title: How effective are maternal effects at having effects?
abstract: 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.
authors.affiliation: School of Biological and Environmental Science, University of Stirling, Stirling FK9 4LA, UK. a.beckerman@sheffield.ac.uk
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Beckerman
authors.forename: Tim G
authors.initials: TG
authors.lastname: Benton
authors.forename: Craig T
authors.initials: CT
authors.lastname: Lapsley
authors.forename: Nils
authors.initials: N
authors.lastname: Koesters
mesh_terms: D000053:Acari / Q000254:growth & development / Q000502:physiology*; D000818:Animals; D052284:Clutch Size; D005260:Female; D016014:Linear Models; D008297:Male; D008425:Maternal Behavior; D011157:Population Dynamics; D011897:Random Allocation; D012044:Regression Analysis