Drivers Of Such Variations Research Articles

The effect of environmental variation on the relationship between survival and risk-taking behaviour in a migratory songbird.

Temporal changes in environmental conditions may play a major role in the year-to-year variation in fitness consequences of behaviours. Identifying environmental drivers of such variation is crucial to understand the evolutionary trajectories of behaviours in natural contexts. However, our understanding of how environmental variation influences behaviours in the wild remains limited. Using data collected over 14 breeding seasons from a collared flycatcher (Ficedula albicollis) population, we examined the effect of environmental variation on the relationship between survival and risk-taking behaviour, a highly variable behavioural trait with great evolutionary and ecological significance. Specifically, using annual recapture probability as a proxy of survival, we evaluated the specific effect of predation pressure, food availability, and mean temperature on the relationship between annual recapture probability and risk-taking behaviour (measured as flight initiation distance [FID]). We found a negative trend, as the relationship between annual recapture probability and FID decreased over the study years and changed from positive to negative. Specifically, in the early years of the study, risk-avoiding individuals exhibited a higher annual recapture probability, whereas in the later years, risk-avoiders had a lower annual recapture probability. However, we did not find evidence that any of the considered environmental factors mediated the variation in the relationship between survival and risk-taking behaviour.

The Physical Drivers and Observational Tracers of CO-to-H2 Conversion Factor Variations in Nearby Barred Galaxy Centers

The CO-to-H2 conversion factor (α CO) is central to measuring the amount and properties of molecular gas. It is known to vary with environmental conditions, and previous studies have revealed lower α CO in the centers of some barred galaxies on kiloparsec scales. To unveil the physical drivers of such variations, we obtained Atacama Large Millimeter/submillimeter Array bands (3), (6), and (7) observations toward the inner ∼2 kpc of NGC 3627 and NGC 4321 tracing 12CO, 13CO, and C18O lines on ∼100 pc scales. Our multiline modeling and Bayesian likelihood analysis of these data sets reveal variations of molecular gas density, temperature, optical depth, and velocity dispersion, which are among the key drivers of α CO. The central 300 pc nuclei in both galaxies show strong enhancement of temperature T k ≳ 100 K and density cm−3. Assuming a CO-to-H2 abundance of 3 × 10−4, we derive 4–15 times lower α CO than the Galactic value across our maps, which agrees well with previous kiloparsec-scale measurements. Combining the results with our previous work on NGC 3351, we find a strong correlation of α CO with low-J 12CO optical depths (τ CO), as well as an anticorrelation with T k. The τ CO correlation explains most of the α CO variation in the three galaxy centers, whereas changes in T k influence α CO to second order. Overall, the observed line width and 12CO/13CO 2–1 line ratio correlate with τ CO variation in these centers, and thus they are useful observational indicators for α CO variation. We also test current simulation-based α CO prescriptions and find a systematic overprediction, which likely originates from the mismatch of gas conditions between our data and the simulations.

Impacts of Eucalyptus plantation on soil and water losses in a typical small watershed in mountainous area of southern China.

Unreasonable exploitation of artificial forest causes severe soil erosion in the mountainous areas of sou-thern China. The spatial-temporal variations of soil erosion in typical small watershed with artificial forest has signifi-cant implications for artificial forest exploitation and sustainable development of mountainous ecological environment. In this study, we used revised universal soil loss equation (RUSLE) and geographic information system (GIS) to evaluate the spatial and temporal variations of soil erosion and its key drivers of Dadingshan watershed in mountainous area of western Guangdong. The results showed that the erosion modulus was 1948.1 t·km-2·a-1 (belonging to light erosion) in the Dadingshan watershed. However, the spatial variation of soil erosion was substantial, with variation coefficient of 5.12. The maximal soil erosion modulus was 191127 t·km-2·a-1. Slight erosion (<500 t·km-2·a-1) accounted for 80.6% of the total watershed area. The moderate erosion and above (>2500 t·km-2·a-1) were mainly distributed in young Eucalyptus forest area with less than 30% of the vegetation coverage, which contributed nearly 75.7% of total soil erosion. During 2014-2019, the interannual variations of mean erosion of Dadingshan catchment was modest, but the spatial variation of soil erosion was large. Vegetation cover, slope, and rainfall were key drivers of such variation. The destruction of natural vegetation resulted by plantation exploitation was the primary cause of soil erosion in afforestation areas. Soil erosion significantly increased with the increases of slope gradient in the young forest area, which was aggravated by extreme rainfall. However, soil erosion gradually decreased with the increases of the age of Eucalypt plantation. Therefore, the hot spot of soil erosion was young forest areas of Eucalypt plantation with slope >25°, and the key period for soil erosion control was the first 2-3 years after Eucalyptus planting. We suggested that reasonable afforestation measures should be used in area with >25° slopes, and that the destruction of natural vegetation should be avoided on hillslope with >35° slope gradient. The road construction standards and forest management should be further improved to address the challenge of extreme rainfalls.

Decoupling pioneering traits from latitudinal patterns in a north American bird experiencing a southward range shift.

Ecogeographic rules describe spatial patterns in biological trait variation and shed light on the drivers of such variation. In animals, a consensus is emerging that 'pioneering' traits may facilitate range shifts via a set of bold, aggressive and stress-resilient traits. Many of these same traits are associated with more northern latitudes, and most range shifts in the northern hemisphere indicate northward movement. As a consequence, it is unclear whether pioneering traits are simply corollaries of existing latitudinal variation, or whether they override other well-trodden latitudinal patterning as a unique ecogeographic rule of phenotypic variation. The tree swallow Tachycineta bicolor is a songbird undergoing a southward range shift in the eastern United States, in direct opposition of the poleward movement seen in most other native species' range shifts. Because this organic range shift countervails the typical direction of movement, this case study provides for unique ecological insights on organisms and their ability to thrive in our changing world. We sampled female birds across seven populations, quantifying behavioural, physiological and morphological traits. We also used GIS and field data to quantify a core set of ecological factors with strong ties to these traits as well as female performance. Females at more southern expansion sites displayed higher maternal aggression, higher baseline corticosterone and more pronounced elevation of corticosterone following a standardized stressor, contrary to otherwise largely conserved latitudinal patterning in these traits. Microhabitat variation explained some quantitative phenotypic variation, but the expansion and historic ranges did not differ in openness, distance to water or breeding density. This countervailing range shift therefore suggests that pioneering traits are not simply corollaries of existing latitudinal variation, but rather, they may override other well-trodden latitudinal patterning as a unique ecogeographic rule of phenotypic variation.

Patterns and predictors of inter-litter differences in rabbit pup locomotor activity, based on an automatized quantification method

Individual-level sibling interactions in the litter huddle have been studied extensively, especially in the domestic rabbit (Oryctolagus cuniculus). However, little is known about inter-litter differences in pup activity patterns during early postnatal life, in particular regarding the drivers of such variation. In our study on 2–3-day-old rabbit pups, we predicted lower locomotor activity in litters with lower mean body masses on the day of birth (starting body mass) and with lower daily milk intake per pup, possibly constituting a behavioral strategy of pups to cope with associated energetic constraints. For an automatized assessment of pup locomotor activity in the litter huddle, we successfully developed and validated a method based on the quantification of dissimilarities between consecutive frames of video footage. Using this method, we could confirm a U-shaped time course of litter-level locomotor activity, with maximum values shortly before and after the once-daily nursing typical for the rabbit. As predicted, between-litter variation in mean starting body mass and in daily milk intake affected the degree of locomotor activity in the litter huddle, in an interactive way. That is, in litters with heavier starting body masses, pup locomotor activity was greater in pups with an initially higher milk intake, suggesting that only pups with better body condition and a higher energy intake could afford higher levels of activity. This interaction was exclusively apparent during the middle phase of the 24 h inter-nursing interval, when litter activity was low. Shortly before nursing, when pups show higher levels of locomotor behavior in anticipation of the mother's arrival, and shortly after nursing when the pups were more active possibly due to adjustments of their positions in the huddle, activity levels were decoupled from pups’ starting body mass and previous milk intake. Our findings highlight the importance of pup body mass and daily energy intake, two parameters known to be related to maternal characteristics, in shaping inter-litter differences in pup locomotor activity.

Patterns of populist mobilization: comparing narratives on COVID-19 in the global South

Abstract This article explores the narratives shaping the official discourse on COVID-19 in five countries governed by populists in different world regions. It is based on the assumption that a crisis like the pandemic constitutes a perfect occasion for populist mobilization, allowing populist leaders to construct reality in their favour by deliberately promoting own narratives about the pandemic, its origin and management. Analyzing 357 original-language speeches and statements by representatives of the populist governments of Brazil, Israel, India, Mexico and Turkey, the article shows that populists in power use crises to mobilize support in very different ways. Surprisingly, most populist governments neither resorted to anti-scientific claims or conspiratorial discourses attributing the crisis to obscure elites, nor blamed minorities not belonging to the ‘true people’. By contrast, except for Bolsonaro in Brazil, all other populist governments tried to mobilize support by emphasizing the strength of the ‘people’ or even by promoting an inclusive discourse of national unity, leaving aside the more divisive elements of their general populist discourse. Based on the cases analysed, the article concludes by developing hypotheses on the possible drivers of such variations in patterns of populist mobilization.

Regional variation of medical expenditures attributable to hypertension in China's middle-aged and elderly population.

Hypertension is a prevalent and costly health condition in China. Little is known about variation of the inpatient and outpatient expenditures attributable to hypertension between prefecture-level administrative regions (PARs) and the drivers of such variation among China's middle-aged and elderly population. We obtain data from China Health and Retirement Longitudinal Survey between 2011 and 2015, panel tobit models were used in our study to estimate differences across 122 PARs. Expenditure variation was explained by the characteristics of individuals and regions, including measures of healthcare supply. The cost of treatment for patients with hypertension varies greatly geographically, with the highest outpatient and inpatient costs being 77 and 102 times the lowest, respectively. After adjustment for the individual and PAR character, there are associations between expenditure and region bed density. There were significant regional differences in the outpatient and inpatient costs of middle-aged and elderly patients with hypertension in China, the difference between individuals may be an important reason, which has little to do with regional economic development differences, but is related to regional bed density.

Methods Used in the Spatial and Spatiotemporal Analysis of COVID-19 Epidemiology: A Systematic Review.

The spread of the COVID-19 pandemic was spatially heterogeneous around the world; the transmission of the disease is driven by complex spatial and temporal variations in socioenvironmental factors. Spatial tools are useful in supporting COVID-19 control programs. A substantive review of the merits of the methodological approaches used to understand the spatial epidemiology of the disease is hardly undertaken. In this study, we reviewed the methodological approaches used to identify the spatial and spatiotemporal variations of COVID-19 and the socioeconomic, demographic and climatic drivers of such variations. We conducted a systematic literature search of spatial studies of COVID-19 published in English from Embase, Scopus, Medline, and Web of Science databases from 1 January 2019 to 7 September 2021. Methodological quality assessments were also performed using the Joanna Briggs Institute (JBI) risk of bias tool. A total of 154 studies met the inclusion criteria that used frequentist (85%) and Bayesian (15%) modelling approaches to identify spatial clusters and the associated risk factors. Bayesian models in the studies incorporated various spatial, temporal and spatiotemporal effects into the modelling schemes. This review highlighted the need for more local-level advanced Bayesian spatiotemporal modelling through the multi-level framework for COVID-19 prevention and control strategies.

Intraspecific variability in herbivore response to elemental defences is caused by the metal itself

Some plants are able to accumulate on their leaves metals taken from the soil, using this as a defence against herbivorous arthropods. However, herbivore response to metal accumulation in plants is known to be variable. While some species and taxonomic groups are less affected than others, hormetic effects have also been observed in spider mites, herbivorous crop pests. Still, knowledge on the range and causes of intraspecific variation in the response of herbivores to metal accumulation is lacking. Here, using two species of spider mites, Tetranychus urticae and Tetranychus evansi, we tested the variation in 17 populations in response to cadmium-accumulating tomato plants and the drivers of such variation. We observed a nonlinear, hormetic response of mites to plants with cadmium in some, but not all, populations. The same pattern was recaptured in artificial diets with different concentrations of cadmium but not in artificial diets with sugars, which change in the plant in response to cadmium. This indicates that herbivores on metal-accumulating plants respond to metals, not to the variations in leaf carbohydrates. Therefore, metals exert different effects on herbivores according to the amount accumulated, but independently of other studied plant traits. This knowledge is key to the understanding of the mechanisms underlying herbivore responses to metal-based plant defences and to pesticides containing heavy metals. Additionally, our findings draw attention to the need of considering intraspecific variation and nonlinearities when studying the effects of metals and other contaminants on herbivorous arthropods.

Prehatching temperatures drive inter-annual cohort differences in great tit metabolism

Basal metabolic rate (BMR) constitutes the lowest metabolic rate in a resting animal and is, therefore, considered to reflect the energetic cost of maintenance in endotherms. BMR is a reversible plastic trait that changes with environmental and ecological circumstances, albeit being heritable and susceptible to selection. Inter-individual variation within populations of small birds is substantial, and while many of the drivers of such variation have been identified, many remain unexplained. We studied winter BMR variation of juveniles over a 15-year period in a wild population of great tits Parus major at the northern border of their distribution. BMR during winter consistently changed between years, even after controlling for environmental factors, suggestive of a non-reversible developmental plasticity shaping the adult metabolic phenotype. BMR in cohorts of wintering great tits varied among winters as a response to minimum ambient temperatures experienced early in life, during the prehatching period. This developmental plasticity might be adaptive if temperatures experienced by growing embryos would metabolically prime them to an environment that they will likely encounter in future life. However, in line with a more unpredictable future climate, the risk of phenotype-environment mismatch is likely to lead to certain cohorts being poorly adapted to prevailing winter conditions, resulting in wider annual fluctuations in population size.

Disentangling the beta-diversity in anuran parasite communities.

There is great heterogeneity in parasite communities among hosts, understanding the nature and drivers of such variations is still a great scientific quest. Here, we analyse the variation in parasite communities by addressing the following questions: (i) What is the beta-diversity component (nestedness or turnover) that most contributes to beta diversity in parasite communities among anuran species? (ii) Does the beta diversity of parasite communities follow a non-random pattern? (iii) Is the dissimilarity in composition of parasite communities related to the phylogenetic or functional dissimilarity among hosts? We found that turnover in parasite assemblages was the main component of beta diversity, but the variation observed both in the total beta diversity and in its components did not differ from the respective null models. The dissimilarity among parasite communities was not related to the phylogenetic species variability or functional dissimilarity among anuran species for most localities. In short, our findings may indicate a process of resource tracking by the parasite species, in which the resource may not necessarily be conserved phylogenetically in their hosts.

Linking environmental factors with reflex action mortality predictors, physiological stress, and post-release movement behaviour to evaluate the response of white sturgeon (Acipenser transmontanus Richardson, 1836) to catch-and-release angling

White sturgeon are the largest freshwater fish in North America and are the focus of an intense catch-and-release (C&R) fishery; the effects are largely unknown. We assessed the effect of fight and handling time, water temperature, river discharge rate, and fish size on physiological and reflex impairment responses of wild white sturgeon to angling. Sixty of these fish were tagged with acoustic transmitters to assess survival and post-release behaviour. Survival was high (100%). Water temperature and discharge influenced post-capture blood physiology. Specifically, lactate, chloride, and cortisol concentrations were elevated in individuals fought longer, and captured at higher water temperatures and river discharge. Cortisol was affected by fish size, with lower concentrations found in larger individuals. Only lactate and chloride were positively related to reflex impairment scores. Post-release movements were correlated with physiological state, fight characteristics and the environment. Specifically, higher blood lactate and chloride and those with longer fight times moved shorter distances after release. Contrastingly, higher levels of circulating glucose and potassium, as well as larger fish captured during periods of high discharge moved longer distances. Sturgeon tended to move shorter distances and at slower rates when reflex impairment was high, although reflex impairment in general did not explain a significant proportion of the variance in any movement metric. Our results show intriguing variance in the physiological and behavioural response of individual white sturgeon to C&R angling, with some degree of environmental dependence, and highlights the importance of understanding drivers of such variation when managing fisheries.

Explaining local variation in referrals from health services to children's social care in England 2013-16: a study using 'children in need' administrative data.

BackgroundReferral rates from Health service to Children’s Social Care (CSC) services vary across England. In 2019, the National Audit Office (re)iterated the urgent need to understand the drivers of such variation.MethodsUsing administrative data (Children in Need Census, 2013–16), we calculated annual referral rates from Health to CSC services (Health referral rate) by Local Authority (LA) areas. We used multilevel linear regression to investigate the relationship between age-adjusted Health referral rates and local need (demand factors) and local practice/systems (supply factors). We present a tool to compare unadjusted and adjusted LA rates.ResultsThere was high LA variation in Health referral rates, particularly for infants (mean = 29.0/1000 children < 1 y; range = 6.5–101.8; sd = 12.4). LA variation persisted after age-adjustment. Child poverty (local need) and overall referral rate (local practice/systems) explained 60% of variation in age-adjusted Health referral rates. Overall referral rate was the strongest predictor. Adjusted referral rates were substantially different from unadjusted rates. After adjustment, 57.7% of LAs had higher/lower Health referral rates than expected.ConclusionsWhile higher levels of local need are associated with higher Health referrals, some areas have high Health referrals irrespective of local need. Our tool demonstrates the benefits of using adjusted rates to compare LAs.

Macroecological patterns and correlates of ant–tree interaction networks in Neotropical savannas

AbstractAimSimilar to species richness, ecological interactions can vary across latitudinal and environmental gradients. Knowing the patterns and drivers of such variation could help us to better understand the role of species interactions in maintaining biodiversity. In this study, we analysed the macroecological patterns of the structure and interaction beta diversity of interaction networks involving trees and ants.LocationTwenty‐nine sites encompassing 20 degrees of latitude throughout the Neotropical savanna.Time period2010–2015.Major taxa studiedTrees and arboreal nesting ants.MethodsFor each site, we built an interaction network and calculated network size, interaction diversity (Shannon diversity of interactions), specialization, modularity, nestedness, and interaction dissimilarity (contribution of each network to the regional pool of possible interactions). We also determined how interaction beta diversity varied among all sampling sites. Net primary productivity (NPP), temperature and rainfall were evaluated as potential correlates of the observed changes in network descriptors and interaction beta diversity.ResultsWe found no latitudinal gradient in network specialization, nestedness or modularity. However, sites at higher latitudes had larger networks, higher interaction diversity and higher interaction dissimilarity, and this was correlated mainly with the latitudinal variation in NPP. Interaction rewiring generated by the reassembly of the interactions between the same species in different sites was the main contributor to the total interaction beta diversity. However, the level of interaction rewiring was independent of the geographical and environmental distance between sampling sites.Main conclusionsAnt–tree network structure remained relatively invariant across the latitudinal and environmental gradient possibly due to high interaction rewiring among the partners. Moreover, our findings show that more productive sites, located at higher latitudes, have high dissimilarity to the regional pool of possible interactions (i.e., strong interaction filtering), indicating that these sites significantly contribute to the maintenance of interaction biodiversity in Neotropical savannas.

Dynamics of net ecosystem methane exchanges on temporal scale in tropical lowland rice

Net ecosystem methane exchanges (NEME) from lowland rice often show significant variations in diurnal, seasonal and yearly scales and with crop phenology. Air and soil temperatures, standing water, and radiation are believed to be primary drivers of such variations. We studied the dynamics of net ecosystem methane exchange in three consecutive years (2014–16) using eddy covariance technology. Wet season (July–October) showed higher diurnal methane flux variations than that of dry season (December–March) due to prolonged anoxic condition and higher methanogens in the former. Significant diurnal variations in NEME were also noticed during different crop growth stages. Variations were higher in flowering stage followed by ripening in 2015 and 2016. But in 2014, it was highest at panicle initiation (PI) stage. Principal component bivariate plot analysis and performance analytic correlation were performed for variables such as net ecosystem carbon dioxide exchange (NEE), NEME, sensible heat (Hs), latent heat (LE), photosynthetically active radiation (PAR), net radiation (NR), air temperature and soil temperature (5 cm depth) in order to assess their relationships. The NEME was positively correlated to air and soil temperatures in all the years. However, in year 2016, NEME also showed positive correlation to PAR and NR. These relationships could provide valuable information to partitioning and process-based simulation modelling for projecting and up scaling of NEME to regional and global scales.

Regional Variation of Cost of Care in the Last 12 Months of Life in Switzerland: Small-area Analysis Using Insurance Claims Data.

Health care spending increases sharply at the end of life. Little is known about variation of cost of end of life care between regions and the drivers of such variation. We studied small-area patterns of cost of care in the last year of life in Switzerland. We used mandatory health insurance claims data of individuals who died between 2008 and 2010 to derive cost of care. We used multilevel regression models to estimate differences in costs across 564 regions of place of residence, nested within 71 hospital service areas. We examined to what extent variation was explained by characteristics of individuals and regions, including measures of health care supply. The study population consisted of 113,277 individuals. The mean cost of care during last year of life was 32.5k (thousand) Swiss Francs per person (SD=33.2k). Cost differed substantially between regions after adjustment for patient age, sex, and cause of death. Variance was reduced by 52%-95% when we added individual and regional characteristics, with a strong effect of language region. Measures of supply of care did not show associations with costs. Remaining between and within hospital service area variations were most pronounced for older females and least for younger individuals. In Switzerland, small-area analysis revealed variation of cost of care during the last year of life according to linguistic regions and unexplained regional differences for older women. Cultural factors contribute to the delivery and utilization of health care during the last months of life and should be considered by policy makers.

Mixed Sex Effects on the Second-to-Fourth Digit Ratio of Túngara Frogs (Engystomops pustulosus) and Cane Toads (Rhinella marina).

Sexual dimorphism in the ratio of digit lengths has been correlated to behavioral, physiological, and morphological traits in a variety of taxa. While sexual dimorphism in the second-to-fourth digit length ratio (2D:4D) is a well-established indicator of prenatal androgen exposure in mammals, investigations into the patterns of 2D:4D and the drivers of such variation in other taxa are lacking. We used linear mixed effects models to gain a mechanistic understanding of the factors that drive variation in the scaling relationship between the lengths of the second and fourth digits in two species of anurans: túngara frogs (Engystomops pustulosus) and cane toads (Rhinella marina). We found evidence for sexual dimorphism of the 2D:4D scaling relationship on the front feet of túngara frogs, with female frogs having a larger ratio than males resulting from a relatively longer second digit on females. To our knowledge, this mammal-like pattern of sex differences in digit ratio has not yet been reported for anurans. However, given the reduced number of digits on the front feet of anurans, and uncertainty about which digit was lost during evolutionary history, this apparent sexual dimorphism in the front feet of túngara frogs should be treated with caution. In contrast, we found no evidence of sexual dimorphism in 2D:4D on either the front or rear feet of cane toads. This study highlights ambiguities in 2D:4D across taxa and suggests that further research is needed to evaluate the effect of androgens on 2D:4D in animals other than placental mammals.

The Economic Effects of Constitutions: Do Budget Institutions Make Forms of Government More Alike?

According to an influential theoretical argument, presidential systems tend to present smaller governments because the separation between those who decide the size of the fiscal purse and those who allocate it creates incentives for lower public expenditures. In practice, forms of government vary greatly, and budget institutions -the rules according to which budgets are drafted, approved, and implemented- are one (of many) drivers of such variation. This paper argues that under more hierarchical budget rules, presidential and parliamentary systems generate a similar incentive structure for the executive branch in shaping the size of government. This hypothesis is tested on a broad cross-section of countries, presidentialism is found to have a negative impact on government size only when executive discretion in the budget process is low (that is, in a context of separation of powers). However, the negative effect of presidentialism on expenditures vanishes or is even reversed when the executive`s discretion over the budget process is higher. Hence, budget institutions that impose restrictions on the legislature`s ability to amend budget proposals can make political regimes look more alike in terms of fiscal outcomes.

Color Polymorphism in Spiny Spiders (Gasteracantha fornicata): Testing the Adaptive Significance of a Geographically Clinal Lure

AbstractMany sit‐and‐wait predators use conspicuous displays of color to attract prey. These displays sometimes express discrete polymorphisms; however, the adaptive drivers of such variation are not well understood. Here, we explore a previously unknown color polymorphism in the orb‐web spider Gasteracantha fornicata. We discovered that in North Queensland, Australia, female spiders exhibit dorsal bands appearing (to the human observer) either white or yellow and characterized by sigmoidal spectral curves centered on approx. 447 and 496 nm, respectively. Based on sensory drive theory, we hypothesized that morphs may be alternatively favored by the switch in ambient viewing conditions engendered by sunny vs. cloudy skies. We addressed this hypothesis indirectly by studying morph frequencies across a approx. 200 km geographic gradient of solar exposure (a surrogate for cloudiness), and by investigating the phenotypic signature of catch success via a resource stress experiment and in wild spiders. Our data indicate substantial geographic variation in morph frequency, with white morphs dominating at more cloudy northern locations. Rather than a gradual cline, morph frequency inverted mid‐way along this range and was closely fit by a logistic relationship with latitude. Experimentally restricted access to larger prey caused spiders to lose more mass than size and to exhibit less bright dorsal markings. Wild‐sampled spiders from two localities of divergent morph frequency indicated no differences in residual mass, but intriguingly, the white morph was larger and heavier (than the yellow morph) where it was relatively rare. Our data hint at negative frequency dependence, but remain broadly consistent with a sensory drive explanation based on cloudiness, and we suggest these as worthy avenues for closer investigation.