This glossary defines the technical terms used on the site that new users might not be familiar with. As well as a definition, we provide an indication of where on the site the term is used (i.e. Relates to).

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Abdomen: the end part of an ant, after the head and thorax

Active surveillance: a planned process targeted to find and identify a particular new pest. Relates to Prevention.

Antenna club: enlarged segments that form a club-like structure at the end of the antenna. They can be composed of two, three or four segments. Relates to Identification.

Antenna scrobe: an impression following some length of the head used to hold part or the entire antenna.

Axil: the upper angle between a leaf stalk or branch and the stem or trunk from which it is growing.


Biological control: a means of controlling pests using other living organisms that relies on predation, herbivory or parasitism. There are currently no effective biological controls for invasive ants.

Biosecurity: the protection of a country’s economy, environment and peoples’ health from biological threats such as pests and diseases.

Budding: mode of colony reproduction where new queens do not participate in mating flights, but instead walk away from the nest they were born in with a small group of workers and establish new colonies nearby.

Buffer zone: An area surrounding or adjacent to an area officially delimited for phytosanitary purposes in order to minimize the probability of spread of the target pest into or out of delimited area, and subject to phytosanitary or other control measures, if appropriate.


Clonal reproduction: A form of asexual reproduction in which eggs are not fertilised by males. 

Community: A group of native plants, animals and other organisms that interact with each other in a specific geographical area. 

Containment: keeping an invasive species within a defined area.

Control: reducing the population of an invasive species.

Cost-benefit analysis: a means of assessing the costs (financial social and environmental) of a number of different management options and weighing them against the benefits gained by undertaking these actions.

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Delimiting: determine the boundary of something. With respect to an ant invasion, delimiting the invasion means finding out how far the ants have spread.

Destruction: a control method that neutralises a potential threat  such as heat treatment, fumigation or cold treatment.  This action may result in the destruction of the carrier item: e.g. if a potted plant that is found to have ants nesting among its roots and is heat treated the plant may also be killed.

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EC50: median effective concentration. This may be reported for sub-lethal or ambiguously lethal effects and is used in tests involving species such as aquatic invertebrates where death may be difficult to determine.

Effective management: achieving operational success (e.g. reducing the pest to defined levels) and desired outcomes (reduced impact and recovery of impacted values) of invasive species management.

Environmental Impact Assessment (EIA): an analysis of the potential non-target effects of a management plan or activity  on the environment (including social and economic impacts) . The analysis also  includes suggestions how these potential non target effects can be mitigated.

Environmental threat: invasive ants pose an environmental threat when they are present in sufficient numbers to have measureable and quantifiable ecological effects.

Eradication: the removal of every individual of a species from the infested country, such that the only way the species could re-establish is to re-enter the country from another country. Eradication should be demonstrated by surveillance.

Extra-floral nectary: these are sources of nectar outside the flowers of plants. 

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Formicidae: the family to which all ants belong.

Freedom: the provable absence of a pest organism from a country or region such that the only way the pest could establish is if it were introduced from an external country or region.

Fynbos: Native shrub land in South Africa.

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Gaster: the end section of the ant connected to the mesosoma by the waist.

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Half-life: the half-life is the time required for half of the compound to break down in the environment. Thus, 1 half-life = 50% remaining, 2 half-lives = 25% remaining, 3 half-lives = 12% remaining, 4 half-lives = 6% remaining, 5 half-lives = 3% remaining. Some chemicals metabolise or degrade into other chemicals of toxicological significance, and half-lives can vary widely depending on environmental factors.

Honeydew: Is a sugar rich substance excreted by sap-sucking insects and often deposited on leaves and stems. Some ants 'farm' insects that produce honeydew. 

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Impact(s): A routinely used term in invasion ecology and management that refers to the negative effects of an invasive species on resident native organisms (biodiversity), agriculture, economy, health or lifestyle.

Incursion: A single arrival event of an invasive species in a new environment. Typically an incursion is identified at the time of arrival (or first detection), and an incursion response plan developed. The arrival of an organism within a country after it has crossed the border.

Incursion response plan: Effectively an emergency response plan to deal with a newly detected incursion of an invasive species. Incursion response plans include a number of steps including: 1) initial detection and response; 2) delimiting survey and; 3) draft management plan, including a surveillance plan, a plan for treatment and eradication (if possible), a communications strategy, specifications for movement controls, monitoring progress, a budget, and an organisational plan.

Infestation: a single discrete area where the invasive species is localised. An incursion consists of one or more infestations.

Introduced species: plants, animals and other organisms taken beyond their natural range by people, deliberately or unintentionally.

Invaded area: a location in which an invasive species is present. As opposed to an uninvaded area, where an invasive species is not present. 

Invasive ants / invasive ant species: an exotic or non-native ant species that becomes destructive to the environment or human interests in one or more ecological or environmental contexts. Not all invasive ants have major negative effects, and for many species the effects are density-dependent (i.e. effects only occur or are perceived by humans as negative when a threshold of abundance is reached). These are outbreaking species. Threat ant species are those invasive ant species known to have significant impacts in multiple ecological or environmental contexts and / or are prone to outbreaks. Emerging threat ant species are those that have recently been identified as having, or having potential to result in significant impacts. In the context of this Activity, this also refers to exotic or non-native ant species that may be considered a threat for the first time, for which there are no existing processes for biosecurity or management.

Invasive species: introduced species that become destructive to the environment or human interests.

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LC50: lethal concentration in a single exposure that causes death in 50% of animals tested.

LD50: lethal dose in a single exposure that causes death in 50% of animals tested.

LOEL: lowest observed effect level. Relating to a pesticide, the lowest level at which effects are observed.

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Management: reducing or eliminating the impacts of established invasive species, by eradication, containment, exclusion, or population reduction by physical, chemical or biological control. Note that although the title of the SPC and SPREP Guidelines for Invasive Species Management in the Pacific refers to management, in this latter context biosecurity is included as part of management.

Median tooth: tooth in the middle of the apical margin of the clypeus, usually with another tooth on either side.

Monitoring: programmes to detect change, e.g. in the distribution of invasive species, the success of management projects etc.

Monogyne: a monogyne ant colony only has one queen. A polygyne colony has multiple queens. The Red Imported Fire Ant has colonies with both monogyne and polygyne forms. 

Monomorphic: A monomorphic ant species is one in which all workers are of the same size. This in contrast to polymorphic ant species. 

Movement Contol: preventing an invasive ant from spreading by Controlled Area Notices and Restricted Place Notices and their conditions. Also includes the processing of movement permits, management of perimeter controls, hygiene barriers and signage, and the provision of conveyance decontamination sites.

Mutualism: a relationship between two organisms that both benefit from.

Myrmicinae: one of the ant (Formicidae) subfamilies.

Myrmicines : ants belonging to the subfamily Myrmicinae.

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NOEL: no observed effect level. Relating to a pesticide, the level below which no effects are observed. RfD: Reference Dose, or in this case, the estimated amount of fipronil ingested per day, for the rest of their life without any appreciable risk of adverse health effects.

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Passive surveillance:  the detection of exotic species through haphazard, unplanned and unsolicited observations by the general public, farmers, orchardists, gardeners, veterinarians, plant pathologists and others.

Pathway: a unique means by which a living organism may enter a country.

Pest: a prion, virus, microbe, fungus, plant or animal capable of causing adverse effects to a country’s natural and introduced biodiversity.

Petiole: waist segment connecting the mesosoma to the postpetiole (Myrmicinae) or the gaster (Forminicane and Dolichoderinae).

Pitfall trap: traps placed into the ground to sample animal populations.

pH: a measure of how acidic or alkaline a solution is.

Polygyne: A polygyne ant colony has multiple queens. A monogyne ant colony has one queen. The Red Imported Fire Ant has colonies with both monogyne and polygyne forms.

Polymorphic: workers occurring in different sizes. In Pheidole, there is a distinct large worker caste (referred to as majors or soldiers) and a distinct minor worker caste (referred to as minors). In Solenopsis invicta, S. geminata and Monomorium destructor the castes are less distinct, with wide range of sizes from very small to very large.

Polymorphism: See polymorphic.

Postpetiole: waist segment connecting the petiole to the gaster (Myrmicinae).

Propodeal spines: spines that originate on the propodeum.

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Quarantine: Legal restrictions imposed on an area, animal, place, vehicle or other item that limit movement for a prescribed period.


Raised ridge surrounding antenna: a diagnostic structure of Tetramorium that circles the antenna insertions with an elevated ridge.

Risk: the chance of something happening that will have an impact upon objectives. It is measured in terms of likelihood and consequences.

Risk organism: an organism that could pose a threat to values we wish to protect.

Risk pathway: the way in which a risk organism can be transported into the country.

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Scape: antenna segment number one. Single antenna segment between funiculus and head. In ants it is very long, giving the antenna an "elbow-like" appearance.

Sexual Reproduction: a form of reproduction in which males and females mate to produce offspring. As opposed to asexual reproductive where offspring arise from a single individual. 

Stakeholder: an individual or organization that may be affected by the impacts of a risk organism or control measures taken against it.

Surveillance: A systematic programme of inspection and examination to determine the presence of a risk organism.

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Thorax: the part of an ant between the head and the abdomen. The 'middle' of an ant. 

Transect: a fixed path along which one counts and records occurrences of the species of interest.

Treatment: application of pesticide or other means of control at a single point in time.

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 Tree crotches: an area on a tree where a trunk, or large branches, split into two forming a 'Y' shape. 


Understory: The shrubs and plants growing underneath the main canopy in a forest. 

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Vector: A vector is the object that moves an invasive species from one place to another. This may be a vehicle (car, truck, or boat); a commodity (bananas, taro, breadfruit); or other method of movement. 


Waist segments:  The segment (petiole) or segments (petiole and postpetiole) occurring between the mesosoma and gaster.

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A number of these definitions were sourced or adapted from the PIAkey, the SPREP/SPC Guidelines, the book Managing Biosecurity across borders, an MPI publication, which features an extensive biosecurity glossary geared more toward animal diseases.

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