Offspring size, provisioning and performance as a function of maternal investment in coastal marine invertebrates Sergio A. Carrasco

Introduction Life histories Cominella virgataPinnoctopus cordiformisMytilus galloprovincialis Most benthic marine invertebrate species include larval or juvenile stages specialised for dispersal and colonisation of new habitats Morphology, developmental stages, dispersal, mode of nutrition Variation in offspring size (e.g. latitudinal, populations, inter- and intra- especific) (Marshall and Keough 2008; Kamel et al. 2010)

Introduction Offspring size affect the number of individuals that pass through each stage, with consequences for fitness (i.e. survival, growth, reproduction, competition) If offspring quality is high (i.e. size or energy reserves), more offspring become successful recruits Initial maternal provisioning 7 Ecological implications

Introduction Direct developers It has been suggested that mothers with more control of the provisioning could adaptatively adjust the allocation resources according to local conditions Maternal provision is the primary source of nutrition for the embryos until the juvenile stage Reduced potential for dispersal

Results Whelk’s egg capsules Cominella virgata Cominella maculosa Haustrum scobina

Results Intra-capsular development C. virgataC. maculosaH. scobina 10 wk 8 wk 6 wk

Results Maternal provisioning in hatchlings

Results Hatchling size and performance: Growth & Dessication Dessication (p=0.738) Size (p=0.001) Sites (p=0.006) PH=MP>PHS>TR (three-way ANOVA) Dessication (p=0.74) Size (p=0.01) Sites (p=0.15) (three-way ANOVA)

Results Hatchling size and performance: Survival & Dessication Dessication (p=0.85) Size (p>0.59) Sites (all p=0.78) (GLM) Dessication (p=0.19) Size (all p=0.0029) Sites (p<0.05) MP=PH>TR>PHS (GLM)

Results Predator size & prey species Predator size x prey sp (p=0.036) (two-way ANOVA) (6-10 mm CW) (11-13 mm CW) (17-20 mm CW)

Results Juvenile ontogeny & vulnerability to predators Predator size x prey sp x time (p<0.0001) (three-way ANOVA) (1d) C. maculosa: 1.7 mm and C. virgata: 3.0 mm (1mo) C. maculosa: 2.2 mm and C. virgata: 4.1 mm (2mo) C. maculosa: 2.6 mm and C. virgata: 4.8 mm

Results Juvenile ontogeny traits

Results Octopuses’ egg capsules A, B. Octopus huttoni C, D. Pinnoctopus cordiformis

Results Paralarval traits A, B. Octopus huttoni C, D. Pinnoctopus cordiformis

Results Paralarval traits A, B. Octopus huttoni C, D. Pinnoctopus cordiformis

Main conclusions (3) Offspring size is a key trait for most organisms, influencing an individual’s subsequent performance and having direct consequences in fitness for both the offspring and mother (4) For a wide range of taxa across a variety of habitats, individuals that start juvenile life with a large size often perform better than smaller conspecifics (e.g. growth, survival, competition, reproduction) (1) Per-offspring maternal investment is an integral part of life-history theory with a plethora of models developed to examine the relationship between egg energy and the production and quality of offspring (2) Regardless of the strategy, the division of finite reproductive resources should ultimately result in an optimal equilibrium between the offspring fitness and the maximization of the parental fitness