Biology subjects

Bonduriansky, R.

Publications and source records attributed to Bonduriansky, R..

10 recordsLinked to original sources

bioRxiv2026

Maternal senescence broadly reprograms gene expression in offspring

Offspring of older parents have reduced fitness in many species, but the mechanisms mediating this cross-generational dimension of ageing remain poorly understood. Senescence is associated with genome-wide epigenetic changes that alter transcription, raising the possibility that older parents transmit dysregulated gene expression patterns. Here we show that maternal senescence induces deleterious, transcriptome-wide reprogramming of gene expression in offspring. Gene ontology and pathway enrichment analyses reveal that broad changes in gene expression that characterise maternal senescence in the clonally reproducing arthropod Folsomia candida are also observed at a young age in the offspring of older mothers. These concordant fold-changes are apparent at the whole-transcriptome level, and encompass conserved sequalae of senescence, including reduced carbon and energy metabolism. However, senescent mothers and their offspring also exhibit some contrasting gene expression patterns, representing distinct transcriptomic signatures of senescence that are not reflected in its cross-generational effects. The broad reprogramming of gene expression in offspring of older mothers is associated with substantially reduced fitness. Our findings show that older females can transmit a senescence-like gene expression syndrome to their offspring, inducing deleterious phenotypes from a young age.

genomics↗

bioRxiv2026

Flexible Asexuality: Naturally occurring variation in mechanisms of parthenogenesis within lineages and individuals of a facultative parthenogen, Megacrania batesii

Parthenogenesis is relatively rare and often regarded as an evolutionary dead end. Despite this, certain parthenogenetic animal species have endured for millions of years, but it is unclear what enables the persistence of some parthenogenetic lineages. Transitions from sexual to parthenogenetic reproduction can occur through different evolutionary processes that give rise to diverse cytological reproductive mechanisms. These mechanisms are likely to influence genetic diversity, especially in the early stages after the transition to parthenogenesis and may thus affect lineage persistence. To understand such evolutionary transitions, we used experimental crosses to investigate the mechanism of parthenogenesis and the immediate genetic consequences of switching from sexual to parthenogenetic reproduction in the facultatively parthenogenetic phasmid Megacrania batesii. We obtained DNA sequence data from multiple lineages propagated over three generations via sex, parthenogenesis, or transitions between reproductive modes. We quantified heterozygosity and within-family genetic variation and compared the genetic patterns with predictions for known mechanisms of parthenogenesis. We found that a single generation of parthenogenesis typically resulted in (near-)complete loss of heterozygosity and an absence of within-family genetic variation, consistent with automixis with gamete duplication or terminal fusion and little/no recombination. However, we also found evidence of variation in the mechanism of parthenogenesis among lineages and even within the same individual, associated with drastic differences in the amount of heterozygosity and within-family genetic variation maintained across generations. Our findings show that considerable variation in parthenogenetic mechanisms can exist within populations and suggest that such variation could influence the persistence and evolution of parthenogenetic lineages.

evolutionary biology↗

bioRxiv2024

Weathering the storm for love: Mate searching behaviour of wild males of the Sydney funnel-web spider (Atrax robustus)

The risky business of mate-searching often leaves the actively searching sex facing threats and rapidly changing conditions. Yet, active mate-searching behaviour is rarely studied in invertebrates, and we have limited understanding of how mate-searching strategies have evolved to cope with risks posed by harsh weather. We investigated how mate-searching males move through their habitat and how their movement is affected by weather conditions in the Sydney funnel-web spider (Atrax robustus), one of the worlds most venomous spiders. As is common in mygalomorphs spiders, females are functionally sessile, and are thought to spend their whole lives in a single burrow, whereas males must permanently abandon their burrows to mate during the breeding season. Nineteen male spiders were fitted with micro-radio transmitters and tracked during their mating seasons in 2020 (n = 2), 2021 (n = 8) and 2022 (n = 9) in Lane Cove National Park, in Sydney, Australia. Males moved at night, typically in a zig-zag pattern, and were found in new locations on approximately 50% of daily resightings. Males often spent several days in a females burrow, and some female burrows were visited by multiple males. When outside a females burrow, males constructed and occupied temporary shelters ( temporacula). Males were most likely to move and/or moved furthest when there was no rain, and on warm nights after cool days. Our findings suggest that mate-searching A. robustus males prefer to search for females in less risky conditions, revealing novel risk-minimizing strategies, especially in response to rainfall and temperature.

animal behavior and cognition↗

bioRxiv2024

Does ecology shape geographical parthenogenesis? Evidence from the facultatively parthenogenetic stick insect Megacrania batesii

Closely related sexual and parthenogenetic species often show distinct distribution patterns, known as geographical parthenogenesis. These patterns, characterized by a mosaic of separate sexual and parthenogenetic populations across their natural range, can also be found in facultative parthenogens - species in which every female is capable of both sexual and parthenogenetic reproduction. The underlying mechanisms driving this phenomenon in nature remain unclear. Features of the habitat, such as differences in host plant phenotypes or niche breadth, could favour sexual or asexual reproductive modes and thus help to explain geographical parthenogenesis in natural insect populations. Megacrania batesii is a facultatively parthenogenetic stick insect that displays geographical parthenogenesis in the wild. We aimed to explore whether sexual and parthenogenetic populations of M. batesii displayed niche differentiation or variations in niche breadth that could explain the separation of the two population types. To do this, we sampled host plants from across the range of M. batesii and quantified phenotypic traits that might affect palatability or accessibility for M. batesii, including leaf thickness, toughness, spike size and density, height, and chemical composition. We also quantified host plant density, which could affect M. batesii dispersal. We found little evidence of phenotypic differences between host plants supporting sexual versus asexual M. batesii populations, and no difference in host-plant density or niche breadth between the two population types. Our results suggest that habitat parameters do not play a substantial role in shaping patterns of geographical parthenogenesis in wild populations of M. batesii. Instead, population sex ratio variation could result from interactions between the sexes or dispersal dynamics.

evolutionary biology↗

bioRxiv2022

Genetic and phenotypic consequences of local transitions between sexual and parthenogenetic reproduction in the wild

Transitions from sexual to asexual reproduction have occurred in numerous lineages across the tree of life, but it remains unclear why asexual populations rarely persist. In facultatively parthenogenetic animals, all-female populations can arise when males are absent or become extinct, and such populations can give rise to obligately asexual species. Facultative parthenogens could therefore shed light on the initial stages of transitions to asexuality, and the factors that determine the success or failure of asexual populations. Here, we describe a novel spatial mosaic of mixed-sex and all-female populations of the facultatively parthenogenetic Australian phasmid Megacrania batesii, and use this system to investigate the consequences of reproductive mode variation in the wild. Analysis of single nucleotide polymorphisms (SNPs) indicated multiple, independent transitions between reproductive modes. As expected, all-female populations had drastically reduced heterozygosity and genetic diversity relative to mixed-sex populations. However, we found few consistent differences in fitness-related traits between population types. All-female populations exhibited more frequent and severe (non-functional) wing deformities, but did not show higher rates of appendage loss. All-female populations also harbored more parasites, but only in certain habitats. Reproductive mode explained little variation in female body size, fecundity, or egg hatch-rate. Our results confirm that transitions to parthenogenetic reproduction can lead to dramatic reductions in genetic diversity and heterozygosity. However, our findings also suggest that asexual M. batesii populations consist of high-fitness genotypes that might be able to thrive for many generations, perhaps until they encounter a drastic environmental change to which they are unable to adapt.

evolutionary biology↗

bioRxiv2022

Dietary restriction fails to extend life in stressful environments

Moderate dietary restriction often prolongs life in laboratory animals, and this response has been interpreted as an adaptive strategy that promotes survival during famine. However, dietary restriction can also increase frailty, and it therefore remains unclear whether restricted diets prolong life under stressful conditions like those experienced by wild animals. We manipulated adult dietary protein of Drosophila melanogaster across a gradient of ambient temperature. We found that protein restriction increased longevity of both sexes at benign ambient temperatures (25-27{degrees}C), but failed to extend or even reduced longevity of flies maintained in cold (21-23{degrees}C) or hot (29{degrees}C) conditions. Protein restriction also generally reduced reproductive performance, and did not consistently enhance performance of F1, F2 or F3 descendants. Our results challenge the long-held idea that extended longevity of diet-restricted laboratory animals represents an adaptive survival strategy in natural populations, and suggest instead that this response is an artefact of benign laboratory conditions.

evolutionary biology↗

bioRxiv2020

Sex and Power: sexual dimorphism in trait variability and its eco-evolutionary and statistical implications

Biomedical and clinical sciences are experiencing a renewed interest in the fact that males and females differ in many anatomic, physiological, and behavioral traits. Sex differences in trait variability, however, are yet to receive similar recognition. In medical science, mammalian females are assumed to have higher trait variability due to estrous cycles (the estrus-mediated variability hypothesis); historically in biomedical research, females have been excluded for this reason. Contrastingly, evolutionary theory and associated data support the greater male variability hypothesis. Here, we test these competing hypotheses in 218 traits measured in >26,900 mice, using meta-analysis methods. Neither hypothesis could universally explain patterns in trait variability. Sex-bias in variability was trait-dependent. While greater male variability was found in morphological traits, females were much more variable in immunological traits. Sex-specific variability has eco-evolutionary ramifications including sex-dependent responses to climate change, as well as statistical implications including power analysis considering sex difference in variance.

evolutionary biology↗

bioRxiv2020

A comparison of two methods for estimating measurement repeatability in morphometric studies

O_LIMeasurement repeatability is often reported in morphometric studies as an index of the contribution of measurement error to trait measurements. However, the common method of remeasuring a mounted specimen fails to capture some components of measurement error, and could therefore yield inflated repeatability estimates. Remounting specimens between successive measurements is likely to provide more realistic estimates of repeatability, particularly for small structures that are difficult to measure. C_LIO_LIUsing measurements of 22 somatic and genitalic traits of the neriid fly Telostylinus angusticollis, we compared repeatability estimates obtained via remeasuring (where a mounted specimen is measured twice) versus remounting (where a specimen is remounted between measurements). We also asked whether the difference in repeatability estimates obtained via the two methods depends on trait size. C_LIO_LIRepeatability estimates obtained via remounting were lower than estimates obtained via remeasuring for each of the 22 traits, and the difference between estimates obtained via the two methods was generally greater for small structures (genitalic traits) than for large structures (legs, wings). C_LIO_LIRemounting specimens between successive measurements can provide more accurate estimates of measurement repeatability than remeasuring from a single mount, especially for small structures that are difficult to measure. C_LI

evolutionary biology↗

bioRxiv2019

Sexual conflict explains diverse patterns of transgenerational plasticity

Transgenerational plasticity (TGP) occurs when the environment experienced by parents induces changes in traits of offspring and/or subsequent generations. Such effects can be adaptive or non-adaptive and are increasingly recognised as key determinants of health, cognition, development and performance across a wide range of taxa, including humans. While the conditions that favour maternal TGP are well understood, rapidly accumulating evidence indicates that TGP can be maternal or paternal, and offspring responses can be sex-specific. However, the evolutionary mechanisms that drive this diversity are unknown. We used an individual-based model to investigate the evolution of TGP when the sexes experience different ecologies. We find that adaptive TGP rarely evolves when alleles at loci that determine offspring responses to environmental information originating from the mother and father are subject to sexually antagonistic selection. By contrast, duplication and sex-limitation of such loci can allow for the evolution of a variety of sex-specific responses, including non-adaptive sex-specific TGP when sexual selection is strong. Sexual conflict could therefore help to explain why adaptive TGP evolves in some species but not others, why sons and daughters respond to parental signals in different ways, and why complex patterns of sex-specific TGP may often be non-adaptive.

evolutionary biology↗

bioRxiv2017

Male coercion, female resistance, and the evolutionary trap of sexual reproduction

Recent theory suggests that male coercion could contribute to the maintenance of obligate sex. However, it is unclear how sexually antagonistic coevolution might interact with mate scarcity to influence the probability of invasions of obligately sexual populations by mutants capable of parthenogenetic reproduction. Furthermore, if invasion does occur, it is unclear which factors promote or prevent the complete loss of sex. Using individual-based models, we show that male coercion cannot prevent the invasion of a mutant allele that gives virgin females the ability to reproduce parthenogenetically because mutants always benefit by producing at least some offspring asexually prior to mating. Indeed, the likelihood of invasion generally increases as sexual conflict intensifies, and the effects of sexual conflict and mate scarcity can interact in complex ways to promote invasion. Nonetheless, we find that coercion prevents the complete loss of sex unless linkage disequilibrium can build up between the mutant allele and alleles for effective female resistance. Our findings clarify how costs and limitations of female resistance can promote the maintenance of sexual reproduction, turning sex into an evolutionary trap. At the same time, our results highlight the need to explain why facultative reproductive strategies so rarely evolve in nature.

evolutionary biology↗