What we know so far: The fact that many benthic marine invertebrates have a bi‑phasic life cycle (with a pelagic larva and a benthic post-settlement phase) poses complex questions on the causes and partitioning of mortality. The variability recorded in post-settlement performance may result from previous scenarios experienced by developing embryos and/or larvae. As stated by Pechenik, metamorphosis is not a new beginning, as trait-mediated effects can be propagated through the life cycles of these organisms! Nevertheless, the extent to which latent effects of embryonic and/or larval development regulate the populations of coastal benthic invertebrates is still largely unknown.

Main problems to address and objectives: 1) How variable are adult trophic regimes and what is the natural variability of maternal investment in embryonic yolk reserves i) over a latitudinal and environmental gradient, ii) during and over consecutive reproductive seasons, iii) between different sized females, and iv) within the same brood (at oviposition and after incubation)?; 2) What are the consequences of embryonic variability on newly hatched larvae i) size, ii) feeding plasticity, iii) development to metamorphosis and iv) early post-settlement performance?; 3) What are the natural trophic regimes of larvae and how is their embryonic and feeding history reflected in i) larval size at metamorphosis, ii) the physiological condition of larvae and iii) early post-settlement performance? By answering these questions we can understand how offspring provisioning and larval feeding affect the timing and success of metamorphosis, what trait-mediated effects are carried-over to early juvenile life and test some theories used by marine researchers (see Appendix 4).

Expected results: We expect to confirm that intraspecific variability in offspring provisioning depends not only on environmental variables (recorded along a latitudinal and environmental gradient and reproductive seasons), but also on female’s diet, size and number of produced embryos. We hope to demonstrate that within brood variation can occur as a consequence of differential maternal investment and/or embryo’s location in the brooding chamber. We expect that larvae hatching from high quality embryos outperform conspecifics during early post-settlement development. Finally, we expect to show that in newly settled crabs growing in situ, produced from larvae experiencing natural contrasting feeding regimes (before and during upwelling), the stresses experienced during embryonic and/or larval development are not reset at metamorphosis.

CESAM members on this project

Felisa Rey Eiras

Henrique Queiroga

Newton Carlos Marcial Gomes

Ricardo Jorge Guerra Calado
PI