ORCID Profile
0000-0001-8222-8399
Current Organisation
Aalborg Universitet
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Publisher: The Royal Society
Date: 24-01-2022
Abstract: Understanding how environmental factors affect the thermal tolerance of species is crucial for predicting the impact of thermal stress on species abundance and distribution. To date, species' responses to thermal stress are typically assessed on laboratory-reared in iduals and using coarse, low-resolution, climate data that may not reflect microhabitat dynamics at a relevant scale. Here, we examine the daily temporal variation in heat tolerance in a range of species in their natural environments across temperate and tropical Australia. In iduals were collected in their habitats throughout the day and tested for heat tolerance immediately thereafter, while local microclimates were recorded at the collection sites. We found high levels of plasticity in heat tolerance across all the tested species. Both short- and long-term variability of temperature and humidity affected plastic adjustments of heat tolerance within and across days, but with species differences. Our results reveal that plastic changes in heat tolerance occur rapidly at a daily scale and that environmental factors on a relatively short timescale are important drivers of the observed variation in thermal tolerance. Ignoring such fine-scale physiological processes in distribution models might obscure conclusions about species' range shifts with global climate change. This article is part of the theme issue ‘Species’ ranges in the face of changing environments (part 1)’.
Publisher: Proceedings of the National Academy of Sciences
Date: 20-12-2021
Abstract: About 50 y ago, Crow and Kimura [ An Introduction to Population Genetics Theory (1970)] and Ohta and Kimura [ Genet. Res. 22, 201–204 (1973)] laid the foundations of conservation genetics by predicting the relationship between population size and genetic marker ersity. This work sparked an enormous research effort investigating the importance of population dynamics, in particular small population size, for population mean performance, population viability, and evolutionary potential. In light of a recent perspective [J. C. Teixeira, C. D. Huber, Proc. Natl. Acad. Sci. U.S.A. 118, 10 (2021)] that challenges some fundamental assumptions in conservation genetics, it is timely to summarize what the field has achieved, what robust patterns have emerged, and worthwhile future research directions. We consider theory and methodological breakthroughs that have helped management, and we outline some fundamental and applied challenges for conservation genetics.
Publisher: Public Library of Science (PLoS)
Date: 12-06-2019
Publisher: Springer Science and Business Media LLC
Date: 26-07-2018
Publisher: Wiley
Date: 28-11-2017
DOI: 10.1111/EVO.13391
Abstract: Trait variation is normally separated into genetic and environmental components, yet genetic factors also control the expression of environmental variation, encompassing plasticity across environmental gradients and within-environment responses. We defined four components of environmental variation: plasticity across environments, variability in plasticity, variation within environments, and differences in within-environment variation across environments. We assessed these components for cold tolerance across five rearing temperatures using the Drosophila melanogaster Genetic Reference Panel (DGRP). The four components were found to be heritable, and genetically correlated to different extents. By whole genome single marker regression, we detected multiple candidate genes controlling the four components and showed limited overlap in genes affecting them. Using the binary UAS-GAL4 system, we functionally validated the effects of a subset of candidate genes affecting each of the four components of environmental variation and also confirmed the genetic and phenotypic correlations obtained from the DGRP in distinct genetic backgrounds. We delineate selection targets associated with environmental variation and the constraints acting upon them, providing a framework for evolutionary and applied studies on environmental sensitivity. Based on our results we suggest that the traditional quantitative genetic view of environmental variation and genotype-by-environment interactions needs revisiting.
Publisher: Cold Spring Harbor Laboratory
Date: 05-07-2021
DOI: 10.1101/2021.07.04.450854
Abstract: It is becoming increasingly clear that microbial symbionts influence key aspects of their host’s fitness, and vice versa . This may fundamentally change our thinking about how microbes and hosts interact in influencing fitness and adaptation to changing environments. Here we explore how reductions in population size commonly experienced by threatened species influence microbiome ersity. Consequences of such reductions are normally interpreted in terms of a loss of genetic variation, increased inbreeding and associated inbreeding depression. However, fitness effects of population bottlenecks might also be mediated through microbiome ersity, such as through loss of functionally important microbes. Here we utilise 50 Drosophila melanogaster lines with different histories of population bottlenecks to explore these questions. The lines were phenotyped for egg-to-adult viability and their genomes sequenced to estimate genetic variation. The bacterial 16S rRNA gene was lified in these lines to investigate microbial ersity. We found that 1) host population bottlenecks constrained microbiome richness and ersity, 2) core microbiomes of hosts with low genetic variation were constituted from subsets of microbiomes found in flies with higher genetic variation, 3) both microbiome ersity and host genetic variation contributed to host population fitness, 4) connectivity and robustness of bacterial networks was low in the inbred lines regardless of host genetic variation, 5) reduced microbial ersity was associated with weaker evolutionary responses of hosts in stressful environments, and 6) these effects were unrelated to Wolbachia density. These findings suggest that population bottlenecks reduce hologenomic variation (combined host and microbial genetic variation). Thus, while the current bio ersity crisis focuses on population sizes and genetic variation of eukaryotes, an additional focal point should be the microbial ersity carried by the eukaryotes, which in turn may influence host fitness and adaptability with consequences for the persistence of populations. It is becoming increasingly clear that organisms and the microbes that live on or in them – their microbiome – affect each other in profound ways that we are just beginning to understand. For instance, a erse microbiome can help maintain metabolic functions or fight pathogens causing diseases. A disrupted microbiome may be especially critical for animals and plants that occur in low numbers because of threats from e.g. human exploitation or climate change, as they may already suffer from genetic challenges such as inbreeding and reduced evolutionary potential. The importance of such a reduction in population size, called a bottleneck, on the microbial ersity and the potential interactive effects on host health remains unexplored. Here we experimentally test these associations by investigating the microbiomes of 50 inbred or non-inbred populations of vinegar flies. We found that restricting the population size constrain the host’s genetic variation and simultaneously decreases the ersity of the microbiome that they harbor, and that both effects were detrimental to host fitness. The microbial communities in inbred host populations were less robust than in their non-inbred counterparts, suggesting that we should increasingly consider the microbiome ersity, which may ultimately influence the health and persistence of threatened species.
No related grants have been discovered for Michael Ørsted.