title: Effects of maternal and embryo characteristics on post-fertilization provisioning in fishes of the genus Gambusia.
abstract: Maternal provisioning of embryos in Gambusia (Poeciliidae) entails both production of large, yolky eggs and mother-to-embryo transfer of nutrients, the latter of which is readily quantified using injection of radiolabeled nutrients. We assayed patterns of nutrient transfer in broods of 26 Gambusia geiseri and 23 Gambusia affinis females, using injection of tritiated leucine. We examined maternal and embryo characteristics affecting the instantaneous rate of transfer and characterized the pattern of transfer to individual embryos within broods. Maternal (female size and condition) and brood characteristics (mean embryo size, developmental stage, brood size) did not predict the mean level of nutrient transfer to embryos in a brood for either species. Within broods, individual provisioning of embryos was not related to developmental stage, but was related to embryo mass in G. affinis with nutrient transfer higher to larger embryos. In addition, overall within-brood variation in nutrient transfer, measured as coefficient of variation in embryo radioactivity, was higher in G. affinis than in G. geiseri.
authors.affiliation: Sam Noble Oklahoma Museum of Natural History, Department of Zoology, University of Oklahoma, Norman, OK 73019, USA. emarsh@ou.edu
authors.forename: Edie
authors.initials: E
authors.lastname: Marsh-Matthews
authors.forename: Melody
authors.initials: M
authors.lastname: Brooks
authors.forename: Raelynn
authors.initials: R
authors.lastname: Deaton
authors.forename: Hui
authors.initials: H
authors.lastname: Tan
mesh_terms: D000704:Analysis of Variance; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D003532:Cyprinodontiformes / Q000196:embryology* / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000378:metabolism / Q000502:physiology; D005260:Female; D007930:Leucine / Q000378:metabolism; D010063:Ovum / Q000378:metabolism*; D013045:Species Specificity; D013781:Texas; D014316:Tritium
chemical_list: D014316:Tritium; D007930:Leucine