Record Details

Troyer, Katherine
Posthatching yolk in a lizard: internalization and contribution to growth
Journal of Herpetology
Journal Article
Iguana iguana
The lizard Iguana iguana emerges from the egg with a portion of the original yolk remaining; this yolk mass is drawn into the body cavity by contraction of the embryonic membranes, and is metabolized during the first weeks of life. Iguanas from the same clutch were forced to hatch by rupturing the embryonic membranes artificially: in half of these animals, the posthatching yolk was permitted to retract into the body, and in the other half, the yolk was tied off and removed before it could be internalized. The individuals that were hatched forcibly, but were allowed to internalize their yolk, grew more rapidly than their siblings whose yolks were removed, and as rapidly as siblings that were allowed to hatch without any interference. The posthatching yolk in I. iguana can contribute significantly to growth during the first month of life; for reptiles in general, the posthatching component of yolk provisioning represents an aspect of maternal investment that may critically influence offspring fitness.