Biology subjects

Manser, A.

Publications and source records attributed to Manser, A..

5 recordsLinked to original sources

bioRxiv2026

Assessing a natural gene drive for population control in house mice

House mice are a major invasive pest with significant impact on island ecosystems. Genetic biocontrol via gene editing offers promising new avenues for population control. An alternative idea dating back over half a century is to harness the unmodified, naturally occurring genetic element called t haplotype for population suppression. The t haplotype causes sterility in t/t homozygote males, while +/t heterozygote males transmit the t to most of their offspring via meiotic drive. We use population genetic modelling to systematically explore whether this approach can suppress invasive populations through the accumulation of t/t sterile males. We find that +/t fertile releases combined with the sustained release of t/t sterile males can achieve eradication, but require prolonged interventions, with eradication taking around 25 years under our baseline scenario. We then show that release effort and eradication times may be reduced substantially if releases are combined with trapping, culling, or the release of hyper-competitive (Adonis) males. A direct comparison with tCRISPR, currently the main engineered genetic biocontrol system for house mice, shows that the approach requires greater release effort but achieves comparable eradication times. We provide an R shiny application for exploring model scenarios interactively. Our findings highlight both the potential and the limitations of exploiting this natural meiotic drive system for population control, and identify key gaps in knowledge of mouse reproductive biology and behaviour needed to fully assess its feasibility in the field.

evolutionary biology↗

bioRxiv2025

Living with urban fear: vervet monkey response to an evolutionarily new predator

Humans have facilitated contacts between prey and predator species that have originally not co-evolved, reshuffling the prey-predator arms race. How do prey cope with an evolutionarily new predation risk? We tracked three vervet monkey troops in a South-African semi-urban habitat for 14 months to study their response to domestic dogs. We show that monkeys responded to dogs with a two-pronged behaviour: they emitted alarm calls, and became more vigilant and displayed aggressive behaviours towards the dogs. While their movement highlighted risk-prone behaviour, they appeared to have mapped and planned for risk, as they reacted more strongly when risk was unexpected. The response intensity was further modulated by risk labels typically encountered in their natural environment, but not by labels uniquely associated with dogs. This highlights that vervet monkeys responded with ingrained behaviour to this evolutionarily new threat, anticipating risk based on long-term spatial memory, but failed to integrate evolutionarily new information. TeaserVervet monkeys fear domestic dogs but fail to adjust their antipredator response by discriminating evolutionarily new risk labels.

animal behavior and cognition↗

bioRxiv2023

Vocal-visual combinations in wild chimpanzees

Human communication is strikingly multi-modal, relying on vocal utterances combined with visual gestures, facial expressions and more. Recent efforts to describe multi-modal signal production in our ape relatives have shed important light on the evolutionary trajectory of this core hallmark of human language. However, whilst promising, a systematic quantification of primate signal production which filters out random combinations produced across modalities is currently lacking. Here, through recording the communicative behaviour of wild chimpanzees from the Kibale forest, Uganda we address this issue and generate the first repertoire of non-random combined vocal and visual components. Using collocation analysis, we identify more than 100 vocal-visual combinations which occur more frequently than expected by chance. We also probe how multi-modal production varies in the population, finding no differences between individuals as a function of age, sex or rank. The number of visual components exhibited alongside vocalizations was, however, associated with vocalization type and duration. We demonstrate that chimpanzees produce a vast array of combined vocal and visual components, exhibiting a hitherto underappreciated level of combinatorial complexity. We conclude that a multi-modal approach is crucial to accurately representing the communicative abilities of non-human primates.

animal behavior and cognition↗

bioRxiv2023

A selfish genetic element and its suppressor causes gross damage to testes in a fly

Selfish genetic elements (SGEs), specifically X-chromosome meiotic drive (XCMD), create huge conflicts within a hosts genome and can have profound effects on fertility. Suppressors are a common evolutionary response to XCMD to negate its costs. However, whether suppressors themselves can cause negative non-target effects remains understudied. Here, we examine whether the intragenomic conflicts created by XCMD and its suppressor affect gonad morphology in Drosophila subobscura. We found significant differences in testes, seminal vesicle, and accessory gland size depending on whether a male carried a non-driving X chromosome, an XCMD, and if the XCMD was suppressed. We also found the first evidence of abnormal testes development that is specifically associated with a suppressor of XCMD. Unlike other studies, our evidence suggests that XCMD in D. subobscura creates major abnormalities to male gonads. These abnormalities are most frequent if both XCMD and its suppressor are both present. While costs of suppression have importance in theoretical models, they have largely been ignored in empirical XCMD systems. Overall, this study highlights that genetic conflict, created by SGEs and their suppressors, is a potent evolutionary force that can have major impacts on gonad development and gametogenesis.

evolutionary biology↗

bioRxiv2020

Temperatures that sterilise males better predict global distributions of species than lethal temperatures

Predicting how biodiversity will respond to increased temperatures caused by climate change is vital. However, our understanding of the traits that determine species response to thermal stress remains incomplete. Laboratory measurements of lethal temperatures have successfully been used to predict global species distributions and the vulnerability of species to future climate change. However, although it has long been known that fertility is sensitive to heat stress, temperatures that cause sterility have not been incorporated into predictions about how climate change will affect biodiversity. Here we show that male sterility temperatures predict the global distributions of 43 species of Drosophila substantially better than their lethal temperatures. This strongly suggests that thermal limits to reproduction can underpin how temperature affects species distributions. High temperatures impair male fertility across a broad range of animals and plants, so many organisms may be more vulnerable to high temperatures than currently expected.

ecology↗