Brain size evolution in pipefishes and seahorses: the role of feeding ecology, life history and sexual selection.

Brain size varies greatly at all taxonomic levels. Feeding ecology, life history and sexual selection have been proposed as key components in generating contemporary diversity in brain size across vertebrates. Analyses of brain size evolution have, however, been limited to lineages where males predominantly compete for mating and females choose mates. Here, we present the first original data set of brain sizes in pipefishes and seahorses (Syngnathidae) a group in which intense female mating competition occurs in many species. After controlling for the effect of shared ancestry and overall body size, brain size was positively correlated with relative snout length. Moreover, we found that females, on average, had 4.3% heavier brains than males and that polyandrous species demonstrated more pronounced (11.7%) female-biased brain size dimorphism. Our results suggest that adaptations for feeding on mobile prey items and sexual selection in females are important factors in brain size evolution of pipefishes and seahorses. Most importantly, our study supports the idea that sexual selection plays a major role in brain size evolution, regardless of on which sex sexual selection acts stronger.

Total synthesis of a miniferredoxin.

A miniferredoxin has been designed based on the Desulfovibrio gigas ferredoxin II structure and has been successfully synthesized. The 31 amino acid apoprotein was synthesized via standard Fmoc solid phase peptide synthesis and in vitro cluster insertion carried out. The UV-visible spectrum of the miniferredoxin (peak at 300 nm and a shoulder at 405 nm) shows the same features as that of the D. gigas ferredoxin. Cyclic voltammetry indicated a quasireversible electrode process with a midpoint potential of -370mV vs NHE, which demonstrates that the miniferredoxin is redox active. From these and EPR studies, we propose the incorporation of a Fe4S4 cluster.