Physiological constraints on the ecology of activity-limited ectotherms

2021 ◽  
Author(s):  
Annette Elizabeth Sieg
2020 ◽  
Author(s):  
Efrat Dener ◽  
Hagai Shemesh ◽  
Itamar Giladi

Abstract Aims The evolution and expression of dispersal-related traits are intertwined with those of other life-history functions and are manifested within various physiological constraints. Such a relationship is predicted between inbreeding levels and dispersability, which may be anatomically and ontogenetically linked so that the selection pressures on one may affect the other. While both the effect of inbreeding on reproductive success and on dispersal strategies received much attention, only a few studies considered both simultaneously. Furthermore, such studies often rely on two dichotomic representations of breeding and dispersal: using selfing vs. outcrossing as a representation of breeding level, and dispersal ratio as the sole representation of dispersal strategy. Methods Here we used pollination experiments in the heterocarpic Crepis sancta (Asteraceae) to expand in two different manners on the common practice of using dichotomic representations of breeding and dispersal. First, we used pollination treatments that represent a continuum from selfing through pollination by kin to pollination by a distant neighbor. Second, we measured a whole set of continuous morphological and dispersal-related traits, in addition to measurements of reproductive success and dispersal ratio. Important findings The proportion of developed capitula and the number of both dispersed and non-dispersed achenes were significantly lower in the self-pollination treatment in comparison to the out-crossed treatments. The effect of pollen sources on dispersal ratio was not statistically significant, though self-pollinated plants rarely produced non-dispersing seeds. Achene’s biomass increased with distance between parent plants, but pappus width did not, leading to a nonsignificant effect of pollination on falling velocity. Overall, pollen source affected mainly traits that were associated with reproductive output, but it had no clear effect on predominately dispersal-related traits. Such differences in the response of reproduction and dispersal traits to variation in pollen source suggest that dispersal-related selection is probably weak and/or masked by other forces.


2016 ◽  
Vol 94 (1) ◽  
pp. 49-59 ◽  
Author(s):  
E.L. Kubisch ◽  
V. Corbalán ◽  
N.R. Ibargüengoytía ◽  
B. Sinervo

Recently, Sinervo et al. (2010, Science, 328: 894–899) reported declines of lizard biodiversity due to local warming trends and altered thermal niches. Herein, we applied the Sinervo et al. (2010) physiological model to predict the local extinction risk of three species of lizard from Patagonia. Whereas the previous model used a single equation (for the extinctions of Blue Spiny Lizard (Sceloporus serrifer Cope, 1866) in the Yucatan Peninsula) relating environmental temperatures (Te) to hours of restriction (i.e., the period when lizards are forced into retreat sites because environmental temperatures are too high), we measured habitat-specific equations for the Te values of each species. We analyzed the vulnerability of Darwin’s Ground Gecko (Homonota darwinii Boulenger, 1885), Bariloche Lizard (Liolaemus pictus (Duméril and Bibron, 1837)), and Mountain Slope Lizard (Liolaemus elongatus Koslowsky, 1896) to climate change considering thermal physiological constraints on activity during the reproductive period. While Sinervo et al. (2010) predicted that the Phyllodactylidae family will not suffer from impacts of climate change, our physiological model predicted that 20% of the H. darwinii populations could become extinct by 2080. The physiological model also predicted that 15% of L. pictus populations and 26.5% of L. elongatus populations could become extinct by 2080. The most vulnerable populations are those located near the northern and eastern boundaries of their distributions.


1990 ◽  
Vol 68 (2) ◽  
pp. 313-317 ◽  
Author(s):  
Gerard M. Capriulo ◽  
David Lints ◽  
Martin Lewinter

A general functional relationship between body weight (10−11 to 108 g) and ingestion rate has been found to exist throughout the protistan and metazoan kingdoms. Results, based on a mathematical interpretation of standardized, quantitative data, indicate that ingestion rate is a log–log linear function (i.e., power function) of body weight (I = a W0.829 for cold-blooded forms and I = a W0.778 for warm-blooded forms, where I = ingestion rate and W = body weight). The slopes of the cold-blooded and warm-blooded regression lines are not significantly different from each other (i.e., they are parallel). This allows one to use the difference between the respective curves to estimate the weight-specific cost of warm-bloodedness. Such an analysis of the data indicates that a warm-blooded organism must ingest about ten times more food per unit body weight than cold-blooded forms. This functional relationship may be a manifestation of the physiological constraints placed on organisms by surface area to volume ratio phenomena, related to absorptive surfaces, mouth areas, and body volumes. The present analysis suggests that flexibility in functional design is limited by physical phenomena which affect phenotypic plasticity.


2016 ◽  
Vol 187 (1) ◽  
pp. 29-50 ◽  
Author(s):  
David A. S. Rosen ◽  
Allyson G. Hindle ◽  
Carling D. Gerlinsky ◽  
Elizabeth Goundie ◽  
Gordon D. Hastie ◽  
...  

2021 ◽  
Author(s):  
Daniel Castro Pereira ◽  
Elen A. Peres ◽  
Ricardo Pinto-da-Rocha

Neosadocus harvestmen are endemic to the Southern Brazilian Atlantic Forest. Although they are conspicuous and display great morphological variation, their evolutionary history and the biogeographical events underlying their diversification and distribution are still unknown. This contribution about Neosadocus includes the following: a taxonomic revision; a molecular phylogenetic analysis using mitochondrial and nuclear markers; an investigation of the genetic structure and species' diversity in a phylogeographical framework. Our results show that Neosadocus is a monophyletic group and comprises four species: N. bufo, N. maximus, N. robustus and N. misandrus (which we did not find on fieldwork and only studied the female holotype). There is astonishing male polymorphism in N. robustus, mostly related to reproductive strategies. The following synonymies have resulted from this work: Bunoweyhia variabilis Mello-Leitão, 1935 = Neosadocus bufo (Mello-Leitão, 1926); and Bunoweyhia minor Mello-Leitão, 1935 = Neosadocus maximus (Giltay, 1928). Most divergences occurred during the Miocene, a geological epoch marked by intense orogenic and climatic events in the Brazilian Atlantic Forest. Intraspecific analyses indicate strong population structure, a pattern congruent with the general behavior and physiological constraints of Neotropical harvestmen.


2006 ◽  
Vol 32 (6) ◽  
pp. 1133-1147 ◽  
Author(s):  
Natasha L. Wiggins ◽  
Clare McArthur ◽  
Noel W. Davies ◽  
Stuart McLean

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