Offspring size, provisioning and performance as a function of

maternal investment in coastal marine invertebrates

Offspring size, provisioning and performance as a function of

maternal investment in coastal marine invertebrates

Sergio A. CarrascoSergio 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. virgata C. maculosa H. 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