NEST MICROCLIMATE, EGG TEMPERATURE, EGG WATER LOSS, AND EGGSHELL CONDUCTANCE IN CAPE WEAVERS PLOCEUS CAPENSIS

Ostrich ◽  
1994 ◽  
Vol 65 (1) ◽  
pp. 26-31 ◽  
Author(s):  
C. R. Brown
Keyword(s):  
Water Loss ◽  
Nest Microclimate ◽  
Eggshell Conductance

Nest Microclimate, Water-Vapor Conductance, and Water Loss in Heron and Tern Eggs

The Auk ◽  
1983 ◽  
Vol 100 (1) ◽  
pp. 76-83 ◽  
Author(s):  
Carol Masters Vleck ◽  
David Vleck ◽  
Hermann Rahn ◽  
Charles V. Paganelli
Keyword(s):  
Water Vapor ◽  
Water Loss ◽  
Water Vapor Pressure ◽  
Ambient Air ◽  
Ambient Humidity ◽  
The Difference ◽  
Nest Microclimate ◽  
Predicted Values ◽  
Egg Shell ◽  
Ground Nesting

Abstract Rates of water loss (ṀH2O) were measured in eggs of seven species of tree-nesting Ciconiiformes and three species of ground-nesting Charadriiformes during natural incubation. Measurements of egg temperature, conductance of the egg shell to water vapor, and nest and ambient humidity allow one to calculate the difference in water-vapor pressure (ΔP) between egg and nest and between nest and ambient air. ΔP between egg and nest was significantly lower in ground-nesting species (23 torr) than in tree-nesting species (31 torr). We suggest that low ΔP in ground-nesting species was due to relatively high humidity (ca. 27 torr) in nests built on the ground compared to the humidity in loose stick nests of tree-nesting species (ca. 14 torr). Water-vapor conductance of eggs from more humid nests is relatively higher than that of eggs from less humid nests (107% and 78% of predicted values, respectively), resulting in similar fractional losses in mass for the whole incubation period in both groups of birds. (ṀH2O) was not always constant throughout incubation. We suggest that changes in (ṀH2O) may be due to changes in ambient humidity and/or egg temperature.

scholarly journals Climate variability and parent nesting strategies influence gas exchange across avian eggshells

2021 ◽  
Vol 288 (1953) ◽  
pp. 20210823
Author(s):  
Marie R. G. Attard ◽  
Steven J. Portugal
Keyword(s):  
Seasonal Temperature ◽  
Embryo Survival ◽  
Prolonged Incubation ◽  
Terrestrial Habitats ◽  
Nest Microclimate ◽  
Main Determinants ◽  
Taxonomic Groups ◽  
Respiratory Gases ◽  
Temperature Seasonality ◽  
Eggshell Conductance

Embryo survival in birds depends on a controlled transfer of water vapour and respiratory gases through the eggshell, and this exchange is critically sensitive to the surrounding physical environment. As birds breed in most terrestrial habitats worldwide, we proposed that variation in eggshell conductance has evolved to optimize embryonic development under different breeding conditions. This is the first study to take a broad-scale macro-ecological view of avian eggshell conductance, encompassing all key avian taxonomic groups, to assess how life history and climate influence the evolution of this trait. Using whole eggs spanning a wide phylogenetic diversity of birds, we determine that body mass, temperature seasonality and whether both parents attend the nest are the main determinants of eggshell conductance. Birds breeding at high latitudes, where seasonal temperature fluctuations are greatest, will benefit from lower eggshell conductance to combat temporary periods of suspended embryo growth and prevent dehydration during prolonged incubation. The nest microclimate is more consistent in species where parents take turns incubating their clutch, resulting in lower eggshell conductance. This study highlights the remarkable functional qualities of eggshells and their importance for embryo survival in extreme climates.

Electron Microscopy of Silicon Deposits in Foliar Idioblasts of Magnolia Grandiflora

1976 ◽  
Vol 34 ◽  
pp. 374-375
Author(s):  
Michael T. Postek
Keyword(s):  
Electron Microscopy ◽  
Water Loss ◽  
Normal Development ◽  
Magnolia Grandiflora ◽  
Plant Body ◽  
Normal Metabolism ◽  
Hydrated Oxide

Silicon occurs naturally in plants in the form of its hydrated oxide (SiO2.nH2O) commonly called silica. Silica has been shown to be a necessary element in the normal development of many plants, playing an array of roles including strengthening, protection, and reduction of water loss. Deposition of silica in various portions of the plant body, especially the leaves, may also be viewed as a way for the plant to dispose of any excess silica taken up beyond that necessary for normal metabolism.Studies of this “opaline” silica have thus far been limited to species of the Cyperaceae and Gramineae known to possess significant quantities of silica. Within the Magnoliaceae, certain “glistening” idioblast cells at the foliar veinlet termini and vein sheaths of Magnolia grandiflora (1) have been suspected to be siliceous in nature.

The examination of biophysical parameters of skin (transepidermal water loss, skin hydration and pH value) in different body regions of ponies

2012 ◽  
Vol 15 (3) ◽  
pp. 553-559 ◽  
Author(s):  
M.P. Szczepanik ◽  
P.M. Wilkołek ◽  
M. Pluta ◽  
Ł.R. Adamek ◽  
Z.J.H. Pomorski
Keyword(s):  
Water Loss ◽  
Ph Value ◽  
Neck Region ◽  
Transepidermal Water Loss ◽  
Skin Hydration ◽  
Lumbar Region ◽  
Biophysical Parameters ◽  
Body Regions ◽  
Skin Ph

Abstract The purpose of this study was to evaluate transepidermal water loss, skin hydration and skin pH in normal ponies. Sixteen ponies of both sexes were examined in the study. Measurements were taken from seven different sites: the neck region, the shoulder, thorax, lumbar, inguinal, lip region and the auricle. In each of the regions transepidermal water loss (TEWL), skin hydration and skin pH were measured. For transepidermal water loss, the lowest values were observed in the lumbar region (9.71g/hm2), while the highest values were observed in the lip region (22.35 g/hm2). In the case of skin hydration the lowest values were observed for the thorax region (2.13 CU), and the highest for the lip region (41.81 CU). For skin pH, the lowest results were obtained in the lumbar region (6.93), and the highest in the lip region (7.96).

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