size: 5036KB - Crocodile Specialist Group

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2. Behavioral facilitation of reproductio! has been documenled also is teiid liz3rals such as lhe
wupl3ns (Cnemidophorus spp.). As ir the green anole, h the litde strip€d whipta;l (C inomatus), th.
presence, a[d more specificallt th€ leproductive statuE of the male is an important feature of the
feaaale's housing environrnent. Females housed as isolates or housed with castrate4 se)olaly i.nactive
Dales, fail to ovulate (Cre*s et al., 1986xFigure 3). ODly those feEales expos€d to htact scxually
active males undergo complete o\ariar growth aad lay eggs. It is not known what aspect of the male is
importalt for facilitatiDg th€ stimulatory etrects of the environment, altlough the behavior of the
animals suggest tlat chemicaf signals ale likely to be importa.nt.
3. The tunda&edal importarce of complementary behavioral interactions (e.&, nounting alxd
receptive behaviors) is seen parlicularly clea y i.n studies with the partbenogenetic whiptail,
C enlidophotus unipa.ens. ID this species there are no male individuals ard reproduction is via
obligate parthenogenesis. Rather, tle species coasists e irely of females and sperm are not required
for ovarian development. Intereslingl, these partherogeos exhibit both male-like and fenale-like
behaviors duri.ng spccific stages of the reproductiv€ cycle (Crews, 1989; Crews and litzgerald, 1980).
The,se behaviors are seeD bot! ia the laboratory as wel as in nature (Crews and Young, 191).
Experinents iDdicate that altlough nale individuals are Dot essedial for ovariar glowth id the
parthenogeA participation itr pseudos€xua.l interactioDs geatly facilitates tho nte of ovalialr growth
(Crews et al., 1986) (Figure 3) as wel as the total number of eggs producEd during a breeding season
(Crews ard Moorg 1991; Crelr$ €t al., 1983). The specific stimuli respoDsible for tffs facilitation is not
kno\n!, but lhe question is amenable to experime ation.
4. In the gekkonid lizard, the leopard gecko (n , kphoris ma.ularius), lenales will only lay eggs
if sexually active males are present (Figure 4). Fbtler, tle fertility of the ruale is i$porta . That i5,
females housed with sexuatly actrve but vasectohized Eales will lay eggq but the eggs often lack a shell
coati.ng (J. J. Bull unpublished data). This suggests t-hat not only is the b€havior of the male important,
but tlat at least id some species th€re must exist semory receptors withh the f€nale's reproductive
tract that are activated by sp€rm deposition. Sp€cialized sperm storage ducts occur id many .eptiles.
This may b€ why i! mary reptiles the female c-atr continue to lay fertile eggs for years in captivity in tte
absence of males. These data aiso suggest [hat wbjle it is advisable in a captii€ breealitrg prograD to
establish that each male is depositing sperm during math& a fortile male is not an absolute
requirement so long as the females mate successfully at least ocrisionally.
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