DOI: 10.5061/dryad.9ghx3ffhc
title: The thermal environment of sperm affects offspring success: a test of the anticipatory paternal effects hypothesis in a broadcast spawner

description: There has been an explosion of recent evidence that environments
 experienced by fathers or their ejaculates can influence offspring
 phenotypes (paternal effects). However, little is known about whether such
 effects are adaptive, which would have far-reaching implications for the
 many species facing rapidly changing environments. For example, some
 arguments suggest paternal effects might be a source of cross-generational
 plasticity, preparing offspring to face similar conditions to their father
 (anticipatory hypothesis). Alternatively, ejaculate-mediated effects on
 offspring may be non-adaptive by-products of stress. Here, we conduct an
 experiment to distinguish between these predictions, exposing ejaculates
 of the externally fertilizing mussel Mytilus galloprovincialis to ambient
 (19 °C) and high (24 °C) temperatures, then rearing offspring groups in
 temperatures that match and mismatch those of sperm. We find that,
 overall, high-treated sperm induced higher rates of normal offspring
 development, and higher success in transitioning to second-stage larvae,
 which may represent adaptive epigenetic changes or selection on sperm
 haplotypes. However, progeny of high-treated sperm did not perform better
 than those of ambient-treated sperm when rearing temperatures were high.
 Overall, these findings offer little support for anticipatory hypothesis
 and suggest instead that beneficial paternal effects may be eroded when
 offspring develop under stressful conditions.
description: These data were collected from an experiment testing whether
 ejaculate-mediated paternal effects of temperature are adaptive for
 offspring, using the externally fertilizing mussel <em>Mytilus
 galloprovincialis</em>. Mussels were induced to spawn, and
 ejaculates from males (<em>n </em>= 34) were split into two
 aliquot; one aliquot was exposed to ambient temperature (19 °C) and the
 other to high temperature (24 °C). The aliquots were used to fertilise
 separate batches of pooled eggs (i.e., eggs pooled from mulriple females),
 and fertilization rates measured after 2 h. Each batch of eggs was then
 split into two aliquots that were exposed to different rearing
 temperatures over 48 h; again using ambient (19 °C) and high (24 °C)
 temperature treatments. After 48 h, the number of surviving offspring was
 counted, along with the proportion that were trocophore
 (first-stage) <em>vs. </em>veliger (second-stage) larvae and
 the portion that exhibited normal <em>vs. </em>abnormal
 morphology and swimming.
description: The dataset is ordered with variables in columns and samples in
 rows. Columns represent 'Block' (experimental day),
 'Male' (unique ID for each male sperm donor),
 'Sperm_temp' (sperm temperature treatment),
 'Rearing_temp' (rearing temperature treatment),
 'Sample' (unique ID for each sample), 'Trocophore'
 (number of trocophore larvae), 'Veliger' (number of veliger
 larvae), 'Abnormal' (number of larvae with abnormal morphology
 or swimming), 'Normal' (number of larvae with normal morphology
 and swimming), 'Total' (total number of surviving larvae at 48
 h), 'Fert' (number of fertilized eggs out of a haphazard count
 of 100 in the original batch of eggs), and 'Fert_rate'
 (fertilization expressed as a proportion).