The Southern Pine Beetle
Glossary

Acarology: the branch of zoology that treats of mites and ticks.

Aerotriangulation: a method by which aerial photographs are oriented and placed in proper relationship to one another.

Aggregation: the massing of populations of male and female adults on a tree about to be attacked.

Allocation: the combination of emerging and reemerging beetles from one tree going from source to sink trees, i.e., from trees that have been attacked to those being attacked.

Alpha-pinene: the most significant host-tree odor in the behavioral complex of the SPB.

Arthropods: animals with segmented bodies and paired, jointed appendages—e.g., insects and spiders.

Attractant: a chemical or odor that affects SPB behavior by attracting beetles to a particular area.

Bark beetles: group of beetles, mainly of the family Scolytidae, whose adults bore through the bark of host trees to lay their eggs, and whose larvae tunnel and feed under the bark.

Biome: an ecological formation considered in terms of both plants and animals of the area concerned and usually identified in terms of characteristic vegetation forms.

Bole: the trunk or stem of a tree.

Cambium: the layer of cells that lies between, and gives rise by active division to, secondary xylem and secondary phloem, i.e., to wood and the innermost living bark.

Canadian Standard Freeness: a measure of the drainage characteristics of pulps.

Clearcutting: removal of the forest stand completely, in one cut.

Climax species: species capable of perpetuation under the prevailing climate and soil conditions.

Colonization: the phase of the SPB’s life cycle that includes mating, egg laying, and gallery construction.

Cord: a unit of gross volume measurement for stacked round or cleft wood, based on external dimensions, e.g., a stack of wood 4 ft high, 4 ft thick, and 8 ft long.

Diameter at breast height (d.b.h.): diameter of a tree at 4.5 ft (1.37 m) above the ground, measured from the high side of slope.

Diapause: a condition of suspended animation, or resting period, during which development ceases, as during the egg overwintering period.

Diel: involving a 24-hour period that usually includes a day and its adjoining night.

Dispersal: the act or result of dispersing or scattering: usually refers to the redistribution of larvae after eggs have hatched—e.g., dispersal of first instars.

Ecology: the study of plants and animals in relation to their environment.

Ecosystem: an assemblage of living plants and animals and their environment.

Edge: the area where two types of vegetation meet and intermix.

Efficacy: effectiveness, as of an insecticide; a product’s ability to control the specified target pest or to produce the specified action.

Electrophoresis: slow movement of colloidal particles in an electric field; a process used to separate and identify compounds.

Endo-brevicomin: a pheromone, produced by male SPB, which inhibits the responses of both sexes to attractive host trees and thus facilitates attacks on other new trees.

Evapotranspiration: evaporation of transpired water from the surface and crown of plants.

Frass: solid insect excrement.

Frontalin: the primary aggregation pheromone of the SPB.

Frontalure: the synthetic SPB attractant, a mixture of frontalin and alpha-pinene.

Glue-line test: a test of the load carrying capacity (strength) of glued joints.

Histogram: a graph of frequency distribution in which equal intervals of values are marked on a horizontal axis and the frequency corresponding to each interval is indicated by the height of a rectangle having the interval at its base.

Host: any organism upon or within which another organism lives.

Hydric: characterized by, relating to, or requiring an abundance of water.

Hyphae: the individual threads that make up the mycelium of a fungus.

Infestation geometry: spatial arrangement of trees and susceptibility factors.

Inhibitor (re behavioral chemicals): a chemical or odor that affects SPB behavior by repulsing beetles from a particular area.

Instar: period or stage between molts of an insect larva.

Isomer: one of two or more compounds composed of the same percentage of elements but differing in structure and properties.

Larva: immature form of an insect that undergoes complete metamorphosis; a caterpillar, maggot, or grub.

Life table: tabulation of mortality factors acting on an insect population, which displays the relative importance of each factor and permits estimation of survival; when coupled with a knowledge of fecundity, can be used to estimate the size of the succeeding generation.

Lipids: the class of substances including fats, waxes, phosphatides, cerebrosides, and some steroids and carotenoids.

Multivoltine: having many broods and generations in a year or season.

Mycangium: specialized body structures on the exterior of SPB, in which mites or fungi reside.

Myrtenol: a pheromone produced by both male and female SPB, which encourages males to stop near the source of the pheromones, esp. the entrance holes belonging to female SPB.

No. 1 structural (grade): the highest quality of softwood dimension lumber, graded for its load-carrying capacity according to the grading rules of the Southern Pine Inspection Bureau.

Nonlinear least-squares technique: method of fitting data to a nonlinear model by minimizing the sum of squares of the differences between the predicted (model) values and the actual values.

Oleoresin exudation pressure: pressure within resin ducts in some conifers.

Orthophotography: photographic reproduction of aerial photographs in which displacements of images due to tilt and relief have been removed.

Overwintering: the phenomenon of SPB larvae remaining in the tree through the winter months.

Oviposit: to lay eggs.

Parasitism: the mode of life of a parasite, i.e., as between it and its host.

Parasitoid: a life form that usually develops from egg to adult on a single host, using the host for food but not killing it until the parasitoid has fully matured.

Pheromone: substance released by one individual that modifies the behavior of another of the same species, e.g., the SPB pheromone is an odor released by females that attracts males.

Phloem: complex vascular tissue in higher plants, which functions in translocation, support, and storage.

Phoretic: exhibiting phoresy, the nonparasitic association of one kind of animal (as a larval insect) with another in order to obtain transportation.

Population dynamics: the study of changes and the reasons for changes in population size.

Predation: a form of life in which food is primarily obtained by killing and consuming animals.

Predator: a free-living organism that feeds on other organisms; as birds and other insects that feed on SPB.

Primary parasite; a parasite that establishes itself in or on a host that is not a parasite.

Pupa: the resting, intermediate stage of an insect between the larva and the adult.

Radially loaded: a term applied to toughness tests where a standard stick of wood is oriented in such a way that the breaking load is applied perpendicular to the grain and parallel to the annual rings.

Ratio of increase (R.I.): ratio of emerging brood adult SPB to original attacking (parent) adults.

Reemergence: the phase of SPB activity when adults come back out of the bark after ovipositing.

Resinosis: abnormal exudation of resin from conifers or abnormal impregnation of conifer tissue with resin.

Respiration: process in plants of absorbing oxygen from the air, oxidizing organic compounds to simpler compounds and carbon dioxide, and yielding energy.

Scribner rule: a diagram rule for estimating board-foot yields from timber (logs). It assumes 1-inch boards and 1/4-inch kerf, makes a liberal allowance for slabs, and disregards taper.

Selection cutting: periodic harvest removal of trees (particularly mature trees), either singly or in small groups (as opposed to clearcutting, in which all trees are removed in a single operation).

Significance: when a statistical hypothesis is tested, it is declared true if a calculated probability exceeds a given value, referred to generally as the significance level.

Silviculture: theory and practice controlling the establishment, composition, and growth of trees.

Socioeconomic model: a collection of computer programs used to translate the volume of timber, water, and other factors into dollar impacts of a particular simulated SPB outbreak.

Southern pine bark beetle: As a group, the major bark beetles attacking pines in the South—southern pine beetle, Ips grandicollis, I. avulsus, I. calligraphus, and D. terebrans.

Stand geometry: the spatial arrangement of trees.

Stemflow: water that is caught on leaves, needles, branches, and bole and eventually flows down the bole onto the forest floor.

Stochastic: random, as in processes or variables.

Stumpage: current value of standing timber, considered with reference to its quantity or marketable value.

Succession (forest): the establishment, development, and maturation of forest communities under the influence of site factors and reaction of vegetation upon them; the progressive development of vegetation on the same site resulting from the successive replacement of one community by another of different growth form, e.g., moss, weed-grass meadow, hardwood thicket, poplar forest, spruce-fir forest.

Survivorship: rate of survival or proportion of insects surviving over a specific period, e.g., a developmental stage or generation.

Symbiosis: the living together in more or less intimate association or even close union of two dissimilar organisms.

Synergist: an agent that increases the effectiveness of another agent when combined with it.

Tangentially loaded: a term applied to toughness tests where a standard stick of wood is oriented in such a way that the breaking load is applied perpendicular to the grain and the annual rings.

Terpene: general name of hydrocarbons having the formula C₁₀H₁₆, related to isoprene, commonly occurring in many species of wood, and generally having a fragrant odor.

Top-kill: for individual trees, some portion of the live crown and stem killed, from the top down, by any cause.

Toxicity: poisonous quality, especially its degree or strength.

Tracheids: water-conducting tissues in the xylem.

Trans-verbenol: an odor produced by female SPB that can synergize the attractiveness of frontalin.

Verbenone: a pheromone produced mainly in male SPB which, when exuded, helps balance the sex ratio of attacking beetles.

Volatiles: tree-produced or insect-produced odors that affect SPB behavior.

Xylem: woody tissue of higher plants, which functions in support and water conduction.

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