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Anna Sulikowskadrozd - One of the best experts on this subject based on the ideXlab platform.
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evolution of reproductive strategies in the species rich land snail subfamily phaedusinae stylommatophora clausiliidae
Molecular Phylogenetics and Evolution, 2021Co-Authors: Tomasz Mamos, Dennis Uit De Weerd, Parm Viktor Von Oheimb, Anna SulikowskadrozdAbstract:Most of the present knowledge on animal reproductive mode evolution, and possible factors driving transitions between Oviparity and viviparity is based on studies on vertebrates. The species rich door snail (Clausiliidae) subfamily Phaedusinae represents a suitable and unique model for further examining parity evolution, as three different strategies, Oviparity, viviparity, and the intermediate mode of embryo-retention, occur in this group. The present study reconstructs the evolution of reproductive strategies in Phaedusinae based on time-calibrated molecular phylogenetics, reproductive mode examinations and ancestral state reconstruction. Our phylogenetic analysis employing multiple mitochondrial and nuclear markers identified a well-supported clade (including the tribes Phaedusini and Serrulinini) that contains species exhibiting various reproductive strategies. This clade evolved from an oviparous most recent common ancestor according to our reconstruction. All non-oviparous taxa are confined to a highly supported subclade, coinciding with the tribe Phaedusini. Both Oviparity and viviparity occur frequently in different lineages of this subclade that are not closely related. During Phaedusini diversification, multiple transitions in reproductive strategy must have taken place, which could have been promoted by a high fitness of embryo-retaining species. The evolutionary success of this group might result from the maintenance of various strategies.
Richard Shine - One of the best experts on this subject based on the ideXlab platform.
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viviparity does not affect the numbers and sizes of reptile offspring
Journal of Animal Ecology, 2020Co-Authors: Anat Feldman, Shai Meiri, Rachel Schwarz, Richard ShineAbstract:Viviparity (live-bearing) has independently evolved from Oviparity (egg-laying) in more than 100 lineages of squamates (lizards and snakes). We might expect consequent shifts in selective forces to affect per-brood reproductive investment (RI = total mass of offspring relative to maternal mass) and in the way in which that output is partitioned (number vs. size of offspring per brood). Based on the assumption that newly born offspring are heavier than eggs, we predicted that live-bearing must entail either increased RI or a reduction in offspring size and/or fecundity. However, our phylogenetically controlled analysis of data on 1,259 squamate species revealed no significant differences in mean offspring size, clutch size or RI between oviparous and viviparous squamates. We attribute this paradoxical result to (1) strong selection on offspring sizes, unaffected by parity mode, (2) the lack of a larval stage in amniotes, favouring large eggs even in the ancestral oviparous mode and (3) the ability of viviparous females to decrease the mass of uterine embryos by reducing extra-embryonic water stores. Our analysis shows that squamate eggs (when laid) weigh about the same as the hatchlings that emerge from them (despite a many-fold increase in embryo mass during incubation). Most of the egg mass is due to components (such as water stores and the eggshell) not required for oviductal incubation. That repackaging enables live-born offspring to be accommodated within the mother's body without increasing total litter mass. The consequent stasis in reproductive burden during the evolutionary transition from Oviparity to viviparity may have facilitated frequent shifts in parity modes.
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the evolution of Oviparity in squamate reptiles an adaptationist perspective
Journal of Experimental Zoology, 2015Co-Authors: Richard ShineAbstract:Phylogenetically based analyses can suggest directions of evolutionary transitions, based on parsimony, but can never provide unambiguous answers. To clarify the relative frequency of phylogenetic shifts from Oviparity to viviparity versus the reverse, we need additional sources of evidence. Adaptationist thinking (i.e., consideration of selective forces) has revealed a great deal about the transition from Oviparity to viviparity, but has rarely been employed to consider the reverse transition. An evaluation of costs and benefits identifies major obstacles to the re-evolution of Oviparity. For example, even a modest decrease in the degree of embryogenesis completed in utero (i.e., a shift from viviparity back toward "normal" Oviparity) requires the mother to find a suitable nest-site (often, a risky endeavor), and a minor decrease in the duration of uterine retention of eggs may not substantially reduce maternal costs (because many of those costs are minimized by maternal behavioral adaptations to pregnancy). In many climates, a small decrease in the duration of uterine retention of eggs would not allow the female to produce a second clutch within the same season; and thus, would not reduce the fecundity disadvantage of viviparity. Life-history theory thus suggests an asymmetry in the fitness consequences of the intermediate stages between Oviparity and viviparity. That asymmetry facilitates the "forward" transition (based on thermally driven benefits to offspring viability) but opposes the "reverse" transition (based on lower fitness of heavily burdened females that need to seek nest-sites). These factors should constrain the re-evolution of Oviparity to specific conditions (e.g., where abundant nest-sites are available within a female's usual home range, rather than requiring extensive migration).
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evolution of an evolutionary hypothesis a history of changing ideas about the adaptive significance of viviparity in reptiles
Journal of Herpetology, 2014Co-Authors: Richard ShineAbstract:Abstract Most reptiles are oviparous (egg-laying), but viviparity (live-bearing) has evolved about 100 times in lizards and snakes. Geographic biases in the distribution of viviparous species stimulated the “cold-climate hypothesis,” proposed independently by three field-based researchers in the early 1900s. Mell (in China) and Weekes (in Australia) viewed viviparity as a mechanism for thermal buffering of embryos from nighttime frosts, whereas Sergeev (in Russia) suggested that eggs retained in utero would develop faster because they were kept warmer, enabling early hatching. Although alternative adaptationist hypotheses proliferated over the next few decades, many had logical flaws (failing to consider intermediate stages). Phylogenetically based analyses identified around 100 independent origins of viviparity from Oviparity, and revealed a strong trend for viviparity to evolve in cold climates. After experimental studies showed that incubation temperatures affect offspring phenotypes as well as rates o...
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grass snakes exploit anthropogenic heat sources to overcome distributional limits imposed by Oviparity
Functional Ecology, 2010Co-Authors: Kristin Lowenborg, Richard Shine, Simon Karvemo, Mattias HagmanAbstract:P>1. A lack of warm nest-sites prevents oviparous reptile species from reproducing in cool climates; such areas are dominated by viviparous species because sun-seeking pregnant females can maintain high temperatures for their developing offspring. 2. Our field and laboratory studies show that one oviparous species (the grass snake, Natrix natrix) escapes this cold-climate constraint (and hence, extends much further north in Europe than do other oviparous taxa) by ovipositing in a thermally distinctive man-made microhabitat (manure heaps on farms). 3. In the field, temperatures inside manure heaps averaged 30 center dot 7 degrees C, much higher than compost heaps (20 center dot 6 degrees C) or potential natural nest-sites under logs and rocks (15 center dot 5 degrees C). 4. In the laboratory, higher incubation temperatures not only hastened hatching, but also increased hatching success and modified the body sizes, colours, and locomotor abilities of hatchlings. Incubation temperatures typical of manure heaps (rather than alternative nest-sites) resulted in larger, faster offspring that hatched earlier in the season. 5. Thus, anthropogenic activities have generated potential nest-sites offering thermal regimes not naturally available in the region; and grass snakes have exploited that opportunity to escape the thermal limits that restrict geographic distributions of other oviparous reptile taxa.
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did embryonic responses to incubation conditions drive the evolution of reproductive modes in squamate reptiles
Herpetological Monographs, 2006Co-Authors: Richard Shine, Michael B. ThompsonAbstract:Viviparity (live-bearing) has evolved from Oviparity (egg-laying) more than 100 times within snakes and lizards, and thermal factors are thought to have driven this shift. However, other major features of reptilian reproduction may reflect selective pressures related to hydric rather than thermal exchanges between the egg and its incubation environment. Notably, why are intermediate stages of prolonged egg retention so rarely seen? Embryonic stages at oviposition in squamates are largely dichotomous: most oviparous species lay eggs with embryos about one-third developed, whereas viviparous taxa retain the eggs until development is complete. Why don't more species oviposit with embryos at either earlier or later stages? We suggest that the scarcity of squamates that lay eggs soon after ovulation (and thus, with very early-stage embryos) may reflect the need to delay oviposition until embryos have developed sufficient physiological control over water influx and efflux to survive in the challenging hydric environment of the nest. The scarcity of retention to later stages (intermediate between typical Oviparity and viviparity), and the apparent lack of reversals from viviparity back to Oviparity, may be due to a conflict between adaptations for water versus gas exchange; retention of larger embryos in utero requires eggshell thinning to allow gas exchange, but a thinner shell precludes effective hydric control after oviposition. Thus, although the transition from Oviparity to viviparity in squamates has been driven largely by thermal advantages, the clustering of species at two main positions along the Oviparity-viviparity continuum may be due to challenges of controlling embryonic water balance.
Szczepan M. Bilinski - One of the best experts on this subject based on the ideXlab platform.
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Embryos of the viviparous dermapteran, Arixenia esau develop sequentially in two compartments: terminal ovarian follicles and the uterus.
PLOS ONE, 2013Co-Authors: Waclaw Tworzydlo, Elzbieta Kisiel, Szczepan M. BilinskiAbstract:Three main reproductive strategies have been described among insects: most common Oviparity, ovoviviparity and viviparity. In the latter strategy, the embryonic development takes place within the body of the mother which provides gas exchange and nutrients for embryos. Here we present the results of histological and EM analyses of the female reproductive system of the viviparous earwig, Arixenia esau, focusing on all the modifications related to the viviparity. We show that in the studied species the embryonic development consists of two “physiological phases” that take place in two clearly disparate compartments, i.e. the terminal ovarian follicle and the uterus. In both compartments the embryos are associated with synthetically active epithelial cells. We suggest that these cells are involved in the nourishment of the embryo. Our results indicate that viviparity in arixeniids is more complex than previously considered. We propose the new term “pseudoplacento-uterotrophic viviparity” for this unique two-phase reproductive strategy.
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Embryos of the Viviparous Dermapteran, Arixenia esau Develop Sequentially in Two Compartments: Terminal
2012Co-Authors: Ovarian Follicles, Waclaw Tworzydlo, Elzbieta Kisiel, The Uterus, Szczepan M. BilinskiAbstract:Three main reproductive strategies have been described among insects: most common Oviparity, ovoviviparity and viviparity. In the latter strategy, the embryonic development takes place within the body of the mother which provides gas exchange and nutrients for embryos. Here we present the results of histological and EM analyses of the female reproductive system of the viviparous earwig, Arixenia esau, focusing on all the modifications related to the viviparity. We show that in the studied species the embryonic development consists of two ‘‘physiological phases’ ’ that take place in two clearly disparate compartments, i.e. the terminal ovarian follicle and the uterus. In both compartments the embryos are associated with synthetically active epithelial cells. We suggest that these cells are involved in the nourishment of the embryo. Our results indicate that viviparity in arixeniids is more complex than previously considered. We propose the new term ‘‘pseudoplacento-uterotrophic viviparity’ ’ for this unique two-phase reproductive strategy
Kathryn R Elmer - One of the best experts on this subject based on the ideXlab platform.
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evolutionary origins of viviparity consistent with palaeoclimate and lineage diversification
Journal of Evolutionary Biology, 2021Co-Authors: Hans Recknagel, Nicholas A Kamenos, Kathryn R ElmerAbstract:It is of fundamental importance for the field of evolutionary biology to understand when and why major evolutionary transitions occur. Live-bearing young (viviparity) is a major evolutionary change and has evolved from egg-laying (Oviparity) independently in many vertebrate lineages and most abundantly in lizards and snakes. Although contemporary viviparous squamate species generally occupy cold climatic regions across the globe, it is not known whether viviparity evolved as a response to cold climate in the first place. Here, we used available published time-calibrated squamate phylogenies and parity data on 3,498 taxa. We compared the accumulation of transitions from Oviparity to viviparity relative to background diversification and a simulated binary trait. Extracting the date of each transition in the phylogenies and informed by 65 my of global palaeoclimatic data, we tested the nonexclusive hypotheses that viviparity evolved under the following: (a) cold, (b) long-term stable climatic conditions and (c) with background diversification rate. We show that stable and long-lasting cold climatic conditions are correlated with transitions to viviparity across squamates. This correlation of parity mode and palaeoclimate is mirrored by background diversification in squamates, and simulations of a binary trait also showed a similar association with palaeoclimate, meaning that trait evolution cannot be separated from squamate lineage diversification. We suggest that parity mode transitions depend on environmental and intrinsic effects and that background diversification rate may be a factor in trait diversification more generally.
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common lizards break dollo s law of irreversibility genome wide phylogenomics support a single origin of viviparity and re evolution of Oviparity
Molecular Phylogenetics and Evolution, 2018Co-Authors: Hans Recknagel, Nicholas A Kamenos, Kathryn R ElmerAbstract:Abstract Dollo’s law of irreversibility states that once a complex trait has been lost in evolution, it cannot be regained. It is thought that complex epistatic interactions and developmental constraints impede the re-emergence of such a trait. Oviparous reproduction (egg-laying) requires the formation of an eggshell and represents an example of such a complex trait. In reptiles, viviparity (live-bearing) has evolved repeatedly but it is highly disputed if Oviparity can re-evolve. Here, using up to 194,358 SNP loci and 1,334,760 bp of sequence, we reconstruct the phylogeny of viviparous and oviparous lineages of common lizards and infer the evolutionary history of parity modes. Our phylogeny supports six main common lizard lineages that have been previously identified. We find strong statistical support for a topological arrangement that suggests a reversal to Oviparity from viviparity. Our topology is consistent with highly differentiated chromosomal configurations between lineages, but disagrees with previous phylogenetic studies in some nodes. While we find high support for a reversal to Oviparity, more genomic and developmental data are needed to robustly test this and assess the mechanism by which a reversal might have occurred.
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common lizards break dollo s law of irreversibility genome wide phylogenomics support a single origin of viviparity and re evolution of Oviparity
bioRxiv, 2017Co-Authors: Hans Recknagel, Nicholas A Kamenos, Kathryn R ElmerAbstract:Dollo9s law of irreversibility states that once a complex trait has been lost in evolution, it cannot be regained. It is thought that complex epistatic interactions and developmental constraints impede the re-emergence of such a trait. Oviparous reproduction (egg-laying) requires the formation of an eggshell and represents an example of such a complex trait. In reptiles, viviparity (live-bearing) has evolved repeatedly but it is highly disputed if Oviparity has re-evolved. Here, using up to 194,358 SNP loci and 1,334,760 bp of sequence, we reconstruct the phylogeny of viviparous and oviparous lineages of common lizards and infer the evolutionary history of parity modes. Our phylogeny strongly supports six main common lizard lineages that have been previously identified. We find very high statistical support for a topological arrangement that suggests a reversal to Oviparity from viviparity. Our topology is consistent with highly differentiated chromosomal configurations between lineages, but disagrees with previous phylogenetic studies in some nodes. While we find high support for a reversal to Oviparity, more genomic and developmental data are needed to robustly test this and assess the mechanism by which a reversal might have occurred.
Tomasz Mamos - One of the best experts on this subject based on the ideXlab platform.
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evolution of reproductive strategies in the species rich land snail subfamily phaedusinae stylommatophora clausiliidae
Molecular Phylogenetics and Evolution, 2021Co-Authors: Tomasz Mamos, Dennis Uit De Weerd, Parm Viktor Von Oheimb, Anna SulikowskadrozdAbstract:Most of the present knowledge on animal reproductive mode evolution, and possible factors driving transitions between Oviparity and viviparity is based on studies on vertebrates. The species rich door snail (Clausiliidae) subfamily Phaedusinae represents a suitable and unique model for further examining parity evolution, as three different strategies, Oviparity, viviparity, and the intermediate mode of embryo-retention, occur in this group. The present study reconstructs the evolution of reproductive strategies in Phaedusinae based on time-calibrated molecular phylogenetics, reproductive mode examinations and ancestral state reconstruction. Our phylogenetic analysis employing multiple mitochondrial and nuclear markers identified a well-supported clade (including the tribes Phaedusini and Serrulinini) that contains species exhibiting various reproductive strategies. This clade evolved from an oviparous most recent common ancestor according to our reconstruction. All non-oviparous taxa are confined to a highly supported subclade, coinciding with the tribe Phaedusini. Both Oviparity and viviparity occur frequently in different lineages of this subclade that are not closely related. During Phaedusini diversification, multiple transitions in reproductive strategy must have taken place, which could have been promoted by a high fitness of embryo-retaining species. The evolutionary success of this group might result from the maintenance of various strategies.
