size: 5036KB - Crocodile Specialist Group

82
llth Working Meeting of the Crocodile Specialst Group
3'7 August 1992, Victoria Falls, zimbabwe
HoRMoNAL DgrERMIt lATloN oF GENDER AND BBriAl.IouR lN REPI'ILES
David Crews 1'2, Alan Tousigna.ot 2, Thane Wibb€ls 2 and James Perran Ross 3
1. Reptile Conservation Intemational !rc., 16010 A$hlt Drii€, Austh Texas ?&734 USA'
2. Instituto of Reproductive Biologf, Departmont of zoologi/
University of To.as at Austin
Austin, Te)(as 78712
3. Ftorida Museum of Natural History
Gainesvile. FL 32601 USA
The success of captive breeding and husba-ndry oI qocodiLans for conservation ard for
cornnercial purposes depenrls upon sluccessful reproductio!. In addition, importan- t Pamm, €te's of
health, go;h, and successfut adaptation to captive coDdrtioDs are known to be influenced by
conditio,"ns during incubation. These effects, which have importad consequeoces for tbe-commercial
producer, are thJ result of interactions betw€en behavior of animals and the hormones they ses€te' In
iecent ycars significant advances have been made in understardbg the complex ielatioEshi-! between
the behavior, hlormonal activity, anal reproduction in reptiles. Matry of these results have diect
apolication to crocodile farming and others provide intrigui4 insights into some unsolied problems of
ho"taoa.v *d reproduction. In this paper we report otr recent results with reptiles as ttey
"iocoAiU"
miglt apply to crocoiilians and we describe a tecbnique for madPuladry the sex oflatchlings
ind-epenieit of inc'batiotr temperatur€ that has far r€aching potential for conseflttion and commercial
production.
we focus on three factors that inlluence reproduction. These are:
(i) the importance of behaviors of corspecifics,
ii' trow as an embryo can influence th€ adult Phenotype, including reProductive
"ipe.i"n"e
competence, ano
(iii) how these;nd other recent discovedes in reptile reproduction can be tsed to manipulate
sex ratios in caPtive and perhaps wild populations.
Disregaral of these factors may account for the poor success of some captrve breediDg progams'
Behavior of conspecifi cs.
An imporiant source of cues regulating reproducdoo is the animal\ social ervi'onmeDt'
Courtship displays €volved to assist in the identificntioE of individuals of tie same speoes, the
appropriate scx, and their competence to r€produco. The comPleme ary ioteractions-among
iniiviiuah dulng b.ee