Loss of the vitellogenins confers a fitness disadvantage but does not impact brood size in C. elegans.

Organismal homeostasis relies on balancing cellular metabolic decisions with environmental conditions, especially during reproduction. Using Caenorhabditis elegans , we tested whether vitellogenesis, or the deposition of lipid-rich yolk into oocytes, is required for reproductive output and metabolic balance by creating a strain lacking all six vitellogenin genes ( vit-1-6 ). This mutant produced embryos with reduced lipid content compared to wild-type, but the total brood size remained unaffected, unlike the rme-2 mutant, which lacks the yolk receptor. However, progeny survival during L1 starvation was impaired in vit-1-6 animals. This strain offers a new model for studying how vitellogenesis impacts reproductive and organismal fitness.