Abdomen: the back section of the insects, behind the point of attachment for the wings and legs.

Adaptation: a modification that allows an organism to become better suited to its environment.  Modifications can be behavioral, structural, or cellular.

Aerial plankton: a group of mixed organisms (usually small, often insects, spiders, and other arthropods) that use wind currents to travel great distances through the air

Africanized bees: bees that are a hybrid of European honey bees with the more aggressive African honey bees that were accidentally released in South America in the 1950’s.  More commonly known as “killer bees”.

Aggregation: a group of individuals

Air straps: short, retractable respiratory appendages found at the back end of many giant water bugs

Ambush predator: a type of predator that hides and waits for its prey to come near before it quickly snatches the prey up

Ametabolous: in insects, a type of metamorphosis in which all stages but the egg look the same apart from size

Amphipod: a type of small, aquatic crustacean with head and thorax fused, two pairs of antennae, and legs of different structures on the thorax and abdomen

Aquatic: lives in water; in insects, this almost always means living in freshwater systems

Aquifer: a porous layer of loose rock deep underground that retains water, creating a large underground reservoir

Arid: a climatic condition in a region characterized by low rainfall and dry conditions

Arthropod: a group of animals belonging to the phylum Arthropoda, characterized by an exoskeleton, segmented bodies, and jointed appendages

Atmospheric oxygen: the oxygen that makes up part of the air we breathe

Back brooding: in giant water bugs, particularly the belostomatines, the eggs are deposited on the backs of the males who then care for them by bringing them to the surface and performing various underwater behaviors

Belostomatid: an insect belonging to the Order Hemiptera and the family Belostomatidae

Belostomatidae: a family of true bugs, also known as the giant water bugs, recognizable by their raptorial forelegs, legs with swimming hairs, and retractable respiratory appendages

Belostomatinae: a subfamily of the giant water bugs which utilizes back brooding

Belostomatine: a member of the subfamily Belostomatinae

Biological control: the use of one biological organism to control the spread or reproduction of a pest species; biological control species commonly consume, infect, lay eggs in, or otherwise kill the pest species by natural means

Biota: all of the living organisms in a system

Bi-parental care: a form of parental care where both parents are involved in caring for their offspring

Boundary layer: the layer of low flow that occurs when fluids (water, air, etc) flow over the surface of objects in the stream.  See the Water Penny entry for a more detailed description of how a boundary layer works.

Brooding: in giant water bugs, brooding refers to a series of behaviors that promote the survival of offspring in the egg stage of development

Bubble gill: in aquatic insects, an air bubble carried by an insect while underwater from which oxygen can be extracted by the insect as it breathes. Similar to a human carrying a scuba tank.

Bug: an insect that belongs to the order Hemiptera.  See the post about bugs for more information.

Cellular respiration: a four stage process occurring in the mitochondria of eukaryotes by which energy gained from food or photosynthesis is converted into adenosine triphosphate (or ATP, an energy rich molecule that powers many cellular functions) and produces carbon dioxide and water as wastes

Chorion: the eggshell of an insect.

Citizen science: a collaboration between scientists and non-scientist volunteers to answer scientific questions

Complete metamorphosis: see holometabolous

Crepuscular: active at dawn and/or at dusk

Crustacean: a group of arthropods characterized by two pairs of antennae, three body segments (the head and thorax may be fused), and branched legs.  Includes lobsters, crabs, shrimp, and pillbugs/sowbugs.

Decomposer: an organism that helps break down a dead organism

Detritus: this is essentially another word for debris and is made up of decaying organic matter of all sorts.  In aquatic systems, detritus is typically made up of decaying leaves, twigs, algae, and other plant matter.

Dimorphic: from the roots di (two) and morph (shape or form), this word refers to biological species in which individuals belong to one of two forms (shapes, sizes, colors, ornamentations, etc) within a single species

Diptera: the insect order containing the true flies

Direct wing muscles: in insects, wing muscles that attach directly to the wings

Dispersal: the act of organisms moving from one habitat to another

Dissolved oxygen: oxygen that is mixed into water.  The amount of oxygen in water depends on several characteristics of the water, but is always very low compared to the amount of oxygen in air.

Diurnal: active during the day

Dragonfly swarm: a large group of dragonflies flying together, away from water (i.e. over grass, high in the air, etc).  There are two types: static swarms and migratory swarms.  You can learn more about dragonfly swarms on my dragonfly swarm information page.

Ecosystem: the combined biological and physical components of an environment

Ectothermic: animals that are largely unable to regulate their body temperature and are therefore similar in temperature to their environment; “cold blooded”

Effluent: treated wastewater released from a wastewater treatment plant

Effluent dominated stream: a stream in which the majority of the water is effluent.  In extreme cases, no stream would exist at all without the input of effluent.

Electron microscope: a type of high powered microscope that works by aiming an electron “gun” at an object of interest.  Images are formed when the electrons either passing through or bouncing off the samples are detected by sensors.

Electroshocking: a technique for sampling fish in a body of water that uses a backpack sized generator to produce a strong electrical current in the water, temporarilty stunning the fish and causing them to float to the surface

Elytra (singular: elytron): the hardened forewings of beetles.  Elytra means “sheath” in Greek.  See the post about bugs for more information.

Embeddedness: in aquatic sciences, embeddedness refers to the amount of surface area of rocks, boulders, and gravel covered by silt and sand

Emergent brooding: in giant water bugs, particularly the lethocerines, the eggs are deposited on emergent vegetation above the water line and the males care for them by carrying water to them

Emergent vegetation: in aquatic systems, aquatic plants in which part of their bodies extends above the water line.  Examples include cattails, rushes, and sedges.

Endothermic: animals that can regulate their own body temperatures, regardless of the external temperature; “warm blooded”

Entomologist: a scientist who studies insects

Entomophagy: the practice of eating insects

Ephemeral stream: a stream that flows for only a short period of time each year, and often only in response to rain or snowfall events.  These streams are typically flowing for a month or less and are thus ephemeral.

Eukaryote: an organism whose cells contain structures enclosed by membranes, such as the nucleus and mitochondria

Exoskeleton: the hard, tough outer covering of insects and other arthropods

Exothermic: organisms that are largely unable to produce their own body heat and regulate their temperature mostly through behavioral means.  Exothermic animals are often called “cold blooded” animals.

Field-based science – a science in which the research is completed outside of the lab, either in natural settings or in areas impacted by human activities

Field scientist: a scientist who conducts his or her research outdoors and in nature (as opposed to a scientist who conducts research in a lab)

Fitness: in biology, a term that refers to the ability of an organism to reproduce and generate offspring that can also reproduce, thus passing on its genes to future generations

Fliers: in odonates, the behavioral group which includes insects that rarely land and observe their territories on the wing.  Contrast with perchers.

Fly: an insect with only two wings and halteres in place of the hind wings, belonging to the order Diptera

Forelegs: the front pair of legs in insects and other animals that walk with more than one pair of legs on the ground

Forewings: the front pair of wings in insects with wings.

Gravid: full of eggs

Gregarious: tending for form groups with others of the same species

Haltere: in flies, the reduced hind wings.  These structures act as gryroscopes and give flies their remarkable flight abilities.

Headwaters: streams that are close to the source of the water in the system.

Hemielytra: the specialized forewings of the true bugs (Order: Hemiptera) that are leathery on the upper half and membranous on the lower half.  Hemielytra means “half sheath” in Greek.  See the post about bugs for more information.

Hemimetabolous: insects that undergo incomplete metamorphosis and have a life cycle that consists of egg, nymph, and adult

Hemiptera: the order name for the group containing the true bugs.  All members of this group have hemielytra and piercing-sucking mouthparts.

Hemoglobin: a substance found in blood that has a high affinity for oxygen and readily binds with oxygen molecules.  In humans, this substance helps red blood cells absorb oxygen from the lungs so that it may be carried to other parts of the body.  It also gives our blood its red coloration.  In insects, it is typically found in species that live in low oxygen environments where absorbing oxygen through the exoskeleton is insufficient to supply the oxygen needs of the insect.

Hemolymph: insect blood

Herbivore: an animals that eats plants

Hind wings: the back pair of wings in insects with wings

Holometabolous: insects that undergo complete metamorphosis and have a life cycle that consists of egg, larva, pupa, and adult

Hydric: characterized by or requiring and abundance of moisture; see also xeric and mesic

Hymenoptera: an insect order containing the ants, wasps, and bees

Immature: an organism that is not fully developed and not reproductively capable

Incomplete metamorphosis: see hemimetabolous

Indicator species: a species that reveals some characteristic in an environment.  In aquatic systems, indicator species usually tell scientists something about the quality of the water.

Indirect wing muscles: in insects, wing muscles that attach to the walls of the thorax rather than directly to the base of the wings

Insect: an animal that has 3 body segments (head, thorax, abdomen), six legs, two pairs of wings (may be missing in some insects), and one pair of antennae

Insectivore: an animal or plant that eats a diet of mostly or entirely insects

Instar: the stage between molts in immature insects

Invasive species: a species that is transported, either via natural or human based means, into a habitat where it did not exist before.  Invasive species often cause major problems in the habitats they have invaded.

Invertebrate: an animal with no backbone.  Invertebrates include insects, crustaceans (lobsters, shrimp, crabs), centipedes and millipedes, jellyfish, and octopusses.

Invertebrate drift: when aquatic invertebrates drift downstream, carried passively by the current.  This drifting can be accidental or intentional.  This term also refers to the collective community of organisms that are moving downstream via drift at any given time.

Larva (plural: larvae): the immature stage of holometabolous insects

Larviform: adult insects that have similar body structures (i.e. caterpillar or worm like) to larvae.  Larviform adults may have reduced or absent legs, wings, or have indistinct separation between the body segments.

Lethocerine: a member of the subfamily Lethocerinae

Limnology – the study of inland waters, essentially non-oceanic waters

Macroinvertebrate – in aquatic sciences, macroinvertebrate refers to any invertebrate that is readily visible to the naked eye and without the use of a microscope

Macroinvertebrate assemblage: in aquatic entomology, the members that make up the invertebrate fauna that lives in a particular area of a lake or stream

Mammal: a group of animals characterized by bodies covered in hair and mammary glands in females.  These include humans and the “cute and fuzzy” creatures such as cats, dogs, horses, mice, rabbits, squirrels, otters, rhinos, giraffes, etc.

Mandible: in insects, one of the four sets of mouthparts. The mandibles are usually the outermost set of mouthparts along the side of the head and are often used for chewing. They may be highly adapted in non-chewing insects.

Marine: of or pertaining to the ocean.  Marine animals are, for example, animals that live in the ocean.

Maternal care: a form of parental care in which the mother is the primary or sole caregiver

Mesic: characterized or requiring a moderate level of moisture; see also hydric and xeric

Metamorphosis: in insects, a process by which an insect changes from one stage and/or form to another.  See also holometabolous, hemimetabolous, ametabolous, and the entry on metamorphosis in insects.

Migratory dragonfly swarm: a large group of dragonflies (often thousands to millions) all flying together in a single direction as they move from one place to another.  You can learn more about these swarms in my post about mass migrations in dragonflies.

Mimic: in biology, when one organism evolves to look like another organism to increase their ability to survive

Mitochondria: organelles within eukaryotic cells that are the site of cellular respiration (i.e. energy production)

Mitochondrial genome: the genes contained within the mitochondria; these genes are passed directly from the mother to her offspring

Molt: in insects, breaking out of an exoskeleton that has grown too small and expanding the new, larger exoskeleton beneath; the stages between molts are called instars

Momomorphic: from the roots mono (one) and morph (shape or form), species in which all individuals look about the same, i.e. they have one form

Natural history: the study and description of organisms and natural objects, especially their origins, evolution, and interrelationships

Naturalist: a field scientist who studies natural history

Nocturnal: active at night

Nuclear genome: the genes contained within the nucleus of the cell; in sexually reproducing species, these genes result from the combination of genes from the mother and the father

Nymph: the immature stage of hemimetabolous insects

Odonata: the order name for the group containing the dragonflies and damselflies.

Odonate: an insect belonging to the order Odonata

Operculum: a lid-like structure in a biolgical organisms.  Many insect eggs have operculums surounded by weakend fault lines that allow the insect to push the top of the egg off easily when it is ready to hatch.

Organic: in science, organic refers to living organisms

Organic matter: matter made up of organic componants

Organismal respiration: the process by which an organism obtains oxygen from its environment and delivers it to the cells

Outfall: the location at which water is released from a wastewater treatment facility into a lake or stream

Oviposition: in insects, the act of laying eggs

Oviposition site: the site where eggs are laid

Ovipositor: an external, sometimes retractable, tube through which eggs are laid in many insect species

Oxygen toxicity: a state that occurs when an organism receives too much oxygen and begins to experience deleterious effects

Parasite: an organism that lives off another organism to the detriment of the host organism and the benefit of the parasite

Parental care: in animals, a series of behaviors that parents perform to help their offspring survive until they are old enough to survive on their own

Paternal parental care: a form of parental care in which the father is the primary or sole caregiver

Patrolling: in odonates, refers to males that defend their territories by flying through the area rather than sitting on a perch. Patrolling odonates are fliers while those that sit on perches are perchers.

Pelagic zone: in a body of water, the “open water,” or water that is not closely associated with the bottom or the shore

Percher: in odonates, the behavioral group where the insects sit on perches and observe their territories while resting rather than on the wing.  Contrast with flier.

Periphyton: algae growing on any surface within a body of water (lake or stream)

Physical gill: a form of bubble gill respiration in which the air bubble is exposed to the water, allowing the insect to absorb oxygen from the water into the bubble and extending its length of submersion.  See my post on aquatic insect respiratory efficiency for more information on how it works.

Picking: in aquatic invertebrate studies, picking is the process by which a person separates the invertebrates from the algae, sand, rocks, trash, and other non-invertebrate material in a sample.  (Imagine a baboon picking lice out of another baboon’s fur and you should have a pretty good mental image of how it works!)

Piercing-sucking mouthparts: the specialized mouthparts of true bugs that inject digestive chemicals into their food, then suck the food up into their mouths after the chemicals have liquefied it

Plankton: any drifting organisms (animals, plants, archaea, or bacteria) that inhabit the pelagic zone of oceans, seas, or bodies of fresh water

Plastron: in aquatic insects, an air bubble carried by an insect that absorbs oxygen from the water, never decreases in size, and allows the insect to remain submerged nearly indefinitely

Pollution tolerance value: in aquatic research, the pollution tolerance value refers to a numeric value assigned to a macroinvertebrate that reflects its range of tolerance to pollution/impairment in its habitat.  The scale goes from 0-10.

Polymorphic: from the roots poly (many) and morph (form or shape), this word refers to biological organisms that exhibit multiple forms (shapes, sizes, colors, ornamentations, etc) within a single species

Predation: the act of being preyed upon by a predator

Predator: an animal that eats another animal

Prey: an animal that is eaten by another animal

Prokaryote: an organism whose cells contain no membrane bound structures

Proleg: in insects, a leg-like structure that often helps the insects grasp substrates. Prolegs may be found just behind the head on the thorax in flies, only at the end of the insect in dobsonflies and caddisflies, or arranged along the abdomen as seen in caterpillars and many fly larvae.

Pruinose: in dragonflies, individuals with a waxy and/or dusty looking coating on their bodies

Pupa (plural: pupae): in holometabolous insects, the developmental stage between larva and adult where a complete rearrangement of tissues occurs

Pupation: in insects, the transition from the larval stage into the pupal stage

Raptorial forelegs: enlarged forelegs full of strong muscles used for grabbing and holding onto food; often present in predatory insects

Respiratory siphon: a long, snorkel-like tube that allows an aquatic insect to collect air at the surface; present in many giant water bugs and all water scorpions

Respirometry: a scientific technique for measuring either the amount of oxygen consumed or the amount of carbon dioxide produced by an organism.  Gas or liquids of known oxygen and carbon dioxide concentrations are placed into contact with the organism, then sensors measure the amount of oxygen or carbon dioxide in the fluid again.  The difference between the amount going into the system and the amount measured by the sensors after the fluid is exposed to the organism is the amount the organism either produced or consumed.

Riffle: a rocky or sandy relatively shallow area in a stream.  Typically the water flows more quickly and creates greater turbulence in riffle areas than in other areas of the stream.

Riparian zone: the area of land adjacent to a stream or river that is influenced by the water in the stream.  Riparian zones are typically full of leafy trees and other plants that have high water requirements, some of which are only able to live in the areas near streams where water is very abundant.

Scanning electron microscopy: a form of electron microscopy in which the surface features of an object are observed by bouncing electrons off the surface.  Sensors collecting the electrons form an image of the object on the screen.

Scavenger: an animal that eats whatever it can find, often including dead or dying organisms

Sclerotization: in insects, a process by which a soft, flexible exoskeleton is hardened into a hard and/or tough covering

Sediment: solids that settle at the bottom of fluids; in aquatic biology, sediments are the natural materials (rocks, leaves, etc) that make up stream and lake beds.

Sensitization: a condition in which a person becomes increasingly more sensitive to a substance, such as bee venom, with each subsequent exposure

Sessile: an organism that remains largely in on place and is not free-moving

Sexually dimorphic: biological organisms in which the male and female of the species are different colors, shapes, sizes, carry different ornmentation (horns, antlers, feathers), etc.  To the untrained eye, the males and females of some species might appear to be different species because they look so different.

Sit and wait predator: a predator that rests in one location, waiting for food to swim or walk by.  When prey comes long, it will quickly grab the food in a flash of motion and begin to eat it.

Species richness: the number of species found within a particular environment; a measure of diversity in an area

Spiracle: an opening in the exoskeleton of an insect that opens into the tracheae of the insect respiratory system

Spore: the reproductive body of molds that allows molds to spread to new areas

Static dragonfly swarm: a group of approximately 20-1000 dragonflies flying within a well-defined (sometimes large) area rich in small insects that the dragonflies eat.  More information about static swarms can be found on my post about static feeding swarms in dragonflies.

Swarm: a large number of animals (usually insects) of the same species and/or size that mass together, eithering move from one place to another or remaining in place

Swimming hairs: dense hairs covering all or one side of the legs of aquatic insects that help increase their surface area sufficiently to help them move through the water more efficiently

Tarsus (plural: tarsi): one of the small segments found at the end of the insect leg; plural = tarsi

Taxon (plural: taxa): a group of one or more related organisms and which have characteristics in common that are different than other groups

Terrestrial: living on land

Territorial: in animals, an individual that sets up and maintains a territory

Territory: an area containing necessary resources (food, access to mates, habitat, etc) that an animal is able to protect sufficiently to exclude other individuals

Thermal limit: the maximum and minimum temperature at which an organism can survive

Thorax: the middle segment of insects, where the wings and legs are attached

Tolerance value: a number between 0 and 10 assigned to an aquatic macroinvertebrate according to its tolerance to pollution.  Things at the lower end of the scale have a very low tolerance to pollution while things at the high end can tolerate a lot of pollution.

Trachea (plural: tracheae): part the insect respiratory system, large open tubes that transport oxygen and carbon dioxide between the spiracles and the tracheoles

Tracheole: part of the insect respiratory system, a small narrow tube that transports oxygen from the tracheae to individual cells or small groups of cells within the insect body

Trade off: in biology, trade-0ffs occur when one individual or biological process benefits to the detriment of another.  See my post on biological trade-offs for more information.

Transmission electron microscopy: a form of electron microscopy in which very tiny pieces of an organism, often internal structures, are observed by passing electrons through the sample.  Sensors under the sample collect the electrons passing through and create an image on a screen.

Trophic cascade: trophic cascades occur when an organism in one trophic level consumes an organism in the next lower trophic level, which in turn impacts the next lower trophic level that the organism being eaten consumes.  For more information, please see the post Notes from NABS Day 1.

Trophic level: a group of biological organisms that share a feeding style, such as predators, herbivores, and producers

True bug: an insect belonging to the order Hemiptera

Venom: poisonous chemicals that are transmitted from one animal to another via a bite or sting

Ventilatory behavior: a behavior that allows an organisms to breathe more efficiently

Vertebrate: animals with backbones, such as humans, dogs, cats, birds, snakes, and fish

Xeric: characterized by or requiring only a small amount of moisture; see also hydric and mesic


Text ©


4 thoughts on “Glossary

  1. Because many people coming to your blog are going to have questions about what a dragonfly swarm is, I suggest you add glossary terms for swarm, dragonfly swarm, static swarm and migratory swarm, with links to appropriate posts.

    Just a suggestion :-)

  2. Pingback: Friday 5: Papers I Haven’t Had Time to Read | The Dragonfly Woman

  3. Pingback: Insects and Plants Use the Same Strategy for Breathing Underwater | The Dragonfly Woman

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