The cause of variability in quail recruitment in semiarid environments is unclear but variability is associated with precipitation. We hypothesized that variation in the protein and energy nutrition of hens, resulting from variation in the biomass of invertebrates in diets, causes variation in the proportion of reproductively active females in the population. We tested predictions of the hypothesis that: 1) reproducing female northern bobwhite (Colinus virginianus) will consume greater biomass of invertebrates than males and nonlaying females, and 2) the proportion of laying females is related to standing invertebrate biomass. Data were collected from 2 sites in the Gulf Coast Prairies (1992–1993) and 2 sites in the Rio Grande Plains (1993) of Texas. Diets of laying females had 3 to 12.5 times more invertebrates than diets of males and 2.3 to 4.0 times more invertebrates than diets of nonlaying females. Although the mean dry mass (kg/ha) of invertebrates was 2.0 to 5.5 times higher in the Gulf Coast Prairies than in the Rio Grande Plains, the percentage of females laying (60 to 73%) was similar between region-years. Other hypotheses regarding reproductive failure of female quail should be investigated.