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Peter R Oxley - One of the best experts on this subject based on the ideXlab platform.

  • inheritance of thelytoky in the honey bee apis mellifera capensis
    Heredity, 2015
    Co-Authors: Nadine C Chapman, Michael H Allsopp, Peter R Oxley, Thomas E Rinderer, Benjamin P Oldroyd
    Abstract:

    Asexual reproduction via thelytokous parthenogenesis is widespread in the Hymenoptera, but its genetic underpinnings have been described only twice. In the wasp Lysiphlebus fabarum and the Cape honey bee Apis mellifera capensis the origin of thelytoky have each been traced to a single recessive locus. In the Cape honey bee it has been argued that thelytoky (th) controls the thelytoky phenotype and that a deletion of 9 bp in the flanking intron downstream of exon 5 (tae) of the gemini gene switches parthenogenesis from Arrhenotoky to thelytoky. To further explore the mode of inheritance of thelytoky, we generated reciprocal backcrosses between thelytokous A. m. capensis and the arrhenotokous A. m. scutellata. Ten genetic markers were used to identify 108 thelytokously produced offspring and 225 arrhenotokously produced offspring from 14 colonies. Patterns of appearance of thelytokous parthenogenesis were inconsistent with a single locus, either th or tae, controlling thelytoky. We further show that the 9 bp deletion is present in the arrhenotokous A. m. scutellata population in South Africa, in A. m. intermissa in Morocco and in Africanized bees from Brazil and Texas, USA, where thelytoky has not been reported. Thus the 9 bp deletion cannot be the cause of thelytoky. Further, we found two novel tae alleles. One contains the previously described 9 bp deletion and an additional deletion of 7 bp nearby. The second carries a single base insertion with respect to the wild type. Our data are consistent with the putative th locus increasing reproductive capacity.

Benjamin P Oldroyd - One of the best experts on this subject based on the ideXlab platform.

  • The distribution of thelytoky, Arrhenotoky and androgenesis among castes in the eusocial Hymenoptera
    Insectes Sociaux, 2018
    Co-Authors: Frances Goudie, Benjamin P Oldroyd
    Abstract:

    Thelytokous parthenogenesis is the production of females from unfertilized eggs. In this review we categorize the known thelytokous eusocial Hymenopterans (mostly ants) by their modes of worker and queen reproduction. The resultant tabulation reveals that: (1) there are no species in which queens are thelytokous and workers are exclusively arrhenotokous (asexual production of males). (2) When workers are capable of thelytoky, there are no examples of species in which queens are strictly thelytokous. (3) Strict queen thelytoky is only present in species with irreversibly sterile workers. (4) Facultative queen thelytoky and sterile workers can lead to the evolution of androgenesis (males are clonal sons of their fathers). These associations are probably best explained by consideration of differing fitness benefits of thelytoky between workers and queens and suggest that some combinations are unlikely to evolve. We therefore predict that they will hold for all eusocial Hymenoptera. No examples of endobacterium-induced thelytoky are known for the eusocial Hymenoptera, whereas endobacterium-induced thelytoky is widespread in the solitary Hymenoptera. We argue that this is because species in which both queens and workers are thelytokous that are unlikely to persist over evolutionary time. Further, eusocial species have single-locus sex determination, which is not compatible with endobacterium-induced feminization that is typically based on genome duplication. Only two thelytokous eusocial bees are known, and their modes of reproduction are consistent with the associations seen in ants. Thus far, no thelytokous eusocial wasps have been identified.

  • inheritance of thelytoky in the honey bee apis mellifera capensis
    Heredity, 2015
    Co-Authors: Nadine C Chapman, Michael H Allsopp, Peter R Oxley, Thomas E Rinderer, Benjamin P Oldroyd
    Abstract:

    Asexual reproduction via thelytokous parthenogenesis is widespread in the Hymenoptera, but its genetic underpinnings have been described only twice. In the wasp Lysiphlebus fabarum and the Cape honey bee Apis mellifera capensis the origin of thelytoky have each been traced to a single recessive locus. In the Cape honey bee it has been argued that thelytoky (th) controls the thelytoky phenotype and that a deletion of 9 bp in the flanking intron downstream of exon 5 (tae) of the gemini gene switches parthenogenesis from Arrhenotoky to thelytoky. To further explore the mode of inheritance of thelytoky, we generated reciprocal backcrosses between thelytokous A. m. capensis and the arrhenotokous A. m. scutellata. Ten genetic markers were used to identify 108 thelytokously produced offspring and 225 arrhenotokously produced offspring from 14 colonies. Patterns of appearance of thelytokous parthenogenesis were inconsistent with a single locus, either th or tae, controlling thelytoky. We further show that the 9 bp deletion is present in the arrhenotokous A. m. scutellata population in South Africa, in A. m. intermissa in Morocco and in Africanized bees from Brazil and Texas, USA, where thelytoky has not been reported. Thus the 9 bp deletion cannot be the cause of thelytoky. Further, we found two novel tae alleles. One contains the previously described 9 bp deletion and an additional deletion of 7 bp nearby. The second carries a single base insertion with respect to the wild type. Our data are consistent with the putative th locus increasing reproductive capacity.

Parra, José Roberto Postali - One of the best experts on this subject based on the ideXlab platform.

  • Biologia de Microctonus sp. (Hymenoptera: Braconidae), parasitóide de Cyrtomon luridus BOH. (Coleoptera: Curculionidae)
    São Paulo - Escola Superior de Agricultura "Luiz de Queiroz", 2004
    Co-Authors: Tironi Paulo, Von Treuenfels Adrian, Parra, José Roberto Postali
    Abstract:

    Cyrtomon luridus (Boh.), a native insect of wild Solanaceae, has adapted to the medicinal plant Duboisia sp., introduced from Australia, causing damages up to 100% mortality. Microctonus sp. is the most important natural enemy of C. luridus and its potential for biological control was investigated in this work. This study was carried out in Arapongas, Paraná State, Brazil, from 1994 to 1996. Parasitism of C. luridus by Microctonus sp. was highest from February through June (maximum of 54% in May 1996), when the C. luridus adult population was decreasing. The female sex ratio of Microctonus sp. under natural conditions was 0.57 to 0.69, which was close to 1 male : 2 female. Production of males occurs parthenogetically (Arrhenotoky). In the laboratory, parasitism reached 40% when two adult C. luridus were exposed per parasitoid. The number of Microctonus sp. adults that emerged per parasitized beetle ranged from 4.7 to 14.2. Larval-pupal viability was 31.7 to 64.8% and the female sex ratio ranged from 0.0 to 0.37, with prevalence of males. The egg-pupal period was 12.7 days and the pupal-adult period was 10.7 days, resulting in a mean life cycle (egg-adult) of 22.4 days for this parasitoid (25ºC, 70% R.H.). This is the first report of a new species of Microctonus sp. in C. luridus.Cyrtomon luridus (Boh.) é um inseto nativo de solanáceas silvestres e se adaptou à planta medicinal Duboisia sp., introduzida da Austrália, causando danos de até 100% de mortalidade. Microctonus sp. é o mais importante inimigo natural de C. luridus e seu potencial para o controle biológico foi investigado neste trabalho. Os experimentos foram conduzidos em Arapongas, Estado do Paraná, de 1994 a 1996. O parasitismo de C. luridus, por Microctonus sp. foi maior nos meses de fevereiro a junho (máximo de 54% em maio/96), coincidindo com a diminuição da população de adultos de C. luridus. A razão sexual de fêmeas de Microctonus sp., em condições naturais, foi de 0,57 a 0,69; sem cópula há produção de machos (partenogênese arrenótoca). Em laboratório, o parasitismo chegou a 40%, quando se ofereciam 2 adultos de C. luridus para 1 parasitóide. O número de adultos de Microctonus sp. por besouro parasitado variou de 4,7 a 14,2; a viabilidade larval-pupal de 31,7 a 64,8% e a razão sexual de 0 a 0,37, com predominância de machos. O período ovo-adulto foi em média, de 22,4 dias, sendo 12,7 dias para o período ovo-pupa e 10,7 dias para o período pupa-adulto (a 25º C; 70% de U.R). Estes foram os primeiros resultados da biologia desta nova espécie de Microctonus, parasitóide com potencial a ser avaliado para o controle biológico de C. luridus

  • Biology of Microctonus sp. (Hymenoptera: Braconidae), a parasitoid of Cyrtomon luridus BOH. (Coleoptera: Ccurculionidae)
    São Paulo - Escola Superior de Agricultura "Luiz de Queiroz", 2004
    Co-Authors: Von Treuenfels,adrian, Parra, José Roberto Postali
    Abstract:

    Cyrtomon luridus (Boh.), a native insect of wild Solanaceae, has adapted to the medicinal plant Duboisia sp., introduced from Australia, causing damages up to 100% mortality. Microctonus sp. is the most important natural enemy of C. luridus and its potential for biological control was investigated in this work. This study was carried out in Arapongas, Paraná State, Brazil, from 1994 to 1996. Parasitism of C. luridus by Microctonus sp. was highest from February through June (maximum of 54% in May 1996), when the C. luridus adult population was decreasing. The female sex ratio of Microctonus sp. under natural conditions was 0.57 to 0.69, which was close to 1 male : 2 female. Production of males occurs parthenogetically (Arrhenotoky). In the laboratory, parasitism reached 40% when two adult C. luridus were exposed per parasitoid. The number of Microctonus sp. adults that emerged per parasitized beetle ranged from 4.7 to 14.2. Larval-pupal viability was 31.7 to 64.8% and the female sex ratio ranged from 0.0 to 0.37, with prevalence of males. The egg-pupal period was 12.7 days and the pupal-adult period was 10.7 days, resulting in a mean life cycle (egg-adult) of 22.4 days for this parasitoid (25ºC, 70% R.H.). This is the first report of a new species of Microctonus sp. in C. luridus

Jaco M Greeff - One of the best experts on this subject based on the ideXlab platform.

  • effects of thelytokous worker reproduction on kin selection and conflict in the cape honeybee apis mellifera capensis
    Philosophical Transactions of the Royal Society B, 1996
    Co-Authors: Jaco M Greeff
    Abstract:

    Apis mellifera capensis workers are able to produce female eggs by the process of thelytoky, whereas the workers of other races of honeybee and most other eusocial Hymenoptera produce males only (Arrhenotoky). The maximization of inclusive fitness has been studied in eusocial arrhenotokous species, but not in thelytokous ones. Thelytokous worker offspring are female, consequently the kin-structure of colonies is altered. This difference leads to changes in kin-value asymmetries and kin-selection. Following from these changes many of the predictions regarding conflict in thelytokous species differ quantitatively or even qualitatively from those for arrhenotokous species. In A. m. capensis inclusive fitness arguments predict more conflict between workers over reproductive dominance, especially when the colony is queenless. Some of the unique traits of Cape honeybee workers upon queen-loss, for example: (i) extreme aggression amongst workers; (ii) very rapid development of ovaries; and (iii) queen-like pheromones in workers upon queen-loss can be explained as responses to such selection. It is predicted that workers will remove (police) less of their fellow workers' eggs than other races.

Aloyseia Cristina Da Silva Noronha - One of the best experts on this subject based on the ideXlab platform.

  • variacoes morfologicas intra e interpopulacionais de euseius citrifolius denmark muma e euseius concordis chant acari phytoseiidae
    Revista Brasileira De Zoologia, 2002
    Co-Authors: Aloyseia Cristina Da Silva Noronha, Gilberto J. De Moraes
    Abstract:

    The determination of morphologic variability within and between populations of phytoseiid mites is important for the precise species identification. Euseius citrifolius Denmark & Muma, 1970 and Euseius concordis (Chant, 1959) are phytoseiids commonly found on different crops in Brazil and other South American countries. The morphologic characterization of populations preliminarily identified as E. citrifolius and E. concordis was done through examination of 10 adult females and 10 adult males of each population and of 2 to 10 adult females and males resulting from crosses between those populations. The plant substrate and collection site of each population were: E. citrijolius: Bauhinia sp. in Arroio do Meio, Rio Grande do Sul, Coffea arabica Linnaeus in Campinas, Sao Paulo and Terminalia catappa Linnaeus in Petrolina, Pernambuco. E. concordis: Passiflora edulis Sims. i.flavicarpa Deg. in Arroio do Meio, Manihot esculenta (Crantz) in Jaguariuna, Sao Paulo, Hevea brasiliensis Muell. Arg. in Pontes e Lacerda, Mato Grosso, T. catappa in Petrolina and C arabica in Vicosa, Minas Gerais. A comparison of the measurements of different structures of individuals of each population and of type specimens of E. citrifolius and E. concordis confirmed the preliminary identification of the populations. Significant relationships were observed between mean setal lengths and the respective ranges within each population. Females and males of E. citrifolius from Petrolina and E. concordis from Jaguariuna had some of the setae generally shorter than those of other populations of the same species. Measurements of males resulting from heterogamic crosses indicated that E. citrifolius and E. concordis reproduce by pseudo-Arrhenotoky.

  • Variações morfológicas intra e interpopulacionais de Euseius citrifolius Denmark & Muma e Euseius concordis (Chant) (Acari, Phytoseiidae) Intra and interpopulational morphological variations of Euseius citrifolius Denmark & Muma and Euseius concordis (Chant) (Acari, Phytoseiidae)
    Sociedade Brasileira de Zoologia, 2002
    Co-Authors: Aloyseia Cristina Da Silva Noronha, Gilberto J. De Moraes
    Abstract:

    The determination of morphologic variability within and between populations of phytoseiid mites is important for the precise species identification. Euseius citrifolius Denmark & Muma, 1970 and Euseius concordis (Chant, 1959) are phytoseiids commonly found on different crops in Brazil and other South American countries. The morphologic characterization of populations preliminarily identified as E. citrifolius and E. concordis was done through examination of 10 adult females and 10 adult males of each population and of 2 to 10 adult females and males resulting from crosses between those populations. The plant substrate and collection site of each population were: E. citrijolius: Bauhinia sp. in Arroio do Meio, Rio Grande do Sul, Coffea arabica Linnaeus in Campinas, São Paulo and Terminalia catappa Linnaeus in Petrolina, Pernambuco. E. concordis: Passiflora edulis Sims. i.flavicarpa Deg. in Arroio do Meio, Manihot esculenta (Crantz) in Jaguariúna, São Paulo, Hevea brasiliensis Muell. Arg. in Pontes e Lacerda, Mato Grosso, T. catappa in Petrolina and C arabica in Viçosa, Minas Gerais. A comparison of the measurements of different structures of individuals of each population and of type specimens of E. citrifolius and E. concordis confirmed the preliminary identification of the populations. Significant relationships were observed between mean setal lengths and the respective ranges within each population. Females and males of E. citrifolius from Petrolina and E. concordis from Jaguariúna had some of the setae generally shorter than those of other populations of the same species. Measurements of males resulting from heterogamic crosses indicated that E. citrifolius and E. concordis reproduce by pseudo-Arrhenotoky

  • Morphologic and molecular characterization of predatory mites of the genus Euseius (Acari, Phytoseiidae).
    Universidade de São Paulo, 2002
    Co-Authors: Aloyseia Cristina Da Silva Noronha
    Abstract:

    Ácaros fitoseídeos são eficientes predadores de ácaros pragas em algumas culturas. A precisa identificação das espécies é o passo inicial na seleção de inimigos naturais em um projeto de controle biológico. Os ácaros são geralmente identificados com base nas características morfológicas, mas aspectos biológicos e ecológicos, e mais recentemente características moleculares vêm sendo usadas nesse processo. Populações dos fitoseídeos identificados como Euseius citrifolius Denmark & Muma provenientes de Arroio do Meio-RS, Campinas-SP e Petrolina-PE, e Euseius concordis (Chant) procedentes de Arroio do Meio, Jaguariúna-SP, Petrolina, Pontes e Lacerda-MT e Viçosa-MG foram estudados em relação a morfologia, compatibilidade reprodutiva e características moleculares. A caracterização morfológica correspondeu as medições de estruturas de fêmeas e machos. A compatibilidade reprodutiva foi avaliada através de cruzamentos e retrocruzamentos homogâmicos e heterogâmicos. A caracterização molecular foi realizada com o seqüenciamento dos espaços internos transcritos (ITS1 e ITS2) do DNA ribossomal. Relações significativas foram observadas dentro de cada população entre o comprimento médio das setas e as respectivas amplitudes de variação. Ambos os sexos de E. citrifolius de Petrolina e E.concordis de Jaguariúna tiveram algumas setas mais curtas que as demais populações da mesma espécie; esta última diferiu marcadamente da população de Petrolina. A comparação das medições das estruturas de cada população e dos espécimes tipo de E. citrifolius e E. concordis confirmaram a identificação morfológica preliminar das populações ao nível de espécie. Medições de machos resultantes de cruzamentos heterogâmicos indicaram que essas espécies se reproduzem por pseudo-arrenotoquia. Incompatibilidade parcial foi observada nos cruzamentos heterogâmicos envolvendo fêmeas de E. citrifolius de Petrolina; descendentes produziram poucos ovos e inviáveis quando retrocruzadas com machos das populações parentais. Machos de Petrolina produziram descendentes viáveis quando cruzados com fêmeas de Arroio do Meio e Campinas. Não ocorreu oviposição nos cruzamentos e retrocruzamentos heterogâmicos envolvendo fêmeas de E. concordis de Petrolina. Nos cruzamentos heterogâmicos envolvendo machos de Petrolina a oviposição foi reduzida e somente machos (viáveis) foram produzidos. Cruzamentos de fêmeas de Pontes e Lacerda e machos de Jaguariúna e vice-versa produziram somente machos. Entretanto o fluxo gênico entre essas populações seria possível indiretamente, através de cruzamentos entre essas populações e a população de Arroio do Meio. Populações de Arroio do Meio, Jaguariúna, Pontes e Lacerda e Viçosa pertencem a mesma espécie. Maior variação entre as populações foi observada no espaçador ITS1. O seqüenciamento dos espaçadores ITS1 e ITS2 permitiu discriminar entre os grupos de populações identificadas como E. citrifolius de E. concordis. O seqüenciamento dos ITSs pode ser aplicado como uma ferramenta complementar na identificação de fitoseídeos. Apesar do fato de que alguns tipos de diferenças foram sempre observadas nesta tese entre a população de Petrolina identificada preliminarmente como E. concordis, não é conveniente descrever esta população como uma nova espécie, devido a dificuldade em separar indivíduos dessa população daqueles das populações identificadas como E.concordis. Para uma conclusão, é sugerido que outros estudos de cruzamentos sejam conduzidos com populações morfologicamente identificadas como E. concordis coletadas entre Petrolina e Viçosa, e que a caracterização molecular envolvendo o gene citocromo oxidase seja conduzida.Phytoseiidae mites are efficient predators of pest mites on several crops. Precise identification is the initial step in the selection of natural enemies in a biological control project. Mites are usually identified by their morphology, but biological and ecological aspects and, more recently, molecular characteristics have also been used in this process. Populations of phytoseiid mites identified as Euseius citrifolius Denmark & Muma from Arroio do Meio-RS, Campinas-SP and Petrolina-PE, and E. concordis (Chant) from Arroio do Meio, Jaguariúna-SP, Petrolina Pontes e Lacerda-MT and Viçosa-MG were studied in relation to morphology, reproductive compatibility and molecular characteristics. Morphological characterization corresponded to measurements of structures of females and males. Reproductive compatibility was evaluated by homogamic and heterogamic crosses and backcrosses. Molecular characterization was done by sequencing the internal transcribed spacers of the ribosomal DNA (ITS1 and ITS2). Significant relationships were observed within each population between mean setal lengths and the respective ranges. Both sexes of E. citrifolius from Petrolina and E. concordis from Jaguariúna had some setae shorter than other populations of the same species; the latter differed most markedly from the Petrolina population. A comparison of the measurements of structures for each population and type specimens of E. citrifolius and E. concordis confirmed the preliminary morphological identification of the populations at species level. Measurements of males resulting from heterogamic crosses indicated that both species reproduce by pseudo-Arrhenotoky. Partial incompatibility was observed in heterogamic crosses involving females of E. citrifolius from Petrolina; progeny produced just few, unviable eggs when backcrossed with males of the parental populations. Males from Petrolina produced viable offspring when crossed with females from Arroio do Meio or Campinas. No eggs were produced in heterogamic crosses and backcrosses involving females of E. concordis from Petrolina. In heterogamic crosses involving males from Petrolina, oviposition was reduced and only (viable) males were produced. Crosses of females from Pontes e Lacerda and males from Jaguariúna and vice-versa produced only male progeny. However, gene flow between those population could be possible indirectly, through crosses between those populations and Arroio do Meio population. Populations from Arroio do Meio, Jaguariúna, Pontes e Lacerda and Viçosa belong to a same species. Most of the molecular variation between populations was observed in ITS1. The sequencing of ITS1 and ITS2 allowed the discrimination between the group of populations identified as E. citrifolius from that identified as E. concordis. With the information presently available, sequencing of ITSs can be applied as a complementary tool to identify phytoseiids. Despite the fact that some type of differences were always observed in this thesis between the Petrolina population preliminarily identified as E. concordis and the remaining populations, it is not convenient to describe such population as a new species presently, given the difficulty in separating individuals from that population from those of populations identified as E. concordis. For a conclusion, it is suggested that other crossing studies be conducted with populations morphologically identifiable as E. concordis collected between Petrolina and Viçosa, and that the characterization of the cytochrome oxidase gene be conducted