Andréaz Dupoué, Jean-François Le Galliard, Rémy Josserand, Dale F. DeNardo, Béatriz Decencière, Simon Agostini, Claudy Haussy, Sandrine Meylan
The relationships between a parent and its offspring involve conflict in almost all organisms. In nature, parent-offspring conflicts can occur whenever resources become depleted. Conflicts are usually examined after birth of offspring, but gestation also represents a battleground for conflicts between mothers and their embryos. Though mother-offspring conflict has typically been investigated for energy, we recently demonstrated that it may also occur whenever water availability becomes limited. In this new study, we examined the occurrence of an allocation trade-off for water between pregnant female lizards and their offspring, and consequences of water restriction during gestation on maternal growth, survival and reproduction. Using robust experimental methods, we restricted access to water in half of the pregnant females during two weeks, a significant proportion of the gestation time. Changes in physiology (hydration state and stress hormones) during water restriction were examined and compared with those of non-reproductive lizards, and subsequent performance was scored in outdoor enclosures. All lizards were dehydrated and potentially chronically stressed in response to water restriction. In pregnant females, the intensity of dehydration increased with the number of offspring, but water restriction had no impact on current reproduction. Thus, maternal water balance was traded in favour of immediate reproductive success in this lizard species. Water restriction resulted in higher reproductive effort in the second year for females but a lower survival rate for their offspring. Thus, water restriction triggered unforeseen intergenerational conflicts between future offspring survival and future maternal reproductive effort. Such conflicts may be critical for our understanding of major transitions in reproductive strategies.
Functional Ecology: Plain Language Summaries 