Hybridization and variation in the Leptothorax tuberum group (Hymenoptera: Formicidae)

Douwes, Per; Stille, Bo

doi:10.1111/j.1439-0469.1991.tb01629.x

Cited by 19 publications

(28 citation statements)

References 2 publications

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“…P. rugosus where hybrid lineages persist that are reproductively isolated from both parental species (Helms Cahan & Keller 2003;Anderson et al 2006;Schwander et al 2007a,b). The species-rich genus Temnothorax, in which hybridization appears to be particularly common (Douwes & Stille 1991;Seifert 1999), might be a particularly promising candidate for searching for such hybrid species. The literature teems with large numbers of ill-defined 'varieties' or 'races', such as Temnothorax tuberum var.…”

Section: Discussionmentioning

confidence: 99%

“…Hung & Vinson 1977;Ross et al 1987;Vander Meer & Lofgren 1989;Helms Cahan & Vinson 2003;Shoemaker et al 2006) and several other ant genera (Lasius : Pearson 1983b, Seifert 1999, Umphrey 2006Formica: Seifert 1999, Seifert & Goropashnaya 2004Temnothorax: Douwes & Stille 1991, Seifert 1999, Pusch et al 2006aPogonomyrmex: Helms Cahan et al 2002, Julian et al 2002, Schwander et al 2007bCrematogaster: Feldhaar et al 2003, H. Feldhaar 2006. It appears that in some areas of Central Europe, almost half of all female sexuals of the well-studied and highly diverse ant genus Temnothorax mate with allospecific males (Douwes & Stille 1991;Seifert 1999). Morphological studies and the narrowness of hybrid zones suggest that most cases of natural hybridization do not result in either the breakdown of species borders or the evolution of highly viable, permanent hybrid species with the exception of some lineages of Pogonomyrmex harvester ants (see below).…”

Section: Seemingly Indiscriminate Mating and The Commonness Of Hybridmentioning

confidence: 99%

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Lifelong commitment to the wrong partner: hybridization in ants

Feldhaar

Foitzik

Heınze

2008

Phil. Trans. R. Soc. B

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The extraordinary lifelong partner commitment in social insects is expected to increase choosiness in both sexes and therefore to be associated with particularly low hybridization frequencies. Yet, more and more studies reveal that in many ant taxa hybrids are surprisingly common, with up to half of all female sexuals receiving sperm from allospecific males in extreme cases. In a few ant species, hybridization has led to the evolution of reproductively isolated new lineages with a bizarre system of genetic caste differentiation: colonies produce hybrid workers and pure-lineage female sexuals. This requires that colonies either contain multiple queens or that queens mate multiple times. In most other cases, hybridization appears to be an evolutionary dead end and fertile hybrid queens are rarely found. In such cases, haplodiploid sex determination appears to decrease the costs of mating with an allospecific male. As long as hybrid workers are viable, a cross-mated queen can partially rescue its fitness by producing males from unfertilized eggs. Mating with an allospecific partner may thus be an option for queens when conspecific mates are not available. The morphological similarity of most ant males, perhaps resulting from the lack of sexual conflict, may similarly contribute to the commonness of hybridization.

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Section: Discussionmentioning

confidence: 99%

Section: Seemingly Indiscriminate Mating and The Commonness Of Hybridmentioning

confidence: 99%

Lifelong commitment to the wrong partner: hybridization in ants

Feldhaar

Foitzik

Heınze

2008

Phil. Trans. R. Soc. B

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“…The species involved in these artificial hybridisations belonged to the ant genera Leptothorax, Doronomyrmex, and Epimyrma and all produced hybrid combinations are so far unknown to occur in nature. In fact, evidence for hybridisations occurring under natural conditions is rare, even in the well-studied European fauna, and is based upon enzyme genetics (Pearson, 1983, Douwes andStille, 1991), analysis of phenotypic characters (Seifert, 1984(Seifert, , 1991, and karyotyping (Fischer, 1987). The best way to investigate interspecific hybridisations is undoubtedly through the use of molecular genetics.…”

Section: Introductionmentioning

confidence: 99%

Interspecific hybridisations in natural populations of ants by example of a regional fauna (Hymenoptera, Formicidae)

Seifert

1999

Insectes Sociaux

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The identification of hybrids by high-precision stereomicroscopy and chorological data is described in detail by example of the ant species Formica bruni and pressilabris. In a synopsis of heterogenous data, the overall hybrid frequency in the ant fauna of Central Europe is estimated. 17 of the 164 ant species of this region are demonstrated and further 2 species strongly suspected to hybridise. The lowfrequency hybridisers, showing overall hybrid ratios < 3%, were native elements of the Central European fauna before the onset of human cultivation and experienced direct interspecific contact for longer periods of their natural history. They developed more effective mechanisms of reproductive isolation beginning at the prezygotic level. Extremely high (12-31%) local hybridisation ratios occurred in species that invaded the area after anthropogenic changes in landscape structure. The segregated distribution of invaders and autochthonous species in the precultural period apparently did not impose the need to evolve more effective mechanisms for reproductive isolation. Prezygotic mechanisms in particular are deficient. In local situations, 19% of Lasius jensi matings and 44% of Leptothorax albipennis matings leading to successful nest foundations were matings with heterospecific partners. Signs for a dissolution of interspecific phenotypic differences are not detectable in most of the species. The dispersal of hybrid genotypes is apparently inhibited. Factors that probably stabilise the genomic integrity of hybridizing parent species are: (a) inability to produce hybrid queens (in L. jensi ¥ umbratus), (b) aneuploidy of F 1 females with inability to perform a balanced meiosis (in hybrids of L. albipennis with 3 other species), and (c) selection against hybrids in the epigenetic environment of alleles (Leptothorax nylanderi ¥ slavonicus). Extreme ratios of heterospecific matings would mean a dangerous drain of genetic material. A mechanism to reduce these losses is postulated, consisting of a 'cleptogamy' (theft of heterospecific sperm) by queens that missed a conspecific male, an establishment of a functioning colony of F 1 hybrid workers, a depression of the rearing or fertility of hybrid queens, and a maximum production of own sons by the queen. This mechanism could explain the persistence of rare species (Lasius jensi or Leptothorax albipennis) in an environment of more populous heterospecific hybridisation partners.

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“…The "shiny" phenotype might result from a particular combination of genes from two parental species. Similarly, ordinary queens of Acanthomyops latipes (a-females) differ in morphology strongly from fl-queens, which are hybrids between A. latipes and A. claviger (Wing, 1968)i In Solenopsis (Hung and Vinson, 1977) and Leptothorax (Heinze, 1989;Douwes and Stille, 1991) However, parental alleles not necessarily are equally expressed in hybrids (e.g., Hung and Vinson, 1977).…”

Section: Discussionmentioning

confidence: 98%

“…str.). Hybridization of different species of leptothoracine ants is a well known phenomenon both from the field and laboratory experiments (Buschinger, 1972;Seifert, 1984;Heinze, 1989;Jessen and Klinkicht, 1990;Douwes and Stille, 1991) and might explain the rareness as well as the large morphological variation of D. pocahontas adults. The "shiny" phenotype might result from a particular combination of genes from two parental species.…”

Section: Discussionmentioning

confidence: 98%