Abstract Hybridization, polyploidy, and apomixis are related to the diversification of angiosperms, generating complex taxonomic relationships between species. Despite the differences in the frequencies of these phenomena, apomixis, the asexual seed production, tends to be frequently associated with hybridization and polyploidy. Apomixis has received more attention due to its potential to preserve desirable phenotypes in agriculture. The joint study of these three phenomena has been little explored, so the main objective of this review was to describe hybridization, polyploidy and apomixis and then analyze how they can be related. A synthesis of the main results of the studies obtained from a specialized literature search, the main patterns that address these three phenomena together, and their evolutionary and ecological consequences are presented.

Resumen: La hibridación, la poliploidía y la apomixis están relacionadas con la diversificación de las angiospermas, generando relaciones taxonómicas complejas entre especies. A pesar de las diferencias en las frecuencias de estos fenómenos, la apomixis, la producción asexual de semillas, tiende a estar frecuentemente asociada con la hibridación y la poliploidía. La apomixis ha recibido más atención debido a su potencial para preservar fenotipos deseables en la agricultura. El estudio conjunto de estos tres fenómenos ha sido poco explorado, por lo que el objetivo principal de esta revisión fue describir la hibridación, la poliploidía y la apomixis y describir cómo se relacionan. Se presenta una síntesis de los principales resultados de los estudios obtenidos a partir de una búsqueda de literatura especializada, los principales patrones que abordan estos tres fenómenos en conjunto y sus consecuencias evolutivas y ecológicas.

Resumo Os cupins são conhecidos como insetos sociais em todo o mundo. Atualmente na China foram relatadas 473 espécies, 44 gêneros e 4 famílias de cupins. Destas, 111 espécies de Reticulitermes estão amplamente distribuídas em diferentes zonas da China. A temporada de voo de dispersão dessas espécies chinesas de Reticulitermes geralmente começa de fevereiro a junho, mas em algumas regiões diferentes espécies são distribuídas, compartilhando seus limites e tendo temporadas de voo sobrepostas. Essas razões tornam-se importantes fontes de hibridização entre duas populações heteroespecíficas de cupins. Foi confirmado que os ovos fertilizados e não fertilizados de alguns cupins Reticulitermes possuem capacidade de clivagem. Já os ovos não fertilizados de R. aculabialis, R. chinensis e R. labralis clivaram normalmente, e os únicos ovos não fertilizados de R. aculabialis se desenvolvem em embriões. R. flaviceps e R. chinensis foram observados com desenvolvimento embrionário anormal, e não eclosão de ovos por partenogênese. Eles foram relatados como mais ameaçadores para os recursos chineses à medida que se propagam com partenogênese, hibridização e reprodução sexual. Casca de ovo e macrófilos de ovos desempenham papéis importantes na identificação e controle de espécies, embora sejam pragas graves e causem uma ampla gama de danos a estruturas e produtos de madeira em residências, edifícios, materiais de construção, árvores, plantações e florestas na China continental.

Abstract Termites are known as social insects worldwide. Presently in China 473 species, 44 genera and 4 families of termites have been reported. Of them, 111 Reticulitermes species are widely spread in different zones of China. The dispersion flight season of these Chinese Reticulitermes species are usually started from February to June, but in some regions different species are distributed, sharing their boundaries and having overlapping flight seasons. These reasons become important sources of hybridization between two different heterospecific populations of termites. It was confirmed that the fertilized eggs and unfertilized eggs of some Reticulitermes termites have the capacity of cleavage. While the unfertilized eggs of R. aculabialis, R. chinensis and R. labralis cleaved normally and the only R. aculabialis unfertilized eggs develop in embryos. While, the R. flaviceps and R. chinensis were observed with their abnormal embryonic development, and not hatching of eggs parthenogenetically. They were reported more threatening to Chinese resources as they propagate with parthenogenesis, hybridization and sexual reproduction. Eggshell and macrophiles of eggs play important roles in species identification and control. Although, they are severe pests and cause a wide range of damages to wooden structures and products in homes, buildings, building materials, trees, crops, and forests in China’s Mainland.

Abstract Many Melastomataceae are distributed in highland rocky fields (Campos rupestres) landscapes with their intrinsic environmental factors. These factors influence the expression of morphoanatomical characteristics and determine which adaptations are necessary for survival, including reproductive processes. The genus Miconia belongs to the Neotropical tribe Miconieae, the largest in Melastomataceae. Species of Miconieae are known to engage in apomixis, which results in much of the tribe possibly carrying out autonomous or pseudogamous reproduction. Thus, this study seeks to describe the morphoanatomy of the flowers of Miconia polystachya (Naudin) R. Goldenb. and contribute to the understanding of their reproduction. For this, flowers were collected at different stages of development in different seasons (autumn and spring) for morphoanatomical study. The flowers were fixed and cross and longitudinal sections were carried out with a rotating microtome. Pollen viability tests were also performed. The individuals of Miconia polystachya studied in highland rocky fields of the state of Paraná have a high percentage of unviable pollen, verified by the structure of pollen grains showing different degrees of degeneration. However, individuals with mature fruits were observed, corroborating the association between reproduction of this species with apomixis. The described morphological characteristics are similar to those found in previous studies for the family and genus. However, our study provides novel ecological information about the flowering and floral anatomy of M. polystachya, emphasizing the anatomy of hypanthium, fertile verticils and embryonic development of the species. Campos rupestres survival processes apomixis Thus Naudin (Naudin R Goldenb autumn spring microtome performed degeneration However observed M hypanthium

Abstract In this work we reported injuries caused by the spider mite Oligonychus yothersi on Vitis vinifera leaves and we also investigate the sex ratio of this species under laboratory conditions. To access the aspects regarding reproduction, females were placed individually in arenas made of V. vinifera leaves to oviposit and all progeny were mounted on slides when they reached adulthood to confirm the offspring sex. Our study showed that O. yothersi reproduces by thelytokous /arrhenotokous parthenogenesis, generating low number of males. Additionally, we found vine plants with leaf browning, particularly on the adaxial surface, where mites were usually found. conditions reproduction V O arrhenotokous parthenogenesis males Additionally browning surface

ABSTRACT Background: Scorpions are a leading cause of envenomation in Brazil. The species Tityus serrulatus is associated with the most severe cases, especially in children. Despite not being endemic to the state of Santa Catarina, such occurrences have increased more than 500% in the state recently. Therefore, this study aimed to analyze the occurrence of envenomation by T. serrulatus, attended by the Center for Toxicological Information and Assistance of Santa Catarina. Methods: This was a retrospective and descriptive study of the occurrence of T. serrulatus, identified by the agency, from 2014 to 2021 in Santa Catarina, using data obtained by the BI-DATATOX system. Results: A total of 112 occurrences were classified as envenomation. Of these cases, 48.2% were recorded in the Itajaí Valley region and 33% in Greater Florianópolis. Men were involved in 59.8% of these, and the most common age group was 20-39 years (39.3%). Most envenomation occurred in urban areas (89.3%) under non-occupational circumstances (83%). Stings were more frequent on the hands (50.9%). Care was sought within 1 h after the event in 75.9% of the cases, and 94.6% were classified as mild. Conclusions: Occurrence of envenomation involving T. serrulatus in Santa Catarina increased significantly during the study period. Most cases occurred in urbanized areas, which suggests that they might have been transported from other states, and it must be considered that, in the urban environment, scorpions find a large supply of food and shelter and a reduced number of specific predators, allied to parthenogenesis. Background Brazil children 500 recently Therefore T Methods agency 201 202 BIDATATOX BI DATATOX system Results 11 482 48 2 48.2 33 Florianópolis 598 59 8 59.8 2039 20 39 20-3 39.3%. 393 39.3% . 3 (39.3%) 89.3% 893 89 (89.3% nonoccupational non occupational 83%. 83 83% (83%) 50.9%. 509 50.9% 50 9 (50.9%) 759 75 75.9 946 94 6 94.6 mild Conclusions period states environment predators parthenogenesis 4 48. 5 59. 203 20- 39.3 (39.3% 89.3 (89.3 (83% 50.9 (50.9% 7 75. 94. 39. (39.3 89. (89. (83 50. (50.9 (39. (89 (8 (50. (39 ( (50 (3 (5

SIGNIFICANCE: • The laying workers of the Cape honey bee continue to negatively affect the South African beekeeping industry, with more losses suffered in the northern regions of the country • The reproductive parasites enter susceptible host colonies, activate their ovaries, and lay diploid eggs, leading to colony dwindling and collapse. • Diploidy in eggs produced by unmated laying workers arises from thelytokous parthenogenesis, first discovered in honey bees by a hobbyist beekeeper. • We examine the consequences of thelytokous parthenogenesis and outline what is being done to understand and limit the spread of the laying workers of the Cape honey bee.

Resumo A sincronia espacial e temporal e a compatibilidade entre o oócito receptor e o núcleo celular doador são necessárias para o processo de clonagem de embriões a fim de permitir a reprogramação nuclear e o desenvolvimento embrionário precoce. O objetivo do presente estudo foi avaliar três métodos de sincronização do ciclo celular em uma cultura primária de fibroblastos bovinos durante 24, 48 ou 72 h. Estes fibroblastos foram utilizados como doadores nucleares para avaliar o seu potencial de desenvolvimento in vitro e a qualidade dos embriões produzidos por meio da técnica de Handmade cloning (HMC). Não foram encontradas diferenças entre os métodos utilizados para a sincronização de fibroblastos em G0 / G1 (p> 0,05). Produção de clones de fibroblastos nos quatro grupos - sem tratamento a 0 h e com restrição de soro RS, alta confluência celular ACC e RS + ACC às 24 h - resultou em altas taxas de clivagem que não foram diferentes. As taxas de produção de embriões foram de 37,9%, 29,5% e 30,9% nos grupos 0h, RS24h e RS + ACC24h, respectivamente, e 19,3% no grupo ACC, que foi significativamente diferente dos outros três (p <0,05). Não houve diferenças no parâmetro de qualidade entre os clones produzidos com fibroblastos submetidos à sincronização diferente. Finalmente, quando a produção geral de clones foi comparada versus partenotos e embriões de FIV, a única diferença foi entre clones e embriões partenogênicos com zona pelúcida (30,2% vs 38,6%). O número de blastômeros dos blastocitos produzidos através da FIV foi significativamente maior do que os de embriões ativados partenogeneticamente e de clones (117, 80, 75,9 e 67,1, respectivamente). A avaliação de três métodos de sincronização em diferentes pontos de tempo não demonstrou um aumento na porcentagem de fibroblastos nas fases G0/G1 do ciclo celular. No entanto, obteve-se boa qualidade e altas taxas de clonagem, sugerindo que nem sempre é necessário submeter as células a quaisquer tratamentos de sincronização, uma vez que renderiam resultados de clonagem igualmente bons.

Abstract Spatial and temporal synchrony and compatibility between the receptor oocyte and the donor cell nucleus are necessary for the process of embryo cloning to allow nuclear reprogramming and early embryonic development. The objective of the present study was to evaluate three cell cycle synchronization methods on a primary bovine fibroblast culture for 24, 48, or 72 h. These fibroblasts were used as nuclear donors to evaluate their in vitro developmental potential and the quality of the embryos produced through handmade cloning (HMC). No differences were found between the methods used for fibroblast synchronization in G0/G1 (p > 0.05). Production of clones from fibroblasts in four groups- no treatment at 0 h and using serum restriction SR, high culture confluence HCC, and SR+HCC at 24 h- resulted in high cleavage rates that were not different. Embryo production rates were 37.9%, 29.5%, and 30.9% in the 0h, SR24h, and SR+HHC24h groups, respectively, and 19.3% in the HCC group, which was significantly different from the other three (p < 0.05). There were no differences in the quality parameter among the clones produced with fibroblasts subjected to the different synchronization. Finally, when overall clone production was compared versus parthenotes and IVF embryos, the only difference was between clones and parthenogenetic embryos with zona pellucida (30.2% vs 38.6%). The number of blastomeres from the blastocytes produced through IVF was significantly greater than those from embryos activated parthenogenetically and from clones (117, 80, 75.9, and 67.1, respectively). The evaluation of three synchronization methods at different time points did not demonstrate an increase in the percentage of fibroblasts in the G0/G1 phases of the cell cycle; however, good quality and high cloning rates were obtained, suggesting that it is not always necessary to subject the cells to any synchronization treatments, as they would yield equally good cloning results.

Abstract The first gynandromorph of the insect order Zoraptera is reported. A gynandromorph of Zorotypus brasiliensis Silvestri is described from a likely parthenogenetic population in the Atlantic Forest around the border of the Brazilian states of Minas Gerais, Rio de Janeiro, and São Paulo. As has been previously surmised for this species, the sample consisted of only females, tending to support the hypothesis of thelytokous parthenogenesis for this population. The gynandromorph is largely female in outward appearance, but exhibits male secondary sexual traits on the left side of the apical abdominal segments. The left (male) antenna consists of antennomeres of different proportions to those of the right (female) antenna. The internal genitalia and associated sclerites, however, are female although some are augmented in their form relative to normal-type females. Comments are made on possible factors resulting in the development of the gynandromorph. This is the 16th insect order with gynandromorphism reported.

The objectives of this study are to know the development time of each state and stage of Caliothrips phaseoli o n Phaseolus vulgaris L. (Fabaceae), Cicer arietinum L. (Fabaceae), Nicotiana glauca Graham and N. tabacum L. (Solanaceae), the types of reproduction of these thrips and their index of masculinity. The study was conducted under the following ambient conditions: 25 ± 1 °C; 72 ± 6% relative humidity and 12h light/12h dark. For breeding, mature leaves of each plant were placed in dark glass bottles inside breeding cages. The development of each state and stage was inspected daily, counting also the number of individuals and the sex of emerged adults. It was found that N. glauca, P. vulgaris and N. tabacumare host plants ofC. phaseoli. The pubescence density ofC. arietinumlimited the feeding and prevented C. phaseolioviposition, therefore it could not represent an effcient host for these thrips. The average duration of the total cycle of C. phaseoli reached in the solanaceaes was higher in N. tabacum(20,6 days) and lower in N. glauca(16 days), while in the fabaceae (P. vulgaris) it reached an intermediate value (19 days). In N. tabacumand P. vulgarisit was the same since no signifcant differences were found between them. In all three plants, the state which needed more development time was the egg (6-8 days), followed by the larva II (4, 4.5 days), while the larva I and the quiescent states varied between 1.85 and 3.36 days. This species reproduces by amphigonia and parthenogenesis with exclusively male offspring in the latter case.

Los objetivos del presente estudio fueron I) conocer el tiempo de desarrollo de cada estado y estadio de Caliothrips phaseolie n Phaseolus vulgarisL. (Fabaceae), Cicer arietinum L. (Fabaceae), Nicotiana glauca Graham y N. tabacum L. (Solanaceae), y II) el tipo de reproducción bajo condiciones de laboratorio (25 ± 1 ºC; 72 ± 6% de humedad relativa y 12 hs luz / 12 hs oscuridad). Para la cría se utilizaron hojas maduras de cada planta que se colocaron en frascos oscuros de vidrio dentro de jaulas de cría. Diariamente se controló el desarrollo de cada estado y estadio deC. phaseolisobre cada planta, contándose además el número de individuos y el sexo de los adultos emergidos. Se comprobó que N. glauca, P. vulgarisy N. tabacumson plantas hospederas de C. phaseoli. La densidad de la pubescencia de C. arietinum limitó la alimentación e impidió la oviposición de C. phaseoli, por lo que no representaría una planta hospedera efciente para este trips. La duración promedio del ciclo total de C. phaseoli alcanzado en las solanáceas fue mayor en N. tabacum (20,6 días) y menor en N. glauca (16 días), mientras que en la fabácea (P. vulgaris) alcanzó un valor intermedio (19 días). En N. tabacum y P. vulgaris fue la misma ya que no se encontraron diferencias signifcativas entre ellas. En las tres especies vegetales, el estado que necesitó más tiempo de desarrollo fue el de huevo (6-8 días), seguido por el de larva II (4 - 4,5 días), mientras que la larva I y los estados quiescentes variaron entre 1,85 y 3,36 días. Esta especie se reproduce por anfigonia y partenogénesis con descendencia exclusiva de machos en este último caso.

ABSTRACT We evaluated the influence of host preference, mating, and release density on Telenomus remus (Nixon, 1937) (Hymenoptera: Platygastridae) parasitizing eggs of Spodoptera frugiperda (Smith, 1797) (Lepidoptera: Noctuidae). First, we tested host preference of T. remus (free choice test) offered a choice between eggs of Corcyra cephalonica (Stainton, 1865) (Lepidoptera: Pyralidae) and S. frugiperda. Parasitism capacity and host preference (S. frugiperda) of T. remus reared on either of the two hosts did not differ. Secondly, we evaluated the influence of mating behavior of T. remus females on its parasitism. Only the offspring sex ratio differed between treatments, indicating that the species reproduces by parthenogenesis of the arrhenotoky type. Finally, we evaluated the influence of release density on T. remus parasitism. This was tested by releasing different numbers of the parasitoid per S. frugiperda egg using T. remus reared for different numbers of generations on C. cephalonica eggs. The regression analysis between percentage of parasitism and density of released T. remus females showed a quadratic effect for all tested parasitoid generations (F35, F40, and F45) with maximum parasitism from 65.07% to 71.69%. Our results allow the conclusion that (a) T. remus prefers S. frugiperda eggs, regardless of the host on which this parasitoid was reared, showing no preimaginal conditioning; (b) Mating does not affect the number of eggs parasitized by T. remus or the development of its offspring; and (c) The optimal T. remus release density when reared on C. cephalonica is between 0.133 and 0.150 females/S. frugiperda.

RESUMO Em bovinos, o desenvolvimento embrionário é caracterizado pelo surgimento de duas camadas distintas, o trofectoderma e a massa celular interna. Este último irá sofrer diferenciação para formar o disco embrionário, o qual consiste em epiblasto e hipoblasto. O objetivo deste estudo foi caracterizar ultraestruturalmente o embrião bovino proveniente de diferentes técnicas de produção in vitro, com ênfase no trofectoderma e na massa celular interna. Embriões bovinos com sete dias de gestação (fecundação = D1), derivados de técnicas de produção in vitro, foram fixados para processamento de microscopia de luz e eletrônica de transmissão. Os resultados sugerem que os embriões produzidos por transferência nuclear de células somáticas e partenogênese apresentaram alterações significativas em suas estruturas macro e microscópica. O tamanho foi reduzido, e a massa celular interna não tinha uma forma definida. Além disso, organelas responsáveis por processos de absorção, comunicação, crescimento e metabolismo celular estavam em menor número e tinham alterações na forma quando comparadas aos resultados em embriões produzidos por fertilização in vitro. Conclui-se que os embriões produzidos por SCNT e partenogênese apresentam diferenças morfológicas quando comparados aos embriões de fertilização in vitro, tais como blastocele pouco desenvolvida, massa celular interna pouco definida e diferenças morfológicas nas organelas.

In cattle, embryo development is characterized by the appearance of two distinct cell layers, the trophectoderm and the inner cell mass. The latter will undergo differentiation to form the embryonic disc consisting of the epiblast and hypoblast. The aim of this study was to ultrastructurally characterize the bovine embryo from different in vitro production techniques, with emphasis on trophectoderm and inner cell mass cells. Bovine embryos on day 7 (conception = D1) of pregnancy, derived via in vitro production techniques, were fixed for light and transmission electron microscopy processing. Results suggested that embryos produced by nuclear transfer of somatic cells and parthenogenesis showed significant changes in macroscopic and microscopic structure. Size was reduced, and the inner cell mass had no defined shape. Furthermore, organelles responsible for the absorption processes, communication, growth, and cellular metabolism were fewer and had changes in shape, when compared to results in embryos produced by in vitrofertilization. We concluded that embryos produced by parthenogenesis and SCNT exhibit morphological differences when compared with IVF embryos, such as undeveloped blastocoel, poorly defined distribution of ICM, and morphological differences in organelles.

Resumo Sequências do Espaço Transcrito Interno 2 (ITS2) têm sido utilizadas em estudos taxonômicos e sua utilidade constatada pela confiabilidade que o método confere à identificação das espécies de Trichogramma. Esta técnica molecular foi bem sucedida em distinguir dezessete espécies nativas e introduzidas de Trichogramma, coletadas na América do Sul. As sequências do DNAr variaram de 379 a 632 pb. Em 11 linhagens de T. pretiosum estudadas, o endosinbionte Wolbachia foi detectado pela primeira vez. Estas linhagens telítocas foram encontradas no Peru (9), Colômbia (1) e Estados Unidos (1). Uma chave dicotômica para identificação de espécies foi construída baseada no tamanho do produto da PCR do ITS2 e em análises de restrição utilizando-se três endonucleases (EcoRI, MseI and MaeI).

Abstract ITS2 (Internal transcribed spacer 2) sequences have been used in systematic studies and proved to be useful in providing a reliable identification of Trichogramma species. DNAr sequences ranged in size from 379 to 632 bp. In eleven T. pretiosum lines Wolbachia-induced parthenogenesis was found for the first time. These thelytokous lines were collected in Peru (9), Colombia (1) and USA (1). A dichotomous key for species identification was built based on the size of the ITS2 PCR product and restriction analysis using three endonucleases (EcoRI, MseI and MaeI). This molecular technique was successfully used to distinguish among seventeen native/introduced Trichogramma species collected in South America.

Home range is defined as the area within which an individual moves to acquire resources necessary to increase their fitness and may vary inter and intra-specifically with biotic and abiotic factors. This study details the home range of the parthenogenic lizard, Aspidoscelis cozumela,an active forager microendemic to Cozumel Island, México, with high preference for open sand beaches. The home range of A. cozumelawas compared with other species of Aspidoscelis(gonochoric and parthenogenetic) and other lizards that occupy coastal habitats. Furthermore, the biotic and abiotic factors that may influence home range were analyzed. This study was conducted in the beach located on the East side of the island (area of 4 000 m2) that is composed primarily of halophyte vegetation with high levels of sunlight. From 1999 to 2001, nine samples were taken which included the dry, rainy, "nortes", and breeding seasons. During each sampling, capture-mark-recapture techniques were conducted and the date, time of day, and snout-vent length (SVL) were recorded to the nearest millimeter. Individuals were located in the study area using a bi-coordinate reference using 10 x 10 m subdivisions of the habitat. Home range and home range overlap were calculated using the convex polygon method in McPaal and home range/SVL correlation was tested using Pearson's correlation. To calculate females home range, three or more recaptures were considered. A total of 20 home ranges that averaged 45.1 ± 14.0 m2 were obtained and no correlation between SVL and home range size was detected (p = 0.9229, n = 20). However, removing individuals with outlier home ranges (females with home ranges > 100 m2, n = 2) resulted in a positive correlation with SVL (r = 0.61, p = 0.0072, n = 18). A 22.9 ± 5.7% overlap in home range was also detected. The small home range of A. cozumelarepresents the smallest home range within the Aspidoscelisgenus recorded to date (including both parthenogenetic and gonochoric species) and contrasts the theoretical predictions of broad home ranges for widely foraging species. Thermoregulatory benefits and a high population density may explain the small home range of A. cozumela.Although this species is highly adapted to the environmental conditions present on the open sand beaches, anthropogenic effects on these habitats by the development of tourism infrastructure may jeopardize their existence on Cozumel Island.

Wolbachia infection is the most widespread in animals. Its ability to manipulate insect reproduction places it at the center of organismal biology, affecting such important processes like sex determination, cell cycle, generation and extinction of species and behaviour of arthropods, including several pest and disease vector insects. Attributes like vertical transmission, the speed at which it drives in the population, the ability to block the pathogenic activity of several microorganisms and the ability to shorten the lifespan of its host point to this bacterium as a potential tool to control harmful insects and nematodes. What are the possibilities offered by this pandemic? In the present work a detailed and updated review of the main aspects of this infection is presented, as well as the practical implications for managing pest and disease vector insects and nematodes. This review is based on the symposium of the same title held in the VIII Argentinean Meeting of Entomology.

La infección causada por Wolbachia es la más extendida entre los animales. La capacidad de esta bacteria para manipular la reproducción de sus hospedadores la posicionan en el centro de la biología de los organismos, influyendo en procesos tan capitales como la determinación del sexo, el ciclo celular, la formación y extinción de especies y el comportamiento de artrópodos entre los que se cuentan varias plagas y vectores de enfermedades. Cualidades tales como la herencia vertical de Wolbachia, la velocidad a la que se propaga en las poblaciones que afecta, la capacidad de bloquear la actividad patogénica de diversos microorganismos o de acortar el ciclo de vida de sus hospedadores la señalan como un potencial instrumento para el control de poblaciones de insectos y nematodos perjudiciales. ¿Cuáles son las posibilidades que nos ofrece esta pandemia? En la presente contribución se presenta una revisión de los aspectos fundamentales de esta infección y sus implicancias prácticas para el manejo de insectos plaga. Esta revisión está basada en el simposio del mismo nombre acontecido en el VIII Congreso Argentino de Entomología.

During early embryo development the zona pellucida acts as a barrier against polyspermia and guarantees communication between blastomeres before and during compaction. However, the development of new technologies of embryo production such as "Handmade Cloning" demands removal of this membrane. The aim of this study was to determine the effect of zona pellucida removal on in vitro bovine embryo development. First, the consequences of zona pellucida removal was assessed by comparing the percentage of first cleavage, percentage of blastocysts and cell number among zona-included and zona-free embryos; either through the removal of the zona pellucida immediately after IVF or parthenogenesis. Embryo development was also evaluated when zona pellucida was removed before parthenogenesis. In a second set of experiments, the gene expression levels of BAX, BCL2, CASP3, CDH1, OCT4 and SOX2 were evaluated in zona-free and zona-included IVF-derived embryos. No significant differences were found in the percentage of first cleavage, percentage of blastocyst and cell number on IVF-embryos cultured with or without zona. Parthenogenetic embryos followed the same general pattern even when the zona pellucida was eliminated before activation; however there was a significant increase in the rate of first cleavage when the zona pellucida was removed after activation but this did not impact upon further development. Furthermore, no significant differences in gene expression level were found between zona-free and zona-included IVF-embryos for the studied genes. We concluded that the lack of zona pellucida did not affect the early development when an appropriate system is used for embryo culture to ensure blastomeric contact and normal compaction.

Durante el desarrollo embrionario temprano, la zona pelúcida actúa como barrera contra la polispermia y además garantiza la comunicación entre blastómeras y la compactación de estas. Sin embargo, el desarrollo de nuevas tecnologías reproductivas como "hand made cloning" demandan la eliminación de esta membrana. En este estudio nos propusimos determinar el efecto de la remoción de la zona pelúcida sobre el desarrollo in vitro y la calidad de embriones bovinos producidos por FIV o activación partenogenética. La capacidad de desarrollo se evaluó teniendo en cuenta el porcentaje de la primera división celular, porcentaje de blastocistos y número total de células. La comparación se realizó entre embriones con y sin zona pelúcida, a estos últimos la zona le fue removida después de la fecundación o de la activación partenogenética. Adicionalmente se evaluó el efecto de la remoción de la zona, antes de la activación partenogenética, sobre la capacidad de desarrollo. En un segundo experimento se evaluó el efecto de remover la zona pelúcida sobre los niveles de expresión génica (BAX, BCL2, CASP3, CDH1, OCT4 and SOX2) en embriones producidos por FIV. No se encontraron diferencias significativas en los parámetros incluidos para evaluar el desarrollo embrionario entre embriones con y sin zona pelúcida, producidos por FIV o partenogénesis, en estos últimos eliminando la zona antes de la activación. Sin embargo, en los embriones partenogenéticos en los que se eliminó la zona después de la activación, aumentó significativamente el porcentaje de la primera división comparado con los embriones con zona, sin embargo, esto no tuvo ningún efecto sobre el posterior desarrollo hasta blastocisto. De igual modo, no se encontraron diferencias significativas en los niveles de expresión génica entre embriones con y sin zona pelúcida producidos por FIV, para los genes estudiados. De esta forma se concluye que la ausencia de zona pelúcida no afecta el desarrollo temprano de embriones bovinos cuando se utiliza un sistema de cultivo que garantice el correcto contacto y compactación celular.