Developmental Plasticity and Evolution. In: Mary Jane West-Eberhard, Editor, Oxford University Press (2003) Pp. xi+794. Price $50.00 paper.

SYNOPSIS. Maternal effects comprise a class of phenotypic effects that parents have on phenotypes of their offspring that are unrelated to the offspring's own genotype. Although biologists have known about the importance of these effects for decades, maternal effects have only recently been studied widely by evolutionary ecologists. Moreover, the impact of maternal effects on the rate and direction of evolution of other components of the phenotype has only recently been fully elucidated by theoretical genetic models. This paper provides a brief overview of maternal effects research, focusing on research conducted in animal systems. First, I review and summarize definitions and theoretical treatments of maternal effects. Then I survey the diversity of maternal effects and some of the kinds of ecological and evolutionary impacts that maternal effects have been shown to have on offspring performance. Third, I discuss some of the ecological and evolutionary implications of maternal effects in ecological research. In this context, it is argued that the kinds of maternal effects that have been studied, and some of the potential implications of maternal effects that have not been explored are both artifacts of research effort. Hence, I identify several fruitful areas for future maternal effects research. Lastly, I describe the necessity of explicitly incorporating maternal effects in ecological research, whether or not the researcher is focusing on them as the topic of the research.

Maternal effects in animal ecology

Keywords: Mecanique des sols ; Drainage ; Ecoulement souterrain Reference Record created on 2004-09-07, modified on 2016-08-08

Applications of soil physics.

Biochemistry and morphogenesis

For many years ecologists have documented the remarkable within-species variation inherent in natural systems-for example, variability in juvenile growth rates, mortality rates, fecundities, time to reproductive maturity, the outcomes of competitive interactions, and tolerance to pollutants. Over the past 20 years, it has become increasingly apparent that at least some of this variation may reflect differences in embryonic or larval experiences. Such experiences may include delayed metamorphosis, short term starvation, short term salinity stress, or exposure to sublethal concentrations of pollutants or sublethal levels of ultra violet irradiation. Latent effects-effects that have their origins in early development but that are first exhibited in juveniles or adults-have now been documented among gastropods, bivalves, echinoderms, polychaetes, crustaceans, bryozoans, urochordates, and vertebrates. The extent to which latent effects alter ecological outcomes in natural populations in the field, and the mechanisms through which they are mediated are largely unexplored.

Larval experience and latent effects—metamorphosis is not a new beginning

Flexible-shelled eggs of common snapping turtles (Chelydra serpentina) were incubated on two substrates (sand and vermiculite) at each of three temperatures (26.0°, 28.5°, 31.0°C) and three moisture regimes (water potentials initially -150 kPa, -550 kPa, -950 kPa) in a factorial experiment assessing the influence of these variables on the water relations of eggs and the development of embryos. Hatching success was high on wet substrates at 26.0° and 28.5°, but declined at the highest temperature and on drier media. Net absorption of water by viable eggs, duration of incubation by embryos, and size of hatchlings were positively correlated with wetness of substrates and negatively correlated with temperature. Turtles hatching from eggs at 26.0° were males regardless of the wetness of the medium, whereas those emerging from eggs at 28.5° and 31.0° were females. These patterns of response characterized eggs incubated on sand as well as those on vermiculite. Findings from this study indicate that temporal and spatial variations in moisture and temperature within and among natural nests probably elicit ecologically important variation in size and sex of hatchling snapping turtles.

https://www.jstor.org/stable/info/1938369

Influence of Moisture, Temperature, and Substrate on Snapping Turtle Eggs and Embryos

Locomotor performance of hatchling snapping turtles ( Chelydra serpentina ) was assessed while turtles were running on land and swimming in water. Hatchlings from eggs incubated on a relatively wet substrate were faster than hatchlings from eggs incubated on a drier medium, both in absolute distance and in body lengths moved per unit time. The superior performance of turtles from the wet substrate was not due to differences in hydration of tissues, because differences in performance persisted after turtles from both groups had been fully hydrated. The superior performance of turtles from the wet substrate may stem from a greater aerobic capacity, because these animals accumulated lactate more slowly during locomotion than did turtles from eggs incubated on the dry substrate. These observations may provide a physiological basis for the improved survival of larger hatchlings of many species of reptiles.

Hydric Conditions During Incubation Influence Locomotor Performance of Hatchling Snapping Turtles

Temperature and moisture influence the development of embryonic reptiles in the laboratory but the importance of these variables to embryos developing in nature is a topic of debate. We measured temperature and water potential in 12 nests of painted turtles, Chrysemys picta, and subsequently assessed the influence of these factors on survival by embryos, net change in mass of eggs, length of incubation, and live mass and body size of hatchlings. Average temperature in nests varied between 23.4 and 26.2 °C, and average water potential ranged from − 0.06 MPa to − 2.11 MPa. Hatching success varied from 33 to 100%, and was correlated more highly with the water potential in nests than with temperature

https://www.jstor.org/stable/pdfplus/2390185.pdf

Effects of the microclimate in natural nests on development of embryonic painted turtles, Chrysemys picta

Eggs of painted turtles (Chrysemys picta) were incubated at temperatures of 22.0, 27.0, and 32.0 C on substrates with water potentials of -150, -300, and -1100 kPa using a 3 x 3 factorial design. The thermal and hydric environments affected fluxes in water between eggs and their surroundings during the course of incubation. Eggs lost the greatest amount of water during incubation at high temperature and low water potential, and gained the greatest amount of water at low temperature and high water potential. Both the thermal and hydric environments also affected mass, linear dimensions, and composition of hatchlings. The effects of each environmental variable were independent of the effects of the other. Hatchlings from eggs incubated at high temperatures or on substrates with low water potentials were smaller and had larger residual yolks than those from eggs at lower temperatures or on wetter substrates. Embryos from eggs incubated at low temperatures or on wet substrates mobilized more non-lipids from their yolks than embryos at higher temperatures or on dry substrates. In addition, embryos from eggs on dry substrates catabolized more lipids and fewer non-lipids than those from eggs on wet substrates. Environmen- tally induced variation in development may be important to survival and fitness of individuals after hatching.

Influence of the hybric and thermal environments on eggs and hatchlings of painted turtles (Chrysemys picta)

Eggs of painted turtles (Chrysemys picta) absorb water across that portion of the eggshell in contact with the substrate and simultaneously lose water by transpiration from that part of the eggshell exposed to air inside the nest chamber. Depending upon the rates of influx and efflux, eggs may experience increases or decreases in mass during incubation, or mass may remain essentially constant between oviposition and hatching. Water exchanges are especially sensitive to such factors as substrate water potential, relative surface exposed to the nest atmosphere, hydraulic conductance of the eggshell, and conductance of the eggshell to water vapor. Hatchlings emerging from eggs absorbing and storing large quantities of water are heavier than hatchlings emerging from eggs taking up smaller quantities of water from the substrate. Furthermore, water absorption equal to, or in excess of, water loss by transpiration assures that the original shape of the egg will be preserved, thereby guaranteeing that sufficient ...

Mary J. Packard

Papers

Influence of Moisture, Temperature, and Substrate on Snapping Turtle Eggs and Embryos

Hydric Conditions During Incubation Influence Locomotor Performance of Hatchling Snapping Turtles

Effects of the microclimate in natural nests on development of embryonic painted turtles, Chrysemys picta

Influence of the hybric and thermal environments on eggs and hatchlings of painted turtles (Chrysemys picta)

Water Relations of Chelonian Eggs