Local resource enhancement (LRE) occurs when relatives help one another instead of competing with one another in LRC or LMC. In cooperative breeders, mothers are assisted by their previous offspring in raising new offspring. In animals with these systems, females are predicted to preferentially have offspring that are the helping sex if there are not enough helpers. However, if there are already enough helpers, it is predicted that females would invest in offspring of the other sex, as this would allow them to increase their own fitness by having dispersing offspring with a greater rate of reproduction than the helpers. It is also predicted that the strength of the selection upon the mothers to adjust the sex ratio of their offspring depends upon the magnitude of the benefits they gain from their helpers.