Bioenergetics of early life-history stages of the brachyuran crab Cancer setosus in response to changes in temperature

Abstract

In many marine invertebrates, a latitudinal cline in egg size is considered an adaptive response to a decrease in temperature, and enhances the energetic fitness of their larvae at hatching. However, the amount of energy carried over from the egg to the larval stage depends on the metabolic efficiency of egg development. In the present study, eggs of the brachyuran crab Cancer setosus were sampled for their dry mass (DM), carbon (C), nitrogen (N), and fatty acid (FA) content throughout development from blastula stage until hatching of zoea 1-larvae at Antofagasta (23°S) and Puerto Montt 41°S (Chile) under different temperature treatments (12, 16 and 19°C). Hatching zoea 1 larvae contained 60 ± 3% of the initial blastula egg C content, regardless of site or temperature. However, the ontogenetic decrease in egg C content was to a significantly higher extend based on the utilization of energy-rich FA at 12°C (− 1.16 µg/egg) compared to the 19°C treatments in Antofagasta and Puerto Montt (− 0.63 to − 0.73 µg FA per egg). At 19°C egg-metabolism was based to a substantial extend on protein, which allowed for the saving of energy-richer lipids. We conclude that the production of larger eggs with high FA content appears to be adaptive not only to fuel the larval development, but is also a response to the prolonged egg developmental times at lower temperatures.

Temperature effects on zoeal morphometric traits and intraspecific variability in the hairy crab Cancer setosus across latitude

“…Quintana and Saelzer (1986) showed that zoeal development of C. setosus larvae of a population from Coliumo Bay (Concepción, central Chile) takes about 60 days under natural temperature conditions (13.5-14.6°C), while larvae from the Antofagasta region have a 1.5 times exceeded zoeal development at 16°C and show higher survival rates (Weiss et al 2009b), and larvae from Concepcion are capable to develop through all zoeal instars at lower temperatures. These Wndings indicate a better cold adaptation of larvae originating from a southern population (see also Fischer and Thatje 2008;Fischer et al 2009a) and from an evolutionary point of view could be considered ancestral to further abbreviated larval developments (Strathmann 1978), which is favourable for larvae from colder regions.…”

“…Animals from colder regions have to invest less energy in the maintenance of the standard metabolism and therefore can direct more energy into growth. Fischer et al (2009a) suggested that blastula eggs of C. setosus at Puerto Montt at 12°C were provided by 30% more fatty acids as blastula eggs produced in Antofagasta at 20°C, and larvae utilise a higher percentage of fatty acids at colder temperatures. Indeed, these Wndings may indicate that a metabolism based on fatty acids might produce larger larvae.…”

“…Among the most conspicuous characteristics is a synchronisation of a single egg batch release with seasonality at the species southernmost distribution boundary in central southern Chile (Puerto Montt, 41°44Ј S), contrasted by multiple annual ovipositions in northern Chile (Antofagasta, 23°45Ј S) (Fischer and Thatje 2008). In addition, a correlation of changes in egg energy contents and temperature was observed along latitude as well as in subsequent ovipositions in the same female (Fischer and Thatje 2008;Fischer et al 2009a). These Wndings are consistent with the concept of a latitudinal gradient in energy provisioning into oVspring of a broad variety of marine invertebrates (for review see Thatje et al 2005).…”

Seasonal variations in larval biomass and biochemical composition of brown shrimp, Crangon crangon (Decapoda, Caridea), at hatching

“…In crustaceans, larval traits at hatching are related to key variables associated with embryonic development (Gimé-nez and Anger 2001;Webb et al 2007). For example, the average egg incubation temperature exerts significant effects on the development time and bioenergetics of the embryo and influences the initial larval biomass at hatching (Paschke 1998;Fischer et al 2009). In C. crangon, the initial larval biomass was negatively correlated with the incubation temperature during egg development.…”

“…Newly laid eggs contain all the energy that is necessary for embryonic development (Jaeckle 1995), and therefore, the initial larval biomass depends on both these initial energy reserves and their subsequent utilization during embryogenesis (Anger 2001). Also, it is influenced by physico-chemical factors experienced during embryogenesis, for example, temperature (Wear 1974;Fischer et al 2009), oxygen (Fernandez et al 2006) and salinity (Giménez and Anger 2001), so that previous environmental conditions may also affect the larval capacity to face starvation during periods of planktonic food limitation (Paschke et al 2004;Calado et al 2007). …”