Data from: Maternal body size influences offspring immune defence in an oviparous snake

Like most ectothermic vertebrates, keelback snakes (Tropidonophis mairii) do not exhibit parental care. Thus, offspring must possess an immune system capable of dealing with challenge such as pathogens, without assistance from an attendant parent. We know very little about immune system characteristics of neonatal reptiles, including the magnitude of heritability and other maternal influences. We scored white blood cell (WBC) concentrations and differentials in 246 hatchling snakes from 49 clutches, plus their field-caught mothers. WBC concentrations were lower in hatchlings than in adults, and hatchlings had more basophils and fewer azurophils than adults. A hatchling keelback's WBC differential was also influenced by its sex and body size. Although hatchling WBC measures exhibited negligible heritability, they were strongly influenced by maternal body size (but not maternal body condition, parasite infection, Relative Clutch Mass or time in captivity). Larger mothers produced offspring with more azurophils and fewer lymphocytes. If these maternal effects on WBC differentials enhance offspring fitness, the impact of maternal body size on reproductive success may be greater than expected simply from allometric increases in the numbers and sizes of progeny.