Biology subjects

Rogell, B.

Publications and source records attributed to Rogell, B..

6 recordsLinked to original sources

bioRxiv2022

What is particular about microplastics? A meta-analysis of the toxicity of microplastics and suspended sediments

Microplastics (MP) are perceived as a threat to aquatic ecosystems but bear many similarities to suspended sediments which are often considered less harmful. It is, therefore pertinent to determine if and to what extent MPs are different from other particles occurring in aquatic ecosystems in terms of their adverse effects. We applied meta-regressions to hazard data extracted from the literature and harmonized the data to construct Species Sensitivity Distributions (SSDs) for both types of particles. The results demonstrate that the average toxicity of MPs is approximately one order of magnitude higher than that of suspended solids. However, the estimates were associated with large uncertainties and did not provide very strong evidence. In part, this is due to the general lack of comparable experimental studies and dose-dependent point estimates. We, therefore, argue that a precautionary approach should be used and MP in the 1-1000 {micro}m size range should be considered moderately more hazardous to aquatic organisms capable of ingesting such particles. Organisms inhabiting oligotrophic habitats like coral reefs and alpine lakes, with naturally low levels of non-food particles are likely more vulnerable, and it is reasonable to assume that MP pose a relatively higher risk to aquatic life in such habitats. SynopsisA meta-analysis indicates that microplastics are one order of magnitude more toxic than suspended sediments/solids, an estimate surrounded by considerable uncertainty. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=110 SRC="FIGDIR/small/514507v2_ufig1.gif" ALT="Figure 1"> View larger version (46K): org.highwire.dtl.DTLVardef@18826c5org.highwire.dtl.DTLVardef@1a98189org.highwire.dtl.DTLVardef@17762d7org.highwire.dtl.DTLVardef@fa4a6d_HPS_FORMAT_FIGEXP M_FIG C_FIG

ecology↗

bioRxiv2021

Rapid mosaic brain evolution under artificial selection for relative telencephalon size in the guppy (Poecilia reticulata)

The vertebrate brain displays enormous morphological variation and the quest to understand the evolutionary causes and consequences of this variation has spurred much research. The mosaic brain evolution hypothesis, stating that brain regions can evolve relatively independently, is an important idea in this research field. Here we provide experimental support for this hypothesis through an artificial selection experiment in the guppy (Poecilia reticulata). After four generations of selection on relative telencephalon volume (relative to brain size) in replicated up-selected, down-selected and control-lines, we found substantial changes in telencephalon size, but no changes in other regions. Comparisons revealed that up-selected lines had larger telencephalon while down-selected lines had smaller telencephalon than wild Trinidadian populations. No cost of increasing telencephalon size was detected in offspring production. Our results support that independent evolutionary changes in specific brain regions through mosaic brain evolution can be important facilitators of cognitive evolution.

evolutionary biology↗

bioRxiv2020

The evolution of a placenta is not linked to increased brain size in poeciliid fishes

Maternal investment is considered to have a direct influence on the size of energetically costly organs, including the brain. In placental organisms, offspring are supplied with nutrients during pre-natal development, potentially modulating brain size. However, the coevolution of the placenta and brain size remains largely unknown in non-mammalian taxa. Here, using eight poeciliid fish species, we test if species with placental structures invest more resources into offspring brain development than species without placental structures. We predict that matrotrophy may entail higher nutrient provisioning rates to the developing embryo than lecithotrophy, resulting in larger brain sizes in offspring of matrotrophic species, and that a relatively larger part of the total brain growth would occur at younger ages (leading to a shallower ontogenetic brain size allometry). We took non-invasive brain size measurements during the first four weeks of life, and compared these to somatic growth measurements. Contrary to our expectations, we did not find any differences in brain size between the two maternal strategies. Furthermore, we did not find any differences in how relative brain size changed over ontogenetic development, between placental and non-placental species. In contrast to the marsupial/placental transition, the species investigated here only exhibit pre-natal provisioning, which may reduce the potential for maternal investment into brain size. Consequently, our results suggest that coevolution between placental structures and juvenile brain size is not a general pattern.

evolutionary biology↗

bioRxiv2020

Variation in developmental rates is not linked to environmental unpredictability in annual killifishes

Comparative evidence suggests that adaptive plasticity may evolve as a response to predictable environmental variation. However, less attention has been placed on unpredictable environmental variation, which is considered to affect evolutionary trajectories by increasing phenotypic variation (or bet-hedging). Here, we examine the occurrence of bet-hedging in egg developmental rates in seven species of annual killifish, which originate from a gradient of variation in precipitation rates, under three treatment incubation temperatures (21{degrees}C, 23{degrees}C, and 25{degrees}C). In the wild, these species survive regular and seasonal habitat desiccation, as dormant eggs buried in the soil. At the onset of the rainy season, embryos must be sufficiently developed in order to hatch and complete their life-cycle. We found substantial differences among species in both the mean and variation of egg development rates, as well as species-specific plastic responses to incubation temperature. Yet, there was no clear relationship between variation in egg development time and variation in precipitation rate (environmental predictability). The exact cause of these differences therefore remains enigmatic, possibly depending on differences in other natural environmental conditions in addition to precipitation predictability. Hence, if species-specific variances are adaptive, the relationship between development and variation in precipitation is complex, and does not diverge in accordance with simple linear relationships.

evolutionary biology↗

bioRxiv2019

Coevolution between life-history and metabolic rate depends on ontogenetic stage

Metabolic rate is considered to determine the energetic investment placed into life-history traits, regulating the speed of an organisms life-cycle and forming the so called \"pace-of-life\". However, how metabolic rate and life-history traits co-evolve remains unclear. For instance, the energetic demands of life-history traits, including the number of energy allocation trade-offs, is unlikely to remain constant over ontogeny. Therefore, the predicted coevolution between metabolic rate and life-history could be specific to particular ontogenetic stages, rather than a stable property of an organism. Here, we test the ontogenetic dependency of the coevolution between metabolic rate and the pace of life-history, under strictly standardized conditions using 30 species of killifish, which are either annual species adapted to ephemeral pools or non-annual species inhabiting more permanent waterbodies. Standard metabolic rates were estimated at three ontogenetic stages, together with relevant life-history traits, i.e. growth (juveniles), maturity (young adults), and reproductive rate (reproductive adults). Life-history traits largely followed predicted pace-of-life patterns, with overall faster/higher rates in annual species. The divergences in life-history traits across species tended to increase over ontogeny, being smallest during juvenile growth and largest in reproductive adults. However, associations between life-history strategy and metabolic rate followed a reversed pattern, being strongest in juveniles, but lowest in reproductive adults. Our results are concordant with the number of energetic trade-offs increasing over ontogeny, which results in a stronger covariation between physiology and life-history traits earlier in ontogeny.

evolutionary biology↗

bioRxiv2017

Mitochondrial genome variation affects the mutation rate of the nuclear genome in Drosophila melanogaster

Mutations are the raw material for evolutionary change. While the mutation rate has been thought constant between individuals, recent research has shown that poor genetic condition can elevate the mutation rate. Mitonuclear genetic conflict is a potential source of poor genetic condition, and considering the high mutation rate of mitochondrial genomes, there should be ample scope for mitochondrial mutations to interfere with genetic condition, with concomitant effects on the nuclear mutation rate. Moreover, because theory suggests mitochondrial genetic effects will often be male-biased, such effects could be more strongly felt in males than females. Here, by mating irradiated male Drosophila melanogaster to isogenic females bearing six distinct mitochondrial haplotypes, we tested whether mitochondrial genetic variation affects DNA repair capacity, and whether effects of mutation load on reproductive function are shaped by interactions between sex and mitochondrial haplotype. We found mitochondrial genetic effects on DNA repair, and that the mutational variance of reproductive fitness was higher in males bearing haplotypes characterized by high female fitness. These results suggest that mitochondrial genome variation may affect the mutation rate, and that induced mutations interact more strongly with male than female reproductive function. The potential for haplotype-specific effects on the nuclear mutation rate has broad implications for evolutionary dynamics, such as the accumulation of genetic load, adaptive potential, and the evolution of sexual dimorphism.

evolutionary biology↗