TY - JOUR

T1 - Sex-specific reproductive trade-offs in the gregarious fucoid macroalga Ascophyllum nodosum

AU - Kurr, Martyn

AU - Davies, Andrew

PY - 2018

Y1 - 2018

N2 - The existence of sex-specific reproductive trade-offs are well established in plants. They usually occur because females invest more resources into reproduction than males, and have to compensate by sacrificing growth or defence. Investigations into by-sex differences in resource allocation by seaweeds are comparatively scarce. A small number of authors report differences between the sexes in some red algae, but known by-sex differences in brown algae are largely confined to the reproductive structures. In this study, sex-specific reproductive trade-offs are investigated in the common temperate brown alga, Ascophyllum nodosum from three distinct populations. Quantified investments into growth, defence, and reproduction of a large number of individuals (n =720) selected across a full annual cycle, are presented in parallel with feeding trials using a common gastropod herbivore, and a comprehensive assessment of the biotic and abiotic stressors impacting on A. nodosum at three sites. These reveal that sex-specific reproductive trade-offs occur in two of the three populations, as females invest more into reproduction than males and are subsequently less-chemically defended for the months post-gamete release. Feeding-trials confirm that this leaves females more vulnerable to grazing pressure during these months, although mortality and competitive ability appear unaffected in the field. Possible causes of the trade-offs made by females are discussed, and new avenues of investigation are identified which could reveal interesting parallels between seaweeds and higher plants.

AB - The existence of sex-specific reproductive trade-offs are well established in plants. They usually occur because females invest more resources into reproduction than males, and have to compensate by sacrificing growth or defence. Investigations into by-sex differences in resource allocation by seaweeds are comparatively scarce. A small number of authors report differences between the sexes in some red algae, but known by-sex differences in brown algae are largely confined to the reproductive structures. In this study, sex-specific reproductive trade-offs are investigated in the common temperate brown alga, Ascophyllum nodosum from three distinct populations. Quantified investments into growth, defence, and reproduction of a large number of individuals (n =720) selected across a full annual cycle, are presented in parallel with feeding trials using a common gastropod herbivore, and a comprehensive assessment of the biotic and abiotic stressors impacting on A. nodosum at three sites. These reveal that sex-specific reproductive trade-offs occur in two of the three populations, as females invest more into reproduction than males and are subsequently less-chemically defended for the months post-gamete release. Feeding-trials confirm that this leaves females more vulnerable to grazing pressure during these months, although mortality and competitive ability appear unaffected in the field. Possible causes of the trade-offs made by females are discussed, and new avenues of investigation are identified which could reveal interesting parallels between seaweeds and higher plants.

U2 - 10.1080/09670262.2017.1328746

DO - 10.1080/09670262.2017.1328746

M3 - Article

VL - 53

SP - 1

EP - 13

JO - European Journal of Phycology

JF - European Journal of Phycology

SN - 0967-0262

IS - 1

ER -