TY - JOUR
T1 - External incubation alters the composition of squamate eggshells
AU - Cox, David L.
AU - Koob, Thomas J.
AU - Mecham, Robert P.
AU - Sexton, Owen J.
PY - 1984
Y1 - 1984
N2 - 1. 1. Eggshells of the skink, Eumeces fasciatus, and of the rough green snake, Opheodrys vernalis, contain 28-40% of total shell mass as calcium at oviposition. After incubation, both calcium concentration and content were reduced 17-41%. 2. 2. Protein accounted for 33-65% of shell mass in Eumeces and Opheodrys eggshells at oviposition. Reductions in protein concentration and content from 22-86% following incubation were observed. 3. 3. Comparing amino acid compositions of eggshells collected following oviposition with those collected from the same clutch after hatching reveals similarities among all eggshells except those of Eumeces from Michigan which lack desmosine and isodesmosine. 4. 4. Concentrations of desmosines in eggshells from Missouri and Michigan Eumeces appeared to decrease following incubation by 49.7% and 12.2%, respectively. 5. 5. Although neither the mechanisms involved in apparent losses of calcium and protein, nor the fate of the mobilized materials are known, possible pathways for mobilization of eggshell constituents are outlined and their pertinence to the physiology of squamate eggs and the evolution of viviparity in reptiles is suggested.
AB - 1. 1. Eggshells of the skink, Eumeces fasciatus, and of the rough green snake, Opheodrys vernalis, contain 28-40% of total shell mass as calcium at oviposition. After incubation, both calcium concentration and content were reduced 17-41%. 2. 2. Protein accounted for 33-65% of shell mass in Eumeces and Opheodrys eggshells at oviposition. Reductions in protein concentration and content from 22-86% following incubation were observed. 3. 3. Comparing amino acid compositions of eggshells collected following oviposition with those collected from the same clutch after hatching reveals similarities among all eggshells except those of Eumeces from Michigan which lack desmosine and isodesmosine. 4. 4. Concentrations of desmosines in eggshells from Missouri and Michigan Eumeces appeared to decrease following incubation by 49.7% and 12.2%, respectively. 5. 5. Although neither the mechanisms involved in apparent losses of calcium and protein, nor the fate of the mobilized materials are known, possible pathways for mobilization of eggshell constituents are outlined and their pertinence to the physiology of squamate eggs and the evolution of viviparity in reptiles is suggested.
UR - https://www.scopus.com/pages/publications/0021700620
U2 - 10.1016/0305-0491(84)90409-7
DO - 10.1016/0305-0491(84)90409-7
M3 - Article
C2 - 6509937
AN - SCOPUS:0021700620
SN - 0305-0491
VL - 79
SP - 481
EP - 487
JO - Comparative Biochemistry and Physiology -- Part B: Biochemistry and
JF - Comparative Biochemistry and Physiology -- Part B: Biochemistry and
IS - 3
ER -