Dispersal is an important fitness component of any organism, with implications in the evolutionary shaping of life histories. Dispersal impacts the distribution and abundance of populations, the propensity to within-species genetic divergence, and the community structure and dynamics of species at different sites. Until late last century, the conventional view was that the high dispersal potential of small (< 1 mm) organisms would result in a low capability for population differentiation, weak biogeographic structure, and low speciation rates and species diversity in the lowest body size range. This traditional view was definitely challenged in the last decades after the application of molecular markers to small invertebrates dwelling in ponds and lakes.

To understand why observed patterns (e.g., deep population differentiation) departure from classical predictions, dispersal of small organisms needs to be quantitatively characterized. Due to the difficulty of direct measures of dispersal, such a quantification is dramatically scarce. Additionally, we are interested in knowing whether dispersers are a bias sample of the genotypes if compared to those that remain in the locality where they were produced.

Cyclically parthenogenetic rotifers are small zooplankters dwelling in ponds and lakes and combining asexual (clonal) proliferation with sexual reproduction. This reproduction results in diapausing eggs, whose resistance allows them to disperse.

Using well-studied rotifer populations, one of our aims is to quantify the short-distance wind-mediated dispersal of rotifer diapausing eggs and characterize its associated factors (e.g., wind speed). With this aim, we set up windsocks around a small pond located in the Prat de Cabanes-Torreblanca Natural Park, a coastal Mediterranean wetland declared Nature Reserve in 1988. Currently, we are collecting wind-dispersing zooplankton propagules, especially rotifer diapausing eggs. In parallel, we are measuring environmental parameters in the pond and sampling rotifer populations as we want to quantify and sample diapausing eggs in the water column and in the pond sediment.

A second aim is to compare morphology and other features of dispersal and non-dispersal diapausing eggs. Furthermore, we will be able to hatch these eggs, to create clones by asexual proliferation and to compare life-history traits between dispersing and non-dispersing clones, all of them coming from diapausing (sexually-produced) eggs. We are particularly interested in knowing whether they differ in their propensity for sexual reproduction, as a hypothesis of interest is that dispersers are genotypes with an early engagement to sex.