Spatial Model of Territorial Competition and Population Dynamics in the Fire Ant Solenopsis invicta (Hymenoptera: Formicidae)

Korzukhin, M. D.; Porter, Sanford D.

doi:10.1093/ee/23.4.912

Cited by 12 publications

(10 citation statements)

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“…Mean habitat occupancy over the whole range varied from 75.3% (±2.57) in populations that produced only claustral queens to 84.5% (±2.68) in those that invested half their effort in parasitic queens. These values correspond well with rough field estimates of fire ant territory coverage of available habitat (>90%, Korzukhin and Porter 1994).…”

Section: Population Effectssupporting

confidence: 82%

“…Our populations displayed near total occupancy of available habitat (Korzukhin and Porter 1994), closely packed irregularly shaped territories (Adams 1998), size distributions consisting of many small colonies and a few large ones (Tschinkel 2013), and population densities similar to those in the field (323 ±119 colonies/ha simulated versus 300 ±240 in the field, Porter et al 1991). We note, on the other hand, that in our simulated populations, the observed frequency of parasitic founding and the optimal reproductive investment in interior colonies (>40% of colonies headed by parasites, 40-50% investment in parasitic queens) more accurately describe the native S. geminata (35% of colonies, 33% investment in parasites, McInnes and Tschinkel 1995) than S. invicta (3.5% of colonies, <10% investment in parasites, DeHeer and Tschinkel 1998).…”

Section: Discussionmentioning

confidence: 79%

“…First, parasitic queens should increase the average colony size in a landscape. Second, parasitic queens should increase occupancy of the habitat by fire ant colonies (Korzukhin and Porter 1994). Third, in expanding ranges, investment in parasitic queens should slow range expansion by diverting investment from claustral queens that colonize vacant sites.…”

Section: Introductionmentioning

confidence: 99%

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Range expansion drives the evolution of alternate reproductive strategies in invasive fire ants

Helms¹,

Bridge²

2017

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Many species are expanding their ranges in response to climate changes or species introductions. Expansion-related selection likely drives the evolution of dispersal and reproductive traits, especially in invasive species introduced into novel habitats. We used an agent-based model to investigate these relationships in the red imported fire ant, Solenopsis invicta, by tracking simulated populations over 25 years. Most colonies of this invasive species produce two types of queens practicing alternate reproductive strategies. Claustral queens found new colonies in vacant habitats, while parasitic queens take over existing colonies whose queens have died. We investigated how relative investment in the two queen types affects population demography, habitat occupancy, and range expansion. We found that parasitic queens extend the ecological lifespan of colonies, thereby increasing a population's overall habitat occupancy as well as average colony size (number of workers) and territory size. At the same time, investment in parasitic queens slowed the rate of range expansion by diverting investment from claustral queens. Divergent selection regimes caused edge and interior populations to evolve different levels of reproductive investment, such that interior populations invested heavily in parasitic queens whereas those at the edge invested almost entirely in claustral queens. Our results highlight factors shaping ant life histories, including the evolution of social parasitism, and have implications for the response of species to range shifts.

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Section: Population Effectssupporting

confidence: 82%

Section: Discussionmentioning

confidence: 79%

Section: Introductionmentioning

confidence: 99%

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Range expansion drives the evolution of alternate reproductive strategies in invasive fire ants

Helms¹,

Bridge²

2017

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“…The resulting cells, known as Thiessen or Voronoi polygons, among other names (Weaire and Rivier 1984), have also been used in plant ecology to provide indices of neighborhood competition (Czârân and Bartha 1992). Territory partitioning in ant populations has been represented by nonoverlapping circles or rectangles (Korzukhin andPorter 1994, Stoker et al 1994); however, these models assume a strict size hierarchy such that any particular colony is unaffected by the presence of smaller colonies, regardless of the degree of size difference. While this approach yields quantitative predictions of territory size and shape, the methods applied to date have been incomplete, usually assuming that the positions of boundary segments depend only on the distances to the two closest residents.…”

Section: Introductionmentioning

confidence: 99%

Territory Size and Shape in Fire Ants: A Model Based on Neighborhood Interactions

Adams

1998

Ecology

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Many aggressive animals form territory mosaics marked by distinct boundaries. This paper describes an approach to modeling territory size and shape within mosaics based on boundary disputes among neighboring animals. The model assumes that each resident applies pressure against its neighbors, as a result of aggression and display, and that boundaries form curves along which the pressure exerted by adjacent residents is equal. To illustrate, I predicted territory boundaries for populations of the fire ant Solenopsis invicta using several alternative mathematical descriptions of territorial fighting. According to the most successful formula, the aggressive pressure applied at any point on the territory perimeter increases linearly with the biomass of the defending colony but decreases with territory area and with the square of the distance to the colony's nest. An iterative algorithm predicts the size and location of boundary segments given the positions and sizes of colonies.By all measured criteria, this model produced more accurate predictions of territory areas and shapes than alternative models that omit the effects of resident size or the dependence of aggressive pressure on territory area. Modifications can incorporate nest relocations, strategic variation in the degree of aggressive pressure applied, habitat heterogeneity, and other biological details. However, even with simple assumptions, the model predicts much of the variation in the sizes and shapes of fire ant territories in natural conditions. This implies that territories are molded by a balance of aggression between neighbors and that each territory is affected by the actions of numerous residents.

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“…Polygynous colonies establish higher densities per area and are less territorial than the monogynous form (Vargo and Porter 1989, Porter 1991, Macom and Porter 1996. Neighboring colonies of monogynous S. invicta may limit simultaneous foraging along territory boundaries that are rich in resources, or bait (Hays et al 1982, Ryti and Case 1986, Tschinkel 1992, Korzukhin and Porter 1994. Similar studies on territoriality among harvester ants (Pogonomyrmex spp.)…”

Section: Table 3 Results Of the Means-separation Tests For One-way Amentioning

confidence: 90%

Efficacy of Broadcast and Perimeter Applications of S-Methoprene Bait on the Red Imported Fire Ant in Grazed Pastures

Aubuchon

Mullen

Eubanks

2006

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The red imported fire ant, Solenopsis invicta (Buren), is a major pest in the United States because of its painful sting. Toxic bait has been an important management tool against fire ants, but site registrations prohibit applications of most baits on grazed pastures. Extinguish, containing the insect growth regulator methoprene, was selected for this study because it has a broad site registration that includes grazed pastures. The primary objective of this research was to evaluate the efficacy for control of red imported fire ants by using broadcast applications of methoprene bait at a label rate of 1,121 g/ha versus applications around the perimeter of a target area at the reduced rate of 280 g/ha. Grazed pastures in Lee County, Alabama, and Chambers County, Alabama, were selected for this study, with broadcast treatments, perimeter treatments, and controls replicated three times at each site. All mounds were counted and rated using the USDA population index before applications and then at 8 and 16 wk posttreatment. Perimeter applications did not significantly reduce S. invicta mound abundance, but bait treatments significantly reduced mound abundance at 16 wk posttreatment at site 1 where applications were conducted in early evening. However, broadcast applications were not effective at site 2 where treatments were conducted in early morning with warmer temperatures. Emergence of winged alates was observed at 12 wk posttreatment, followed by a high density of incipient mounds that may have masked the full treatment effect of methoprene applications at site 2. Methoprene bait was effective in reducing abundance of S. invicta only when full label rates were applied.

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Spatial Model of Territorial Competition and Population Dynamics in the Fire Ant Solenopsis invicta (Hymenoptera: Formicidae)

Cited by 12 publications

References 0 publications

Range expansion drives the evolution of alternate reproductive strategies in invasive fire ants

Range expansion drives the evolution of alternate reproductive strategies in invasive fire ants

Territory Size and Shape in Fire Ants: A Model Based on Neighborhood Interactions

Efficacy of Broadcast and Perimeter Applications of S-Methoprene Bait on the Red Imported Fire Ant in Grazed Pastures

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