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opencc-by-4.0Nov 2021View details →

Demagnetization energy and internal stress in magnetite from temperature dependent hysteresis measurements - temperature hysteresis data

Data set of hysteresis data files for the Geophysical Research Letters article "Demagnetization energy and internal stress in magnetite from temperature dependent hysteresis measurements" MicroMag 2900/3900 Data Files (Series 0016.002) - The file name and description in the file provide the specimen information. Each file contains information on the instrument, settings, measurement, script, and the measured data: field, moment, and temperature.

Causation without correlation: Parasite-mediated frequency-dependent selection and infection prevalence

Parasite-mediated selection is thought to maintain host genetic diversity for resistance. We might thus expect to find a strong positive correlation between host genetic diversity and infection prevalence across natural populations. Here, we used computer simulations to examine host–parasite coevolution in 20 simi-isolated clonal populations across a broad range of values for both parasite virulence and parasite fecundity. We found that the correlation between host genetic diversity and infection prevalence can be significantly positive for intermediate values of parasite virulence and fecundity. But the correlation can also be weak and statistically non-significant, even when parasite-mediated frequency-dependent selection is the sole force maintaining host diversity. Hence correlational analyses of field populations, while useful, might underestimate the role of parasites in maintaining host diversity.

Age-dependent timing and routes demonstrate developmental plasticity in a long-distance migratory bird

1. Longitudinal tracking studies have revealed consistent differences in the migration patterns of individuals from the same populations. The sources or processes causing this individual variation are largely unresolved. As a result, it is mostly unknown how much, how fast, and when animals can adjust their migrations to changing environments. 2. We studied the ontogeny of migration in a long-distance migratory shorebird, the black-tailed godwit (Limosa limosa limosa), a species known to exhibit marked individuality in the migratory routines of adults. By observing how and when these individual differences arise, we aimed to elucidate whether individual differences in migratory behaviour are inherited or emerge as a result of developmental plasticity. 3. We simultaneously tracked juvenile and adult godwits from the same breeding area on their south- and northward migrations. To determine how and when individual differences begin to arise, we related juvenile migration routes, timing, and mortality rates to hatch date and year of birth. Then, we compared adult and juvenile migration patterns to identify potential age-dependent differences. 4. In juveniles, the timing of their first southward departure was related to hatch date. However, their subsequent migration routes, orientation, destination, migratory duration, and likelihood of mortality were unrelated to the year or timing of migration, or their sex. Juveniles left the Netherlands after all tracked adults. They then flew non-stop to West Africa more often and incurred higher mortality rates than adults. Some juveniles also took routes and visited stopover sites far outside the well-documented adult migratory corridor. Such juveniles, however, were not more likely to die. 5. We found that juveniles exhibited different migratory patterns than adults, but no evidence that these behaviours are under natural selection. We thus eliminate the possibility that the individual differences observed among adult godwits are present at birth or during their first migration. This adds to the mounting evidence that animals possess the developmental plasticity to change their migration later in life in response to environmental conditions as those conditions are experienced.

Non-native species drive biotic homogenization, but it depends on the realm, beta diversity facet and study design: A meta-analytic systematic review

While reducing the species richness of invaded communities is a well-known consequence of biological invasions, non-native species can also reduce variability between communities over time (i.e., beta diversity) in a process known as biotic homogenization. Although biotic homogenization due to non-native species is a common topic of theoretical reviews, we believe no global meta-analysis on the effect of non-native species on beta diversity has been carried out yet. Here, we systematically show that non-native species drive biotic homogenization, but it depends on the realm, beta diversity facet and study design. Biotic homogenization was more intense in marine and freshwater ecosystems than in terrestrial ecosystems. We also found that non-native species reduced both taxonomic and phylogenetic beta diversity, but not the functional beta diversity. Finally, we observed more intense effects using "before vs. after invasion" followed by "uninvaded vs. invaded sites" while the effect size of studies using "communities associated with native vs. non-native species" did not differ from zero. Our findings highlight that non-native species contribute to biotic homogenization as a prevalent pattern in communities worldwide, and that biodiversity conservation strategies should go beyond investigating the reduction in the number of species by also taking into account beta diversity in its multiple facets.

Data from: Emerging experience-dependent dynamics in primary somatosensory cortex reflect behavioral adaptation

Behavioral experience and flexibility are crucial for survival in a constantly changing environment. Despite evolutionary pressures to develop adaptive behavioral strategies in a dynamically changing sensory landscape, the underlying neural correlates have not been well explored. Here, we use genetically encoded voltage imaging to measure signals in primary somatosensory cortex (S1) during sensory learning and behavioral adaptation in the mouse. In response to changing stimulus statistics, mice adopt a strategy that modifies their detection behavior in a context dependent manner as to maintain reward expectation. Surprisingly, neuronal activity in S1 shifts from simply representing stimulus properties to transducing signals necessary for adaptive behavior in an experience dependent manner. Our results suggest that neuronal signals in S1 are part of an adaptive framework that facilitates flexible behavior as individuals gain experience, which could be part of a general scheme that dynamically distributes the neural correlates of behavior during learning.

Condition dependent seminal fluid gene expression and intergenerational paternal effects on ejaculate quality

1. There is increasing evidence to show that the environment experienced by fathers can have intergenerational paternal effects on the phenotype of offspring. Paternal effects can be mediated by ejaculate traits beyond the genes carried by sperm, for example through methylation of DNA during spermatogenesis, or non-sperm components of the ejaculate such as small RNAs or seminal fluid proteins (sfp). 2. Theory suggests that ejaculate-mediated paternal effects can have important evolutionary consequences, especially if they exhibit condition dependent expression. Here we use the nutritional geometry approach to explore condition dependence in ejaculate traits and intergenerational paternal effects in the cricket Teleogryllus oceanicus. 3. We fed males one of 24 chemically defined diets that varied in macronutrient concentration and the ratio of protein (P) to carbohydrate (C). We measured paternal expenditure on testes and accessory gland growth, and the expression of three seminal fluid protein genes that are known to impact sperm viability and the survival of embryos to hatching. We also measured the hatching success and reproductive phenotypes of adult offspring. 4. We found linear effects of P and C on testes and accessory gland mass, and linear and correlated effects of P and C on the expression of two sfp genes. Paternal diet had no effect on the survival of embryos to hatching. 5. There were significant intergenerational effects of paternal diet on the viability of sperm produced by sons, but no paternal effects on the expression of sfp genes in sons or fecundity in daughters. 6. Our data suggest that ejaculate quality can have a significant non-genetic component determined by the paternal environment, which holds important implications for the evolutionary maintenance of variation in heritable male fitness.

Codes for simulation and data for: The relationship between local and regional extinction rates depends on species distribution patterns

The rapid loss of biodiversity poses a great threat to ecosystem functions and services. Credible estimation of species extinction rates is essential for understanding the magnitude of biodiversity loss and for informing conservation, but this has been a challenge because estimated extinctions are unverifiable due to the lack of data. In this study, we investigated the relationship between local and regional extinctions and assessed the effects of range size, spatial segregation, and patchiness of species distribution on this local-regional extinction relationship. We found that regional extinction rates had a convex relationship with local extinction rates, that is, the regional extinction rate was most likely to be lower than the average local rate. The regional rates deviated from local rates as the sampling area decreased. The difference between local and regional extinction rates (local-regional extinction difference) became larger if a higher number of species had larger range sizes and patchiness. We also detected that there were interactive effects among these factors. Species segregation had a weak positive relationship with the local-regional extinction difference if more species had relatively large range sizes. As the sampling areas increased, the range size showed smaller positive effects on local-regional differences, but patchiness showed larger positive effects. The local-regional extinction relationship of this study provides insights into the spatial scaling of biodiversity loss and offers some important cues for estimating regional extinctions from local data in future studies.

Scale dependence of drilling predation in the Holocene of the northern Adriatic Sea across benthic habitats and nutrient regimes

Predation has strongly shaped past and modern marine ecosystems, but the scale dependency of patterns in drilling predation, the most widely used proxy for predator-prey interactions in the fossil record, is a matter of debate. To assess the effects of spatial and taxonomic scale on temporal trends in the drilling frequencies (DF), we analyzed Holocene molluscan assemblages of different benthic habitats and nutrient regimes from the northern Adriatic shelf in a sequence stratigraphic context. Although it has been postulated that low predation pressures facilitated the development of high-biomass epifaunal communities in the eastern, relatively oligotrophic portion of the northern Adriatic shelf, DFs reaching up to 30-40% in the studied assemblage show that drilling predation levels are comparable to those typical of Late Cenozoic ecosystems. DFs tend to increase from the transgressive systems tract (TST) into the highstand systems tract (HST) at the local scale, reflecting an increase in water depth by 20-40 m and a shift from infralittoral to circalittoral habitats over the past 10,000 years. As transgressive deposits are thicker at shallower and highstand deposits are thicker at deeper locations, a regional increase in DFs from TST to HST is evident only when these differences are accounted for. The increase in DF towards the HST can be recognized at the level of total assemblages, classes and few abundant and widespread families, but it disappears at the level of genera and species because of their specific environmental requirements, leading to uneven or patchy distribution in space and time.

Fish resist temptation from junk food: State-dependent diet choice in reproductive Atlantic cod (Gadus morhua) facing seasonal fluxes of lipid-rich prey

In ecological sciences, animal diets are often simplified to "resources" or "caloric quantities". However, in the present study, we investigated the optimal foraging strategy of Atlantic cod (Gadus morhua) when both macro- and micro-nutritional requirements are accounted for. Proteins cannot be synthesized from fatty acids, so the proteins for gonad development must come from other dietary sources. In addition, micronutrients are required in smaller quantities. For example, for cod, arachidonic acid (ARA) acts as a micronutrient precursor for prostaglandins, which is important for reproduction. We formulated a dynamic state-dependent model to make predictions about optimal diet choice and foraging behavior. We applied the model to a case study in the strait between Denmark and Sweden. The model predicted that energy acquired from dietary protein should be twice that acquired from lipids, with a small increase in the lipid requirements when gonads are growing. The model also predicted that the "energy sparing effect of lipids" made it beneficial to engage in risky foraging activity to supplement a lean diet with a little bit of fat. When we re-constructing the model to also optimize ARA uptake, the cod consumed relatively more ARA-rich crabs in the months prior to spawning, despite the otherwise poor energetic value of this prey. In support of the model predictions, field observations indicated that lipid stores reached a peak shortly after the arrival of the lipid-rich migrating herring and the fatty acid signal of these herring were evident in the liver of nearly all cod. Three month later, only half of the cod contained the herring-derived fatty acid signal, supporting the predicted shift in prey type prior to spawning. From these model predictions and field observations, we conclude that, also in the wild, nutritional requirements can be at least as important as pure energy acquisition.

opencc-zeroJan 2022View details →

Long-distance dependencies in birdsong syntax

Songbird syntax is generally thought to be simple, lacking in particular long-distance dependencies in which one element affects choice of another occurring considerably later in the sequence. Here we test for long-distance dependencies in the sequences of songs produced by song sparrows (Melospiza melodia). Song sparrows sing with eventual variety, repeating each song type in a consecutive series termed a "bout." We show that in switching between song types, song sparrows follow a "cycling rule," cycling through their repertoires in close to the minimum possible number of bouts. Song sparrows do not cycle in a set order but rather vary the order of song types from cycle to cycle. Cycling in a variable order strongly implies long-distance dependencies: choice of the next type must depend on the song types sung over the past cycle, in the range of 9-10 bouts. Song sparrows also follow a "bout length rule," whereby the number of repetitions of a song type in a bout is positively associated with the length of the interval until that type recurs. This rule requires even longer-distance dependencies that cross one another; such dependencies are characteristic of more complex levels of syntax than previously attributed to non-human animals.

opencc-zeroJan 2022View details →

What makes a good bat box? How box occupancy depends on box characteristics and landscape-level variables

Bat populations are in steep decline and presently, 16% of all species are classified as "threatened". One main driver identified for this decline is the loss of natural roosting opportunities, caused by the removal of natural habitats. Installation of bat boxes is one solution to compensate for the lack of natural roosting opportunities. Current recommendations for box design emphasize low maintenance costs and are rarely based on empirical evidence. We investigated occupancy of 13634 bat boxes in northern Bavaria, Germany. In our study boxes differed in type, age and mounting height, as well as in maximum community age, i.e. the length of time a group of boxes had been installed in a particular place, the size of box groups and the distance to the next box in the surrounding area, i.e. box isolation. Our results showed that box occupancy depended on box type and bat species. As a case study, we analysed the two most common species found within the investigated boxes, Pipistrellus pipistrellus and Myotis nattereri, in more detail. Both species showed preference to a voluminous box that had a narrow entrance ("Gable box" 14 mm). For P. pipistrellus, only box type affected occupancy, whereas for M. nattereri, the relationship between box type and box age were important. Older boxes, and boxes in areas with higher maximum community age of boxes showed higher box occupancy by bats. Box occupancy decreased with the distance between adjacent box groups ("box isolation"). High mounting height showed a tendency for increased box occupancy, but the effect was only weakly significant.

Stanza Models for Morphologically enhanced Universal Dependencies for Korean (morphUD)

Stanza (<a href="https://stanfordnlp.github.io/stanza/">Stanford NLP Group</a>) models for Morphologically enhanced Universal Dependencies for Korean (morphUD) including ko.vectors.xz files for morphUD and wordUD.    Embedding files are generated with https://doi.org/10.5281/zenodo.5869738   All files are listed in file.txt

The height-dependent delayed ionospheric response to solar EUV - data comparison - secondary files 141 - 143

Secondary files for doy 141 - 143 For comparison with the observational results a TIE-GCM v2.0 model run in the 2.5 × 2.5 configuration is calculated. In order to converge to stable initial condition the model runs for 30 days prior to the final simulation starting at 28 March 2019. This initial run is configured with default parameters. The final run from 27 April 2019 to 24 May 2019 uses the default configuration of TIE-GCM with the Heelis Electric Convection Field Model (Heelis et al., 1982) as the high-latitude potential model. The input forcing is used from the NASA/GSFC’s OMNI data set

The height-dependent delayed ionospheric response to solar EUV - data comparison - secondary files 135 - 140

Secondary files for doy 135 - 140 For comparison with the observational results a TIE-GCM v2.0 model run in the 2.5 × 2.5 configuration is calculated. In order to converge to stable initial condition the model runs for 30 days prior to the final simulation starting at 28 March 2019. This initial run is configured with default parameters. The final run from 27 April 2019 to 24 May 2019 uses the default configuration of TIE-GCM with the Heelis Electric Convection Field Model (Heelis et al., 1982) as the high-latitude potential model. The input forcing is used from the NASA/GSFC’s OMNI data set

The height-dependent delayed ionospheric response to solar EUV - data comparison - secondary files 129 - 134

Secondary files for doy 129 - 134 For comparison with the observational results a TIE-GCM v2.0 model run in the 2.5 × 2.5 configuration is calculated. In order to converge to stable initial condition the model runs for 30 days prior to the final simulation starting at 28 March 2019. This initial run is configured with default parameters. The final run from 27 April 2019 to 24 May 2019 uses the default configuration of TIE-GCM with the Heelis Electric Convection Field Model (Heelis et al., 1982) as the high-latitude potential model. The input forcing is used from the NASA/GSFC’s OMNI data set

The height-dependent delayed ionospheric response to solar EUV - data comparison - secondary files 117 - 122

Secondary files for doy 117 - 122 For comparison with the observational results a TIE-GCM v2.0 model run in the 2.5 × 2.5 configuration is calculated. In order to converge to stable initial condition the model runs for 30 days prior to the final simulation starting at 28 March 2019. This initial run is configured with default parameters. The final run from 27 April 2019 to 24 May 2019 uses the default configuration of TIE-GCM with the Heelis Electric Convection Field Model (Heelis et al., 1982) as the high-latitude potential model. The input forcing is used from the NASA/GSFC’s OMNI data set

opencc-by-4.0Jan 2022View details →

The height-dependent delayed ionospheric response to solar EUV - data comparison

For comparison with the observational results a TIE-GCM v2.0 model run in the 2.5 × 2.5 configuration is calculated. In order to converge to stable initial condition the model runs for 30 days prior to the final simulation starting at 28 March 2019. This initial run is configured with default parameters. The final run from 27 April 2019 to 24 May 2019 uses the default configuration of TIE-GCM with the Heelis Electric Convection Field Model (Heelis et al., 1982) as the high-latitude potential model. The input forcing is used from the NASA/GSFC’s OMNI data set Secondary files: 117 - 122: <a href="https://zenodo.org/record/6004534">https://zenodo.org/record/6004534</a> 123 - 128: <a href="https://zenodo.org/record/6006516">https://zenodo.org/record/6006516</a> 129 - 134: <a href="https://zenodo.org/record/6009777">https://zenodo.org/record/6009777</a> 135 - 140: <a href="https://zenodo.org/record/6014195">https://zenodo.org/record/6014195</a> 141 - 143: <a href="https://zenodo.org/record/6014201">https://zenodo.org/record/6014201</a>

opencc-by-4.0Jul 2021View details →

Multiple parasitoid species enhance top-down control, but parasitoid performance is context-dependent

<ol> <li>Ecological communities are composed of many species, forming complex networks of interactions. Current environmental changes are altering community composition. We thus need to identify which aspects of species interactions are primarily driven by community structure and which by species identity to predict changes in the functioning of communities. Yet, this partitioning of effects is challenging and thus rarely explored.</li> <li>Here we disentangled the influence of community structure and the identity of co-occurring species on the outcome of consumer-resource interactions using a host-parasitoid system.</li> <li>We used four community modules that are common in host-parasitoid communities to represent community structure (i.e., host-parasitoid, exploitative competition, alternative host, and a combination of both exploitative competition and alternative host). We assembled nine different species combinations per community module in a laboratory experiment using a pool of three Drosophila hosts and three larval parasitoid species. To investigate the potential mechanisms at play, we compared host suppression and parasitoid performance across community modules and species assemblages.</li> <li>We found that multiple parasitoid species enhanced host suppression due to sampling effect, weaker interspecific than intraspecific competition between parasitoids, and synergism. However, the effects of community structure on parasitoid performance were species-specific and dependent on the identity of co-occurring species. Consequently, multiple parasitoid species generally strengthen top down-control, but the performance of the parasitoids depends on the identity of either the co-occurring parasitoid species, the alternative host species, or both. </li> </ol>

On the scale dependence in the dynamics of frictional rupture: constant fracture energy versus size-dependent breakdown work

<pre>Potential energy stored during the inter-seismic period by tectonic loading around faults is released during earthquakes as radiated energy, frictional dissipation and fracture energy. The latter is of first importance since it is expected to control the nucleation, the propagation and the arrest of the seismic rupture. On one side, the seismological fracture energy estimated for natural earthquakes (commonly called breakdown work) ranges between 1 $\mathrm{J/m^2}$ and tens of $ \mathrm{MJ/m^2} $ for the largest events, and shows a clear slip dependence. On the other side, recent experimental studies highlighted that, concerning rupture experiments, fracture energy is a material property (energy required to break the fault interface) independently of the size of the event, i.e. of the seismic slip. </pre> <pre>To reconcile these contradictory observations and definitions, we performed stick-slip experiments, as analog for earthquakes, in a bi-axial shear configuration. We estimated fracture energy through both Linear Elastic Fracture Mechanics (LEFM) and a Cohesive Zone Model (CZM) and through the integration of the near-fault stress-slip evolution. We show that, at the scale of our experiments, fault weakening is divided into a near-tip weakening, corresponding to an energy of few $ \mathrm{J/m^2} $, consistent with the one estimated through LEFM and CZM, and a long-tailed weakening corresponding to a larger energy not localized at the rupture tip, increasing with slip.</pre> <pre>Through numerical simulations, we demonstrate that only near-tip weakening controls the rupture initiation and that long-tailed weakening can enhance slip during rupture propagation and allow the rupture to overcome stress heterogeneity along the fault. We conclude that the origin of the seismological estimates of breakdown work could be related to the energy dissipated in the long-tailed weakening rather than to the one dissipated near the tip.</pre>