Glossary

abiotic:

physical properties of an environment, such as climate, soils, atmospheric gases.

adventive:

nonindigenous species which has recently arrived or which appears to be a temporary resident in a new range; its persistence has not been determined.

allele dynamics:

the interactions of alleles with each other.

alleles:

any number of variants of a single gene.

allelopathy:

the production and emittance of organic compounds by an organism that causes detrimental consequences for its neighbors.

allopatric:

two or more species having nonoverlapping ranges of distribution.

annual:

an organism that completes its life cycle in a year or less.

antipodal:

opposites; refers to any objects (such as chromosomes) that are at diametrically opposite extremes.

apomixis:

the development of a seed without fertilization.

arrhenotokous:

capable of producing male offspring only, as in worker bees and some sawflies.

asexual reproduction:

any reproduction not involving the fusion of gametes.

autotroph:

an organism capable of self-nourishment, such as a plant nourishing itself by photosynthesis.

avirulence gene:

a gene that infers the inability to infect another organism.

basic reproduction number (Ro):

the average number of offspring or infectious units from a single organism or infectious agent.

biological control:

control of an invasive species by the introduction of a predator, grazer, or pathogen of that species.



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Predicting Invasions of Nonindigenous Plants and Plant Pests Glossary abiotic: physical properties of an environment, such as climate, soils, atmospheric gases. adventive: nonindigenous species which has recently arrived or which appears to be a temporary resident in a new range; its persistence has not been determined. allele dynamics: the interactions of alleles with each other. alleles: any number of variants of a single gene. allelopathy: the production and emittance of organic compounds by an organism that causes detrimental consequences for its neighbors. allopatric: two or more species having nonoverlapping ranges of distribution. annual: an organism that completes its life cycle in a year or less. antipodal: opposites; refers to any objects (such as chromosomes) that are at diametrically opposite extremes. apomixis: the development of a seed without fertilization. arrhenotokous: capable of producing male offspring only, as in worker bees and some sawflies. asexual reproduction: any reproduction not involving the fusion of gametes. autotroph: an organism capable of self-nourishment, such as a plant nourishing itself by photosynthesis. avirulence gene: a gene that infers the inability to infect another organism. basic reproduction number (Ro): the average number of offspring or infectious units from a single organism or infectious agent. biological control: control of an invasive species by the introduction of a predator, grazer, or pathogen of that species.

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Predicting Invasions of Nonindigenous Plants and Plant Pests biotic: any process or phenomenon that is caused by living organisms. carrying capacity: the theoretical maximum number of individuals in a population that can be supported by a defined set of conditions in an environment. cline: a geographic gradient in the frequency of a gene. confamilial: belonging to the same family. congeners: members of the same genus. congeneric: referring to members of the same genus. conspecific: referring to members of the same species. cryptogam: plants and plant-like organisms that do not reproduce with seeds and do not produce flowers, such as ferns, mosses, fungi, and algae. demographic: refers to any attribute or process relating to a population. deterministic growth rate (λ): a growth rate that has only one outcome as defined by the parameters or conditions under which the population occurs. diapause: a state of arrested growth or development, usually applied only to insects. dichogamy: flowers that are functionally male first, then develop female structures. dioecious: producing male and female structures on two separate plants within the same species. dioecy: in plants, the possession of male and female structures on separate individuals. diploid: possession of two full sets of genes and two sets of chromosomes; one set from the mother, one from the father. dsRNA: double stranded ribonucleic acid. ectophagous: feeding on the outside of the host. endophagous: feeding on the internal organs or at least within the body of the host. endophytic: fungi that reside within plant cells, or plants that live within other plants. entomophagous: insect-feeding. epiphyte: a plant that grows on another plant nonparasitically, or grows on an object. establishment: permanent self-maintenance of a population without additional members arriving through immigration. exploitation competition: competition in which resources obtained by one organism, population, or species results in a lowered resource availability to another organism, population, or species. floras/faunas: the collective assembly of all plants (floras) or animals (faunas) within a prescribed area and within a prescribed taxonomic group (for example all insect species in the United States). founder: an organism which gives rise to a new populations. genetic drift: changes in allelic frequency due to sampling error; that is, changes in frequency that result because the genes appearing in offspring are not

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Predicting Invasions of Nonindigenous Plants and Plant Pests a perfectly representative sampling of the parental genes (such as occurs in small populations). genotypes: the genetic constitution of an individual or group. haustellate: having a tubular organ adapted for sucking blood or the juices of plants. herbivorous: refers to those animals that feed or graze on living plant material, usually in reference to non-reproductive tissue (i.e., leaves, stems). heterogamy: alteration of sexual reproduction with parthenogenesis. hermaphrodite: an organism that possesses the reproductive organs of both sexes. heterozygosity: the proportion of the individuals in a population that are heterozygotes; that is, those individuals that have two different alleles at a locus. homozygous: having two copies of the same allele at a genetic locus. indigenous: native to a prescribed geographic range. interference competition: competition between any two individuals in which one physically excludes or prohibits another from gaining a resource in short supply. intrinsic rate of increase (r): maximum growth rate of a population, estimated as a birth rate minus the death rate; the net increase in the population. inverse density dependence: increase in fitness with increases in density (birth rates rise, mortality rates drop). invasion (biotic or biological): a phenomenon in which a nonindigenous species arrives in a new range in which it establishes, proliferates, spreads, and causes broadly-defined detrimental consequences in the environment. lag phase: phase in the typical cycle of population growth, when there is little or no growth, between introduction of an organism and exponential (log) growth. larval: in connection with arthropods, the immature instars, that is, stages in development. logistic curve: growth curve characterized by oscillation of population growth at a level below the carry capacity. log phase: phase in the typical cycle of population growth, between lag phase and decline, when a population grows exponentially. mandibulate: chewing, in reference to insects that chew prey with those mouth-parts called mandibles. mean population growth rate: the average rate by which a population changes size. mesic: having or characterized by a moderate amount of moisture. mesophytic: referring to intermediate environmental conditions. monoecious: bearing the reproductive structures of both parents on the same plant. monophagous: feeding on a single prey or forage species.

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Predicting Invasions of Nonindigenous Plants and Plant Pests Moran effect: a spatially correlated density independent perturbation, such as weather, which occurs across populations. multilocus genotype: a genotype that results in a trait or traits from the expression of genes at multiple locations within the genome of an organism. mutational variance: variance in the genetic make-up of a population due to mutations in individuals’ chromosomal DNA. naturalization: the establishment of a nonindigenous population in a new range; used mainly in connection with plants. net reproductive rate: average number of offspring an individual in a population will produce in his/her lifetime. nonindigenous: not native; refers to a species, population, organism that occurs at a locale that is not part of its native range. oligophagous: feeds on a few or several prey or forage species. oviposition: passage of the arthropod egg from the oviducts to outside the arthropod; egg-laying. pathotype: an infrasubspecific classification of a pathogen distinguished from others of the species by its pathogenicity on a specific host(s). parasitoids: insects that initially behave as a parasite but eventually act as a predator and devour their host. parthenogenetic: production of individuals from unfertilized eggs. perennials: organisms that may (and usually must) survive several years in order to reproduce. phenological synchrony: correspondence between traits in becoming active at the same season. phenotype: the observable characteristics of an organism. phenotypic plasticity: the phenomenon of organisms displaying a range of phenotypes from the same genotype. phytophagous: feeding on plants. phytosanitary: related to ensuring plant health. plasticity: the capacity of organisms with the same genotype to vary in developmental pattern, in phenotype, or in behavior according to varying environmental conditions. polyphagous: feeds on many prey or forage species. polyploidy: possessing more than two sets of genes and chromosomes. population: a group of genetically related members of the same species living within a prescribed space or range within a prescribed time frame. propagules: seeds, eggs, spores or other resting stages that are capable of being transported. physiognomic: literally the morphology of a plant community; refers to the number and characteristic shape of the layers of plants if the community were viewed in cross-section. predatory guild: a group of several types of predators that feed on a particular developmental stage of a pest.

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Predicting Invasions of Nonindigenous Plants and Plant Pests race: a genetically or geographically distinct subgroup of a species. ruderal: highly disturbed areas, such as rubbish heaps. selfer: an organism that does not require a sexual partner to contribute either egg or sperm; the organism contains both sexes. stochastic: random, involving chance or probability. sympatric: referring to speciation within the same geographical area. true annual population: a population that replicates one time per year. univoltine: one generation per year, used in connection with arthropods. voltinism: the frequency or number of annual broods.