designated as paratypes, both males and females.
The taxonomist must also decide on the deposition of the types in an insect museum. If the author is a member of the staff of a particular museum, the types are usually deposited with that museum. In cases where the author is not employed by a museum, the types are sent to a recognized museum. Many grasshopper types are held in the extensive collections of the Academy of Natural Sciences of Philadelphia, the California Academy of Sciences (San Francisco), the Museum of Zoology, University of Michigan (Ann Arbor), the Lyman Entomological Museum (Ste. Anne de Bellevue, Quebec), and the National Museum of Natural History (Washington, DC). These are favored museums for the deposition of grasshopper types. The author may send the types to one museum and paratypes to the others and, if there is sufficient material, still other specimens to smaller museums.
Although the grasshopper fauna of North America is relatively well known, new species continue to be found in all parts of the continent and to be described in entomological publications. The chance is slim, however, that a scout will pick up a new species where grasshopper infestations occur. In most instances the scout will be able to identify a specimen from the pages of this field guide. On occasion a scout may collect an already described species not treated in the guide, particularly in genera with large numbers of species such as Melanoplus and Trimerotropis. The scout may then resort to a state grasshopper "key" (see Selected References).
What are species? Species in Latin merely means "kind" and so species in an elementary sense are different kinds of organisms. Most, if not all, species of grasshoppers can be distinguished on the basis of obvious anatomical and behavioral characters and are biological realities. In nature, species consist of populations of individuals that usually occur over an extensive geographic range. For this reason one modern view considers a species to be a genetically distinctive group of natural populations that share a common gene pool and are reproductively isolated from all other such groups. The species is the largest unit of population within which effective gene flow occurs or can occur. Higher taxonomic categories, from the genus up, are biologists' inventions that exist only in the human mind. Animals in the same category have anatomical similarities showing clear relationships. Their grouping, however, is a decision based on a mix of objective and subjective evaluations. One taxonomist's family can easily be another's order.