How Many Queens, How Many Nests: Ant Social Structure and Why the Same Species Behaves Differently in a City

1. Introduction: the wrong classifier

Ant treatment is chosen by species. Identify the ant, look up the recommended approach, apply it.

The literature on ant social organisation suggests the species name is the wrong level of description for the decision, because the property that determines whether a strategy can succeed varies within a species as well as between species.

1.1 Why this matters commercially

A monogynous single-nest colony has one reproductive individual whose death ends the colony. A polygynous polydomous network has many, distributed across nests that have not been found. The first is a target; the second is a system, and treating the second as though it were the first produces the pattern every operator recognises, where the ants disappear and return.

2. The vocabulary

Four terms carry the argument and they are frequently conflated.

Polygyny is defined as at least two reproductively active queens present in a colony, and a polygynous colony may be monodomous or polydomous; if polydomous, the queens may or may not be dispersed between multiple nests.⁷

Polydomy is a single colony inhabiting multiple nests.⁶

Unicolonial populations form a network of interconnected nests among which workers move freely and lack aggression, despite having low genetic relatedness.⁶

2.1 Budding

Budding is colony multiplication by fragmentation of main nests,³ and is described as dependent colony foundation, in contrast with founding by a mated queen flying to a new site.⁶ Supercolonies expand through budding rather than winged dispersal.⁸

3. Why the terms are independent

The definitional point in §2 deserves emphasis because it is where practical confusion starts.

Queen number and nest number are separate axes. A colony can hold several queens in one nest, or a single queen across a network of nests, and the polydomy literature is explicit that a polygynous colony may be either monodomous or polydomous.⁷

3.1 Why an operator should care

Nest number determines whether finding and treating one nest can finish the job. Queen number determines whether killing the queen you found accomplishes anything.

Those are different failure modes with different remedies, and a report saying only that a colony is large distinguishes neither.

3.2 The combination that produces the problem

When combined with polydomy, polygyny may lead to unicoloniality.⁶ The two traits together, rather than either alone, produce the structure that resists conventional treatment.

4. The urban shift

The central empirical claim, and it concerns a species that is a significant structural pest.

The odorous house ant, Tapinoma sessile, is a widespread ant native to North America and a challenging urban pest, which serves as a useful system for studying social organisation because of its remarkable dichotomy in colony social and spatial structure between natural and urban environments.¹

4.1 The scale of the difference

Extension guidance describes urban odorous house ant colonies as having multiple queens, forming new colonies via budding, being non-hostile to members of related subcolonies, and potentially containing tens of thousands of workers.¹¹

Set against a natural colony of a small number of workers in one nest,¹ that is a difference of several orders of magnitude in the same species.

4.2 Why this is not a laboratory curiosity

Almost all pest ant biology that a technician encounters is urban biology. If urbanisation systematically shifts social structure, then the textbook description of a species derived from natural populations may not describe the population being treated.

5. How the urban traits cluster

The shift is not a single trait but a suite, and the review literature groups them.

Urban-associated traits are linked to reproduction and dispersal strategies such as polygyny, dependent colony foundation by budding, or parthenogenesis such as thelytoky. Others are behavioural shifts, including loss of aggression among non-nestmates, increased hostility towards other species, and changes in foraging activity. Further features involve shifts in habitat or food preferences, and many of these traits facilitate easy dispersal and high competitiveness.⁶

5.1 The coherence of the suite

Each element suits a fragmented, resource-rich, structurally complex environment. Multiple queens spread reproductive risk across nests that may be destroyed individually. Budding avoids the losses of a mating flight in a landscape where suitable sites are patchy but numerous. Tolerance of non-nestmates permits a network to expand without internal conflict.

A building, and a city block of buildings, is exactly that environment, which is the same argument the indoor thermal refugia article in this journal made about a different set of organisms.

6. What supercoloniality is

The term is used loosely and the definition matters for what follows.

A supercolony is characterised by absence of nest boundaries, allowing workers and queens to move freely between interconnected nests, resulting in vast populations with low genetic relatedness, typically featuring high polygyny, lack of intraspecific aggression, and dense networks of nests expanding through budding.⁸

The structure has evolved convergently in multiple lineages, including the Argentine ant, the tawny crazy ant and the odorous house ant, and similar unicolonial populations occur in some species of the termite genus Reticulitermes.⁸

6.1 The original hypothesis

It was initially hypothesised that unicoloniality is a characteristic of certain species in which all workers of that species are amicable, whatever their nest of origin, so that all members would accept each other irrespective of nest of origin and of the distance between nests.⁸

Section 7 examines what happened when that hypothesis was tested in the species most relevant to structural pest control.

7. The aggression evidence

The study examined the extent to which T. sessile colonies from different habitats and social structures exhibit aggression toward alien conspecifics, and additionally examined interactions between mutually aggressive colonies in fusion experiments.¹

The hypothesis under test was that urban colonies would show significantly lower aggression towards each other than natural colonies, since in many ant species polygyny is associated with reduced aggression.²

7.1 The result

Aggression assays demonstrated high levels of aggression in pairings involving workers from different urban colonies and workers from different natural colonies, but low aggression in pairings involving queens from different urban colonies.¹

A separate large-scale molecular, chemical and behavioural analysis demonstrated high aggression among nests across habitats, suggesting little correlation between aggression and geographic distance or genetic and chemical differentiation.²

8. What that result overturns

The popular picture of a city-wide supercolony of mutually friendly ants does not survive this.

8.1 The distinction that survives

Workers within one supercolony network tolerate each other. Workers from different supercolonies do not. The extension description is precise on this point in saying odorous house ants are non-hostile to members of related subcolonies.¹¹

So a city contains many supercolonies rather than one, each internally unified and externally hostile.

8.2 The queen result

That low aggression appeared specifically in pairings involving queens from different urban colonies¹ is the more interesting half, and we would not attempt to explain it. The authors present it as a finding about the mechanism of supercolony formation rather than as an established explanation.

8.3 The operational consequence

If neighbouring networks are mutually hostile, then a treated property can be recolonised from an adjacent one by a genuinely separate colony, and the boundary between them is invisible.

This is our reading rather than a sourced recommendation, and it suggests that the unit of treatment is the network, which will rarely correspond to the property line the invoice covers.

9. Growth or fusion

How a large polydomous network comes to exist has a direct bearing on whether it can be broken up.

Urban colonies have been shown to have high levels of relatedness among workers, suggesting it is highly unlikely that they could be the product of merging among different and presumably genetically distinct colonies.¹

Current results and previous work on the origin of unicolonial ants support the hypothesis that large polydomous and polygynous colonies arise through the growth of a single colony.¹

9.1 What that implies

A supercolony is one colony that grew, not an alliance that formed. That is consistent with the aggression data in §7, since an entity grown from a single origin would retain internal tolerance while remaining hostile to outsiders.

It also means the network has a history and a point of origin on the site, which supports thorough inspection over the assumption that the ants simply arrived from everywhere.

10. The cost of fusion

The fusion pathway was examined and the reported outcome is worth recording.

Where colonies were observed to merge, they permanently merged after initial fighting and typically only one queen survived after fusion, and it remains unclear whether a similar process occurs in T. sessile or whether colonies in natural populations merge, given that approximately 60 per cent of the workers forced to compete died.¹

10.1 Reading the mortality figure

A fusion event that kills three fifths of the workers involved is not a cheap route to a large colony, which is part of why growth from a single origin is the better-supported explanation.¹

10.2 A caution on this figure

The 60 per cent figure and the single-queen outcome are reported in the discussion of fusion experiments, and the authors are explicit that the transferability to T. sessile is uncertain.¹ We include it as context for the growth-against-fusion question rather than as a property of the pest species.

11. Budding as a founding strategy

The mechanism by which these networks extend, and the one with the clearest control implications.

Budding is colony multiplication by fragmentation of main nests.³ Supercolonies expand through budding rather than winged dispersal,⁸ and in supercolonies budding facilitates local expansion.⁸

11.1 Why this defeats perimeter thinking

A species that founds colonies by mating flight arrives from outside and can be intercepted at the envelope. A species that founds colonies by fragmentation multiplies from wherever it already is.

Exclusion and perimeter treatment address the first mechanism. Against the second they address only recruitment from outside while the interior population continues to divide.

11.2 The two scales of spread

Budding and jump dispersal play different roles. In supercolonies budding facilitates local expansion, allowing occupation of more resources and habitats without significant conflict, while jump dispersal is what enables rapid colonisation of new areas.⁸

The phrase worth noting is the absence of conflict. A species founding colonies by mating flight places daughter colonies into a landscape where they must compete, including with their own species. A budding species extends a network whose parts do not fight each other, which is why the expansion is continuous rather than contested.

11.3 Where a building sits in that

A single structure is a local-expansion problem, and local expansion is the budding mechanism. The arrival of the species in the neighbourhood was probably a jump dispersal event, frequently human assisted, but by the time a technician is called the relevant process is fragmentation on site.⁸

12. The pharaoh ant experiments

The most useful experimental work on budding was done on the species this journal has already examined in a healthcare context.

Demographic data revealed that pharaoh ants are highly polygynous and have a relatively low worker to queen ratio of 12.86.³

12.1 Why that ends the search for the queen

Locating and destroying the queen is a coherent objective in a monogynous species. At thirteen workers per queen it is not an objective at all, which is the structural reason bait carrying a delayed-acting active is the approach that works on this species.

That argument connects directly to the horizontal transfer article in this journal, where delayed action was shown to be the property that lets a toxicant reach individuals the applicator never contacts.

13. The nest site finding

The single most actionable result located for this paper.

Budding experiments demonstrated that the number of available bud nests has a significant effect on colony fragmentation, and increasing the number of bud nests resulted in smaller colony fragments.³

13.1 The reciprocal reading

Available nest sites drive fragmentation. A structure offering many suitable voids is a structure that promotes splitting into many small fragments; a structure offering few produces fewer, larger ones.

We would draw the practical conclusion, flagged as our inference, that void reduction is an anti-budding measure and not merely an exclusion measure. Sealing voids in a pharaoh ant building limits the number of fragments the colony can produce, which is a different rationale from keeping ants out.

13.2 The social control result

The distribution among bud nests was uneven overall, though there was no evidence that different life stages and castes partitioned unevenly among bud nests. This demonstrates that pharaoh ants have the ability to exert social control over colony size and caste proportions during budding, which may contribute to their success.³

Each fragment is therefore a viable unit rather than an incomplete piece, which is why fragmentation produces infestations rather than casualties.

13.3 How a network feeds itself

The organisation of foraging in a polydomous network has been studied directly. Work on the odorous house ant using a protein marker examined dispersed central-place foraging in this species, and a separate field study examined the organisation of foraging within a supercolony.⁴⁵

Related work examined the influence of forager number and colony size on food distribution in the same species.⁴

13.4 Why that framing matters for bait

Dispersed central-place foraging describes a system with many centres rather than one. Food collected at any point can in principle move through the network, which is the property bait depends on, and it is a property of the structure rather than of the product.

We would state the corollary plainly as our own reading: bait works against these species because their social organisation distributes it, so the same bait against a territorial species with distinct foraging areas is doing a different and more local job.

14. Seasonal restructuring

Structure varies within a year as well as between habitats.

Depending on season, the number of nests in a T. sessile colony may alternately fuse into one or a few in winter and grow from spring, to reach maximum nest density in summer, with early-season population growth exponential, and colonies moving on a regular basis.⁸

The research literature on this species includes work specifically on seasonal polydomy and unicoloniality in a polygynous population.⁵

14.1 Seasonal overabundance of nests

Seasonal overabundance of empty nests has been reported to facilitate fragmentation of larger colonies into smaller buds, while a shortage of nests led to fusion of established, unrelated colonies.¹

That is the §13 finding appearing again at landscape scale, with nest availability governing whether a population splits or consolidates.

14.2 The timing implication

A colony consolidated into one or a few nests in winter is a more concentrated target than the same colony at maximum nest density in summer. Whether this is exploitable in a heated building in this climate is a question we cannot answer from the sources.

15. The territorial counterexample

Not every urban pest ant follows the supercolonial pattern, and the most common one here does not.

Pavement ants are found in large numbers on sidewalks during spring and summer engaged in their infamous territorial battles, and this incessant fighting between different colonies is thought to play a role in hindering its spread throughout the continent.¹²

Mapping of pavement ant territories has revealed that many colonies can exist in a small area, and that colony foraging territories are distinct.¹²

15.1 The taxonomy note

The pavement ant in North America was until recently known as Tetramorium caespitum and now has the name Tetramorium immigrans.¹⁰¹² Genetic variation among United States populations is low, and it is believed current populations derived from one or a few closely related colonies introduced from Europe into the northeastern United States about 200 years ago.¹⁰

16. Why pavement ants are different

Distinct, mutually hostile territories change the arithmetic of a treatment.

Because foraging territories are distinct, bait treatment has to reach each colony separately.¹²

16.1 The practical contrast

Against a supercolonial species, bait placed anywhere in the network can in principle travel anywhere in it. Against a territorial species, bait placed in one territory reaches one colony, and a property holding many colonies in a small area requires many placements.

Those are opposite placement strategies derived from the same product, and the species identification is what tells an operator which applies.

16.2 The nesting complication

Pavement ant nests can be located deep inside the soil, making insecticide drenches less effective.⁹

16.3 Where they actually are

The species takes its name from the habit of nesting in soil along edges or in cracks around pavement, patios, driveways, sidewalks and foundations, but they can be found nesting almost anywhere soil is available.¹⁰

That combination is awkward. The nests are outdoors and in soil, frequently under hard surfaces that cannot be lifted, and deep enough that drenching underperforms. The accessible part of the colony is the foraging trail, which is the argument for treating the trail rather than hunting the nest.

16.4 The management framing

The recommended approach outdoors combines habitat modification, exclusion, bait, and residual or non-residual insecticides,¹⁰ and odorous house ants are likewise described as manageable by eliminating habitat and contributing conditions together with multiple insecticide formulations including baits.¹¹

Both formulations put habitat first and chemistry last, which is the same ordering the void reduction argument in §13.1 arrives at from the budding evidence.

17. Repellent and non-repellent

The product property that interacts with social structure.

Non-repellent products act more slowly and are compatible with baiting programmes. They do not scatter ants or break foraging trails, and since ants do not detect them they continue to travel over them and drag the chemical back to the nest where it is mechanically transferred around the colony.¹⁰

Repellent insecticides are described as best used for direct nest drenches and chemical deterrence from gaining entry.¹⁰

17.1 The interference warning

Extension guidance states that while repellent insecticides are good for direct nest drenches or quickly stopping ants entering a structure, they will isolate the colony and the bait stations will become less effective.⁹

That is a specific, mechanistic objection: a repellent barrier prevents the foraging traffic that bait depends on, so combining the two defeats the second.

17.2 The named non-repellents

Most non-repellent insecticides can be used for pavement ants only as a perimeter application to the foundation and immediately surrounding ground, though a few, named as products containing thiamethoxam and indoxacarb, are non-repellents usable as perimeter application or nest drench and in places where ants trail.¹⁰

17.3 The combination that is recommended

Where a property has ants both indoors and out, extension guidance suggests bait stations as a control option indoors and non-repellent insecticides outdoors, with the observation that combining several methods is the most effective approach.⁹¹¹

Manufacturer material proposes the converse pairing in a single location, recommending baiting within an area treated with a non-repellent liquid on the grounds that this increases the number of ants that contact the treated surface, so that bait and non-repellent together reach deep into the colony.¹⁴

17.4 Why these pairings are consistent

Both rest on the same property. A non-repellent does not interrupt traffic, so it can coexist with anything that depends on traffic. A repellent interrupts traffic, so it cannot.

The rule that emerges is not that repellents are bad but that repellency and recruitment-dependent methods are incompatible in the same space, and that the decision is about which of the two is doing the work there.

17.5 Verification

The same guidance suggests that treating a colony and then observing the active workers gives an indication of the effectiveness of the treatment, and that perimeter barrier applications are often worthwhile but need to be used judiciously.⁹

18. The budding claim examined

A claim repeated constantly in this trade deserves scrutiny, particularly because we believe it.

The assertion is that repellent sprays cause colonies to split. A commercial pest control source states that for odorous house ants, repellent sprays can stress colonies, causing them to split into subcolonies, which exacerbates the infestation, and that non-repellent products mitigate this risk.¹³

18.1 What we could and could not find

We located this claim in commercial and trade material.¹³ We did not locate an experimental study demonstrating that repellent insecticide application causes measurable colony fragmentation in a pest ant species.

That is not evidence the claim is false. It is a statement that we could not source it to a controlled result, and readers should weigh it accordingly.

18.2 Why it is nonetheless plausible

Two sourced findings make the mechanism credible. Nest availability significantly affects fragmentation,³ and colonies move on a regular basis.⁸ A disturbance that prompts relocation into a building offering abundant voids combines both conditions.

We would rather present it as a well-motivated hypothesis than as an established fact, and note that the sourced objection to repellents in §17.1, that they isolate the colony from bait, is sufficient on its own to justify the same practical recommendation.

19. When bait is refused

A practical observation from trade material that follows from social structure.

On bait being ignored by trailing ants, one suggested reason is that the colony fragment is not looking for food but is moving between nesting sites, with the recommendation to try several baits to determine which is most effective.¹⁴

19.1 Why this is worth recording

Bait refusal is normally attributed to the wrong formulation, competing food, or the aversion phenomena examined in the glucose aversion article in this journal.

The proposal here is different: that the ants observed are engaged in relocation rather than foraging, which is behaviour specific to a polydomous species that moves regularly. We note this is a manufacturer source with a commercial interest in product selection.¹⁴

20. What follows for practice

Identify the structure, not only the species. Queen number and nest number are separate axes and determine different failure modes.⁷

Expect the urban form. Urban odorous house ant colonies show extreme polygyny and polydomy where natural ones are monogyne and single-nested.¹

Stop looking for the queen in polygynous species. A worker to queen ratio of 12.86 makes queen removal meaningless as an objective.³

Treat void reduction as an anti-budding measure. Available nest number significantly affects fragmentation.³

Do not combine repellents with bait. Repellents isolate the colony and reduce bait station effectiveness.⁹

Place bait per territory for territorial species. Pavement ant foraging territories are distinct and many colonies may occupy a small area.¹²

Expect neighbouring networks to be hostile, not merged. Workers from different urban colonies showed high aggression.¹

Put habitat before chemistry. Both the pavement ant and odorous house ant management descriptions lead with habitat modification and elimination of contributing conditions, with insecticide formulations listed afterwards.¹⁰¹¹

Read refusal as information. Ants ignoring bait may be relocating rather than foraging, which is a statement about what the colony is currently doing rather than about the bait.¹⁴

21. The Manitoba position

What transfers to this province and what does not.

Pavement ants are among the most abundant ants on the continent¹² and are a routine service item here, which means the territorial model rather than the supercolonial one applies to much of the local caseload.

21.1 The species we cannot speak to

The Argentine ant and tawny crazy ant, which supply much of the supercolony literature,⁸ are not species we encounter in this climate. Pharaoh ants are, in heated institutional buildings, and the budding evidence applies there directly.³

21.2 The boreal note

Polydomous supercolonies occur in the Formica rufa group in boreal and temperate forests.⁸ Whether local Formica populations present as structural pests with that organisation is not something we have found data on, and we would treat it as an open local question rather than assume either way.

22. Limitations and open questions

The budding-from-repellents claim is unsourced to experiment. Set out in §18. We believe it and could not demonstrate it, and we have separated our belief from the evidence rather than presenting the two together.¹³

One source is an encyclopedia entry. The supercolony definition, the convergent evolution examples, the seasonal nest fusion pattern and the Formica material are cited from a general reference work rather than primary literature.⁸

Three sources are trade or manufacturer material. The budding claim, the bait refusal explanation and parts of the product guidance come from commercial sources.¹³¹⁴ The manufacturer source has a direct interest in product selection.

The 60 per cent fusion mortality is of uncertain transferability. Stated in §10.2; the authors themselves flag the uncertainty.¹

The pharaoh ant ratio is from one demographic dataset. A worker to queen ratio of 12.86 is a single reported figure,³ and we have not established how it varies across colonies or conditions.

Sections 8.3, 13.1 and 18.2 are our reasoning. The network-as-treatment-unit argument, the void reduction rationale and the plausibility case for the budding claim are ours rather than sourced findings.

No Manitoba survey. We have no local data on ant social structure, no local species inventory we can cite, and §21.2 is left open rather than answered.

Our commercial position. This company sells ant treatments. The argument here implies that a substantial part of the value lies in inspection and in void reduction, which are labour rather than product, and that some common treatment combinations work against each other.

23. Conclusion

Natural colonies of the odorous house ant are small, single-nested and monogyne; urban colonies of the same species show extreme polygyny and polydomy and form supercolonies.¹ The trait suite that accompanies urbanisation includes polygyny, budding, loss of aggression among non-nestmates and shifts in foraging, and polygyny combined with polydomy may produce unicoloniality.⁶

That structure is not species-wide amicability. Aggression assays found high aggression between workers of different urban colonies and between workers of different natural colonies, with low aggression only in pairings involving queens, and high aggression among nests across habitats uncorrelated with distance.¹² A city holds many hostile networks rather than one friendly one.

Budding is where the practical leverage sits. Pharaoh ants carry roughly one queen per thirteen workers, which ends queen removal as an objective, and the number of available bud nests significantly affects fragmentation, with more nests producing smaller fragments.³ That makes the voids in a building a determinant of how badly an infestation splits, which is a finding about carpentry rather than chemistry.

The conclusion is that the first question on an ant job is not which species but how it is organised: how many queens, how many nests, and whether the ants in front of you are foraging or moving house. The product decisions follow from the answer, and at least one common combination, repellent barrier plus bait station, is self-defeating whichever species is involved.

References

1. Behavioral assays reveal mechanisms of supercolony formation in odorous house ants. Scientific Reports. doi:10.1038/s41598-023-35654-y. Principal source. Used for the statement that the odorous house ant, Tapinoma sessile, is a widespread North American ant and challenging urban pest showing a remarkable dichotomy in colony social and spatial structure between natural and urban environments, with natural colonies typically consisting of a small number of workers inhabiting a single nest and monogyne, whereas urban colonies show extreme polygyny and polydomy and form large supercolonies; for the study design examining aggression toward alien conspecifics across habitats and social structures and interactions between mutually aggressive colonies in fusion experiments; for the result that aggression assays demonstrated high levels of aggression in pairings involving workers from different urban colonies and workers from different natural colonies but low aggression in pairings involving queens from different urban colonies; for the report that seasonal overabundance of empty nests facilitated fragmentation of larger colonies into smaller buds while a shortage of nests led to fusion of established unrelated colonies, with colonies permanently merging after initial fighting and typically only one queen surviving, and that it is unclear whether a similar process occurs in T. sessile given that approximately 60 per cent of workers forced to compete died; and for the finding that urban colonies have high levels of relatedness among workers making it highly unlikely they are the product of merging among genetically distinct colonies, with current and previous work supporting the hypothesis that large polydomous and polygynous colonies arise through the growth of a single colony. https://www.nature.com/articles/s41598-023-35654-y
2. Behavioral assays reveal mechanisms of supercolony formation in odorous house ants. PubMed Central PMC10238414. Mirror record for the same study. Used for the statement of the study hypothesis that urban colonies would show significantly lower aggression towards each other than natural colonies, since in many ant species polygyny is associated with reduced aggression with unicolonial populations the most extreme example; and for the account of a large-scale molecular, chemical and behavioural analysis demonstrating high aggression among nests across habitats, suggesting little correlation between aggression and geographic distance or genetic and chemical differentiation. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10238414/
3. Buczkowski, G. (2009). Colony Budding and its Effects on Food Allocation in the Highly Polygynous Ant, Monomorium pharaonis. Ethology, 115, 1091 to 1099. doi:10.1111/j.1439-0310.2009.01698.x. Source for the definition of budding as colony multiplication by fragmentation of main nests; for the demographic finding that pharaoh ants are highly polygynous with a relatively low worker to queen ratio of 12.86; for the budding experiment result that the number of available bud nests has a significant effect on colony fragmentation and that increasing the number of bud nests resulted in smaller colony fragments; and for the finding that the overall distribution among bud nests was uneven although there was no evidence that different life stages and castes partitioned unevenly, demonstrating that pharaoh ants can exert social control over colony size and caste proportions during budding. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1439-0310.2009.01698.x
4. Publications list, Center for Urban and Industrial Pest Management, Purdue University Department of Entomology. Consulted to confirm the bibliographic details of the budding and polydomy work cited here, including Buczkowski and Bennett (2008) on seasonal polydomy and unicoloniality in a polygynous population of Tapinoma sessile, Ecological Entomology 33, 780 to 788, and Buczkowski and Bennett (2006) on dispersed central-place foraging in the polydomous odorous house ant, Insectes Sociaux 53, 282 to 290. https://www.entm.purdue.edu/ants/publications.php
5. Urban Antomology: A Research Update. Pest Control Technology. Trade publication written by the researcher responsible for much of the underlying work. Used for the existence of field study work on the organisation of foraging in an odorous house ant supercolony and on seasonal polydomy and unicoloniality in a polygynous population. https://www.pctonline.com/article/urban-antomology---a-research-update/
6. Becoming urban: How city life shapes the social structure and genetics of ants. Molecular Ecology. doi:10.1111/mec.16657. Source for the account of urban-associated traits linked to reproduction and dispersal strategies such as polygyny, dependent colony foundation by budding, and parthenogenesis such as thelytoky; behavioural shifts including loss of aggression among non-nestmates, increased hostility towards other species and changes in foraging activity; and ecology-related features involving shifts in habitat or food preferences, with many of these traits facilitating easy dispersal and high competitiveness. Also used for the statements that polydomy is a single colony inhabiting multiple nests, that polygyny combined with polydomy may lead to unicoloniality, and that unicolonial populations form a network of interconnected nests among which workers move freely and lack aggression despite low genetic relatedness. https://onlinelibrary.wiley.com/doi/10.1111/mec.16657
7. Polydomy: the organisation and adaptive function of complex nest systems in ants. Current Opinion in Insect Science. doi:10.1016/j.cois.2014.05.002. Used for the formal definition that polygyny means at least two reproductively active queens are present in a colony, that such a colony may be monodomous or polydomous, and that if polydomous the queens may or may not be dispersed between multiple nests. https://www.sciencedirect.com/science/article/pii/S221457451400073X
8. Supercolony. Encyclopedia entry. Cited as a general reference rather than primary literature. Used for the characterisation of a supercolony as featuring absence of nest boundaries allowing workers and queens to move freely between interconnected nests, vast populations with low genetic relatedness, high polygyny, lack of intraspecific aggression and dense nest networks expanding through budding rather than winged dispersal; for the convergent evolution of the structure in the Argentine ant, tawny crazy ant and odorous house ant and the occurrence of similar unicolonial populations in some species of the termite genus Reticulitermes; for the original hypothesis that unicoloniality is a characteristic of certain species in which all workers are amicable whatever their nest of origin; for the seasonal pattern in which T. sessile nests may fuse into one or a few in winter and grow from spring to maximum nest density in summer with exponential early-season growth and colonies moving on a regular basis; and for polydomous supercolonies in the Formica rufa group in boreal and temperate forests. https://en.wikipedia.org/wiki/Supercolony
9. Immigrant Pavement Ant, Tetramorium immigrans Santschi, 1927. Ohio State University Buckeye Yard and Garden Line. Extension source. Used for the statements that pavement ant nests can be located deep inside the soil making insecticide drenches less effective; that while repellent insecticides are good for direct nest drenches or quickly stopping ants entering a structure they will isolate the colony and the bait stations will become less effective; and that non-repellent, non-residual insecticides act slowly, do not interrupt foraging behaviours and pheromone trails, and are carried back to the colony and shared with nestmates. https://bygl.osu.edu/node/2389
10. Pavement Ants. Utah State University Extension. Extension source. Used for the statements that non-repellent products act more slowly and are compatible with baiting programmes, do not scatter ants or break foraging trails, and are carried back to the nest and mechanically transferred around the colony because ants do not detect them; that repellent insecticides are best used for direct nest drenches and chemical deterrence from gaining entry; that most non-repellents can be used for pavement ants only as a perimeter application to the foundation and immediately surrounding ground while a few products containing thiamethoxam and indoxacarb can also be used as nest drenches and where ants trail; and for the taxonomic revision from Tetramorium caespitum to Tetramorium immigrans with low genetic variation among United States populations believed to derive from one or a few closely related colonies introduced from Europe into the northeastern United States about 200 years ago. https://extension.usu.edu/pests/research/pavement-ants
11. Odorous House Ants. Utah State University Extension. Extension source. Used for the description of odorous house ants as having multiple queens, forming new colonies via budding, being non-hostile to members of related subcolonies, and having colonies that may contain tens of thousands of workers, together with the statement that they are persistent and may continue to be a nuisance without proper follow-up. https://extension.usu.edu/planthealth/research/odorous-house-ant
12. Pound the Pavement. Pest Control Technology, reporting Purdue University research. Trade publication. Used for the statements that pavement ants engage in territorial battles and that this incessant fighting between different colonies is thought to play a role in hindering the species' spread across the continent; that territory mapping revealed many colonies can exist in a small area with distinct colony foraging territories bearing on bait treatment; that the species is now one of the most abundant on the continent; and for the taxonomic renaming from Tetramorium caespitum to Tetramorium immigrans. https://www.pctonline.com/news/pavement-ant-tips-purdue/
13. Ants, Moisture, and Pest Control. Commercial pest control company article. Trade source with a direct commercial interest, cited as the statement of a widely repeated trade claim rather than as evidence. Used for the assertion that for odorous house ants repellent sprays can stress colonies causing them to split into subcolonies and exacerbate the infestation, and that non-repellent products mitigate this risk. https://www.colonialpest.com/insight/ants-moisture-and-pest-control/
14. Ant Control Chemicals and Insecticide Products. Manufacturer technical material. Commercial source with a direct interest in product selection. Used for the observation that one reason a bait may be ignored by trailing ants is that the colony fragment is not looking for food but is moving between nesting sites, with the recommendation to try several baits; and for the statement that with highly polygyne species there can be hundreds of queens across multiple nests. https://www.mgk.com/pest/ants/