females but not males. Females appear to have a series of mating 

 avoidance behaviors as a way of selecting the fittest males. 

 Females are active in escorting but not once they have been 

 mated. 



Rostal has undertaken a similar study with captive reared L. 

 kempi at the Cayman Turtle Farm. These smaller, quicker animals 

 have a less diverse and possibly more subtle behavioral 

 repertoire. Much of the mating occurs at night in these turtles, 

 and they appear very secretive. Endocrine levels are being 

 determined for comparisons with wild ridleys and other sea turtle 

 species. 



Reproductive hormone studies 



Several studies are being compiled by Wibbels on work with 

 Limpus in Australia, NMFS in Florida and Marquez in Mexico. 

 Testosterone and spermatogenesis peak prior to mating and 

 decrease through a distinct mating season. Some males appear to 

 be multi-annual, like females. A softened medial plastron patch 

 is characteristic of reproductively active males in several 

 species. In females, estrogen is secreted at fairly low levels 

 over the non-nesting years to drive a slow follicle enlargement 

 phase. A peak in estrogen occurs in spring prior to migration 

 and during maturation of subsequent clutches. Thyroxin (T4) 

 peaks in early spring prior to a testosterone surge which appears 

 to initiate migratory behavior. 



Figler has studied the hormone arginine vasotocin in sea 

 turtles. He found a steep peak in the circulating level of this 

 molecule coincident with oviposition. This hormone may be of use 

 when nesters have difficulty in dropping eggs. This work was 

 supported by Sea Grant #NA83AA-D-00061, NSF grant #BNF-8418538, 

 Cayman Turtle Farm and by Sea Turtles, Inc. 



339 



