Growth of the haremic sandperch Parapercis cylindrica (family Pinguipedidae) was examined in relation to sex change using otolith microstructure and gonad histology. The influence of previous growth history on the timing of sex change and which individuals underwent sex change were also explored. Examination of otolith increments shows that P. cylindrica has a maximum longevity of 411 d, which is reduced in a lower latitude population. P. cylindrica is a monandric hermaphrodite, with males being larger than females at any given age. An abrupt optical discontinuity or 'check' on sagittal cross-sections was found to be associated with sex change. This check appears to be formed at the initiation of sex change. Growth rate following sex change, inferred from otolith increment widths, increased markedly and more than doubled in some individuals. Individuals retained accelerated growth for a period of up to 30 d, after which time growth rate declined. Larval growth, relative size at metamorphosis, juvenile growth, and female growth (all determined from otolith microstructure), did not influence which individuals changed sex, or the timing of their sex change. Evidence suggests that sex change and subsequent growth acceleration in these haremic fish are influenced by the strong size-based social hierarchy in which they live. KEY WORDS: Sex change · Monandric protogyny · Growth acceleration · Otolith increments · Larval growth · PinguipedidaeResale or republication not permitted without written consent of the publisher

In 1950, Rensch noted that in clades where males are the larger sex, sexual size dimorphism (SSD) tends to be more pronounced in larger species. This fundamental allometric relationship is now known as 'Rensch's rule'. While most researchers attribute Rensch's rule to sexual selection for male size, experimental evidence is lacking. Here, we suggest that ultimate hypotheses for Rensch's rule should also apply to groups of individuals and that individual trait plasticity can be used to test those hypotheses experimentally. Specifically, we show that in the sex-changing fish Parapercis cylindrica, larger males have larger harems with larger females, and that SSD increases with harem size. Thus, sexual selection for male body size is the ultimate cause of sexual size allometry. In addition, we experimentally illustrate a positive relationship between polygyny potential and individual growth rate during sex change from female to male. Thus, sexual selection is the ultimate cause of variation in growth rate, and variation in growth rate is the proximate cause of sexual size allometry. Taken together, our results provide compelling evidence in support of the sexual selection hypothesis for Rensch's rule and highlight the potential importance of individual growth modification in the shaping of morphological patterns in Nature.

International audienceCorals and coral-associated species are highly vulnerable to the emerging effects of global climate change. The widespread degradation of coral reefs, which will be accelerated by climate change, jeopardizes the goods and services that tropical nations derive from reef ecosystems. However, climate change impacts to reef social–ecological systems can also be bi-directional. For example, some climate impacts, such as storms and sea level rise, can directly impact societies, with repercussions for how they interact with the environment. This study identifies the multiple impact pathways within coral reef social–ecological systems arising from four key climatic drivers: increased sea surface temperature, severe tropical storms, sea level rise and ocean acidification. We develop a novel framework for investigating climate change impacts in social–ecological systems, which helps to highlight the diverse impacts that must be considered in order to develop a more complete understanding of the impacts of climate change, as well as developing appropriate management actions to mitigate climate change impacts on coral reef and people