Data from: Social and physical environment independently affect oviposition decisions in Drosophila

In response to environmental stimuli, including variation in the presence
of conspecifics, genotypes show highly plastic responses in behavioral and
physiological traits influencing reproduction. Although extensively
documented in males, such female responses are rather less studied. We
expect females to be highly responsive to environmental variation and to
differentially allocate resources to increase offspring fitness, given the
major contribution of mothers to offspring number, size, and developmental
conditions. Using Drosophila melanogaster, we (a) manipulate exposure to
conspecific females, which mothers could use to anticipate the number of
potential mates and larval density, and; (b) test how this interacts with
the spatial distribution of potential oviposition sites, with females from
higher densities expected to prefer clustered resources that can support a
larger number of larvae. We found that high density females were slower to
start copulating and reduced their copulation duration, the opposite
effect to that observed in males. There was a parallel, perhaps related,
effect on egg production behavior: females previously housed in groups
laid fewer eggs than those housed in solitude. Resource patchiness also
influenced oviposition: females preferred aggregated substrate, which
attracted more females to lay eggs. However, we found no interaction
between prior housing conditions and resource patchiness, indicating that
females did not perceive the value of different resource distributions
differently when exposed to environments that could signal expected levels
of larval competition. We show that, although exposure to consexual
competition changes copulatory behaviors of females, the distribution of
oviposition resources has a greater effect on oviposition decisions.