scholarly journals How effective are maternal effects at having effects?

2005 ◽  
Vol 273 (1585) ◽  
pp. 485-493 ◽  
Author(s):  
Andrew P Beckerman ◽  
Tim G Benton ◽  
Craig T Lapsley ◽  
Nils Koesters
Keyword(s):  
Maternal Effects ◽  
Reproductive Effort ◽  
Competitive Environment ◽  
Offspring Size ◽  
Offspring Performance ◽  
Trade Off ◽  
Offspring Number ◽  
Size Number ◽  
Per Capita ◽  
Offspring Investment

The well studied trade-off between offspring size and offspring number assumes that offspring fitness increases with increasing per-offspring investment. Where mothers differ genetically or exhibit plastic variation in reproductive effort, there can be variation in per capita investment in offspring, and via this trade-off, variation in fecundity. Variation in per capita investment will affect juvenile performance directly—a classical maternal effect—while variation in fecundity will also affect offspring performance by altering the offsprings' competitive environment. The importance of this trade-off, while a focus of evolutionary research, is not often considered in discussions about population dynamics. Here, we use a factorial experiment to determine what proportion of variation in offspring performance can be ascribed to maternal effects and what proportion to the competitive environment linked to the size–number trade-off. Our results suggest that classical maternal effects are significant, but that in our system, the competitive environment, which is linked to maternal environments by fecundity, can be a far more substantial influence.

scholarly journals Beyond size–number trade-offs: clutch size as a maternal effect

2009 ◽  
Vol 364 (1520) ◽  
pp. 1097-1106 ◽  
Author(s):  
Gregory P Brown ◽  
Richard Shine
Keyword(s):  
Clutch Size ◽  
Experimental Studies ◽  
Reproductive Traits ◽  
Nest Site Selection ◽  
The Body ◽  
Offspring Size ◽  
Trade Off ◽  
Trade Offs ◽  
Size Number ◽  
Hatchling Size

Traditionally, research on life-history traits has viewed the link between clutch size and offspring size as a straightforward linear trade-off; the product of these two components is taken as a measure of maternal reproductive output. Investing more per egg results in fewer but larger eggs and, hence, offspring. This simple size–number trade-off has proved attractive to modellers, but our experimental studies on keelback snakes ( Tropidonophis mairii , Colubridae) reveal a more complex relationship between clutch size and offspring size. At constant water availability, the amount of water taken up by a snake egg depends upon the number of adjacent eggs. In turn, water uptake affects hatchling size, and therefore an increase in clutch size directly increases offspring size (and thus fitness under field conditions). This allometric advantage may influence the evolution of reproductive traits such as growth versus reproductive effort, optimal age at female maturation, the body-reserve threshold required to initiate reproduction and nest-site selection (e.g. communal oviposition). The published literature suggests that similar kinds of complex effects of clutch size on offspring viability are widespread in both vertebrates and invertebrates. Our results also challenge conventional experimental methodologies such as split-clutch designs for laboratory incubation studies: by separating an egg from its siblings, we may directly affect offspring size and thus viability.

Number and Size of Offspring

2021 ◽  
pp. 115-128
Author(s):  
Jeffrey A. Hutchings
Keyword(s):  
Life History ◽  
Clutch Size ◽  
Parental Investment ◽  
Adaptive Significance ◽  
Offspring Size ◽  
Structural Constraints ◽  
Offspring Survival ◽  
Trade Off ◽  
Offspring Number ◽  
Parental Fitness

Offspring number and size are two of the most variable life-history traits. Among species, much of this variability can be attributed to genetic, developmental, physiological, or structural constraints. Some trait combinations are not possible because of differences associated with a species’ evolutionary history. Substantial variation in propagule number and size can exist among populations of the same species, generating questions concerning the adaptive significance of this variability. The most influential models are those attributed to Lack on clutch size and to Smith and Fretwell on offspring size. Fundamental to both sets of models is a trade-off between offspring number and parental investment per offspring. When offspring survival or fitness continuously varies with offspring size, the fitness of the parent depends on both offspring size and the number of offspring of that size that the parent can produce. If offspring survival is independent of offspring size, parental fitness is maximized when individuals maximize the production of minimally sized propagules.

scholarly journals Clutch Frequency Affects the Offspring Size-Number Trade-Off in Lizards

PLoS ONE ◽  
2011 ◽  
Vol 6 (1) ◽  
pp. e16585 ◽  
Author(s):  
Zheng Wang ◽  
Yuan Xia ◽  
Xiang Ji
Keyword(s):  
Offspring Size ◽  
Trade Off ◽  
Size Number

Offspring Size and Number

2001 ◽  
Author(s):  
Frank J. Messina ◽  
Charles W. Fox
Keyword(s):  
Marine Invertebrates ◽  
Offspring Size ◽  
Fixed Amount ◽  
Trade Off ◽  
Offspring Number ◽  
Trade Offs ◽  
Primary Determinant ◽  
Survival And Reproduction ◽  
Future Reproduction ◽  
Broad Variation

If we look across all organisms, we find that some species produce only one or a few large offspring per reproductive bout (e.g., most birds and mammals), others produce 10s or 100s of intermediatesize offspring (e.g., most plants and insects), and yet others produce many 1000s of offspring (e.g., some marine invertebrates). How can we account for such broad variation? In this chapter, we review many of the environmental and demographic variables that influence the evolution of offspring size and number. In the first section, we discuss how the trade-off between offspring size and number is an important determinant of offspring size. An individual’s resources can be allocated to three basic functions— growth, somatic maintenance, or reproduction. Resources directed toward reproduction can in turn be used to produce either many small offspring or a few large offspring. Thus, for a fixed amount of resources available for reproduction, it necessarily follows that there is a trade-off between the number and size of offspring during a given bout of reproduction. Trade-offs between offspring size and number during a single reproductive bout are a primary determinant of offspring size for most semelparous organisms, which reproduce once in their lifetime (e.g., salmon and century plants). For iteroparous organisms, however, lifetime reproduction is divided into many discrete bouts, with intervening periods of no reproduction. Evolutionary explanations for the number and size of offspring in these organisms must also consider how reproductive effort during any one period affects future survival and reproduction. The second part of our chapter considers the evolution of offspring number among long-lived, iteroparous organisms, especially vertebrates. We focus on the clutch sizes of birds that produce altricial (nidicolous) young. Because each nestling requires much parental care, we expect strong selection toward producing the most appropriate number of offspring for a given environment. The trade-off between current and future reproduction can also affect semelparous animals if offspring must be distributed among scattered resources. Many insects, for example, lay eggs on small, discrete hosts, and their sedentary offspring often cannot move between hosts. A female that places too many eggs on a host faces the same diminishing returns as a bird that produces more nestlings than it can provision.

scholarly journals Repeated loss of variation in insect ovary morphology highlights the role of developmental constraint in life-history evolution

2020 ◽  
Author(s):  
Samuel H. Church ◽  
Bruno A. S. de Medeiros ◽  
Seth Donoughe ◽  
Nicole L. Márquez Reyes ◽  
Cassandra G. Extavour
Keyword(s):  
Life History ◽  
Nurse Cell ◽  
Life History Evolution ◽  
Trade Off ◽  
Offspring Number ◽  
Size Number ◽  
History Of ◽  
Insect Ovary ◽  
Ovariole Number ◽  
History Evolution

AbstractThe number of offspring an organism can produce is a key component of its evolutionary fitness and lifehistory. Here we perform a test of the hypothesized trade off between the number and size of offspring using thousands of descriptions of the number of egg-producing compartments in the insect ovary (ovarioles), a common proxy for potential offspring number in insects. In contrast to prior claims, we find that ovariole number is not generally negatively correlated with the size of insect eggs, and we highlight several factors that may have contributed to this size-number trade off being strongly asserted in previous studies. We reconstruct the evolutionary history of the nurse cell arrangement within the ovariole, and show that the diversification of ovariole number and egg size have both been largely independent of nurse cell presence or position within the ovariole. Instead we show that ovariole number evolution has been shaped by a series of transitions between variable and invariant states, with multiple independent lineages evolving to have almost no variation in ovariole number. We highlight the implications of these invariant lineages on our understanding of the specification of ovariole number during development, as well as the importance of considering developmental processes in theories of life-history evolution.

Sign in / Sign up

Export Citation Format

Share Document