科研之友
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摘要
Successful development of embryos is important to captive breeding programs and studies of offspring phenotype. Here we compare the effects of three thermal regimes on gestation length and success in two viviparous lizards: McCann's Skink (Oligosoma maccanni), which is diurnal, and the Common Gecko (Hoplodactylus maculatus), primarily nocturnal. We hypothesized that large inter-specific differences in gestation length in the field would be reduced or eliminated under identical thermal regimes in the laboratory. Females were collected in early pregnancy and housed under regimes offering basking opportunity for 7, 5 or 3.5 d/wk (8 h/d). Gestation success was high in skinks under the two warmest regimes (78-83% of females produced viable offspring), but significantly lower under the coolest regime (53% success). Developmental success was high for geckos under all regimes (>= 80% of females produced fully developed embryos), but parturition was not always spontaneous. Gestation length in geckos that delivered spontaneously was about 50% longer than in skinks, implying the involvement of non-thermal factors, including larger mass of the conceptus and offspring. Common Geckos are remarkable in recruiting the next season's clutch into vitellogenesis while still pregnant, and, in the field, in delaying parturition of fully developed embryos for months over winter; however, in the laboratory, prolonged gestation was sometimes associated with offspring death in utero. Thus, a phenomenon that appears adaptive in the wild can have costs under laboratory conditions. Although more research is needed to understand cues for parturition and consequences for offspring phenotypes, the results for these two model species should assist captive management for their respective genera.
- 出版日期2010-8
