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opencc-by-4.0Sep 2024View details →

Seasonal and between-population variation in heat tolerance and cooling efficiency in a Mediterranean songbird

Data collection This database contains physiological data on thermoregulation in response to heat -- heat tolerance limit (HTL), body temperature (Tb), resting metabolic rate (RMR), evaporative water loss (EWL) and evaporative cooling efficiency (EHL/MHP) -- collected during winter and summer in two populations on Great tits Parus major submitted to different thermal environments (one from a montane, more thermally stable site; and the other from a lowland, warmer and more thermally heterogeneous site) in southwestern Iberia. Physiological data were collected by using open flow through respirometry (see Material and Methods for detailed protocols).  Statistical analyses  We evaluated seasonal and between population differences to asses the degree of phenotypical flexibility in those physiological thermoregulatory traits both above and below thermoneutrlaity. See detailed analyses below:  We conducted all statistical analyses in R 4.1.2 (R Core Team, 2021). We used the segmented package (Muggeo, 2009) to determine inflection points in Tb, RMR, EWL, and EHL/MHP for each site and season. Then, the data were split based on inflection points for subsequent analyses below and above thermoneutrality (as in Whitfield et al., 2015). Linear and linear mixed-effects models were fitted to the data by using the lme4 package (Bates et al., 2015). We used the emmeans package (Lenth, 2022) to perform post-hoc pairwise contrasts between groups, and visually checked model assumptions in model residuals. First, to assess seasonal and between-population variation in heat tolerance, we fitted a linear model with HTL (please see Heat Tolerance Limits sheet on dataset) as response variable and body mass, site, season, and the site×season interaction as predictors. Then, we fitted linear models to each thermoregulatory trait (namely Tb, RMR, EWL and EHL/MHP; please see Physiological Data sheet on dataset), using a single Tair stage per individual within (Tair ~ 30 ºC) and above thermoneutral zone (Tair ~ 37 ºC) of Great tits (as inflection points of all variables were below this last Tair stage), including body mass, site, season, and the site×season interaction as predictor variables. Second, for summer measurements, we fitted linear mixed-effects models to evaluate population variation in the slopes of Tb, RMR, EWL and EHL/MHP against Tair above thermoneutrality, as we could obtain several measurements per individual above inflection points for each trait during this season. Initial models included Tair, body mass, site, and the Tair×site interaction as predictor variables, with ring as a random effect. When site emerged as a significant predictor, we additionally fitted separate population-specific models to calculate the slopes and y-intercepts of each thermoregulatory trait in response to Tair.

opencc-zeroDec 2016View details →

Data from: Seasonal variation in daily patterns of social contacts in the European badger Meles meles

Social interactions among hosts influence the persistence and spread of infectious pathogens. Daily and seasonal variation in the frequency and type of social interactions will play an important role in disease epidemiology and, alongside other factors, may have an influence on wider disease dynamics by causing seasonal forcing of infection, especially if the seasonal variation experienced by a population is considerable. We explored temporal variation in within-group contacts in a high-density population of European badgers Meles meles naturally infected with Mycobacterium bovis (the causative agent of bovine tuberculosis). Summer contacts were more likely and of longer duration during the daytime, while the frequency and duration of winter contacts did not differ between day and night. In spring and autumn, within-group contacts peaked at dawn and dusk, corresponding with when they were of shortest duration with reduced potential for aerosol transmission of pathogens. Summer and winter could be critical for transmission of M. bovis in badgers, due to the high frequency and duration of contacts during resting periods, and we discuss the links between this result and empirical disease data. This study reveals clear seasonality in daily patterns of contact frequency and duration in species living in stable social groups, suggesting that changes in social contacts could drive seasonal forcing of infection in wildlife populations even when the number of individuals interacting remains similar.

opencc-zeroDec 2014View details →

Data from: Seasonal and ontogenetic variation of skin microbial communities and relationships to natural disease dynamics in declining amphibians

Recently, microbiologists have focused on characterizing the probiotic role of skin bacteria for amphibians threatened by the fungal disease chytridiomycosis. However, the specific characteristics of microbial diversity required to maintain health or trigger disease are still not well understood in natural populations. We hypothesized that seasonal and developmental transitions affecting susceptibility to chytridiomycosis could also alter the stability of microbial assemblages. To test our hypothesis, we examined patterns of skin bacterial diversity in two species of declining amphibians (Lithobates yavapaiensis and Eleutherodactylus coqui) affected by the pathogenic fungus Batrachochytrium dendrobatidis (Bd). We focused on two important transitions that affect Bd susceptibility: ontogenetic (from juvenile to adult) shifts in E. coqui and seasonal (from summer to winter) shifts in L. yavapaiensis. We used a combination of community-fingerprinting analyses and 16S rRNA amplicon sequencing to quantify changes in bacterial diversity and assemblage composition between seasons and developmental stages, and to investigate the relationship between bacterial diversity and pathogen load. We found that winter-sampled frogs and juveniles, two states associated with increased Bd susceptibility, exhibited higher diversity compared with summer-sampled frogs and adult individuals. Our findings also revealed that hosts harbouring higher bacterial diversity carried lower Bd infections, providing support for the protective role of bacterial communities. Ongoing work to understand skin microbiome resilience after pathogen disturbance has the potential to identify key taxa involved in disease resistance.

Figure 2 in Seasonal and diel variation of shrimp (Crustacea, Decapoda) on sandbanks of a tropical floodplain river

Figure 2. Seasonal variation of mean number of sergestid (empty bars) and palaemonid (filled bars) shrimp in diurnal (A) and nocturnal (B) samples from sandbanks of the Cinaruco River during 1999 (mean + SE). n= 7, except in November when only six sandbanks were sampled. No samples were taken during January or from July to October. A smoothed hydrograph of the Cinaruco River is superimposed to show water level variation during 1999.

Figure 4 in Seasonal and diel variation of shrimp (Crustacea, Decapoda) on sandbanks of a tropical floodplain river

Figure 4. Abundance (mean + SE) of Acetes paraguayensis and palaemonids during day and night for variable levels of submerged vegetation (A) and ridge-and-trough topography (B). Absent, moderate and abundant submerged vegetation and ridge-and-trough topography in the sandbanks are represented by black, light grey and dark grey bars, respectively. Plots were generated by pooling all sampling dates and sandbanks.

Figure 3 in Seasonal and diel variation of shrimp (Crustacea, Decapoda) on sandbanks of a tropical floodplain river

Figure 3. Abundance (mean + SE) of Acetes paraguayensis (empty bars) and palaemonids (filled bars) from sandbanks of the Cinaruco River during 1999 (pooling all sampling dates together) n = 7, except sandbank 3 (sampled only six times).

Figure 1 in Seasonal and diel variation of shrimp (Crustacea, Decapoda) on sandbanks of a tropical floodplain river

Figure 1. Locations of sampling sites on Cinaruco River near Laguna Larga (LL). Sampled sandbanks are shown with codes from S1 to S7. This NASA LandSat image was taken during the dry season of 2000.

opennotspecifiedNov 2010View details →

Figure 5 in Foraging mode of Australolacerta rupicola (FitzSimons, 1933) (Sauria: Lacertidae): evidence of seasonal variation in an extremely active predator?

Figure 5. Australolacerta rupicola feeding on a spider (a) and a grasshopper (b). Credit: S. Kirchhof.

opennotspecifiedNov 2009View details →

Figure 1 in Clues supporting photoperiod as the main determinant of seasonal variation in amphibian activity

Figure 1. Path diagram of structural equation model, evaluating 265 the hypotheses that anuran species respond to the month as a latent variable that is a construct of photoperiod, temperature and rainfall. The whole model is congruent with observed data as indicated by its non-significant probability. Paths values are standardized effects ± 1 standard error. Asterisks (*) denote significant coefficients (P <0.05) and "ns" denote non-significant coefficients (P> 0.05). Arrow width represents the strength of the causal link. Month, latent variable; S, number of species calling per month; P, photoperiod; T, mean monthly temperature; R, monthly rainfall; u1 to u4, associated error variable.

opennotspecifiedNov 2009View details →

Figure 3 in Clues supporting photoperiod as the main determinant of seasonal variation in amphibian activity

Figure 3. Correlation between residuals of the regression between photoperiod and amphibian activity and the fit of the sinusoidal model.

opennotspecifiedNov 2009View details →

Figure 2 in Clues supporting photoperiod as the main determinant of seasonal variation in amphibian activity

Figure 2. Linear regression of the number of species calling per month (S) between September 1998 and April 2000 with photoperiod (P).

opencc-zeroSep 2021View details →

Seasonal variation in community composition and distributional ranges of birds along a subtropical elevation gradient in China

Aim Seasonal variation in community composition and species distributional ranges along elevational gradients remain poorly known but are essential to inform conservation. In this study, we aim to understand how species richness, community composition, and elevational ranges of montane birds change between the breeding and the non-breeding season. Location The east slope of the southern Gaoligong Mountains, Yunnan, southwestern China, elevational range: 700 - 3400 m a.s.l.; latitudinal range: 24°56´- 26°09´ N. Methods We compared bird species richness and community composition in nine 300-m elevational bands in the breeding (April - May) and non-breeding (December - January) seasons. We also calculated seasonal elevational shifts of 97 species with sufficient data recorded in both seasons and assessed how species' traits influenced these shifts. Results Species richness declined in high and low elevations between the breeding and non-breeding season. The temporal beta diversity shift from the breeding to the non-breeding season was mainly caused by species losses rather than species gains in high- and low- elevation communities. Communities in middle elevations showed a contrasting pattern, with seasonal composition change resulting mainly from species gains. We also found that species' seasonal distribution shifts were mainly associated with breeding elevation and diet. Notably, high- and middle-elevation breeders and insectivores significantly shifted their elevational ranges downslope in the non-breeding season. In addition, species that participate in mixed-species flocks and that rely on forests also showed significant downslope shifts in the non-breeding season. Main Conclusions These results show complex patterns of the interconnectedness of bird communities along the elevational gradient. Keeping forests at middle elevations intact appears especially important as they are used in winter by species that breed at both high and middle elevations. Furthermore, our results suggested conservation actions maintaining connectedness in low and middle elevations are urgently needed to conserve regional biodiversity and highlight the importance of seasonality in montane ecosystem research.

opencc-zeroSep 2021View details →

Data from: Variation in seasonal timing traits and life history along a latitudinal transect in Mimulus ringens

Seasonal timing traits are commonly under recurrent, spatially-variable selection, and are therefore predicted to exhibit clinal variation. Temperate perennial plants often require vernalization to prompt growth and reproduction; however, little is known about whether vernalization requirements change across the range of a broadly distributed species. We performed a critical vernalization duration study in Mimulus ringens, coupled with population genomic analysis. Plants from 8 populations spanning the latitudinal range were exposed to varying durations of 4°C vernalization between 0-56 days, and flowering response was assessed. RADSeq was also performed to generate 1,179 polymorphic SNPs, which were used to examine population structure. We found unexpected life history variation, with some populations lacking vernalization requirement. Population genomic analyses show that these life history variants are highly divergent from perennials, potentially revealing a cryptic species. For perennial populations, minimum vernalization time was surprisingly consistent. However, once vernalized, northern populations flowered almost 3 weeks faster than southern. Further, southern populations exhibited sensitivity to vernalization times beyond flowering competency, suggesting an ability to respond adaptively to different lengths of winter. M. ringens therefore reveals evidence of clinal variation, and provides opportunities for future studies addressing mechanistic and ecological hypotheses both within and between incipient species.

opencc-zeroSep 2021View details →

Seasonal variation of population and individual dietary niche in the avivorous bat, Ia io

The variation in niche breadth can affect how species respond to environmental and resource changes. However, there is still no clear understanding of how seasonal variability in food resources impacts the variation of individual dietary diversity, thereby affecting the dynamics of a population's dietary niche breadth. Optimal foraging theory (OFT) and the niche variation hypothesis (NVH) predict that when food resources are limited, the population niche breadth will widen or narrow due to increased within-individual dietary diversity and individual specialization or reduced within-individual dietary diversity, respectively. Here, we used DNA metabarcoding to examine the composition and seasonality of diets of the avivorous bat Ia io. Furthermore, we investigated how the dietary niches changed among seasons and how the population niche breadth changed when the availability of insect resources was reduced in autumn. We found that there was differentiation in dietary niches among seasons and a low degree of overlap, and the decrease of insect resource availability and the emergence of ecological opportunities of nocturnal migratory birds might drive dietary niche shifts toward birds in I. io. However, the population's dietary niche breadth did not broaden by increasing the within-individual dietary diversity or individual specialization but rather became narrower by reducing dietary diversity via predation on bird resources that served as an ecological opportunity when insect resources were scarce in autumn. Our findings were consistent with the predictions of OFT because birds as prey for bats provided extremely different resources from those of insects in size and nutritional value. Our work highlights the importance of size and quality of prey resources along with other factors (i.e., physiological, behavioral, and life-history traits) in dietary niche variation.

opencc-by-4.0Jan 2023View details →

Data for Measurement report: Diurnal variations of brown carbon during two distinct seasons in a megacity in Northeast China

Data described in the manuscript "Measurement report: Diurnal variations of brown carbon during two distinct seasons in a megacity in Northeast China" submitted to Atmospheric Chemistry and Physics

opennotspecifiedNov 2017View details →

FIG. 2 in Host-parasite relationships between a Malagasy fruit bat (Pteropodidae) and associated bat fly (Diptera: Nycteribiidae): seasonal variation of host body condition and the possible impact of parasite abundance

FIG. 2. Body Condition Index (BCI) of R. madagascariensis in the Grotte des Chauves-souris, Parc National d'Ankarana, based on five different field sessions and separated into the different age and sex classes. AF = adult female, AM = adult male, NF = neonate female, NM = neonate male, SAF = sub-adult female, SAM = sub-adult male

FIG. 4 in Daily and seasonal variation in non-acoustic communicative behaviors of male greater short-nosed fruit bats (Cynopterus sphinx)

FIG. 4. Seasonal variation in duration and frequency of A — scent marking, B — wing flapping and C — open wing gesture behaviors. Mean ± SEM of frequency and duration varying between observed months (from January to December 2012). Mean ± SEM of number of attempts and duration was calculated from seven observation sessions for each month

FIG. 2 in Daily and seasonal variation in non-acoustic communicative behaviors of male greater short-nosed fruit bats (Cynopterus sphinx)

FIG. 2. Inter-individual variation in the mean frequency of A — scent marking, B — wing flapping and C — open wing gesture behavior between mating and non-mating seasons. Data shown as the mean of number of attempts (± SEM) made by focal bats between two mating and two non mating seasons. Each data point represents individual focal bat (Animal ID — A to F)

FIG. 3 in Daily and seasonal variation in non-acoustic communicative behaviors of male greater short-nosed fruit bats (Cynopterus sphinx)

FIG. 3. Daily variation in duration and frequency of A — scent marking, B — wing flapping and C — open wing gesture behaviors. Mean ± SEM of frequency and duration between observation sessions (one hour time interval). Mean ± SEM number of attempts and duration of each attempt were calculated for each observation session across 12 months (between January and December 2012) for all focal bats

FIG. 1 in Daily and seasonal variation in non-acoustic communicative behaviors of male greater short-nosed fruit bats (Cynopterus sphinx)

FIG. 1. Non-acoustic communicative displays of male C. sphinx. A — male bat scent marking the interior of palm leaves with its saliva during night time. Circled areas in the picture shows scent marked part of the leaf. B — Tagged male bat co-roosting with females (untagged) in the day roost and displaying open wing gesture during morning hours in the mating season