The terms are defined as they are used in this book. Some of them may have other meanings in other contexts.
aberration An individual with a clearly abnormal phenotype which occurs very rarely in a species. The unusual appearance of an aberration is usually the result of a freakish developmental abnormality or a rare mutation. To qualify as an aberration (rather than a form or morph), an individual must exhibit characteristics which are shown by no more than 0.01% of the members of its species. Aberrations are popularly referred to as "sports."
allele One of the alternative forms of a gene which may be present at any one particular locus on a chromosome. Every individual has two alleles, one inherited from its mother and one inherited from its father, at any one locus.
allopatric Literally, in different places, and so referring to species occupying different geographic areas.
allotype A supplemental type specimen of the opposite sex to the original (holotype).
am line Antemedial line. A usually prominent, more-or-less irregular line running across the forewing (from costa to inner margin) of most moths; located approximately one-third of the distance from the base to the outer margin of the forewing. Sometimes referred to as the transverse anterior (t.a.) line.
anomalous stimulus A stimulus unexpected to a predator on the basis of its recent experiences, resulting in physiological effects which produce responses that interfere with effective predation. anti-hybridization device See isolating mechanism. apostatic selection Selection of prey items by a predator which promotes inter- or intraspecific diversity (e.g., polymorphism) in that prey.
browser A computer software program that allows the user to navigate through files written in HTML on the World Wide Web or in this case on a CD-ROM containing the files.
chi-square A statistical test used to determine whether an experimental result would conform to an expected result if chance alone were operating. The chi-square value is usually converted to a probability (P) value, i.e., the probability that the expected result is due to chance. When P is less than 0.05, statistical significance is claimed.
CM Carnegie Museum, Pittsburgh, Pennsylvania. Specimens from this museum were made available by Dr. Harry K. Clench.
costa The leading margin of the forewing or hindwing in butterflies and moths.
cryptic coloration The resemblance, by virtue of color and pattern, of an organism to its habitual background. This resemblance is usually enhanced by a variety of co-adapted behaviors (e.g., stillness, selection of appropriate substrates, resting attitudes, etc.).
dominant An allele whose effect is capable of masking the effect of its allelic (recessive) partner at the same locus (e.g., the allele for melanism in most moths).
form A distinctive variant within a species which occurs at a frequency greater than 0.01%, and so is characterized by genetic continuity from generation to generation, and is maintained in the species by some selective advantage. Form is here used synonymously with "morph."
founder principle The fact that a few individuals founding an outlying population of a species may, by chance, have gene frequencies which are quite different from those of their parental population.
frenulum The coupling device which holds the forewings and hindwings of a moth together during flight. A difference between males and females with regard to this coupling device (fig. 2.3) is a reliable indicator of sex in most moths.
gene A hereditary factor, responsible for the production of a particular enzyme or structural protein whose presence or absence may have an effect on the appearance or behavior of an individual. Genes are comprised of two alleles at a particular locus on a chromosome.
gene pool All of the genes at all of the loci in all Of the individuals in a population.
genetic drift The fact that chance, rather than selection, may affect gene frequencies when a population is very small (usually fewer than fifty individuals). This phenomenon, like that of the founder principle, is due to "sampling error". genotype The genetic constitution of an individual organism.
gynandromorph An individual in which male and female parts develop simultaneously. The resulting individual may be referred to as a sexual mosaic, i.e., showing both male and female characteristics. If, as is commonly the case, the two sides of an organism differ in sex, the individual is referred to as a bilateral gynandromorph.
heterozygous Having two different alleles of a gene at a locus on the chromosomes.
holotype The one individual from which a species (or other taxon) is described. The specimen should bear a type label, and is usually deposited in a major museum.
homozygous Having two identical alleles of a gene at a locus on the chromosomes.
hybrid An individual resulting from a mating of members of two different species. Such individuals are usually sterile and/or adaptively inferior to members of both parental species, and so represent a waste of their parents' gametes. Hybrids provide evidence for a lack, or breakdown, of isolating mechanisms between the species involved.
HTML Hyper-Text Markup Language. A scripting language which allows establishing links within and between text files and image files. A browser is used to navigate the files and links.
industrial melanism The observed increase in the incidence of melanism (melanic morphs) in many species, particularly bark-like cryptic moths, in those parts of the world which are heavily industrialized.
infrasubspecific Literally, below the subspecies; and so used to describe such variants as seasonal forms, polymorphic forms, and aberrations. Infrasubspecific names have no formal taxonomic standing, but have been frequently applied and may be convenient when one wishes to refer to particular well-known variants (e.g., polymorphic forms) within a species.
instar The stage between successive molts in an insect larva (caterpillar).
intersex An individual which develops first as one sex and then the other.
interspecific Literally, between species; and so used to describe differences in appearance or behavior between or among species.
intraspecific Literally, within the species; and so used to describe differences in appearance or behavior between or among the members of a species.
isolating mechanism Some difference between species which minimizes the probability of mating between them. Isolating mechanisms include mechanical difficulties in mating (genitalic differences), and various behavioral (courtship) and ecological (habitat, seasonal) differences which tend to separate the species involved. Isolating mechanisms are sometimes referred to as anti-hybridization devices.
melanism The deposition of melanin pigment in a structure, rendering that structure blackish. In moths, generally refers to a blackening of the wings that is controlled by a single gene (as opposed to polygenic "darkening").
morph See form.
mosaic See gynandromorph and somatic mosaic.
nomenclature Anything pertaining to the formal naming of organisms, or to the system of names used for a group of organisms.
novel stimulus An unfamiliar stimulus, usually to a predator, which is avoided by reason of the startle it elicits, or because of a preference for a familiar stimulus.
P The probability that an experimental result is due to chance. The lower the value of P, the more likely it is that the result is significant, i.e., unlikely to be due to chance. Significance is usually claimed when P is 0.05 (5%) or lower.
paratype A specimen collected at the same time as the holotype, and believed to be identical with it.
phenotype The appearance and behavior of an organism; the product of its genotype and the environment in which it develops.
pheromone A chemical substance produced by one organism for purposes of communication with another member of its species.
pm line Postmedial line. A usually prominent, more-or-less irregular line running across the forewing (from costa to inner margin) of most moths; located approximately two-thirds of the distance from the base to the outer margin of the forewing. Sometimes referred to as the transverse posterior (t.p.) line.
PMNH Peabody Museum of Natural History, Yale University, New Haven, Connecticut. Specimens from this museum were made available by Dr. Charles L. Remington.
polygenic Used in reference to a trait of an organism which is influenced by a number of genes, each having small, similar and additive effects. Such traits exhibit continuous variation in a population, rather than the discontinuous variation characteristic of polymorphisms.
polymorphism The occurrence together of two or more distinctly different forms (morphs) of a species, the rarest form comprising more than 0.01% of the population and so being maintained by selection.
protean behavior Behavior which is sufficiently erratic and unsystematic to prevent its predictability to a predator, and so functioning to reduce predator efficiency.
pupa The life-cycle stage between larva and adult (imago) in insects having complete metamorphosis.
recessive An allele whose effect may be masked by its allelic (dominant) partner at the same locus. Such alleles must be present in "double dose" (homozygous) in order for their effect to be expressed in an individual.
reniform An ordinary spot on the noctuid forewing, often somewhat kidney-shaped and lying slightly within the pm line. Prominent in most Catocala.
Robinson trap A light-trap utilizing a mercury vapor lamp, designed by H. S. & P. J. M. Robinson on the basis of their studies of the responses of moths to light.
searching image behavior A change in the perceptual or response tendencies of a predator after a few successful encounters with a particular prey item, with the effect that the predator exhibits an increased tendency to take that particular prey item.
sex ratio The relative proportions of males and females in a sample from a population. Usually expressed as the percentage of males.
somatic mosaic An individual in which different parts have different genetic composition (though not of different sex). Such individuals usually have a bizarre appearance, and are popularly described as "freaks" or "monstrosities."
speciation The evolutionary processes leading to the formation of species.
"sport" See aberration.
st line Subterminal line. A line paralleling the pm line and lying approximately halfway between that line and the outer margin of the fore-wing. This line is often whitish, and may be blurred, vague, or obsolete in many Catocala.
subreniform An ordinary spot of the noctuid forewing, lying just below the reniform. The subreniform may be open ( a continuous loop of the pm line) or dosed (a cut-off loop from the pm line), though this difference is rarely of value in terms of specific identification.
subspecies Members of a species from a particular geographic region which are phenotypically distinct from members of the same species in other regions. Sometimes referred to as "incipient species," as it is believed that some genetic differentiation has already proceeded, and that continued isolation might produce sufficient differentiation for speciation to occur.
sugaring A technique for attracting certain moths, usually involving the application of a sugary (and slightly alcoholic) mixture to tree trunks.
sympatric Literally, in the same place; and so referring to species occupying the same geographic area.
synonym Another scientific name for a species, usually applied by an author who is unaware that the species in question has been previously named. The "rule of priority" governs in such situations, i.e., the first name published has precedence and is the name by which the species is formally known.
tapping A collecting procedure involving the rapping of tree trunks with a stick to drive off the cryptic moths. The moths may then be netted in flight, or captured when they alight again.
taxon A general term used to refer to any taxonomic category of individuals believed to be related to one another (e.g., species, genus, family, order, etc.). The plural is taxa.
taxonomy The branch of biology dealing with the naming and classifying of organisms.
type The individual(s) from which a species (or other taxon) is described. See allotype, holotype and paratype.
USNM United States National Museum, Smithsonian Institution, Washington D.C. Specimens from this museum were made available by Dr. Douglas C. Ferguson.
variety A general term used to refer to individuals of a species which differ from the normal in some way, including forms and aberrations.