scholarly journals Urbanization-driven changes in web-building are decoupled from body size in an orb-web spider

2017 ◽  
Author(s):  
Maxime Dahirel ◽  
Maarten De Cock ◽  
Pieter Vantieghem ◽  
Dries Bonte
Keyword(s):  
Body Size ◽  
Environmental Changes ◽  
Spatial Scales ◽  
Local Scale ◽  
List Type ◽  
Behavioural Responses ◽  
Prey Biomass ◽  
Araneus Diadematus ◽  
Biomass Availability ◽  
Web Building

AbstractIn animals, behavioural responses may play an important role in determining population persistence in the face of environmental changes. Body size is a key trait central to many life history traits and behaviours. While behaviours are typically assumed to be highly plastic, size correlations may impose constraints on their adaptive value when size itself is subject to environmental changes.Urbanization is an important human-induced rapid environmental change that imposes multiple selection pressures on both body size and (size-constrained) behaviour. How these combine to shape behavioural responses of urban-dwelling species is unclear.Using web-building, an easily quantifiable behaviour linked to body size, and the garden spider Araneus diadematus as a model, we disentangle direct behavioural responses to urbanization and body size constraints across a network of 63 selected populations differing in urbanization intensity at two spatial scales.Spiders were smaller in highly urbanized sites (local scale only), in line with expectations based on reduced prey biomass availability and the Urban Heat Island effect. The use of multivariate mixed modelling reveals that although web traits and body size are correlated within populations, behavioural responses to urbanization do not appear to be constrained by size: there is no evidence of size-web correlations among populations or among landscapes. Spiders thus altered different components of their web-building behaviours independently in response to urbanization: mesh width and web surface decreased independently with urbanization at the local scale, while web surface also increased with urbanization at the landscape scale. These responses are expected to compensate, at least in part, for reduced prey biomass availability.Our results demonstrate that responses in typically size-dependent behaviours may be decoupled from size changes, thereby allowing fitness maximisation in novel environments. The spatial scale of the behavioural responses to urbanization suggest contributions of both genetic adaptation and plasticity. Although fecundity decreased with local-scale urbanization, Araneus diadematus abundances were remarkably similar across urbanization gradients; behavioural responses thus appear overall successful at the population level.

scholarly journals Intraspecific variation shapes community-level behavioural responses to urbanisation in spiders: from traits to function

2016 ◽  
Author(s):  
Maxime Dahirel ◽  
Jasper Dierick ◽  
Maarten De Cock ◽  
Bonte Dries
Keyword(s):  
Ecosystem Functioning ◽  
Urban Areas ◽  
Environmental Changes ◽  
Environmental Gradients ◽  
Species Turnover ◽  
Community Level ◽  
List Type ◽  
Trait Variation ◽  
Behavioural Responses ◽  
Intraspecific Trait Variation

SummaryApproaches based on functional traits have proven especially valuable to understand how communities respond to environmental gradients. Until recently, they have, however, often ignored the potential consequences of intraspecific trait variation (ITV). This position becomes potentially more problematic when studying animals and behavioural traits, as behaviours can be altered very flexibly at the individual level to track environmental changes.Urban areas are an extreme example of human-changed environments, exposing organisms to multiple, strong, yet relatively standardized, selection pressures. Adaptive behavioural responses are thought to play a major role in animals’ success or failure in these new environments. The consequences of such behavioural changes for ecosystem processes remain understudied.Using 62 sites of varying urbanisation level, we investigated how species turnover and ITV influenced community-level behavioural responses to urbanisation, using orb web spiders and their webs as models of foraging behaviour.ITV explained around 30% of the total trait variation observed among communities. Spiders altered their web-building behaviour in cities in ways that increase the capture efficiency of webs. These traits shifts were partly mediated by species turnover, but ITV increased their magnitude. The importance of ITV varied depending on traits and on the spatial scale at which urbanisation was considered. Available prey biomass decreased with urbanisation; the corresponding decrease in prey interception by spiders was less important when ITV in web traits was accounted for.By facilitating trait-environment matching despite urbanisation, ITV thus helps communities to buffer the effects of environmental changes on ecosystem functioning. Despite being often neglected from community-level analyses, our results highlight the importance of accounting for intraspecific trait variation to fully understand trait responses to (human-induced) environmental changes and their impact on ecosystem functioning.

scholarly journals Changes in body size spectra of benthic caridean shrimps (Decapoda: Caridea) and snails (Gastropoda) as response to seasonal variability

2016 ◽  
Vol 64 (1) ◽  
pp. 33
Author(s):  
Ernesto Iván Badano ◽  
Fabio A. Labra ◽  
Cecilia G. Martínez-Pérez ◽  
Carlos H. Vergara
Keyword(s):  
Body Size ◽  
Environmental Changes ◽  
Spatial Scales ◽  
Taxonomic Group ◽  
Eastern Coast ◽  
Power Scaling ◽  
Regression Analyses ◽  
Size Spectra ◽  
Taxonomic Groups ◽  
The Impact

Ecologists have been largely interested in the description and understanding of the power scaling relationships between body size and abundance of organisms. Many studies have focused on estimating the exponents of these functions across taxonomic groups and spatial scales, to draw inferences about the processes underlying this pattern. The exponents of these functions usually approximate -3/4 at geographical scales, but they deviate from this value when smaller spatial extensions are considered. This has led to propose that body size-abundance relationships at small spatial scales may reflect the impact of environmental changes. This study tests this hypothesis by examining body size spectra of benthic shrimps (Decapoda: Caridea) and snails (Gastropoda) in the Tamiahua lagoon, a brackish body water located in the Eastern coast of Mexico. We measured water quality parameters (dissolved oxygen, salinity, pH, water temperature, sediment organic matter and chemical oxygen demand) and sampled benthic macrofauna during three different climatic conditions of the year (cold, dry and rainy season). Given the small size of most individuals in the benthic macrofaunal samples, we used body volume, instead of weight, to estimate their body size. Body size-abundance relationships of both taxonomic groups were described by tabulating data from each season into base-2 logarithmic body size bins. In both taxonomic groups, observed frequencies per body size class in each season were standardized to yield densities (i.e., individuals/m3). Nonlinear regression analyses were separately performed for each taxonomic group at each season to assess whether body size spectra followed power scaling functions. Additionally, for each taxonomic group, multiple regression analyses were used to determine whether these relationships varied among seasons. Our results indicated that, while body size-abundance relationships in both taxonomic groups followed power functions, the parameters defining the shape of these relationships varied among seasons. These variations in the parameters of the body size-abundance relationships seems to be related to changes in the abundance of individuals within the different body size classes, which seems to follow the seasonal changes that occur in the environmental conditions of the lagoon. Thus, we propose that these body size-abundance relationships are influenced by the frequency and intensity of environmental changes affecting this ecosystem.

scholarly journals Body size, reef area and temperature predict global reef-fish species richness across spatial scales

2018 ◽  
Vol 28 (3) ◽  
pp. 315-327 ◽  
Author(s):  
D. R. Barneche ◽  
E. L. Rezende ◽  
V. Parravicini ◽  
E. Maire ◽  
G. J. Edgar ◽  
...  
Keyword(s):  
Species Richness ◽  
Body Size ◽  
Reef Fish ◽  
Fish Species ◽  
Spatial Scales ◽  
Reef Area ◽  
Reef Fish Species

scholarly journals Cell proliferation controls body size growth, tentacle morphogenesis, and regeneration in hydrozoan jellyfish Cladonema pacificum

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7579 ◽  
Author(s):  
Sosuke Fujita ◽  
Erina Kuranaga ◽  
Yu-ichiro Nakajima
Keyword(s):  
Cell Proliferation ◽  
Body Size ◽  
Environmental Changes ◽  
Size Control ◽  
Cellular Mechanisms ◽  
Proliferating Cells ◽  
Size Growth ◽  
Local Cell ◽  
Proliferating Cell

Jellyfish have existed on the earth for around 600 million years and have evolved in response to environmental changes. Hydrozoan jellyfish, members of phylum Cnidaria, exist in multiple life stages, including planula larvae, vegetatively-propagating polyps, and sexually-reproducing medusae. Although free-swimming medusae display complex morphology and exhibit increase in body size and regenerative ability, their underlying cellular mechanisms are poorly understood. Here, we investigate the roles of cell proliferation in body-size growth, appendage morphogenesis, and regeneration using Cladonema pacificum as a hydrozoan jellyfish model. By examining the distribution of S phase cells and mitotic cells, we revealed spatially distinct proliferating cell populations in medusae, uniform cell proliferation in the umbrella, and clustered cell proliferation in tentacles. Blocking cell proliferation by hydroxyurea caused inhibition of body size growth and defects in tentacle branching, nematocyte differentiation, and regeneration. Local cell proliferation in tentacle bulbs is observed in medusae of two other hydrozoan species, Cytaeis uchidae and Rathkea octopunctata, indicating that it may be a conserved feature among hydrozoan jellyfish. Altogether, our results suggest that hydrozoan medusae possess actively proliferating cells and provide experimental evidence regarding the role of cell proliferation in body-size control, tentacle morphogenesis, and regeneration.

scholarly journals Memories of Migrations Past: Sociality and Cognition in Dynamic, Seasonal Environments

2021 ◽  
Vol 9 ◽  
Author(s):  
Eliezer Gurarie ◽  
Sriya Potluri ◽  
George Christopher Cosner ◽  
Robert Stephen Cantrell ◽  
William F. Fagan
Keyword(s):  
Environmental Changes ◽  
Animal Movement ◽  
Spatial Scales ◽  
Rapid Change ◽  
Reference Memory ◽  
Migratory Behavior ◽  
Migration Behavior ◽  
Long Distance ◽  
Trade Offs ◽  
Resource Dynamics

Seasonal migrations are a widespread and broadly successful strategy for animals to exploit periodic and localized resources over large spatial scales. It remains an open and largely case-specific question whether long-distance migrations are resilient to environmental disruptions. High levels of mobility suggest an ability to shift ranges that can confer resilience. On the other hand, a conservative, hard-wired commitment to a risky behavior can be costly if conditions change. Mechanisms that contribute to migration include identification and responsiveness to resources, sociality, and cognitive processes such as spatial memory and learning. Our goal was to explore the extent to which these factors interact not only to maintain a migratory behavior but also to provide resilience against environmental changes. We develop a diffusion-advection model of animal movement in which an endogenous migratory behavior is modified by recent experiences via a memory process, and animals have a social swarming-like behavior over a range of spatial scales. We found that this relatively simple framework was able to adapt to a stable, seasonal resource dynamic under a broad range of parameter values. Furthermore, the model was able to acquire an adaptive migration behavior with time. However, the resilience of the process depended on all the parameters under consideration, with many complex trade-offs. For example, the spatial scale of sociality needed to be large enough to capture changes in the resource, but not so large that the acquired collective information was overly diluted. A long-term reference memory was important for hedging against a highly stochastic process, but a higher weighting of more recent memory was needed for adapting to directional changes in resource phenology. Our model provides a general and versatile framework for exploring the interaction of memory, movement, social and resource dynamics, even as environmental conditions globally are undergoing rapid change.

scholarly journals A comprehensive analysis of vomeronasal organ transcriptome reveals variable gene expression depending on age and function in rabbits

2020 ◽  
Author(s):  
PR Villamayor ◽  
D Robledo ◽  
C Fernández ◽  
J Gullón ◽  
L Quintela ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transient Receptor Potential ◽  
Expression Patterns ◽  
Vomeronasal Organ ◽  
Receptor Potential ◽  
Transient Receptor Potential Channel ◽  
List Type ◽  
Gene Repertoire ◽  
Behavioural Responses ◽  
Transient Receptor

ABSTRACTThe vomeronasal organ (VNO) is a chemosensory organ specialized in the detection of pheromones and consequently the regulation of behavioural responses mostly related to reproduction. VNO shows a broad variation on its organization, functionality and gene expression in vertebrates, and although the species analyzed to date have shown very specific features, its expression patterns have only been well-characterized in mice. Despite rabbits represent a model of chemocommunication, unfortunately no genomic studies have been performed on VNO of this species to date. The capacity of VNO to detect a great variety of different stimuli suggests a large number of genes with complex organization to support this function. Here we provide the first comprehensive gene expression analysis of the rabbit VNO through RNA-seq across different sexual maturation stages. We characterized the VNO transcriptome, updating the number of the two main vomeronasal receptor (VR) families, 129 V1R and 70 V2R. Among others, the expression of transient receptor potential channel 2 (TRPC2), a crucial cation channel generating electrical responses to sensory stimulation in vomeronasal neurons, along with the specific expression of some fomyl-peptide receptors and H2-Mv genes, both known to have specific roles in the VNO, revealed a the particular gene expression repertoire of this organ, but also its singularity in rabbits. Moreover, juvenile and adult VNO transcriptome showed consistent differences, which may indicate that these receptors are tuned to fulfill specific functions depending on maturation age. We also identified VNO-specific genes, including most VR and TRPC2, thus confirming their functional association with the VNO. Overall, these results represent the genomic baseline for future investigations which seek to understand the genetic basis of behavioural responses canalized through the VNO.HIGHLIGHTSFirst description of the rabbit vomeronasal organ (VNO) transcriptomeVNO contains a unique gene repertoire depending on the speciesHigh fluctuation of the VNO gene expression reveals changes dependent on age and specific functionsMost vomeronasal-receptors (VR) and transient receptor potential channel 2 (TRPC2) genes are VNO-specificReproduction-related genes shows a wide expression pattern

Size overlap in intertidal decapod communities along the chilean coast

2020 ◽  
Vol 84 (2) ◽  
Author(s):  
Patricio De los Ríos-Escalante ◽  
Guillermo Figueroa-Muñoz ◽  
Marco A. Retamal ◽  
Rolando Vega-Aguayo ◽  
Carlos Esse
Keyword(s):  
Body Size ◽  
Null Model ◽  
Local Scale ◽  
Ecological Niches ◽  
Similar Species ◽  
Chilean Coast ◽  
Niche Specialization ◽  
High Diversity

The intertidal crustaceans on the Chilean coast are characterized by high diversity and niche specialization. The present study applied a size overlap null model for intertidal decapod communities at four different sites on the Chilean coast. The results revealed that there is a size overlap for the four sites, though body size is significantly different for each location. This means that the reported species would share their ecological niches. The results agree with the first classic environmental descriptions for Chilean intertidal decapods at a local scale and support the observations for similar species on the southern Pacific and southern Atlantic coasts.

scholarly journals Local-scale Arctic tundra heterogeneity affects regional-scale carbon dynamics

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
M. J. Lara ◽  
A. D. McGuire ◽  
E. S. Euskirchen ◽  
H. Genet ◽  
S. Yi ◽  
...  
Keyword(s):  
Spatial Scale ◽  
Spatial Scales ◽  
Regional Scale ◽  
Hierarchical Cluster ◽  
Carbon Dynamics ◽  
Local Scale ◽  
Reduced Representation ◽  
Soil Carbon Dynamics ◽  
Biogeochemical Models ◽  
Northern Alaska

Abstract In northern Alaska nearly 65% of the terrestrial surface is composed of polygonal ground, where geomorphic tundra landforms disproportionately influence carbon and nutrient cycling over fine spatial scales. Process-based biogeochemical models used for local to Pan-Arctic projections of ecological responses to climate change typically operate at coarse-scales (1km2–0.5°) at which fine-scale (<1km2) tundra heterogeneity is often aggregated to the dominant land cover unit. Here, we evaluate the importance of tundra heterogeneity for representing soil carbon dynamics at fine to coarse spatial scales. We leveraged the legacy of data collected near Utqiaġvik, Alaska between 1973 and 2016 for model initiation, parameterization, and validation. Simulation uncertainty increased with a reduced representation of tundra heterogeneity and coarsening of spatial scale. Hierarchical cluster analysis of an ensemble of 21st-century simulations reveals that a minimum of two tundra landforms (dry and wet) and a maximum of 4km2 spatial scale is necessary for minimizing uncertainties (<10%) in regional to Pan-Arctic modeling applications.

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