Habitat uncertainty explains variation in offspring provisioning strategies in a temporary pond crustacean

Abstract

In temporally variable environments producing offspring with variable phenotypes can help parents to buffer against different future environmental conditions. Freshwater zooplankton can produce clutches with eggs of different sizes, but it remains unknown whether such variable offspring provisioning could be promoted by uncertainty in the quality of growing seasons. We studied provisioning patterns in 572 clutches that were produced throughout the life of 77 fairy shrimp pairs from six temporary pools along a gradient in habitat uncertainty (i.e. probability of early drying). Our results show that larger embryos hatch earlier during inundations, which is a benefit under time stress, but that the production of larger offspring comes at a cost of reduced numbers. Parents from all pools produced variably sized offspring within each clutch. This could represent a bet hedging strategy in relation to variation in hydroperiod among inundations that is inherent to all studied pools. In addition, parents from more uncertain habitats produced larger clutches of smaller eggs and they invested more in early-life reproductive output at the expense of longevity. Overall, our study illustrates that natural variation in inundation regime could be reflected in adaptive variable egg provisioning in zooplankton