Detailed explanations of technical terms relating to the study of Lepidoptera.
| abdomen | The segmented part of the body behind the thorax, containing the respiratory, digestive and reproductive organs. |
| aberration | An individual with abnormal appearance, usually caused by climatic extremes, pathogens, or genetic mutation. |
| aestivation | A state of diapause during periods of heat or drought, such as the dry season in tropical regions. The opposite of hibernation. |
| anatomy | The study of the internal and external structure of animals. |
| androconia | Specialised wing scales in male butterflies, from which pheromones are disseminated to attract or convey chemical messages to females. |
| antennae | The pair of segmented sensory organs arising from the heads of insects, used to detect pheromones. Also known as “feelers”. |
| apex | The tip of the forewing, where the costa and outer margin meet. |
| aposematic | Warning coloration e.g. bright yellow, orange or red, often in association with a black ground colour. Examples include the yellow and black bands on the abdomen of wasps & hornets, and the fiery orange colour of toxic butterflies such as the Monarch Danaus plexippus. |
| aphytophagous | Carnivorous on homopterans – as with some Lycaenidae caterpillars that feed on aphids, coccids, psyllids or membracids. |
| basal | The area of the wings that is closest to the thorax. |
| bivoltine | Having 2 generations per year. |
| brood | A single generation of a population. Hence double-brooded refers to a species having 2 generations per year. |
| calcareous | Alkaline soils and rocks, e.g. chalk, limestone. |
| camouflage | A form of concealment in which the subject is similar in colour and pattern to the surface on which it rests, e.g. the Green Hairstreak Callophrys rubi which is similar in colour and texture to living foliage. |
| cell | The areas of the wings that are enclosed between veins. |
| chitin | The tough matter which forms the outer casing of the head, thorax, abdomen, legs, antennae etc of an insect. |
| chrysalis | The third stage of the lifecycle of a butterfly, in which the metamorphosis from caterpillar to adult butterfly takes place. |
| cladistics | A diagrammatic system of taxonomy based on quantitative analysis of comparative morphological and behavioural data, hostplant usage, DNA analysis etc. This is used to construct tree diagrams ( cladograms ) that deduce and illustrate relationships between taxa. |
| cline | A progressive change in visible characteristics apparent over the range of a species. The 2 extremes of appearance are linked by a series of intermediates. |
| colony | A locally isolated population of any given subspecies, the result of fragmented distribution in species with critical habitat requirements. |
| coppicing | A method of woodland management whereby trees are cut every 5-15 years just above the base of the trunk. This stimulates the growth of a number of narrow trunks called poles. These are used to manufacture fence posts, or burnt to produce charcoal. Coppicing exposes the ground to sunlight, thereby stimulating the germination of herbaceous plants that are favoured by butterflies as larval foodplants or nectar sources. |
| costa | The leading edge of the forewing or hindwing. |
| costal fold | A fold in the leading edge of the forewing, which contains androconia. Found in the males of certain Pyrgines e.g. Erynnis tages. |
| cremaster | Tiny hooks at the tip of the abdomen of a pupa, used to secure the pupa to a silk pad spun by the caterpillar. |
| crepuscular | The habit of becoming active in the half light of dusk or dawn, and being quiescent during bright daylight and total darkness. |
| cryptic | Coloration and patterning which conceals an insect from predators. Examples include camouflage, disguise and disruptive patterning. |
| desertification | The gradual conversion of forested land into arid grassland and finally into desert, as a result of climate change and / or destructive use of land. |
| desiccation | Excessive loss of water from plant or animal tissues. |
| diematic | Patterning or posture that simulates the appearance of a predatory or harmful creature, e.g. the “snake-head” marking on the forewing of an Attacus Atlas moth or the “owl-eyes” on the wings of Automeris moths. |
| diapause | Suspension of activity and development, usually as the result of climatic influence. Examples include hibernation and aestivation. |
| dimorphism | The occurrence of 2 distinct forms of a species in a given population. Examples include sexual dimorphism ( male and female being markedly different ) and seasonal dimorphism ( dry season and wet season forms being markedly different ). |
| discal | The central area of the forewing or hindwing. |
| disguise | A form of concealment in which the subject strongly resembles a naturally occurring object. Examples include the Comma Polygonia c-album which when it’s wings are closed, resembles a dead leaf, and the Buff-tip moth Phalera bucephala which resembles a broken twig. |
| dispersal | Extension of the range of a butterfly beyond it’s local breeding area, caused when females stray away from existing colonies. |
| disruptive coloration | The breaking up of wing outlines by mottling, marbling or bands of contrasting colours. Birds tend to target butterflies by shape, so any pattern that breaks up the shape into irregular sections will assist the butterfly in evading attention. |
| diurnal | The habit of becoming active during daylight hours. |
| DNA | Deoxyribonucleic acid – the molecules from which chromosomes and genes are constructed. |
| dorsal | The back of the body, or the upper ( recto ) surface of the wings. |
| ecology | The study of relationships and dependencies of animals and plants with each other and the environment. |
| endemic | The restriction of a taxa to within a limited and well defined area such as an island, mountain range or country beyond which it is absent. |
| evolution | The theoretical ability, as postulated by Darwin and others, of a species developing by degrees into a genetically and physically different organism, by a process known as natural selection. |
| falcate | Hooked, as in the apex of a Brimstone butterfly’s forewing. |
| family | An assemblage of closely related genera. |
| fauna | The entire range of animal species within a geographical region. |
| flora | The entire range of plant species within a geographical region. |
| form | An ecological, seasonal or sexually dimorphic variety of a species or subspecies, e.g. the form valesina is an ecological variety of the female of the Silver-washed Fritillary – Argynnis paphia f. valesina. |
| genitalia | The sexual organs. The male equivalent of a penis is called an aedeagus, the female organ is called a bursa copulatrix. |
| genus ( pl. genera ) | An assemblage of species that are more closely related to each other than to species in any other genus. In the case of butterflies and moths, all the species within a given genus will share identical wing venation and various other characteristics. |
| girdle | A silk thread around the “waist” of a chrysalis, supporting it’s weight. |
| gynandromorph | A sterile individual which possesses both male and female characteristics. Only obvious in sexually dimorphic species. |
| habitat | A type of environment or life-zone with particular characteristics that have a limiting effect on the biodiversity of the fauna. Examples include calcareous grassland, sub-alpine meadows, and tropical dry forest. |
| hair pencil | A tuft of androconial scales found at the tip of the abdomen of male Danaines and certain moth families. |
| hibernaculum | A “nest” made by larvae, within which they overwinter. Comprised of a tent of leaves held together with strands of silk, or of a more substantial communal web within which a brood of larvae shelter in the early instars. |
| hibernation | The dormant stage of the lifecycle in which a species passes the winter months. Depending on the species, hibernation can occur in the egg, caterpillar, chrysalis or adult stage of the lifecycle. |
| honey dew | A sugary by-product expelled by the oak aphid Phylloxera quercus, as it sucks protein-rich fluids from oak leaves. Vast quantities of this substance coat the upper surface of oak leaves in mid-summer, and are used as an adult food source by many butterfly species, and also by ants. |
| honey gland | A gland on the backs of Lycaenid larvae which secretes a sugary substance that is attractive to certain ant species that form symbiotic relationships with the relevant butterfly species. |
| hyaline | Translucent or transparent “windows” that form part of the pattern of a butterfly’s wings. Occurs mainly in tropical Ithomiines ( Glasswings ) and Satyrines ( Cithaerias, Dulcedo, Haetera etc ). |
| hybrid | The progeny that results from the cross-fertilisation of 2 species. Hybrids of either sex are always sterile. |
| imago | The final adult stage of an insect. |
| instar | The stage of a caterpillars development between moults. Depending on the species, a caterpillar can have 4, 5, or 6 instars. |
| instinct | Inherited behaviours and responses, as opposed to those that are learnt by individuals during their own lifetimes. Courtship rituals can appear to be intelligent but are merely a series of instinctive responses to specific stimuli. A female for example might settle if showered with pheromones by a male, and the male then has to respond in a particular way which signals the female to initiate the next phase of the ritual, and so on. |
| intelligence | The ability of a species to reason and learn, to understand, and profit from experience. Avian predators exhibit intelligence, but there is no evidence that true intelligence occurs in any insect species. |
| larva | The second stage in the lifecycle of a butterfly or moth. Also known as a caterpillar. Examples include silkworms, loopers and woolly bears. |
| lunule | A crescent shaped mark, typically found in a series around the wing margins of Polyommatinae ( Blues ), Melitaeini ( Fritillaries ) etc. |
| margin | The outer border of the wings. |
| mark & recapture | A technique used in the study of population dynamics. Butterflies are captured, painted with a unique identification mark, and released. By comparing the percentage of marked / unmarked butterflies captured on successive days, the size of butterfly populations can be estimated. The technique is also used to “tag” butterflies when studying migration. |
| melanism | Increased development of black pigments on the wings, prevalent when pupae are subjected to abnormally cold climatic conditions. The higher percentage of blackness on the wings increases heat absorption and enables the butterflies to remain active in colder conditions. |
| metamorphosis | The transformation of a caterpillar into a chrysalis, and the development of the adult butterfly within the chrysalis. |
| metapopulation | A population comprised of a semi-permanent core colony, surrounded by a number of smaller marginal colonies that wax and wane in size, often periodically collapsing, to be later re-colonised from the core colony. |
| microhabitat | A small and well defined sub-habitat e.g. the forest floor within a mid-elevation transitional wet rainforest, or a damp gully at a particular elevation on a grassy mountainside. |
| migration | The spontaneous dispersal of a species over long distances in order to seek suitable breeding sites, e.g. the Clouded Yellow migrates from North Africa, across Europe and northwards into Britain. Migration is probably triggered by climatic conditions, length of day, habitat overcrowding, habitat degradation and other unknown factors. |
| mimicry | The close visual and behavioural resemblance of one species to another, presumed to be an evolutionary development. |
| mimicry, Batesian | Similarity of appearance between an unpalatable or noxious species ( the model ) and an unrelated palatable species ( the mimic ). |
| mimicry, Mullerian | Similarity of appearance among a group of related or unrelated species that are all unpalatable or toxic to predators. Avian predators associate the patterning of the whole group with the unpleasant experience of tasting just one or two butterflies. |
| monocotyledon | Any flowering plant whose first sprout from the seed has only one leaf, e.g. grasses, sedges, rushes, orchids, palms, bamboo. These are used as larval foodplants of Hesperiinae, Morphinae and Satyrinae. |
| morphology | The study of development and change of structure and form. |
| mud-puddling | The act of imbibing dissolved mineral salts from damp ground. Almost exclusively confined to male butterflies, which need to replace salts lost during copulation. In some species it may even be necessary for males to acquire these salts prior to copulation. |
| myrmecophile | A species that lives in a dependent, mutually beneficial, or symbiotic relationship with one or more species of ant. |
| natural selection | “Survival of the fittest”. An evolutionary process whereby individuals that exhibit beneficial anatomical or behavioural adaptations pass on their characteristics genetically to subsequent generations. At the same time, less desirable characteristics are gradually eliminated from populations as a result of heavier predation and other environmental factors. |
| nectaring | The act of feeding on the nectar of flowering herbs, bushes or trees. |
| neotropics | Mexico and all of the countries of Central America and South America. |
| nocturnal | The habit of becoming active during night time. |
| nomenclature | The assignment of scientific names to families, genera and species. |
| ocellus | A rounded spot or marking on the wings, effectively a “false-eye” that may temporarily startle a predator, or divert attack away from the body of the butterfly. |
| osmaterium | A fleshy forked eversible organ located behind the head of caterpillars in the family Papilionidae. It secretes a noxious fluid which deters attacks by parasitic and predatory wasps, ants, and birds. |
| oviposit | To lay eggs, either singly or in batches. |
| ovum ( plural ova ) | Egg. The first stage in the lifecycle of a butterfly. |
| Palaearctic | The zoogeographical region that comprises of Europe, North Africa, and the temperate and sub-arctic areas of Asia. |
| palpi | The pair of sensory organs that project from between the antennae of adult butterflies. Used to detect pheromones. |
| parasite | An organism which feeds and develops on or within another species, but does not bring about it’s death. An example is Trombidium breei, a mite which parasitises Common Blue butterflies. |
| parasitoid | An organism which feeds and develops within another species, ultimately leading to it’s death, e.g. the wasp Apanteles glomeratus whose grubs kill vast numbers of larvae of the Large White Pieris brassicae. |
| patrolling | Flying back and forth over a fixed area. Used to describe the flight of males when actively searching for females. |
| perching | Mate location whereby a male waits on a protruding leaf or twig, darting out to intercept and investigate passing insects to seek females. The male nearly always returns to the perch afterwards, and defends the territory by ejecting other males. |
| pheromone | An airborne chemical substance disseminated by male butterflies that induces receptiveness or passiveness in females of the same species. Related substances are used by female moths e.g. Saturniidae and Lasiocampidae, to attract male moths from a considerable distance. |
| phylogenetics | The study of natural evolutionary relationships between groups of living things, inferred using DNA analysis. The results are usually output as cladistic diagrams ( phylogenetic trees ) |
| pigment | A chemical which in the case of butterflies is derived from the caterpillar’s food plants, and which produces the base colour of individual wing scales. |
| plantation | Secondary forest which has been planted with plots of a single species of tree, typically oak, beech or spruce. The trees are allowed to reach maturity and then felled en masse. Butterfly diversity in such habitats is poor as most species are unable to survive in the cool shady forest. The creation of wide tracks, large semi-permanent glades, enlarged intersections, and scalloping of ride edges are management techniques used to encourage butterflies to breed in such forests. |
| polymorphism | The occurrence of 2 or more forms of a given species within the same population, as in the Mocker Swallowtail Papilio dardanus. |
| polyphagous | Describing a species whose larvae feed on a wide range of different plant species from different genera or families. Such highly adaptable species tend to be much more widespread and abundant than those which specialise on particular larval foodplants. |
| polyvoltine | Having several generations per year. Also univoltine, bivoltine, trivoltine, meaning having one, two or three generations per year. |
| population | Members of a species that live together in the same area, and whose subsequent generations maintain uniform genetic character. |
| proboscis | The tube through which adult butterflies suck liquid foods, and which is coiled between the labial palpi when not in use. |
| pupa ( pl. pupae ) | The 3rd stage in the lifecycle of a butterfly in which the bodily tissues are broken down and reform as an adult butterfly. Also known as a chrysalis. |
| race | A distinctive population which is visually separable from other races of the same species, but which is not sufficiently different to be regarded as a sub-species. Examples include the “Castle Eden Argus” and the “Scotch White-spot”, collectively known as the Northern Brown Argus. Both are races of the sub-species Aricia artaxerxes artaxerxes. |
| range | The entire area within which a species naturally occurs. The distribution of a species within it’s range is often patchy, but in the more adaptable species can be contiguous. |
| recessive | Suppressed by a corresponding dominant gene, so that the recessive form, which is normally different in appearance, occurs less frequently in the population than the dominant form. |
| reflectance basking | Basking with the wings held half open, so as to reflect sunlight falling on the wings of whites, blues and coppers onto the thorax and abdomen, to facilitate rapid warming. |
| reticulation | A network pattern. |
| scales | Microscopic plates which arise from individual cells on the wings, body and legs of butterflies and moths. The wing scales overlap like the tiles on a roof, and are easily dislodged, appearing as coloured dust on the fingers when butterfly wings are handled. The scales on the body and legs are long and thin, giving the appearance of fur or hair. |
| species | A group of individuals that interbreed, producing and maintaining genetically identical fertile healthy offspring over a period of millions of generations. By definition a species cannot interbreed with another taxon to produce fertile offspring. |
| sphragis | A plug or structure which seals the genital opening of fertilised females of certain species, e.g. Parnassius apollo, or Euphydryas aurinia, physically preventing further copulation. |
| spiracles | A series of breathing holes arranged in a row on each side of the abdominal part of larvae, pupae and adult butterflies. |
| submarginal | The area slightly inboard of the margins on the wings, often marked with lunules, ocelli or chevrons. |
| sub-species | A population that is permanently isolated geographically from other populations of the same species, and which has constant and obvious differences in appearance and ecology compared with other populations of the same species. Sub-species never naturally interbreed, but have the potential to produce fertile offspring if interbred in captivity. The term “subspecies” is regarded as unscientific by some taxonomists who consider “species” to be the terminal taxonomic rank, and “sub-species” to be merely a convenient way of naming geographical races. |
| symbiosis | The co-existence and inter-dependence of 2 organisms, such that one or both of the organisms is incapable of surviving without the cooperation of the other. The Large Blue Maculinea arion for example is incapable of surviving unless it feeds during it’s larval stage on the grubs of the ant Myrmica sabuleti. The ant benefits from having the larva in it’s nest, but can survive without it. |
| sympatric | Occurring in the same area. |
| synonym | Duplicated scientific names applied to the same taxon. The first published species name is valid. Others are called junior or invalid synonyms. When taxonomists revise the classification of a species it is often transferred to a newly created genus, e.g. the Meadow Brown was originally given the name Papilio jurtina, but is now called Maniola jurtina. |
| taxon ( pl. taxa ) | Any scientifically defined biological unit, e.g. the class Insecta, the family Nymphalidae, the genus Apatura, or the species iris. |
| taxonomy | The scientific classification of organising animals and plants into groups as defined by presumed relationships. Patterns of wing venation for example are commonly used to assign species into appropriate genera. |
| territory | A fixed area defended by the male of a species, often centred on a perching place such as a particular leaf, which is used as a lookout post from which to survey passing females. |
| thorax | The muscular middle section of an insect’s body, which acts as an anchor for the legs, wings, head and abdomen. |
| transect | A regular weekly walk that follows a fixed route through a butterfly habitat. The route is divided into sections, each representing a different sub-habitat. The butterflies seen in each section are counted, and the figures compared to those obtained in other sections, or from the same section in previous years. The figures are analysed to determine the management factors that affect butterfly populations. |
| tubercles | Wart-like nodules which are formed in bands on the abdominal segments of certain species of caterpillar. In some subfamilies e.g. Nymphalinae, the tubercles are greatly enlarged and extended to form rows of branched spines along the back and sides. |
| univoltine | Having a single generation per year. |
| variety | An unscientific term approximately synonymous with “form”. |
| vein | A tubular blood vessel, particularly in reference to the tubes supporting the membrane of butterfly wings. |
| venation | The pattern and arrangement of veins on the wings. |