THE CHROMOSOMES OF BISEXUAL AND PARTHENOGENETIC SPECIES OF<i>CALLIGRAPHA</i>(COLEOPTERA: CHRYSOMELIDAE) WITH NOTES ON SEX RATIO, ABUNDANCE AND EGG NUMBER

Robertson, J. G.

doi:10.1139/g66-085

Cited by 39 publications

(44 citation statements)

References 23 publications

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“…The presence of B-chromosomes in P. dulcamarue is not a very rare finding in Chrysomelidae since they have been recorded in Diubrotica and some related galerucine genera (SMITH 1972), in five species of Galerucella galerucines (NOKKALA and NOKKALA 1987), in several Culligrapha chrysomelines (ROBERTSON 1966), and also in other fleabeetles such as two species of Aphthona at least (SEGARRA and PETITPIERRE unpubl.). The origin of the B-chromosomes of P. dulcamarae probably stems from the neoXY formation, because this event in beetles usually produces two dispensable elements, a centric fragment and the yp, which can sometimes survive as supernumeraries (SMITH and VIRKKI 1978).…”

Section: Discussionmentioning

confidence: 96%

Cytogenetic diversity of the European Psylliodes flea-beetles (Coleoptera, Chrysomelidae)

Segarra

Petitpierre

2008

Hereditas

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Seven European species of Psylliodes flea-beetles have been chromosomally analyzed. The range of diploid numbers in the nine presently known species is wide, from 20 to 36 chromosomes, but most species display 2n=34 and 16+Xyp male karyotypic formula, which is presumably the ancestral value for the genus. Two species, P. dulcamarae and P. affinis, share a neoXY sex chromosome system, have lower diploid numbers than the remaining, and are probably derived by chromosome fusion events. Moreover, the presumed phylogenetic interrelationships based on chromosomes are in good agreement with the female spermathecal groups and with the choice of host-plant. P. dulcamarae shows a B-chromosome polymorphism having three different karyomorphs.

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Section: Discussionmentioning

confidence: 96%

Cytogenetic diversity of the European Psylliodes flea-beetles (Coleoptera, Chrysomelidae)

Segarra

Petitpierre

2008

Hereditas

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“…Further support for the asymmetric hybridization scenario Robertson (1966) showed a consistent association of unisexuality with tetraploidy in these leaf beetles. This is consistent with findings on invertebrate unisexuals of hybrid origin, most of which are polyploids thought to form via backcrossing of F 1 hybrids with one of the parentals (Suomalainen et al 1987;Saura et al 1993;Simon et al 2003).…”

Section: Figmentioning

confidence: 63%

“…Each unisexual Calligrapha taxon is generally well differentiated from congeners, exhibiting diagnostic morphological characters that are shared by populations throughout their geographic range (Brown 1945;Gó mez-Zurita et al 2004). Among these species, C. scalaris is unique in having been described as facultatively parthenogenetic based on variably biased population sex ratios (Robertson 1966). However, the rarity of facultative thelytoky in general (Normark 2003) and the specific observation of diploid sexuals and tetraploid asexuals within this species (Robertson 1966) suggests that the local coexistence of obligately bisexual and unisexual lineages presents a more likely explanation for observed sex ratios in this species.…”

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confidence: 88%

“…Among these species, C. scalaris is unique in having been described as facultatively parthenogenetic based on variably biased population sex ratios (Robertson 1966). However, the rarity of facultative thelytoky in general (Normark 2003) and the specific observation of diploid sexuals and tetraploid asexuals within this species (Robertson 1966) suggests that the local coexistence of obligately bisexual and unisexual lineages presents a more likely explanation for observed sex ratios in this species. Both bisexual and unisexual species of North American Calligrapha sensu stricto are monophagous on particular shrubs and trees (Brown 1945).…”

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confidence: 88%

“…Asexuality is very rare among beetles, with only about a hundred known unisexual taxa, mostly among the weevils (Curculionidae; e.g., Suomalainen et al 1987). Among the eight leaf beetle genera in which asexuality has been suggested (Cox 1996), Calligrapha stands out because it includes seven distinct unisexual species and because female-only thelytoky and associated allotetraploidy has been well documented among them (Brown 1945;Robertson 1966;Gó mez-Zurita et al 2004). Each unisexual Calligrapha taxon is generally well differentiated from congeners, exhibiting diagnostic morphological characters that are shared by populations throughout their geographic range (Brown 1945;Gó mez-Zurita et al 2004).…”

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confidence: 99%

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The Evolution of Unisexuality in Calligrapha Leaf Beetles: Molecular and Ecological Insights on Multiple Origins via Interspecific Hybridization

2006

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Abstract. Interspecific hybridization is a well-established cause of unisexual origins in vertebrates. This mechanism is also suspected in other apomictic taxa, but compelling evidence is rare. Here, we evaluate this mechanism and other hypotheses for the evolutionary origins of unisexuality through an investigation of Calligrapha leaf beetles. This group provides an intriguing subject for studies of unisexual evolution because it presents a rare insect example of multiple apomictic thelytokous species within a primarily bisexual genus. To investigate unisexual evolution, this study conducts the first molecular systematic analysis of Calligrapha. This involved the collection and analysis of about 3000 bp of DNA sequences-representing RNA and protein-coding loci from mitochondrial and nuclear genomes-from 54 specimens of 25 Calligrapha species, including four unisexual tetraploid taxa. Phylogenetic and molecular clock analyses indicated independent and single evolutionary origins of each of these unisexual species during the Pleistocene. Significant phylogenetic incongruence was detected between mitochondrial and nuclear datasets and found to be especially associated with the asexual taxa. This pattern is expected when unisexual lineages arise via interspecific hybridization and thus represent genetic mosaics that possess certain nuclear alleles from the paternal species lineage and mitochondrial DNA (mtDNA) alleles from the maternal parent. Analyzing the mtDNA and nuclear relatedness of unisexuals with corresponding haplotypes of bisexual Calligrapha species allowed the putative identification of these maternal and paternal species lineages for each unisexual species. Strong phenotypic similarities between unisexual taxa and their paternal parent species supported a model that involves both backcrosses of interspecific hybrids with a paternal parent and unreduced gametes. This model accounts for the origins of apomixis, polyploidy, and an overrepresentation of paternal nuclear alleles (and associated phenotypes) in unisexuals. This model is also consistent with the tetraploid karyotypes of unisexual Calligrapha, in which three sets of chromosomes (of presumed paternal ancestry) are quite morphologically homogeneous compared to the fourth. Especially intriguing was a consistent association of unisexual species with the host plant of the paternal parent but never with the maternal host. The statistical implausibility of these patterns occurring by chance further supports our inference of parental species. Moreover, it points to a potentially critical role for host-association in the formation and preservation of unisexual lineages. These findings suggest that ecological factors are critical for the diversification of unisexual as well as bisexual taxa and thus point out new research directions in the area of ecological speciation.

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Assessment of the role of Wolbachia in mtDNA paraphyly and the evolution of unisexuality in Calligrapha (Coleoptera: Chrysomelidae)

Gómez‐Zurita

2019

Ecology and Evolution

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Calligrapha is a New World leaf beetle genus that includes several unisexual species in northeastern North America. Each unisexual species had an independent hybrid origin involving different combinations of bisexual species. However, surprisingly, they all cluster in a single mtDNA clade and with some individuals of their parental species, which are in turn deeply polyphyletic for mtDNA. This pattern is suggestive of a selective sweep which, together with mtDNA taxonomic incongruence and occurrence of unisexuality in Calligrapha, led to hypothesize that Wolbachia might be responsible. I tested this hypothesis studying the correlation between diversity of Wolbachia and well‐established mtDNA lineages in >500 specimens of two bisexual species of Calligrapha and their derived unisexual species. Wolbachia appears highly prevalent (83.4%), and fifteen new supergroup‐A strains of the bacteria are characterized, belonging to three main classes: wCallA, occupying the whole species ranges, and wCallB and wCallC, narrowly parapatric, infecting beetles with highly divergent mtDNAs where they coexist. Most beetles (71.6%) carried double infections of wCallA with another sequence class. Bayesian inference of ancestral character states and association tests between bacterial diversity and the mtDNA genealogy show that each mtDNA lineage of Calligrapha has specific types of infection. Moreover, shifts can be explained by horizontal or vertical transfer from local populations to an expanding lineage and cytoplasmic incompatibility between wCallB and wCallC types, suggesting that the symbionts hitchhike with the host and are not responsible for selective mtDNA sweeps. Lack of evidence for sweeps and the fact that individuals in the unisexual clade are uninfected or infected by the widespread wCallA type indicate that Wolbachia does not induce unisexuality in Calligrapha, although they may manipulate host reproduction through cytoplasmic incompatibility.

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THE CHROMOSOMES OF BISEXUAL AND PARTHENOGENETIC SPECIES OFCALLIGRAPHA(COLEOPTERA: CHRYSOMELIDAE) WITH NOTES ON SEX RATIO, ABUNDANCE AND EGG NUMBER

Cited by 39 publications

References 23 publications

Cytogenetic diversity of the European Psylliodes flea-beetles (Coleoptera, Chrysomelidae)

Cytogenetic diversity of the European Psylliodes flea-beetles (Coleoptera, Chrysomelidae)

The Evolution of Unisexuality in Calligrapha Leaf Beetles: Molecular and Ecological Insights on Multiple Origins via Interspecific Hybridization

Assessment of the role of Wolbachia in mtDNA paraphyly and the evolution of unisexuality in Calligrapha (Coleoptera: Chrysomelidae)

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