5 research outputs found

    Data from: No evidence of sibling cooperation in the absence of parental care in Nicrophorus vespilloides

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    Interactions among siblings fall on a continuum with competition and cooperation at opposite ends of the spectrum. Prior work on the burying beetle Nicrophorus vespilloides suggests that parental care shifts the balance between competition and cooperation by masking a density-dependent shift from cooperation to competition. However, these results should be interpreted with caution because they were based on correlational evidence for an association between larval density at dispersal and mean larval mass at dispersal. Here we test for a causal effect of the initial number of larvae in a brood on the larvae’s subsequent performance (i.e., survival and mass) in the absence of care. We find no effect of the initial larval density on mean larval mass. Thus, our results provide no evidence for sibling cooperation in the absence of care in this species. However, using larval density at dispersal as a predictor of mean larval mass at dispersal, there was a significant correlation between larval density and mean larval mass. Our study highlights the importance of using experimental designs that exclude confounding effects due to shared environmental conditions that otherwise could be misinterpreted as evidence for sibling cooperation

    MagnevilleRatzRichardsonSmiseth

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    This file consists of a spreadsheet, which provides data for the effects of larval density at dispersal, initial larval density, initial number of larvae in the brood, carcass size and shared environmental conditions on mean larval mass and larval survival

    Long‐duration remote underwater videos reveal that grazing by fishes is highly variable through time and dominated by non‐indigenous species

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    In the marine environment, fish contribute to key ecological processes such as controlling food-webs through top-down impacts, especially on algae. To date, the assessment of fish grazing activity has mostly been performed using short-term (<1 h) censuses by divers or remote cameras which do not allow estimating the variability of grazing rate within and between days. However, understanding the temporal variation of fish activity and hence contribution of species to ecosystem functioning is of particular interest in the context of biological invasion. Here, using long-duration remote underwater cameras, we recorded fish abundance and grazing events over three consecutive days in October 2019 in a shallow Mediterranean ecosystem from northern Crete. This novel approach allowed us to assess temporal variation of abundance and grazing activity of the two native (Sarpa salpa and Sparisoma cretense) and the two non-indigenous fish species (Siganus rivulatus and Siganus luridus). Non-indigenous Siganus rivulatus was the most common species in the studied coastal habitat, followed by the two native species while the non-indigenous Siganus luridus was scarce. Overall, the non-indigenous S. rivulatus and the native S. salpa are responsible for more than 90% of the recorded grazing activity with similar bite rates between the two species. More than 70% of the grazing activity arose in grazing pulses in the afternoon, supporting the diel feeding hypothesis according to which feeding is greater in the afternoon when nutritive quality of macrophytes is the highest. In addition, some of the highest peaks in grazing activity were driven by a few individuals. Hence, surveys of only abundance could not provide accurate estimates of herbivory. Last, Siganus rivulatus presence did not significantly affect grazing activity of the native Sarpa salpa. Our results demonstrate that long-duration remote underwater videos are a useful tool to accurately assess the contribution of fishes to ecosystem functioning
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