Data from: Seasonal variation in heteromorphic sperm size in Littorina snails on the Swedish West Coast
type: Dataset
description: Abstract of the journal article "Seasonal variation in heteromorphic sperm size in Littorina snails on the Swedish West Coast": Sperm are among the most morphologically diverse cells in the animal kingdom, with many species producing distinct sperm morphs-a phenomenon known as sperm heteromorphism. Typically, fertilizing eusperm are accompanied by non-fertilizing parasperm, which in some taxa play roles related to sperm competition. In Littorina snails, a genus of marine gastropods, the function of parasperm remains unresolved, but it appears to represent a substantial reproductive investment and thus may change through the breeding season. Here, we investigated seasonal changes in parasperm volume and eusperm length in four Littorina species, including two with distinct ecotypes. Measurements were taken across their breeding seasons to assess temporal shifts in sperm size and variation in size. Both parasperm and eusperm exhibited pronounced seasonal dynamics, with larger sizes typically occurring early in the breeding season and smaller sizes toward the end. Seasonal fluctuations in parasperm volume may reflect changes in reproductive investment or sperm competition intensity, whereas increasing variation in eusperm length toward the end of the season may indicate reduced control of spermatogenesis and lower selective pressure for optimal sperm lengths. We suggest that hormonal fluctuations or temperatures might cause the observed differences. Our findings provide the first evidence of seasonal size variation in heteromorphic sperm in a marine invertebrate, paralleling patterns observed in avian systems. These results suggest that seasonal environmental and reproductive factors shape sperm traits in Littorina, highlighting the plasticity of sperm form and function in response to ecological pressures. Description of the data: # R-Code Analysis.r This is the R-Code that was used for all analyses and plotting. # csv files Analysis.csv This is the data that was acquir…
creative work status: completed
  type: DefinedTerm
  in defined term set: http://publications.europa.eu/resource/authority/dataset-status
  term code: COMPLETED
creator: Luisa Kumpitsch
creator: Emily Cramer
  type: Person
  family name: Cramer
  given name: Emily
creator: Erica H. Leder
  type: Person
  family name: Leder
  given name: Erica H.
date modified: 2026-01-27
date published: 2026-01-27
funding: Ecological systems biology: disentangling the molecular mechanisms of parallel evolution
  type: Grant
  funder: Swedish Research Council
keywords: Medical and Health Sciences
  type: DefinedTerm
  term code: 3
keywords: Behavioural ecology
license: https://creativecommons.org/licenses/by/4.0/
publisher: University of Gothenburg
version: 0

PropertyValue
property ID: DOI
value: 10.17044/SCILIFELAB.31150372

Luisa Kumpitsch
type: Person
affiliation: Science for Life Laboratory
family name: Kumpitsch
given name: Luisa

Science for Life Laboratory
type: Organization

Swedish Research Council
type: Organization

University of Gothenburg
type: Organization