Data for: Protective geometry and reproductive anatomy as candidate determinants of clutch size variation in pentatomid bugs

Many animals lay their eggs in clusters. Eggs on the periphery of clusters
can be at higher risk of mortality. We asked whether the most commonly
occurring clutch sizes in pentatomid bugs could result from geometrical
arrangements that maximize the proportion of eggs in the cluster’s
interior. Although the most common clutch sizes do not correspond with
geometric optimality, stink bugs do tend to lay clusters of eggs in shapes
that protect increasing proportions of their offspring as clutch sizes
increase. We also considered whether ovariole number, an aspect of
reproductive anatomy that may be a fixed trait across many pentatomids,
could explain observed distributions of clutch sizes. The most common
clutch sizes across many species correspond with multiples of ovariole
number. However, there are species with the same number of ovarioles that
lay clutches of widely varying size, among which multiples of ovariole
number are not over-represented. In pentatomid bugs, reproductive anatomy
appears to be more important than egg mass geometry in determining clutch
size uniformity. In addition, within this group of animals that has lost
most of its variation in ovariole number, clutches with a broad range of
shapes and sizes may still be laid.