Abdomen: The posterior one of the three major subdivisions of an insect’s body.
Abiotic: Non-living.
Accessory genitalia: An organ of sexual reproduction, found only in male insects in order Odonata, and located on the second and third abdominal segments. Also called “secondary genitalia”.
Alarm pheromone: A chemical message released by a social insect in response to perceived danger that triggers immediate and cooperative defensive behavior by other colony members.
Alarm response: A signal performed by an animal in response to perceived danger that serves to warn other animals. Can be visual, auditory, or chemical.
Ametabolous: In insects, the simplest form of metamorphosis. Immature stages look like adults but lack genitalia, and grow progressively larger to become adults.
Anaerobic:
Referring to environmental conditions: An environment in which oxygen is absent.
Referring to an animal: An animal who can exist only in the absence of oxygen.
Anal: Towards the posterior end or side.
Anapsid: A skull without openings near the temple; seen among living animals only in turtles.
Androconial scale: A wing or body scale on male insects in order Lepidoptera (butterflies and moths) that disperse sexual pheromones.
Antennae: Paired sensory appendages, located on either side of an invertebrate animal’s head. Singular: antenna.
Anterior: Towards the head; at or towards the front.
Barb: One of the stiff filaments that form a row on each side of a feather‘s shaft. Together, rows of barbs form a feather’s vane.
Barbel: A fleshy, flexible sensory structure that protrudes near the mouth of some fish that is sensitive to touch and chemicals.
Basal: At or toward the base of the main body or an appendage’s attachment point.
Batesian mimicry: The similarity in appearance of a palatable, edible species and a species that is unpalatable or toxic to predators, resulting in benefit to the palatable species gaining benefit and the toxic species gaining no benefit. See also “Mullerian mimicry“.
Behavioral thermoregulation: Maintenance of body temperature through behaviors like basking, sheltering, and shivering.
Book lungs: One of two types of breathing organs found in the opisthosomas of spiders and characterized by many thin, delicate layers. See also “tracheal spiracle“.
C
Carapace:
In turtles, the domed, upper part of the shell, composed of two layers of bony plates.
Carnivore: A heterotroph that feeds on animal flesh. Also any species classified in class Mammalia, order Carnivora.
Caste: A specialized group within an insect colony, with very distinct functions.
Caterpillar: The larval stage of insects classified in order Lepidoptera.
Cell:
When referencing insects: An area of wing membrane on insects partially or completely bounded by veins.
Cephalothorax: The first subdivision of a spider’s body, composed of the combined head and thorax. Houses the eyes, brain, mouth, fangs, stomach, venom glands, and chelicerae. Also known as the “prosoma“.
Cerci: Paired sensory appendages located at the posterior of the abdomen on some insects.
Chelicera(ae): The jaws of an arachnid, located on the cephalothorax or prosoma, and each consisting of a base segment and a terminal fang.
Chelicerata: A sub-phylum of phylum Arthropoda in which animals are characterized by:
Chemoreceptor: A type of sensory cell that responds to chemical substances; provides information about smells, tastes, and touch.
Chitin: A chemical component of exoskeleton that is flexible, tough, water-proof, and resistant to many chemicals.
Chrysalid: A butterfly pupa not otherwise encased in a cocoon. Also referred to as “chrysalis“.
Chrysalis: A butterfly pupa not otherwise encased in a cocoon. Also referred to as “chrysalid“.
Cloaca: A chamber in reptiles into which the digestive, urinary, and reproductive systems empty. Connects to the vent.
Cocoon: A protective case in which an insect larva will pupate.
Compound eye: A visual organ composed of a few to several thousand light-sensitive units called “ommatidia” that radiate outward and terminate in a lens, which combined form facets of the eye.
Core use area: A portion of a larger home range within which an animal spends most of its time, including where it sleeps or rests, eats, and raises young, and that the animal routinely and actively defends against same-species intruders.
Covert: In birds, a feather or feathers that cover the base of a main wing feather. Can be a “greater covert”, a “median covert”, or a “minor covert”, depending on the covert’s location on the wing. Also referred to as “wing covert“.
Crop: An extension of the esophagus found in insects and birds used for food storage.
Cuticle: The outer covering of an insect’s body.
D
Detritivore: A heterotroph that feeds on dead material (detritus). Also called a “scavenger”.
Dimorphism: The occurrence of two distinct forms of the same species.
Distal: At or near the farthest end of an appendage’s attachment site.
Diurnal: During the daytime; applies to events that occur during the day or species that are active during the day.
Dorsal: Pertaining to the back of an organism. The surface of an organism that is farthest away from the substrate. Compare to “ventral” and “lateral“.
E
Ecology: The scientific study of relationships among and between organisms, including the influence of all living and non-living aspects of their environment.
Ecosystem: An ecosystem is the combination of the living things found within a defined area and the physical, non-living environment that supports them. Every animal is one part of the much larger ecosystem.
Elytrum(a): The hardened, leathery forewing(s) of beetles.
Estivation: Dormancy that occurs in some animals during periods of hot, dry environmental conditions; generally lasts as long as the triggering conditions.
Exoskeleton: An external, waterproof, protective body covering of insects that houses and supports internal muscles, organs, and other tissues.
Eye spots: Markings on the wings of certain insects, intended to mimic the eyes of threatening animals, such as snakes and birds.
F
Facet: The external surface of an individual unit of a compound eye.
Feather: The body covering of birds that consists of a quill embedded in the skin and a shaft that carries the barbs.
Frass: Fine powdery material excreted by plant-eating insects as the product of digestion.
Freeze avoidance: Physiological adaptation in some animals that prevents tissue injury from ice crystal formation through the use of super-cooled fluids. See “super-cooled fluids”.
Freeze tolerance: Physiological adaptation in some animals that allows them to survive the freezing of the water in their body tissues.
G
Gape: The distance between an animal’s upper and lower jaws.
Gaster: In insects classified in order Hymenoptera, the enlarged portion of the abdomen posterior to the petiole.
Genital lock: the temporary inability of copulating animals to separate while mating.
Genotypic sex determination (GSD): The genetic determination of sex by sex chromosomes. Seen in mammals, birds, amphibians, and some fishes. Compare with “temperature-dependent sex determination (TSD)”.
Gill: The respiratory organ of an aquatic animal.
Gill cover: A tough, flexible outer wall that protects the gill chamber in fish and forces water over the gills through pumping action.
Gravid: The state of being pregnant or bearing fertilized eggs.
Grooming: The behavior of caring for the body surface.
H
Habitat: The particular place in which an organism lives and is made up of a specific physical environment or a type of plant. Habitats can cover many square miles or be as small as a puddle of water. Every animal is adapted for a particular habitat and struggles to survive if transported to a different habitat.
Haltere: The vestigial hind wing of a fly (Diptera) that stabilizes the insect’s flight and provides its brain sensory information about flight speed and direction.
Hamulus(i): A row of hooks along the costal (front) margin of the hind wing in insects of order Hymenoptera that hook into a fold on the fore wing and turns the separate fore wing and hind wing into a single functional wing. See also “wing coupling“.
Head:
Pertaining to insects: The first of three major subdivisions of an insects body, located on the anterior end, and holding the insect’s brain, eyes, antennae, and mouth parts.
Hemielytron(a): A type of fore wing in insects of order Heteroptera which has a leathery base and a membranous tip.
Hemimetabolous development: incomplete metamorphosis. Immature nymphs resemble adults. Successive molts result in size increases and the development of both wings and sexual organs.
Hemipenis: One half of a paired organ in male reptiles in order Squamata used for mating.
Hemiptera: An order of insects known informally as “true bugs” and characterized by:
No true pupal stage in life cycle.
Absence of eleventh abdominal segment or cerci.
Mouth parts are either modified into a rostrum or absent.
Two pairs of wings: fore wings cover and protect the membranous hind wings at rest.
Herbivore: A heterotroph that obtains energy by feeding on green plants.
Heterotroph: An organism that is unable to manufacture its own food and must consume other organisms to obtain carbon.
Hibernation: A period of reduced metabolic rate during winter.
Holometabolous development: complete metamorphosis. Insect passes through four distinct stages in its life cycle (egg, larva, pupa, and adult). Immature nymphs do not resemble adults.
Home range: The area in which an animal normally lives and uses during a year; varies with factors like available food resources, modes of food gathering, and animal body size.
Homoptera: A plant-eating order of insects.
Humus: A component of soil consisting of semi-decomposed organic matter.
Hymenoptera: an order of insects that includes ants, bees, wasps, and sawflies, and characterized by:
Two pairs of wings with relatively few veins
Fore wings slightly longer than hind wings.
Hind wings can be hooked to fore wings in flight by means of hamuli.
Long antennae with 10 or more segments.
Ovipositors can pierce, sting, or saw, depending on the species.
Ants, bees, and wasps have conspicuously constricted waist (“wasp waist”).
Hyperparasite: An organism that parasitizes another parasitic species.
I
Ichneumonid: A wasp species classified in family Ichneumonidae, order Hymenoptera that parasitizes other insects.
Indirect flight muscle: A muscle within an insect’s thorax, connected to the thoracic exoskeleton interior and not directly connected to the wings, that causes the wings to beat by compressing the thoracic box.
Individual distance: The distance between one individual animal and another of the same species at which aggressive or avoidance behaviors begin.
Innate: Refers to a behavior that is genetically based and not a result of learning.
Inquiline: An animal that lives either in another animal’s body or in another animal’s nest without causing harm.
Insecta: A class of arthropods that represents insects and that are characterized by:
Keel: A prominent ridge on a solid structure. In birds, a site on the sternum bone to which flight muscles attach.
Keeled scale: A type of body scale on reptiles characterized by a prominent, central ridge. Contrast with “smooth scale“.
Keystone species: A species that has a disproportionately strong influence on an ecosystem.
L
Labial palp: One of a pair of jointed sensory structures on the labium of an insect.
Labial mask: A prehensile structure found on nymphs in insect order Odonata that covers the mouth parts and used as a weapon to capture prey.
Labium: The lower “lip” of the mouth in insects.
Labrum: A broad structure on the face of an insect that forms the upper “lip” of the mouth.
Larva(ae): A form within an animal’s overall development that occurs after the animal hatches from its egg and during which it can move under its own power and feed itself.
Larval stage: The second stage of a holometabolous insect’s life cycle, between the egg and pupal stages.
Lateral: Referring to the side or the side of an organism’s body. Compare with “dorsal” and “ventral“.
Lek: A territory that a male animal defends against rival males of the same species.
Lentic: Describes habitats in very slow-moving or still water, like ponds and lakes. Compare to “lotic“.
Lepidoptera: an order of insects that includes butterflies and moths and is characterized by:
Wings with overlapping scales.
Sucking probosces (adults); some species have chewing mouth parts.
Litter layer: The surface layer of organic soil material.
Littoral: Refers to the shallow water regions of aquatic ecosystems in which rooted plants can grow and light penetrates to the bed or bottom of the water.
Lotic: Describes habitats in running water (water with currents), like streams and rivers. Compare to “lentic“.
In birds: Refers to the two parts of a bird’s bill (i.e. “upper mandible” and “lower mandible”).
Margin: The edge of an insect’s wing.
Marsh: A permanent area of wet soil found around the margins of ponds and lakes or in undrained flood plains. Also an informal synonym of “swamp” and “bog.
Maxilla(ae): One of a pair of mouth parts found in some arthropod animals, located behind the mandibles, and used for eating.
Mechanoreceptor: A sensory organ that responds to mechanical deformation (i.e. compression and elongation).
Mesothorax: The second segment of an insect’s thorax which bears a pair of legs and often a pair of wings.
Metamorphosis: The transformation of a larva into an adult animal form. In insects, can be ametabolous, hemimetabolous/incomplete or holometabolous/complete.
Metathorax: The third segment of an insect’s thorax, which bears a pair of legs and often a pair of wings.
Molt: Periodic shedding by an animal of its outer skin (reptiles) or exoskeleton (arthropods like insects and crustacheans) to allow for growth; seasonal changes in pelage (mammals) or feathers (birds).
Microbivore: An animal that feeds on microorganisms.
Mullerian mimicry: The similarity in appearance between two animal species, both of which are distasteful to their respective predators, and from which both species benefit. See also “Batesian mimicry“.
Myriapod: An animal classified in subphylum Myriapoda.
Myriapoda: A subphylum of phylum Arthropoda characterized by:
Distinct heads
Elongated bodies composed of up to 100 segments, each bearing a pair of uniramous appendages.
N
Naiad: The larval form of an aquatic hemimetabolous insect.
Natant: Floating entirely underwater.
Neuston: Organisms resting or swimming on the water surface.
Nocturnal: During the nighttime. Applies to activities that occur at night or species that are active at night.
Nymph: The larval form of terrestrial hemimetabolous insect.
O
Ocellus(i): A simple eye composed of a single, light-sensitive lens.
Odonata: An order of insects that includes dragonflies and damselflies and is characterized by:
Opisthosoma: The posterior segment of a spider’s body that houses the intestines, respiratory organs, reproductive organs, silk glands, and spinnerets; the abdominal segment of a spider’s body.
Orientating response: The reflexive movement of an animal in response to a stimulus that allows closer examination of the stimulus.
Ovipary: A reproductive method in which little or no embryonic development takes place inside the female organism’s body and in which eggs are laid. Embryos develop within the eggs, outside of the mother’s body, and eventually hatch into young animals. Compare with “vivipary” and “ovovivipary“.
Ovipositor: The appendage located at the posterior end of female insects through which they lay eggs; sometimes modified into a stinger connected to venom sacs (see “Hymenoptera“).
Ovovivipary: A reproductive method in which young organisms develop inside eggs held within the female’s body but separated from the mother’s body by the egg membranes. Compare with “vivipary” and “ovipary“.
P
Palp(i): A sensory appendage near the mouth of many invertebrate animals.
Parasite: An animal who lives in or on another host animal from whom it obtains food.
Parasitism: The interaction between two animals, one of which lives in or on another host animal and obtains food at the expense of the host.
Parasitoid: An parasite whose parasitism kills the host animal, or an animal that lives part of its life as a parasite and part as a predator.
Parthenogenesis: Asexual reproduction, in which eggs develop without being fertilized by sperm.
In spiders, the short, narrow connection between the prosoma and the opisthosoma.
Sometimes used to describe the petiole or “wasp waist” of insects classified in family Apocrita of order Hymenoptera (bees, wasps, and ants).
Pedipalps: The second of six pairs of appendages attached to the prosoma in arachnids used for killing and manipulation of prey. Depending on the species, can also be used for walking, as tactile and olfactory organs, and as copulatory organs in male spiders.
Pelage: The body covering of hair on mammals.
Petiole: The constriction at the base of the gaster of insects classified in ants, bees, and wasps (family Apocrita, order Hymenoptera). Also referred to as a “wasp waist” and “pedicel“.
Pheromone: A chemical substance made and emitted by an animal that causes a physiological and/or behavioral response from another animal of the same species once sensed.
Photic zone: The layer of water in which animals are exposed to sunlight.
Plastron: In turtles, the lower part of the shell, consisting of two layers of bony plates corresponding to the shoulder girdle and abdominal ribs.
Plumose: Branched.
Posterior: Away from the head.
Plankton: Minute to microscopic organisms that float or drift passively with currents in bodies of water. Plankton can be either “phytoplankton” or “zooplankton“.
Predation: The act of one organism (a predator) catching, killing, and consuming another organism (a prey) for food.
Predator: An animal that catches, kills, and consumes prey for food.
Preening: A grooming behavior performed by birds that spreads special oil secreted by their preen glands over their feathers to keep the feathers supple and water-resistant.
Primary feather: An outer flight feather on birds’ wings. See also “secondary feather“.
Proboscis(es): In Lepidopteran insects, an elongated, tube-like mouth part adapted for sucking liquids.
Prolegs: In certain insect larvae, unjointed, fleshy legs located on the abdomen of certain species. Also called “false legs”, as opposed to “true legs” which are jointed and located on insects’ thoraxes.
Prosoma: The anterior segment of a spider’s body that bears the eyes, brain, mouth, fangs, stomach, venom glands, and chelicerae. Also known as the “cephalothorax“.
Prothorax: The first segment of an insect’s thorax, which bears a pair of legs.
Pruinose: Powdery appearance.
Pterostigma: A pigmented spot on the anterior margin of an insect’s wing.
Puddling: Also known as “mud-puddling”. A behavior in which many male butterflies and/or moths congregate on damp ground to imbibe water and dissolved mineral salts. The males incorporate these minerals into their spermatophores, which they then transfer to the females with which they mate as a nuptial gift. The minerals are thought to enhance the fecundity of the females and the fitness of the fertilized eggs.
Pupa: The third, inactive stage of a holometabolous insect’s life cycle, during which the insect transforms into its adult form.
Pupate: The process of a larva becoming a pupa.
Push-ups: A territorial and/or courtship behavior performed by some lizard species that consists of sharply raising and lowering the body by alternately bending and straightening the front pair of legs.
Pygidium: The last or terminal segment of an insect’s body.
Q
Quadrupedal: Refers to animals that walk on four legs.
Queen: In insects, the primary female who reproduces to populate the colony.
R
Radula: In most animals classified in Mollusca, a strip of flesh with rows of tiny teeth used for rasping food.
Raptorial legs: Strong, muscular forelegs of some predatory insects, used to grasp and hold their prey.
Scent marking: The deliberate placement of scented secretions like urine, feces, or saliva in the environment as a means of communication with other animals.
Sclerite: A hard section of an invertebrate animal’s external skeleton, made of sclerotin.
Sclerotin: A hard, durable combination of chitin and protein that makes up sclerites.
Scute: An enlarged, bony dermal plate or scale, found in reptiles.
Secondary feather: An inner flight feather on a bird, located on the trailing edge of the wing between the body and the bend of the wing. See also “primary feather“.
Segment: A section of an insect’s body or appendage, bordered by flexible membranes.
Semipalmate: In birds, refers to partially webbed feet; webbing between the toes does not extend to the tips of the toes.
Seta(e): A thin, flexible, hair-like structure that contributes to the sensations of touch, smell, taste, or sound in certain species.
Sexual dimorphism: A type of dimorphism in which males and females of the same species have different appearances.
Shuddering: A territorial and/or courtship behavior performed by some lizard species that consists of rapid, sharp, vertical head bobs.
Simple eye: An eye consisting of a single ocellus and that is sensitive only to light intensity. Contrast with “compound eye“.
Slit organ: A sensory organ in arachnids like spiders that sense changes in pressure and stress on their external cuticles and gives information about vibration and movement of the animals themselves.
Smooth scale: A type of body scale on reptiles that is completely flat, with no raised, center ridge. Contrast with “keeled scale“.
Social insects: Insects that live in colonies, exhibit it a division of labor among castes, and cooperate for the survival of the group.
Solitary insects: Insects that do not form long-term associations with other members of their species.
Speculum: In some birds, a well-defined patch of colored—often iridescent—feathers found on the secondary feathers or the secondary coverts.
Spermatophore: A packet of sperm contained in a gelatinous protein casing, produced by the accessory genitalia of some male insects, and transferred to females by either indirect means (placed on the ground for females to pick up) or direct means (physically inserted into females’ bodies).
Spinneret: One of a pair of movable, hardened, cone-shaped, segmented tubes located on spiders’ opisthosomas through which liquid spider silk flows to the external environment.
Spiracle: A hole in the exoskeleton of an insect that allows gases to enter and exit for breathing; usually located on the abdomen; usually capable of being opening and closed by the animal.
Stenophagic: Refers to an animal that has a very specialized, restricted diet.
Stigma: A darkened area on an insect’s wing.
Stinger: A modified ovipositor that serves as a means to pierce the bodies of other animals and inject venom for either predation or defense.
Stridulate: To make sound by rubbing a file across a membrane.
Substrate: An object upon which an animal grows; to which an animal is attached. Also refers to an underlying layer, such as a river bed.
Sunbathing: The exposure of its body to sunshine by an animal as a means to gain body heat.
Super-cooled fluids: Fluids that remain in the liquid state below their freezing points, such as glycerol and sorbitol, and help freeze avoidant animals avoid tissue injury from ice crystal formation. See “freeze avoidance”.
Synanthrope: An organism that benefits from the activities of humans.
Syrinx: The vocal structure in birds.
T
Tadpole: A round-bodied, long-tailed larva of a frog. Also informally called a “pollywog”.
Tapetum: A layer of light-reflecting cells found in the retina of many nocturnal animals that cause “night shine” or the animals’ eyes shine in the dark when they look in the direction of a light source.
Tegmen (tegmina): The fore wing of an insect when the wing is tough and leathery.
Temperature-dependent sex determination (TSD): The determination of sex by the thermal conditions experienced by developing embryos during incubation. Seen in crocodylians, many turtle species, and some lizard species. Compare to “genotypic sex determination (GSD)“.
Tentacle: In many invertebrate animals, a long, flexible, movable sensory structure.
Terrestrial: Related to land or dwelling on land.
Territory: A portion of a home range that an animal actively defends.
Thorax: In insects, the three middle of the three major subdivisions of an insect’s body, between the head and the abdomen; body segment to which all the legs and wings are attached; made up of three segments (see “prothorax“, “mesothorax“, and “metathorax“).
Threat display: A form of visual communication by which an animal may intimidate predators, other potentially dangerous animals, or rivals of the same species so as to avoid direct physical contact.
Torpor: A state of decreased metabolic rate that occurs during cold temperatures during which an animal’s body temperature may fall to nearly match environmental temperatures. See also “hibernation“.
Trachea: In insects, breathing tubes that carry gases to and from an insect’s spiracles and internal organs.
Tracheal spiracle: One of two breathing organs found in spiders, located in front of spiders’ spinnerets. See also “book lung“.
Tympanum(a): An auditory sense organ composed of a membrane that vibrates in response to pressure changes and transmits sound waves to an animal’s brain. Also called a “tympanic membrane”.
U
Uniramous: Unbranched. Term used to describe the appendages attached to individual body segments of animals classified in subphylum Myriapoda.
V
Vent: Anus; the opening of the cloaca to outside of the body.
Venter: The underside of a lizard’s body.
Venter display: A territorial and/or courtship behavior performed by some lizard species that consists of raising the body to display their abdominal color patches.
Ventral: The side of the body opposite the back. The surface of an organism that is closest to the substrate. Compare to “dorsal” and “lateral”.
Vertebrate: An animal with a vertebral column (“backbone”).
Vomeronasal organ: A special organ found in amphibians, lizards, snakes, and some mammals that senses smell/taste information. Also called “Jacobson’s organ“.
Vivipary: A reproductive method in which an embryo grows within a female organism’s body, which nourishes it, and in which active young are produced. Compare with “ovipary” and “ovovivipary“.
W
Wasp waist: The constriction at the base of the gaster of insects classified in ants, bees, and wasps (family Apocrita, order Hymenoptera). Also referred to as a “petiole” and “pedicel“.
Wing covert: In birds, a feather or feathers that cover the base of a main wing feather. Can be a “greater covert”, a “median covert”, or a “minor covert”, depending on the covert’s location on the wing. Also referred to as “covert”.
Wing coupling: The attaching of the two pairs of wings of many insects during flight, resulting in each joined fore wing and hind wing pair functioning as a single wing. See also “hamulus“.
X
Xeric: Refers to environmental conditions characterized by limited, minimal, or inadequate supply of fresh water, as in deserts, extremely cold environments, and salt marshes.
Xylophagous: Wood-eating.
Y
Yolk: A material composed of a mixture of lipids and proteins that act as a food source for embryos that develop inside of eggs.
Yolk sac: A structure composed of a membrane that surrounds yolk and the yolk itself.
Z
Zoology: The scientific study of animals, including their anatomy, physiology, genetics, evolution, behavior, and ecology.
Zooplankton: Animal plankton that do not photosynthesize. Compare with “phytoplankton“.
