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Sample records for arrhenotoky

  1. Arrhenotoky and oedipal mating in the northern fowl mite (Ornithonyssus sylviarum (Acari: Gamasida: Macronyssidae

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    McCulloch John B

    2012-12-01

    Full Text Available Abstract Background The northern fowl mite (NFM; Ornithonyssus sylviarum is a blood-feeding ectoparasite of birds and a major pest of poultry in the United States. Mite populations spread rapidly in commercial flocks, reach peak burdens of >70,000 mites per bird and have developed resistance to many pesticides. Despite decades as a pest in the United States, the reproductive biology of NFM remains unclear. Based on karyotypes, the NFM has haplodiploid sex determination, which suggests unmated females could produce male offspring (arrhenotoky. Thus, unmated females could disseminate to a new host and initiate an infestation by producing and mating with sons (oedipal mating. Methods We used small capsules to isolate and recover NFM on host chickens. Mites in capsules could blood feed, develop and reproduce, but could not contact other mites. Individual larvae were matured in isolation to produce known, unmated females. We evaluated reproduction of (I previously mated females (i in isolation, or (ii paired with a male, and (II unmated (virgin females in isolation. In each treatment we recorded the number and sexes of offspring produced over time. Results Mated NFM produced female and male offspring in isolation, or when paired with a male. When paired with a male, females produced a female-biased sex ratio of the offspring (F:M ratio ~5:1. Unmated, female NFM produced exclusively male offspring when in isolation. When paired with their sons that had developed to maturity, the "virgin" females were able to mate and subsequently produce female offspring. Conclusions This study found that females with immediate access to sperm produced mostly female offspring. Virgin female NFM initially produced only male offspring and subsequently used oedipal mating to produce female offspring. Using this reproductive system NFM could successfully colonize new hosts as immature, or unmated females. The strong female-biased sex ratio of NFM populations suggests a

  2. Performance of arrhenotokous and thelytokous Thrips tabaci (Thysanoptera: Thripidae) on onion and cabbage and its implications on evolution and pest management.

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    Li, Xiao-Wei; Fail, Jozsef; Wang, Ping; Feng, Ji-Nian; Shelton, A M

    2014-08-01

    Onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), is an important pest on onion and cabbage. Two reproductive modes--arrhenotoky and thelytoky--are found in this species and co-occur in the field. We compared life table traits between arrhenotokous and thelytokous T. tabaci on cabbage and onion. Experiments were conducted in cages to determine which reproductive mode is more competitive. Additionally, host adaption of the arrhenotokous and thelytokous T. tabaci between onion and cabbage was investigated. On onion, arrhenotokous T. tabaci performed better than thelytokous T. tabaci, while on cabbage the opposite occurred. When comparing life table and demographic growth parameters (net reproductive rates R(o), mean generation time T, the intrinsic rate of natural increase r(m), finite rate of increase A, and population doubling time T(d)) on different host plants, we found that arrhenotokous T. tabaci performed better on onion than on cabbage, whereas thelytokous T. tabaci performed better on cabbage than on onion. Host-related performance differences in this species suggest that the divergence between two reproductive modes might be associated with host adaption. Pest management strategies for this global pest should recognize that the two reproductive modes can impact population dynamics on different crops.

  3. Detection of Gene Flow from Sexual to Asexual Lineages in Thrips tabaci (Thysanoptera: Thripidae).

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    Li, Xiao-Wei; Wang, Ping; Fail, Jozsef; Shelton, Anthony M

    2015-01-01

    Populations of Thrips tabaci are known to have two sympatric but genetically isolated reproductive modes, arrhenotoky (sexual reproduction) and thelytoky (asexual reproduction). Herein, we report behavioral, ecological and genetic studies to determine whether there is gene flow between arrhenotokous and thelytokous T. tabaci. We did not detect significant preference by arrhenotokous males to mate with females of a particular reproductive mode, nor did we detect significant behavioral differences between arrhenotokous males mated with arrhenotokous or thelytokous females in their pre-copulation, copulation duration and mating frequency. Productive gene transfer resulting from the mating between the two modes was experimentally confirmed. Gene transfer from arrhenotokous T. tabaci to thelytokous T. tabaci was further validated by confirmation of the passage of the arrhenotokous male-originated nuclear gene (histone H3 gene) allele to the F2 generation. These behavioral, ecological and genetic studies confirmed gene transfer from the sexual arrhenotokous mode to the asexual thelytokous mode of T. tabaci in the laboratory. These results demonstrate that asexual T. tabaci populations may acquire genetic variability from sexual populations, which could offset the long-term disadvantage of asexual reproduction.

  4. Detection of Gene Flow from Sexual to Asexual Lineages in Thrips tabaci (Thysanoptera: Thripidae.

    Directory of Open Access Journals (Sweden)

    Xiao-Wei Li

    Full Text Available Populations of Thrips tabaci are known to have two sympatric but genetically isolated reproductive modes, arrhenotoky (sexual reproduction and thelytoky (asexual reproduction. Herein, we report behavioral, ecological and genetic studies to determine whether there is gene flow between arrhenotokous and thelytokous T. tabaci. We did not detect significant preference by arrhenotokous males to mate with females of a particular reproductive mode, nor did we detect significant behavioral differences between arrhenotokous males mated with arrhenotokous or thelytokous females in their pre-copulation, copulation duration and mating frequency. Productive gene transfer resulting from the mating between the two modes was experimentally confirmed. Gene transfer from arrhenotokous T. tabaci to thelytokous T. tabaci was further validated by confirmation of the passage of the arrhenotokous male-originated nuclear gene (histone H3 gene allele to the F2 generation. These behavioral, ecological and genetic studies confirmed gene transfer from the sexual arrhenotokous mode to the asexual thelytokous mode of T. tabaci in the laboratory. These results demonstrate that asexual T. tabaci populations may acquire genetic variability from sexual populations, which could offset the long-term disadvantage of asexual reproduction.

  5. Restricted Gene Flow among Lineages of Thrips tabaci Supports Genetic Divergence Among Cryptic Species Groups

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    Jacobson, Alana L.; Nault, Brian A.; Vargo, Edward L.; Kennedy, George G.

    2016-01-01

    Knowledge of the relative influence of population- versus species-level genetic variation is important to understand patterns of phenotypic variation and ecological relationships that exist among and within morphologically indistinguishable cryptic species and subspecies. In the case of cryptic species groups that are pests, such knowledge is also essential for devising effective population management strategies. The globally important crop pest Thrips tabaci is a taxonomically difficult group of putatively cryptic species. This study examines population genetic structure of T. tabaci and reproductive isolation among lineages of this species complex using microsatellite markers and mitochondrial COI sequences. Overall, genetic structure supports T. tabaci as a cryptic species complex, although limited interbreeding occurs between different clonal groups from the same lineage as well as between individuals from different lineages. These results also provide evidence that thelytoky and arrhenotoky are not fixed phenotypes among members of different T. tabaci lineages that have been generally associated with either reproductive mode. Possible biological and ecological factors contributing to these observations are discussed. PMID:27690317

  6. New Wolbachia supergroups detected in quill mites (Acari: Syringophilidae).

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    Glowska, Eliza; Dragun-Damian, Anna; Dabert, Miroslawa; Gerth, Michael

    2015-03-01

    Wolbachia is the most abundant intracellular bacterial genus infecting a wide range of arthropods and filarial nematodes. Wolbachia have evolved parasitic, mutualistic and commensal relationships with their hosts but in arthropods generally act as reproductive parasites, inducing a wide range of phenotypic effects such as cytoplasmic incompatibility, parthenogenesis, feminization and male-killing. Up to now, the genus has been divided into 14 supergroups successively named A-O. Here, we describe two new Wolbachia supergroups from syringophilid mites (Acari: Cheyletoidea). These obligatory ectoparasites of birds inhabit the quills of feathers in many avian groups. The species of this family reproduce in a haplodiploid mode sensu arrhenotoky and are usually strongly female-biased. Based on the sequences of four protein-coding genes (ftsZ, gltA and groEL and coxA) and the 16S rRNA we identified strains of three Wolbachia supergroups (F and two distinct, yet undescribed ones) in five quill mite species. Our results suggest that in some cases the distribution of the bacteria can be better correlated with the mite's bird host rather than with mite taxonomy as such. The discovery of two new Wolbachia supergroups not only broadens the knowledge of the diversity of this bacterium but also raises questions about potential effects induced in quill mites and transmission mechanisms of the endosymbionts in this peculiar bacteria-quill mite-bird system.