Maternal nutrition affects offspring performance via maternal care in a subsocial spider

Provisioning of nutrients to the young during parental care is one of the mechanisms by which parents can affect growth and survival of their young and thus their reproductive success. We examined the hypothesis that food quality, i.e., ratio of macronutrients, provided to the young via maternal care affects their performance and the female's reproductive success. The subsocial spider Stegodyphus lineatus exhibits intensive maternal care behaviors, including feeding the young and matriphagy (consumption of the mother). Our results showed that a protein-enriched diet resulted in larger females at maturation and higher survival of young, relative to intermediate or lipid-enriched diets. However, fecundity was not affected by female diet. We suggest that most of the nutrients are provided to the young during maternal care rather than deposited in the eggs, allowing females to economize on limited nutritional reserves. Females before maternal care showed a low protein and high lipid content relative to females before maturation and oviposition, suggesting a change in the nutritional requirement of females before maternal care. This change in macronutrient composition may be adaptive for the success of the young in the wild and shows a novel approach to animals' ability to increase their reproductive success. Field-collected females showed a similar macronutrient composition as that of protein-enriched females in the lab, suggesting a high reproductive success of females in the wild. To our knowledge, this is the first time the importance of different macronutrients to females' reproductive success is examined during reproduction.