More frequent fire activity associated with climate warming is expected to increase the extent of young forest stands in fire-prone landscapes, yet growth rates and biomass allocation patterns in young forests that regenerated naturally following stand-replacing fire have not been well studied. We assessed the structural and functional characteristics of young, postfire lodgepole pine (Pinus contorta var. latifolia) trees across the Yellowstone subalpine plateaus to understand the influence of postfire stand density and age on tree-level aboveground biomass (AB), component biomass (bole, branch, foliage), partitioning to components, tree-level aboveground net primary productivity (ANPP) and leaf area (LA). Sixty 24year-old lodgepole pine trees were harvested from 21 sites ranging from 500 to 74,667 stemsÁha À1 for development of allometric equations to predict biomass, ANPP and LA. All traits increased nonlinearly with increasing tree basal diameter. Tree-level total AB and component biomass decreased with increasing stand density and increased with age when compared with measurements from 11-year-old trees. Bole partitioning increased with stand density, while foliage and branch wood partitioning declined. Tree-level ANPP and LA decreased significantly with stand density and age. Overall, our results indicate that stand density and age explain much of the variation in tree characteristics and that 24 years after fire, the initial postfire regeneration density is still exerting significant influence on the structure and function of individual trees.

A number of minor errors were published in J. Exp. Biol. 218, 1410-1418 The corrected sections are reproduced below, with changes highlighted in bold. These changes do not affect the conclusions of the paper. RESULTS Metabolic substrates: respiratory quotientMean respiratory quotient (RQ=VĊ O2 /VȮ 2 , where VĊ O2 is the rate of CO 2 production and VȮ 2 is the rate of O 2 consumption) across treatments and size classes was 0.743. Mean RQ of the mating males (median=0.71) was significantly lower than that of the courting males (median=0.76) [Kruskal-Wallis test, K 1 =24.091 (where the subscript 1 indicates d.f.), P<0.001]. A non-parametric test was used because these data failed a normality test (Shapiro-Wilk, P<0.05). This difference in RQ between courting and mating males was driven by small courting males having a significantly higher RQ than small mating males (Kruskal-Wallis test, K 3 =31.394, P<0.001; multiple comparisons using Dunn's method; Fig. 5). This suggests that small, mating males were using different metabolic substrates after mating from those used by the small, courting males. The shift in RQ, seen only in small males (Fig. 5), provides support for the hypothesis that smaller males are investing in plug production, as a shift in the substrates used in metabolism could be due to shunting resources to plug production from muscular activity (i.e. mate searching and courtship).The authors apologise for any inconvenience this may have caused. ABSTRACTThe non-sperm components of an ejaculate, such as copulatory plugs, can be essential to male reproductive success. But the costs of these ejaculate components are often considered trivial. In polyandrous species, males are predicted to increase energy allocation to the production of non-sperm components, but this allocation is often condition dependent and the energetic costs of their production have never been quantified. Red-sided garter snakes (Thamnophis sirtalis parietalis) are an excellent model with which to quantify the energetic costs of non-sperm components of the ejaculate as they exhibit a dissociated reproductive pattern in which sperm production is temporally disjunct from copulatory plug production, mating and plug deposition. We estimated the daily energy expenditure and resting metabolic rate of males after courtship and mating, and used bomb calorimetry to estimate the energy content of copulatory plugs. We found that both daily energy expenditure and resting metabolic rate were significantly higher in small mating males than in courting males, and a single copulatory plug without sperm constitutes 5-18% of daily energy expenditure. To our knowledge, this is the first study to quantify the energetic expense of size-dependent ejaculate strategies in any species.

A number of minor errors were published in J. Exp. Biol. 218, 1410-1418 The corrected sections are reproduced below, with changes highlighted in bold. These changes do not affect the conclusions of the paper. RESULTS Metabolic substrates: respiratory quotientMean respiratory quotient (RQ=VĊ O2 /VȮ 2 , where VĊ O2 is the rate of CO 2 production and VȮ 2 is the rate of O 2 consumption) across treatments and size classes was 0.743. Mean RQ of the mating males (median=0.71) was significantly lower than that of the courting males (median=0.76) [Kruskal-Wallis test, K 1 =24.091 (where the subscript 1 indicates d.f.), P<0.001]. A non-parametric test was used because these data failed a normality test (Shapiro-Wilk, P<0.05). This difference in RQ between courting and mating males was driven by small courting males having a significantly higher RQ than small mating males (Kruskal-Wallis test, K 3 =31.394, P<0.001; multiple comparisons using Dunn's method; Fig. 5). This suggests that small, mating males were using different metabolic substrates after mating from those used by the small, courting males. DISCUSSION Size-dependent strategies of ejaculate expenditureThe shift in RQ, seen only in small males (Fig. 5), provides support for the hypothesis that smaller males are investing in plug production, as a shift in the substrates used in metabolism could be due to shunting resources to plug production from muscular activity (i.e. mate searching and courtship).The authors apologise for any inconvenience this may have caused. 1796