The potential for long-lasting effects of larval experience on early juvenile stages is growing in recognition as an important aspect of the ecology of organisms with complex life cycles. For marine species, most studies of recruitment have focused on the numbers of settlers that arrive to a site, largely ignoring the potential variability in larval condition or quality and how such variability may influence the likelihood of recruitment success. In this study, I investigated the effect of larval nutritional history on early juvenile performance, and whether these effects are mediated by conditions in the juvenile habitat for the marine mussel Mytilus galloprovincialis. I raised larvae in the laboratory under different food concentrations. Larvae raised with the highest food concentrations were significantly larger in size at metamorphosis and had higher proportional lipid content at metamorphosis than those from lower food concentrations. Half of the newly metamorphosed juveniles were outplanted into intertidal and subtidal habitats for 2 wk. The other half were maintained in the laboratory at two different juvenile rations for up to 20 d. Juveniles raised with high larval food had higher juvenile growth rates and attained larger juvenile sizes than those from lower larval food in all cases. There was a significant positive relationship between size at metamorphosis and juvenile growth for juveniles maintained in the laboratory. Early juvenile growth rates did not change over time (between 10 and 20 d post-metamorphosis). Juveniles raised in higher juvenile rations had elevated growth rates and attained larger final sizes after 20 d than juveniles from low juvenile rations across all sizes at metamorphosis. For juveniles in the field, there was no effect of tidal height on growth for 2 wk post-metamorphosis. Field conditions were more favorable than laboratory conditions for juvenile growth, yet even these more favorable conditions did not compensate for the effects of larval nutritional history on early juvenile growth. Losses of juveniles from both the field and the laboratory were higher for those that had been raised in lower larval food conditions than for those that had been raised in higher larval food, suggesting that vulnerability to early juvenile mortality may also be affected by larval history.
For organisms with complex life cycles, larval history is increasingly being found to influence later juvenile or adult performance; however, most experiments maintain manipulations in the larval environment at a constant level. Here, I assess the effects of constant vs. variable larval food availability on the marine mussel Mytilus galloprovincialis. In the laboratory, I raised larvae in four food concentrations: constant high, constant low, initial low switched to high, and initial high switched to low. After settlement, I outplanted juveniles to the field for two weeks. Changes in food availability affected larval size and lipid stores, and covariance between the two. Losses of juveniles were greater, and juvenile growth was lower, for those that had been reared as larvae in constant low food compared to those reared in constant high larval food. For the switched treatments, losses were greater, and growth was lower, for juveniles that had experienced initial low larval food relative to those that had experienced initial high larval food, regardless of average larval size or lipid stores from the different treatments. Thus, the timing of pulses of larval food may impact dynamics of later stages.
Coastal upwelling is an ocean feature thought to have important impacts on benthic marine communities by enhancing planktonic productivity in the nearshore environment. In this study, growth rates of 3 species of filter-feeders were examined over a geographic region that includes sites where upwelling is typically weak (south of Point Conception, California, USA) and sites where upwelling is often strong and frequent (at and to the north of Point Conception). The growth of the mussel Mytilus californianus, the gooseneck barnacle Pollicipes polymerus and the acorn barnacle Balanus glandula, as well as the body condition of M. californianus, were all up to 3-6 times higher at sites furthest south of Point Conception, and decreased dramatically moving north around the point. Spatial variation in food availability (measured as chlorophyll a, particulate organic carbon and particulate organic nitrogen) and food quality (measured as C/N ratios) did not explain these patterns of growth. Tidal height of the organisms also failed to account for persistent spatial variation in growth rates. Water temperature varied in a pattern consistent with growth rates (i.e. mean temperatures were warmer in the south), and was the one factor most often selected in stepwise regressions for models contributing to patterns of filter-feeder growth. This study suggests that factors other than, or in conjunction with, productivity may drive large-scale differences in benthic filter-feeder growth rates.
Damaging effects of UVB in conjunction with other stressors associated with global change are well-established, with many studies focused on vulnerable early life stages and immediate effects (e.g., mortality, developmental abnormalities). However, for organisms with complex life cycles, experiences at one life stage can have carry-over effects on later life stages, such that sublethal effects may mediate later vulnerability to further stress. Here, we exposed embryos in benthic egg masses of the New Zealand intertidal gastropod Siphonaria australis to treatments of either periodic stress (e.g., elevated UVB, salinity, and water temperature mimicking tidepool conditions in which egg masses are commonly found during summer) or control conditions (low UVB, ambient salinity, and water temperatures). Although there was high mortality from stressed egg masses, 24% of larvae hatched successfully. We then exposed the hatching larvae from both egg mass treatments to different combinations of water temperature (15 or 20 °C) and light (high UVB or shade) 12 h per day for 10 days. The most stressful larval conditions of 20 °C/high UVB resulted in low survival and stunted growth. Carry-over effects on survival were apparent for shaded larvae exposed to elevated temperature, where those from stressed egg masses had 1.8× higher mortality than those from control egg masses. Shaded larvae were also larger and had longer velar cilia if they were from control egg masses, independent of larval temperature. These results demonstrate that previous experience of environmental stress can influence vulnerability of later life stages to further stress, and that focus on a single life stage will underestimate cumulative effects of agents of global change.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.