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opencc-zeroNov 2022View details →

Data for: The effect of brief or prolonged bouts of winning or losing male-male contests on plasticity in sexually selected traits

Fight outcomes often affect male fitness by determining their access to mates. Thus 'winner-loser' effects, where winners often win their next contest, while losers tend to lose, can influence how males allocate resources towards pre- and post-copulatory traits. We experimentally manipulated the winning/losing experiences of pairs of size-matched male Gambusia holbrooki for either a day, a week or three weeks to test whether prior winning/losing experiences differentially affect the plasticity of male investment into either mating effort (pre-copulatory) or ejaculates (post-copulatory). When winner/loser pairs directly competed for a female, winners had better pre-copulatory outcomes than losers for three of the four traits we measured: mating attempts, successful attempts, and time spent with the female (but not aggression). However, winners and losers did not differ in either their total sperm counts nor sperm velocity. Interestingly, absolute male size, an important predictor of fighting success, mediated winner-loser effects on how long males then spent near a female. Compared to losers, smaller winners spent more time with the female than did larger winners, suggesting that how males respond to prior social experiences is size-dependent. We discuss the general importance of controlling for inherent male condition when comparing male investment into condition-dependent traits.

opencc-zeroNov 2022View details →

Data and code from: Experimental evolution of environmental tolerance, acclimation, and physiological plasticity in a randomly fluctuating environment

Environmental tolerance curves, representing absolute fitness against the environment, are an empirical assessment of the fundamental niche, and emerge from the phenotypic plasticity of underlying phenotypic traits. Dynamic plastic responses of these traits can lead to acclimation effects, whereby recent past environments impact current fitness. Theory predicts that higher levels of phenotypic plasticity should evolve in environments that fluctuate more predictably, but there have been few experimental tests of these predictions. Specifically, will still lack experimental evidence for evolution of acclimation effects in response to environmental predictability. Here, we exposed 25 genetically diverse populations of the halotolerant microalgae Dunaliella salina to different constant salinities, or to randomly fluctuating salinities, for over 200 generations. The fluctuating treatments differed in their autocorrelation, which determines the similarity of subsequent values, and thus environmental predictability. We then measured acclimated tolerance surfaces, mapping population growth rate against past (acclimation) and current (assay) environments. We found that experimental mean and variance in salinity caused the evolution of niche position (optimal salinity) and breadth, with respect to not only current but also past (acclimation) salinity. We also detected weak but significant evidence for evolutionary changes in response to environmental predictability, with higher predictability leading notably to an upwards shift in optimal salinities and stronger acclimation effect of past environment on current fitness. We further showed that these responses are related to the evolution of plasticity for intracellular glycerol, the major osmoregulatory mechanism in this species. However the direction of plasticity evolution did not match simple theoretical predictions. Our results underline the need for a more explicit consideration of the dynamics of environmental tolerance and its underlying plastic traits to reach a better understanding of ecology and evolution in fluctuating environments.

opencc-zeroNov 2022View details →

The risk faced by the early bat: individual plasticity and mortality costs of the timing of spring departure after hibernation

Hibernation is a widespread adaptation in animals to seasonally changing environmental conditions. In the face of global anthropogenic change, information about plastic adjustments to environmental conditions and associated mortality costs are urgently needed to assess population persistence of hibernating species. Here, we used a five-year data set of 1,047 RFID-tagged individuals from two bat species, Myotis nattereri and Myotis daubentonii that were automatically recorded each time they entered or left a hibernaculum. Because the two species differ in foraging strategy and activity pattern during winter, we expected species–specific responses in the timing of hibernation relative to environmental conditions, as well as different mortality costs of early departure from the hibernaculum in spring. Applying mixed-effects modelling, we were able to disentangle population-level and individual-level plasticity in the timing of departure. To estimate mortality costs of early departure, we used both a capture mark recapture analysis and a novel approach that takes into account individual exposure times to mortality outside the hibernaculum. We found that the timing of departure varied between species as well as among and within individuals, and was plastically adjusted to large-scale weather conditions as measured by the NAO (North Atlantic Oscillation) index. Individuals of M. nattereri, which can exploit milder temperatures for foraging during winter, tuned departure more closely to the NAO index than individuals of M. daubentoniid which do not hunt during winter. Both analytical approaches used to estimate mortality costs showed that early departing individuals were less likely to survive until the subsequent hibernation period than individuals that departed later. Overall, our study demonstrates that individuals of long-lived hibernating bat species have the potential to plastically adjust to changing climatic conditions, although the potential for adjustment differs between species.

opencc-zeroDec 2022View details →

Data from: Genetic divergence along a climate gradient shapes chemical plasticity of a foundation tree species to both changing climate and herbivore damage

Climate change is threatening the persistence of many tree species via independent and interactive effects on abiotic and biotic conditions. In addition, changes in temperature, precipitation, and insect attacks can alter the traits of these trees, disrupting communities and ecosystems. For foundation species such as Populus, phytochemical traits are key mechanisms linking trees with their environment and are likely jointly determined by interactive effects of genetic divergence and variable environments throughout their geographic range. Using reciprocal Fremont cottonwood (Populus fremontii) common gardens along a steep climatic gradient, we explored how environment (garden climate and simulated herbivore damage) and genetics (tree provenance and genotype) affect both foliar chemical traits and the plasticity of these traits. We found that: 1) Constitutive and plastic chemical responses to changes in garden climate and damage varied among defense compounds, structural compounds and nitrogen. 2) For both defense and structural compounds, plastic responses to garden climate depended on the climate in which a population or genotype evolved. Specifically, trees originating from cool provenances showed higher defense plasticity in response to climate changes than trees from hotter provenances. 3) Trees from cool provenances growing in cool conditions expressed the lowest constitutive defense levels but the strongest induced (plastic) defenses. 4) The combination of hot growing conditions and simulated herbivory switched the strategy used by these genotypes, increasing constitutive defenses but erasing the capacity for induction. Because Fremont cottonwood chemistry plays a major role in shaping riparian communities and ecosystems in the southwestern US, the effects of changes in phytochemical traits can be wide-reaching. As the southwestern US is confronted with warming temperatures and insect outbreaks, these results improve our capacity to predict ecosystem consequences of climate change and inform selection of tree genotypes for conservation and restoration purposes.

opencc-zeroDec 2022View details →

Exploring links between climatic predictability and the evolution of within- and transgenerational plasticity

In variable environments, phenotypic plasticity can increase fitness by providing tight environment-phenotype matching. However, adaptive plasticity is expected to evolve only when the future selective environment can be predicted based on the prevailing conditions. That is, the juvenile environment should be predictive of the adult environment (within-generation plasticity) or the parental environment should be predictive of the offspring environment (transgenerational plasticity). Moreover, environmental predictability can also shape transient responses such as stress responses in an adaptive direction. Here, we test links between environmental predictability and the evolution of adaptive plasticity by combining time series analyses and a common garden experiment using temperature as a stressor in a temperate butterfly (Melitaea cinxia). Time series analyses revealed that across-season fluctuations in temperature over 48 years are overall predictable. However, within the growing season, temperature fluctuations showed high heterogeneity across years with low autocorrelations and the timing of temperature peaks was asynchronous. Most life-history traits showed strong within-generation plasticity for temperature and traits such as body size and growth rate broke the temperature-size rule. Evidence for transgenerational plasticity, however, was weak and detected for only two traits each in an adaptive and non-adaptive direction. We suggest that the low predictability of temperature fluctuations within the growing season likely disfavours the evolution of adaptive transgenerational plasticity but instead favours strong within-generation plasticity.

opencc-zeroDec 2022View details →

Dietary plasticity linked to divergent growth trajectories in a critically endangered sea turtle

Foraging habitat selection and diet quality are key factors that influence individual fitness and metapopulation dynamics through effects on demographic rates. There is growing evidence that sea turtles exhibit regional differences in somatic growth linked to alternative dispersal patterns during the oceanic life stage. Yet, the role of habitat quality and diet in shaping somatic growth rates is poorly understood. Here, we evaluate whether diet variation is linked to regional growth variation in hawksbill sea turtles (Eretmochelys imbricata), which grow significantly slower in Texas versus Florida (USA), through novel integrations of skeletal growth, gastrointestinal content (GI), and bulk tissue and amino acid (AA)-specific stable nitrogen (δ15N) and carbon (δ13C) isotope analyses. We also used AA δ15N ΣV values (heterotrophic bacterial re-synthesis index) and δ13C essential AA (δ13CEAA) fingerprinting to test assumptions about the energy sources fueling hawksbill food webs regionally. GI content analyses, framed within a global synthesis of hawksbill dietary plasticity, revealed that relatively fast-growing hawksbills stranded in Florida conformed with assumptions of extensive spongivory for this species. In contrast, relatively slow-growing hawksbills stranded in Texas consumed considerable amounts of non-sponge invertebrate prey and appear to forage higher in the food web as indicated by isotopic niche metrics and higher AA δ15N-based trophic position estimates internally indexed to baseline N variation. However, regional differences in estimated trophic position may also be driven by unique isotope dynamics of sponge food webs. AA δ15N ΣV values and δ13CEAA fingerprinting indicated minimal bacterial resynthesis of organic matter (ΣV < 2) and that eukaryotic microalgae were the primary energy source supporting hawksbill food webs. These findings run contrary to assumptions that hawksbill diets predominantly comprise high microbial abundance sponges expected to primarily derive energy from bacterial symbionts. Our findings suggest alternative foraging patterns could underlie regional variation in hawksbill growth rates, as divergence from conventional sponge prey might correspond with increased energy expenditure and reduced foraging success or diet quality. As a result, differential dispersal patterns may infer substantial individual and population fitness costs and represent a previously unrecognized challenge to the persistence and recovery of this critically endangered species.

opencc-by-4.0Jan 2023View details →

Radiation Performance Data of the Fast-, Light-cured Plastic Scintillator Formulations

This repository contains the waveforms from the CAEN DT5730 digitizer of the fast-, light-cured plastic scintillators for the different formulations used in the two level-factorial parameter study (AFIT101-130) and ethanol treatment study (AFIT220-230). Each scintillator was wrapped with two layers of MIL-T-27730A PTFE tape and coupled to a 2" Hamamatsu R7724 PMT biased at -1050 V. The signals were recorded using CAEN CoMPASS software on a CAEN DT5730 digitizer while the scintillators were exposed to Na-22, Cs-137, and AmBe radiation sources. Some of the scintillator formulations were measured more than once, but due to the limitations of the data that can be saved in this repository, not all the experimental data is included; however, this repository consists of the data closest to the average performance of each scintillator. Additionally, the EJ-276 dataset is included. The table below lists the weight percentage of the compounds in each scintillator formulations. The compounds for each formulation were weighed and placed into a 20 mL reaction vial. The compounds were thoroughly mixed together using an alternating combination of an ultrasonic bath and hot plate to gently warm the mixture. To reduce oxygen-induced quenching, the reaction vial was transferred to a glove box pressurized with a nitrogen atmosphere and dissolved oxygen was removed by sparging with nitrogen for 10 min. The reaction vial was sealed before removal from the glove box. Next, the resin solution was cured using a commercially-available 405 nm Formlabs Form Cure for 5 mins and Dymax BlueWave AX-550 VisiCure for 4 mins. Finally, all solid scintillators were sanded and polished using 180 grit, 400 grit, 1000 grit, and 2000 grit sandpaper and a 300~nm alumina slurry. <table> <tbody> <tr> <td>Scintillator</td> <td>DIN</td> <td>PPO</td> <td>Exalite</td> <td>IBOA</td> <td>HDDMA</td> <td>BPADMA</td> <td>TPO</td> </tr> <tr> <td>AFIT101</td> <td>-</td> <td>30</td> <td>0.2</td> <td>49</td> <td>21</td> <td>-</td> <td>0.1</td> </tr> <tr> <td>AFIT102</td> <td>10</td> <td>20</td> <td>0.2</td> <td>49</td> <td>21</td> <td>-</td> <td>0.1</td> </tr> <tr> <td>AFIT103</td> <td>20</td> <td>10</td> <td>0.2</td> <td>49</td> <td>21</td> <td>-</td> <td>0.1</td> </tr> <tr> <td>AFIT104</td> <td>30</td> <td>-</td> <td>0.2</td> <td>49</td> <td>21</td> <td>-</td> <td>0.1</td> </tr> <tr> <td>AFIT105</td> <td>-</td> <td>30</td> <td>0.2</td> <td>49</td> <td>14</td> <td>7</td> <td>0.1</td> </tr> <tr> <td>AFIT106</td> <td>10</td> <td>20</td> <td>0.2</td> <td>49</td> <td>14</td> <td>7</td> <td>0.1</td> </tr> <tr> <td>AFIT107</td> <td>20</td> <td>10</td> <td>0.2</td> <td>49</td> <td>14</td> <td>7</td> <td>0.1</td> </tr> <tr> <td>AFIT109</td> <td>-</td> <td>30</td> <td>0.2</td> <td>49</td> <td>7</td> <td>14</td> <td>0.1</td> </tr> <tr> <td>AFIT110</td> <td>10</td> <td>20</td> <td>0.2</td> <td>49</td> <td>7</td> <td>14</td> <td>0.1</td> </tr> <tr> <td>AFIT111</td> <td>20</td> <td>10</td> <td>0.2</td> <td>49</td> <td>7</td> <td>14</td> <td>0.1</td> </tr> <tr> <td>AFIT113</td> <td>-</td> <td>30</td> <td>0.2</td> <td>49</td> <td>-</td> <td>21</td> <td>0.1</td> </tr> <tr> <td>AFIT114</td> <td>10</td> <td>20</td> <td>0.2</td> <td>49</td> <td>-</td> <td>21</td> <td>0.1</td> </tr> <tr> <td>AFIT130</td> <td>15</td> <td>15</td> <td>0.2</td> <td>49</td> <td>10.5</td> <td>10.5</td> <td>0.1</td> </tr> <tr> <td>AFIT230</td> <td>-</td> <td>30</td> <td>0.2</td> <td>49</td> <td>21</td> <td>-</td> <td>0.1</td> </tr> <tr> <td>AFIT225</td> <td>5</td> <td>25</td> <td>0.2</td> <td>49</td> <td>21</td> <td>-</td> <td>0.1</td> </tr> <tr> <td>AFIT220</td> <td>10</td> <td>20</td> <td>0.2</td> <td>49</td> <td>21</td> <td>-</td> <td>0.1</td> </tr> <tr> <td>AFIT221</td> <td>10</td> <td>20</td> <td>0.2</td> <td>49</td> <td>14</td> <td>7</td> <td>0.1</td> </tr> </tbody> </table> DIN: diisopropyl naphthalene PPO: 2,5-diphenyloxazole Exalite: Exalite 416 IBOA: isobornyl acrylate HDDMA: difunctionized 1,6-hexanediol dimethacrylate BPADMA: bisphenol-A dimethacrylate TPO: diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide

opencc-by-4.0Jan 2023View details →

Dataset for article titled "Assessing continuum plasticity postulates with grain stress and local strain measurements in triaxially compressed sand"

Dataset containing raw and processed data from experiments presented in the article titled "Assessing continuum plasticity postulates with grain-scale stress and strain measurements in triaxially-compressed sand". An enclosed PDF file describes the data.

opencc-by-nc-4.0Jan 2023View details →

Figure 2 in Unravelling the stomach contents of fish and crab species from Cananéia, São Paulo: Are they eating plastic?

Figure 2. The coloured circle represents the food items, and the black and white circle represent the absence and presence of anthropogenic plastic material found in 16 marine fish (benthic fish, pelagic/benthic fish and pelagic fish) and four crab species in the region of Cananéia, São Paulo, Brazil (CR = crustaceans; SE = sediment; MO = mollusc; FI = fish; FO = foraminiferans; PO = polychaetes; BR = bryozoans. N = number of fish analysed. UD = Unidentified).

opencc-zeroFeb 2023View details →

Juvenile hormone regulates the photoperiodic plasticity of elytra coloration in a ladybird Harmonia axyridis

Many animals, including insects, exhibit plasticity of body color in response to environmental changes. Varied expression of carotenoids, major cuticle pigments, significantly contributes to body color flexibility. However, the molecular mechanisms by which environmental cues regulate carotenoid expression remain largely unknown. In this study, we used the ladybird Harmonia axyridis as a model to investigate the photoperiodic-responsive plasticity of elytra coloration and its endocrine regulation. It was found that H. axyridis females under long-day conditions develop elytra that are much redder than those under short-day conditions, resulting from the differential accumulation of carotenoids. Exogenous hormone application and RNAi-mediated gene knockdown indicate that carotenoid deposition was directed through the juvenile hormone (JH) receptor-mediated canonical pathway. Moreover, we characterized an SR-BI/CD36 (SCRB) gene SCRB10 as the carotenoid transporter responding to JH signaling and regulating the elytra coloration plasticity. Taken together, we propose that JH signaling transcriptionally regulates the carotenoid transporter gene for the photoperiodic coloration plasticity of elytra in the beetles, which reveals a novel role of the endocrine system in the regulation of carotenoid-associated animal body coloration under environmental stimuli.

opencc-zeroFeb 2023View details →

Personality and temporal plasticity in fish populations along a gradient of evolutionary divergence

Personality is now recognized as an ecologically and evolutionarily significant phenomenon because it can affect fitness directly. However, empirical studies specifically tackling the importance of personality in the processes of adaptive divergence and speciation are scarce. Whether selection favours plasticity or canalization of personality traits in specific contexts and how ecological conditions affect the presence and the structure of personalities remain to be elucidated. We used five populations of Arctic charr, Salvelinus alpinus, chosen along a gradient of genetic and phenotypic divergence: an anadromous population supposedly close to the ancestral population and two pairs of sympatric lake morphs. Fish were raised individually from eggs in a common-garden experiment to specifically assess the genetic bases of the boldness trait in these populations. Thirty-two individuals per morph were repeatedly tested at 11 months old in an open field test with a shelter to assess boldness. The repeatability of the boldness trait (i.e. personality), within- and among-individual variation and temporal variation were assessed within each population. Then, the temporal plasticity in boldness and boldness mean score were assessed among populations. The results show differences between populations for the three variables, with the highest repeatability in the most diverged population, an increase in boldness over time and a lower mean value (especially the first time they were exposed to the novel environment) in the anadromous population. This suggests that boldness and temporal plasticity differ between the anadromous population and the more diverged lake populations under a controlled embryonic/juvenile environment. Further research is needed to verify the contribution of temporal plasticity for personality traits in the context of rapid adaptive radiation such as that seen in Arctic charr.

opencc-by-4.0Mar 2023View details →

Dataset from Maith, O., Baladron, J., Einhäuser, W., & Hamker, F. H. (2023). Exploration behavior after reversals is predicted by STN-GPe synaptic plasticity in a basal ganglia model. Submitted to iScience.

This dataset contains all analyzed data from the study "Maith, O., Baladron, J., Einhäuser, W., & Hamker, F. H. (2023). Exploration behavior after reversals is predicted by STN-GPe synaptic plasticity in a basal ganglia model. Submitted to iScience.". It includes the behavioral data of 20 human participants (folder "psychExp") and of simulations of a neuro-computational basal ganglia model (folder "simulations") of the study. To replicate the results of the study, the dataset can be analyzed using the code provided separately under the following identifier: https://doi.org/10.5281/zenodo.6555886. The dataset is organized in the directory structure required for this purpose. For the human participants, only preprocessed eye-tracking and general behavioral data (.mat files) and the final analyzed behavioral data (output files) generated with the script "get_vps_outputs.m" (folder psychExp/..../3_srcAna/) are available. For more information about preprocessing steps as well as raw data of the eye-tracking experiment, please contact us by email (click <a href="https://www.tu-chemnitz.de/urz/mail/adrx.html?1-d29sZmdhbmcuZWluaGFldXNlci10cmV5ZXJAcGh5c2lrLg==">here</a>).

Data for: Phenotypic plasticity increases exposure to extreme climatic events that reduce individual fitness

Climate models, and empirical observations, suggest that anthropogenic climate change is leading to changes in the occurrence and severity of extreme climatic events (ECEs). Effects of changes in mean climate on phenology, movement, and demography in animal and plant populations are well documented. In contrast, work exploring the impacts of ECEs on natural populations is less common, at least partially due to the challenges of obtaining sufficient data to study such rare events. Here, we assess the effect of changes in ECE patterns in a long-term study of great tits, near Oxford, over a 56-year period between 1965 and 2020. We document marked changes in the frequency of temperature ECEs, with cold ECEs being twice as frequent in the 1960s than at present, and hot ECEs being ~three times more frequent between 2010 and 2020 than in the 1960s. While the effect of single ECEs was generally quite small, we show that increased exposure to ECEs often reduces reproductive output, and that in some cases, the effect of different types of ECE is synergistic. We further show that long-term temporal changes in phenology, resulting from phenotypic plasticity, lead to an elevated risk of exposure to low-temperature ECEs early in reproduction, and hence suggest that changes in ECE exposure may act as a cost of plasticity. Overall, our analyses reveal a complex set of risks of exposure and effects as ECE patterns change and highlight the importance of considering responses to changes in both mean climate and extreme events. Patterns in exposure and effects of ECEs on natural populations remain underexplored and continued work will be vital to establish the impacts of ECEs on populations in a changing climate.

The PLOD2/Succinate axis regulates the epithelial-mesenchymal plasticity and cancer cell stemness

Aberrant accumulation of succinate has been detected in many cancers. However, the cellular function and regulation of succinate in cancer progression is not completely understood. Using stable isotope-resolved metabolomics (SIRM) analysis, we showed that the epithelial mesenchymal transition (EMT) was associated with profound changes in metabolites, including the elevation of cytoplasmic succinate levels. Treatment with cell-permeable succinate induced mesenchymal phenotypes in mammary epithelial cells and enhanced cancer cell stemness. Chromatin immunoprecipitation (ChIP) and sequence analysis showed that elevated cytoplasmic succinate levels were sufficient to reduce global 5-hydroxymethylcytosinene (5hmC) accumulation and induce transcriptional repression of EMT-related genes. We showed that expression of procollagen-lysine,2-oxoglutarate 5-dioxygenase 2 (PLOD2) was associated with an elevation of cytoplasmic succinate during the EMT process. Silence of PLOD2 expression in breast cancer cells reduced succinate levels and inhibited cancer cell mesenchymal phenotypes and stemness, which was accompanied by elevated 5hmC levels in chromatin. Importantly, exogenous succinate rescued cancer cell stemness and 5hmC levels in PLOD2-silenced cells, suggesting that PLOD2 promotes cancer progression at least partially through succinate. These results reveal the previously unidentified function of succinate in enhancing cancer cell plasticity and stemness.

opencc-by-4.0May 2020View details →

Transgenerational phenotypic plasticity of diapause induction and related fitness cost in a commercial strain of the parasitoid Aphidius ervi Haliday

Dataset. Diapause is an adaptation that insects have evolved to synchronize their life cycle with that of seasonal climatic changes and resources availability. However, cues for its induction are not always clear and, in some cases, a maternal effect may be involved. At the population level, just a part of the individuals may exhibit diapause with important consequences in terms of winter survival. Moreover, clear indicators of diapause state are difficult to identify. Diapause induction was thus investigated in the aphid parasitoid species Aphidius ervi Haliday (Hymenoptera: Braconidae) developing in the aphid Sitobion avenae (Hemiptera: Aphididae) at four crossed photothermal regimes (16 °C and 8 °C, 16:8 h L:D and 8:16 h L:D), and during 2 successive generations. We analyzed the reliability of changes in mummy color to assess for the diapausing state compared to dissections, and we measured parasitoid morphological and physiological traits. We observed that the proportion of dark brown mummies increased after one generation under low photothermal regime compared to other regimes. No diapause was recorded at 16 °C, 16:8 h L:D, while we observed 16.2% and 67.5% diapause incidence at 8 °C, 8:16 h L:D, at 1st and 2nd generation, respectively. Diapause induction is thus increased by short day-length conditions and low temperatures as well as by maternal effects. All parasitoid life-history traits (weight, size, fat content, water content, egg-load, and longevity) were affected by the photothermal regime and/or the generation. These results raise new questions on the environmental thresholds needed to induce diapause and on survival and adaptation potential of commercially available parasitoid strains in different environments.

Microglial cytokines mediate plasticity induced by 10 Hz repetitive magnetic stimulation

Microglia—the resident immune cells of the central nervous system—sense the activity of neurons and regulate physiological brain functions. They have been implicated in the pathology of brain diseases associated with alterations in neural excitability and plasticity. However, experimental and therapeutic approaches that modulate microglia function in a brain-region-specific manner have not been established. In this study, we tested for the effects of repetitive transcranial magnetic stimulation (rTMS), a clinically employed non-invasive brain stimulation technique, on microglia-mediated synaptic plasticity. 10 Hz electromagnetic stimulation triggered a release of plasticity-promoting cytokines from microglia in organotypic brain tissue cultures, while no changes in microglial morphology or microglia dynamics were observed. Indeed, substitution of tumor necrosis factor alpha (TNFα) and interleukin 6 (IL6) preserved synaptic plasticity induced by 10 Hz stimulation in the absence of microglia. Consistent with these findings, in vivo depletion of microglia abolished rTMS-induced changes in neurotransmission in the medial prefrontal cortex (mPFC) of anesthetized mice. We conclude that rTMS affects neural excitability and plasticity by modulating the release of cytokines from microglia.

Denervated mouse CA1 pyramidal neurons express homeostatic synaptic plasticity following entorhinal cortex lesion

Structural, functional, and molecular reorganization of denervated neural networks is often observed in neurological conditions. The loss of input is accompanied by homeostatic synaptic adaptations, which can affect the reorganization process. A major challenge of denervation-induced homeostatic plasticity operating in complex neural networks is the specialization of neuronal inputs. It remains unclear whether neurons respond similarly to the loss of distinct inputs. Here, we used in vitro entorhinal cortex lesion (ECL) and Schaffer collateral lesion (SCL) in mouse organotypic entorhino-hippocampal tissue cultures to study denervation-induced plasticity of CA1 pyramidal neurons. We observed microglia accumulation, presynaptic bouton degeneration, and a reduction in dendritic spine numbers in the denervated layers three days after SCL and ECL. Transcriptome analysis of the CA1 region revealed complex changes in differential gene expression following SCL and ECL compared to non-lesioned controls with a specific enrichment of differentially expressed synapse-related genes observed after ECL. Consistent with this finding, denervation-induced homeostatic plasticity of excitatory synapses was observed three days after ECL but not after SCL. Chemogenetic silencing of the EC but not CA3 confirmed the pathway-specific induction of homeostatic synaptic plasticity in CA1. Additionally, increased RNA oxidation was observed after SCL and ECL. These results reveal important commonalities and differences between distinct pathway lesions and demonstrate a pathway-specific induction of denervation-induced homeostatic synaptic plasticity.

Genetic variation in sexual size dimorphism is associated with variation in sex-specific plasticity in Drosophila

The difference in body size between females and males, or sexual size dimorphism (SSD), is ubiquitous, and yet we have a poor understanding of the developmental-genetic mechanisms that generate it, and how these mechanisms may vary within and among species. Such an understanding of the genetic architecture of SSD is important if we are to evaluate alternative models of SSD evolution, but is difficult to describe because SSD is a characteristic of populations, not individuals. Here, we overcome this challenge by using isogenic lineages of Drosophila to measure SSD for 196 genotypes. We demonstrate extensive genetic variation for SSD, primarily driven by higher levels of genetic variation for body size among females than males. While we observe a general increase in SSD with sex-averaged body size (pooling for sex) among lineages, the vast majority of variation in SSD is independent of sex-averaged body size, and shows a strong genetic correlation with sex-specific plasticity, such that increased female-biased SSD is associated with increased body-size plasticity in females. Our data are consistent with the condition-dependence hypothesis of sexual dimorphism, and suggest that SSD in Drosophila is a consequence of selection on the developmental-genetic mechanisms that regulate the plasticity of body size.

Strong habitat-specific phenotypic plasticity but no genome-wide differentiation across a rainforest gradient in an African butterfly

Habitat-specific thermal responses are well documented in various organisms and likely determine the vulnerability of populations to climate change. However, the underlying roles of genetics and plasticity that shape such habitat-specific patterns are rarely investigated together. Here we examined the thermal plasticity of the butterfly Bicyclus dorothea originating from rainforest and ecotone habitats in Cameroon under common garden conditions. We also sampled wild-caught butterflies from forest and ecotone sites and used RADseq to explore genome-wide population differentiation. We found differences in the level of phenotypic plasticity across habitats. Specifically, ecotone populations exhibited greater sensitivity in wing eyespot features with variable development temperatures relative to rainforest populations. Known adaptive roles of wing eyespots in Bicyclus species suggest that this morphological plasticity is likely under divergent selection across environmental gradients. However, we found no distinct population structure of genome-wide variation between habitats, suggesting high levels of ongoing gene flow between habitats is homogenizing most parts of the genome.