Evolutionary Ecology of Progeny Size in Arthropods

• Published in: Annual review of entomology Vol. 45; no. 1; pp. 341 - 369
• Main Authors: Fox, Charles W, Czesak, Mary Ellen
• Format: Journal Article
• Language: English
• Published: Palo Alto, CA 94303-0139 Annual Reviews 01-01-2000; 4139 El Camino Way, P.O. Box 10139 Annual Reviews, Inc; USA
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Animals; Arthropoda; Arthropods - physiology; Autoecology; Biological and medical sciences; Biological Evolution; egg size; Female; Fundamental and applied biological sciences. Psychology; geographic variation; life history; natural selection; Ovum; parental investment; Protozoa. Invertebrata; Biometrics; Life history; Egg; Arthropoda; Review; Parental investment; Invertebrata; Geographical variation; Natural selection
• ISSN: 0066-4170; 1545-4487
• DOI: 10.1146/annurev.ento.45.1.341

Most models of optimal progeny size assume that there is a trade-off between
progeny size and number, and that progeny fitness increases with increasing
investment per young. We find that both assumptions are supported by empirical
studies but that the trade-off is less apparent when organisms are iteroparous,
use adult-acquired resources for reproduction, or provide parental care. We
then review patterns of variation in progeny size among species, among
populations within species, among individuals within populations, and among
progeny produced by a single female. We argue that much of the variation in
progeny size among species, and among populations within species, is likely due
to variation in natural selection. However, few studies have manipulated
progeny environments and demonstrated that the relationship between progeny
size and fitness actually differs among environments, and fewer still have
demonstrated why selection favors different sized progeny in different
environments. We argue that much of the variation in progeny size among females
within populations, and among progeny produced by a single female, is probably
nonadaptive. However, some species of arthropods exhibit plasticity in progeny
size in response to several environmental factors, and much of this plasticity
is likely adaptive. We conclude that advances in theory have substantially
outpaced empirical data. We hope that this review will stimulate researchers to
examine the specific factors that result in variation in selection on progeny
size within and among populations, and how this variation in selection
influences the evolution of the patterns we observe.