Hierarchical Analysis of Genetic Structure in Native Fire Ant Populations: Results From Three Classes of Molecular Markers

We describe genetic structure at various scales in native populations of the fire ant Solenopsis invicta using two classes of nuclear markers, allozymes and microsatellites, and markers of the mitochondrial genome. Strong structure was found at the nest level in both the monogyne (single queen) and polygyne (multiple queen) social forms using allozymes. Weak but significant microgeographic structure was detected above the nest level in polygyne populations but not in monogyne populations using both classes of nuclear markers. Pronounced mitochondrial DNA (mtDNA) differentiation was evident also at this level in the polygyne form only. These microgeographic patterns are expected because polygyny in ants is associated with restricted local gene flow due mainly to limited vagility of queens. Weak but significant nuclear differentiation was detected between sympatric social forms, and strong mtDNA differentiation also was found at this level. Thus, queens of each form seem unable to establish themselves in nests of the alternate type, and some degree of assortative mating by form may exist as well. Strong differentiation was found between the two study regions usinga all three sets of markers. Phylogeographic analyses of the mtDNA suggest that recent limitations on gene flow rather than longstanding barriers to dispersal are responsible for this large-scale structure.

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Nuclear and mitochondrial genetic structure in two social forms of the fire ant Solenopsis invicta: insights into transitions to an alternate social organization

Heredity ◽

10.1038/hdy.1997.98 ◽

1997 ◽

Vol 78 (6) ◽

pp. 590-602 ◽

Cited By ~ 53

Author(s):

Kenneth G Ross ◽

D Dewayne Shoemaker

Keyword(s):

Genetic Structure ◽

Social Organization ◽

Solenopsis Invicta ◽

Fire Ant ◽

Social Forms

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An Unusual Pattern of Gene Flow between the Two Social Forms of the Fire Ant Solenopsis invicta

Evolution ◽

10.2307/2410170 ◽

1993 ◽

Vol 47 (5) ◽

pp. 1595 ◽

Cited By ~ 10

Author(s):

Kenneth G. Ross ◽

D. DeWayne Shoemaker

Keyword(s):

Gene Flow ◽

Solenopsis Invicta ◽

Fire Ant ◽

Unusual Pattern ◽

Social Forms

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Distinct colony boundaries and larval discrimination in polygyne red imported fire ants (Solenopsis invicta)

10.22541/au.163251827.70085127/v1 ◽

2021 ◽

Author(s):

MacKenzie Kjeldgaard ◽

Pierre-André Eyer ◽

Collin McMichael ◽

Alison Bockoven ◽

Joanie King ◽

...

Keyword(s):

Solenopsis Invicta ◽

Sucrose Solution ◽

Ecological Impact ◽

Egg Laying ◽

Fire Ants ◽

Fire Ant ◽

Red Imported Fire Ant ◽

Invasive Ant ◽

Nestmate Discrimination ◽

Social Forms

Evaluating the factors that promote invasive ant abundance is critical to assess their ecological impact and inform their management. Many invasive ant species show reduced nestmate recognition and an absence of boundaries between unrelated nests, which allow populations to achieve greater densities due to reduced intraspecific competition. We examined nestmate discrimination and colony boundaries in introduced populations of the red imported fire ant (Solenopsis invicta; hereafter, fire ant). Fire ants occur in two social forms: monogyne (colonies with a single egg-laying queen) and polygyne (colonies with multiple egg-laying queens). In contrast with monogyne nests, polygyne nests are thought to be interconnected due to the reduced antagonism between non-nestmate polygyne workers, perhaps because polygyne workers habituate the colony to an odor unique to Gp-9-carrying adults. However, colony boundaries and nestmate discrimination are poorly documented, particularly for worker-brood interactions. To delimit boundaries between field colonies, we correlated the exchange of a N-glycine tracer dissolved in a sucrose solution with social form. We also evaluated nestmate discrimination between polygyne workers and larvae in the laboratory. Counter to our expectations, polygyne colonies behaved identically to monogyne colonies, suggesting both social forms maintain strict colony boundaries. Polygyne workers also preferentially fed larval nestmates and may have selectively cannibalized non-nestmates. The levels of relatedness among workers in polygyne colonies was higher than those previously reported in North America (mean ±SE: 0.269 ± 0.037). Our study highlights the importance of combining genetic analyses with direct quantification of resource exchange to better understand the factors influencing ant invasions.

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Red Imported Fire Ant (Hymenoptera: Formicidae) Worker Head Widths as an Indicator of Social Form in Louisiana

Journal of Entomological Science ◽

10.18474/0749-8004-42.1.20 ◽

2007 ◽

Vol 42 (1) ◽

pp. 20-27 ◽

Cited By ~ 1

Author(s):

Dee Colby ◽

Lacy Inmon ◽

Lane Foil

Keyword(s):

Solenopsis Invicta ◽

Fire Ant ◽

Red Imported Fire Ant ◽

Social Form ◽

Social Forms ◽

Worker Size ◽

Solenopsis Invicta Buren ◽

Imported Fire Ant

Classification of red imported fire ant, Solenopsis invicta Buren, colonies as monogyne or polygyne by using differences in worker size (head widths) was compared to PCR discrimination of alleles for colony social form. Maximum head widths were significantly different between the two social forms, but reliable assignment of social form based on head widths was not possible because of considerable overlap in sizes among ants in the two social forms.

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Spatial Genetic Structure Within Two Contrasting Stands of Scots Pine (Pinus sylvestris L.)

Silvae Genetica ◽

10.1515/sg-2008-0030 ◽

2008 ◽

Vol 57 (1-6) ◽

pp. 193-202 ◽

Cited By ~ 4

Author(s):

I. J. Chybicki ◽

A. Dzialuk ◽

M. Trojankiewicz ◽

M. Slawski ◽

J. Burczyk

Keyword(s):

Genetic Variation ◽

Gene Flow ◽

Genetic Structure ◽

Pinus Sylvestris ◽

Scots Pine ◽

Spatial Genetic Structure ◽

Nuclear Markers ◽

Genetic Pool ◽

Establishment History ◽

Two Populations

AbstractWhen considering neutral nuclear markers, genetic differentiation of Scots pine (Pinus sylvestris L.) populations is known to be low. The homogeneity arises particularly as an effect of common ancestry in a recent evolutionary history as well as an extensive gene flow, especially through pollen. However, within populations several other forces may shape the spatial distribution of genetic variation, including establishment history, environmental and silvicultural selection. These local forces are known to produce non-random spatial patterns of genetic variation, however little is known on fine-scale spatial genetic structure of Scots pine. In this study, two stands of this species with different establishment histories, selected within one larger population located in northern Poland were genotyped and analysed for genetic variation and within-stand spatial genetic structure. Results revealed no differences in genetic variation, although stands are separated about 60 km, suggesting that the two populations share a common genetic pool. The spatial genetic structure in both stands was found to be slightly different and was attributed to differences in the mode of populations’ establishments. Finally, results confirmed that gene flow in Scots pine is extensive, causing genetic homogeneity within a single population.

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