title: Do female newts modify thermoregulatory behavior to manipulate egg size?
abstract: Reproductive females manipulate offspring phenotypes by modifying conditions during embryogenesis. In ectotherms, the environmental control over embryogenesis is often realized by changes in maternal thermoregulation during gravidity. To determine if reproduction influences thermoregulatory behavior in species where females lay eggs shortly after fertilization (strict oviparity), we compared preferred body temperatures (Tp) between reproductive (egg-laying) and non-reproductive female newts, Ichthyosaura alpestris. Next, we exposed reproductive females to temperatures mimicking Tp ranges of reproductive and non-reproductive individuals to find out whether the maternally modified thermal regime influences ovum and jelly coat volume, and early cleavage rates at the time of oviposition. In the thermal gradient, reproductive females maintained their body temperatures within a narrower range than non-reproductive individuals. The exposure of ovipositing females to temperatures preferred during their reproductive and non-reproductive period had a negligible influence on egg size and early cleavage rates. We conclude that the modification of maternal thermoregulatory behavior provides a limited opportunity to manipulate egg traits in newts.
authors.affiliation: Department of Botany and Zoology, Masaryk University, Kotlářská 267/2, 611 37 Brno, Czech Republic.
authors.forename: Eliška
authors.initials: E
authors.lastname: Toufarová
authors.affiliation: Institute of Vertebrate Biology AS CR, Květná 8, 603 65 Brno, Czech Republic. Electronic address: gvozdik@brno.cas.cz.
authors.forename: Lumír
authors.initials: L
authors.lastname: Gvoždík
mesh_terms: D000064:Acclimatization; D000818:Animals; D001522:Behavior, Animal; D001831:Body Temperature; D004625:Embryo, Nonmammalian / Q000502:physiology; D005260:Female; D052287:Oviparity; D010063:Ovum / Q000254:growth & development*; D012455:Salamandridae / Q000502:physiology*
keywords: Amphibians; Egg size; Gravidity; Jelly coat; Mother-offspring conflict; Oviparity; Oviposition rate; Parental effect; Preferred temperature