Maternal care under large clutches with small eggs: The evolution of life history traits in shield bugs

We examined evolutionary associations between parental care and other life-history traits, female body size, egg size, clutch size, reproductive output and developmental period of eggs and hatchlings, in shield bugs using phylogenetic generalized least squares (PGLS) models in the phylolm package for R.
Then, the pattern of evolutionary transitions among character states, parental care and egg size, clutch size or reproductive output, was examined using the Discrete dependent model implemented in BayesTraits.
Our analyses revealed that female body size affected reproductive resource allocation. Contrary to the expectations of current theories, the acquisition of maternal care was associated with small eggs, large clutches, and large egg-resource allocation.
There was a greater trade-off between egg size and clutch size in caring species than in non-caring species.
Egg and hatchling developmental rates were not correlated with egg size, but were slower in caring species than in non-caring species.
Analyses of evolutionary transitions suggest that the establishment of large clutches, small eggs and large egg-resource allocation preceded the evolution of maternal care.