Maternal investment in reproduction and its consequences in leatherback turtles

Maternal investment in reproduction by oviparous non-avian reptiles is usually limited to pre-ovipositional allocations to the number and size of eggs and clutches, thus making these species good subjects for testing hypotheses of reproductive optimality models. Because leatherback turtles (Dermochelys coriacea) stand out among oviparous amniotes by having the highest clutch frequency and producing the largest mass of eggs per reproductive season, we quantified maternal investment of 146 female leatherbacks over four nesting seasons (2001–2004) and found high inter- and intra-female variation in several reproductive characteristics. Estimated clutch frequency [coefficient of variation (CV) = 31%] and clutch size (CV = 26%) varied more among females than did egg mass (CV = 9%) and hatchling mass (CV = 7%). Moreover, clutch size had an approximately threefold higher effect on clutch mass than did egg mass. These results generally support predictions of reproductive optimality models in which species that lay several, large clutches per reproductive season should exhibit low variation in egg size and instead maximize egg number (clutch frequency and/or size). The number of hatchlings emerging per nest was positively correlated with clutch size, but fraction of eggs in a clutch yielding hatchlings (emergence success) was not correlated with clutch size and varied highly among females. In addition, seasonal fecundity and seasonal hatchling production increased with the frequency and the size of clutches (in order of effect size). Our results demonstrate that female leatherbacks exhibit high phenotypic variation in reproductive traits, possibly in response to environmental variability and/or resulting from genotypic variability within the population. Furthermore, high seasonal and lifetime fecundity of leatherbacks probably reflect compensation for high and unpredictable mortality during early life history stages in this species.     

Maturation increases early reproductive investment in Adélie Penguins Pygoscelis adeliae

Correlations between female investment in egg production and age, breeding experience and laying date have been reported in several seabird species. In general, clutch and egg sizes increase with female age and breeding experience but decrease with laying date. Positive correlations of clutch and egg size with age and breeding experience can be caused by an increase in reproductive investment with maturation or they may be an artefact of lower survival rates for individuals with poor-quality phenotypes. Negative correlations of clutch and egg size with laying date might signal an adaptive reduction in egg production or be due in part to variation among individuals. We examined the interactions of female age, breeding experience, laying date and clutch and egg size in Adélie Penguins Pygoscelis adeliae . Breeding experience strongly affected clutch size with 87.3% of all one-egg clutches laid by first-time breeders. In addition, increasing age had a positive influence on egg size and was associated with earlier laying dates. However, there was little evidence to suggest that either clutch or egg sizes are influenced by laying date. Laying dates and clutch and egg sizes did not affect a female's probability of returning to breed in the following year, indicating that increased investment is a product of maturation and not of the loss of poor-quality breeders from the population. Our results suggest that as female Adélie Penguins gain foraging and breeding experience they are able to initiate breeding earlier, to lay complete clutches of two eggs and to lay larger eggs.     

宁波滑蜥两性异形和雌性繁殖

蜥蜴的雌性繁殖特征对理解两性异形的进化原因起着重要作用。于2011年4月在安徽滁州采集宁波滑蜥(Scincella modesta),定量研究该种形态特征的两性异形和雌性繁殖特征,检验成体形态特征两性异形与雌性繁殖的相关性。研究共采集43条(17♀♀,26♂♂)宁波滑蜥,雄性和雌性个体的最大体长分别为47.4 mm和46.6 mm。雌雄两性在体长和头宽上没有差异,而在腹长和头长上差异显著,雄性有较大的头长,雌性有较大的腹长。宁波滑蜥年产单窝卵。窝卵数和窝卵重与雌体体长及腹长呈正相关,卵重与雌体体长无相关性。窝卵数及卵重的变异系数分别为0.20和0.12。卵长径与窝卵数呈负相关,而卵短径与窝卵数无关。雌体主要通过增加窝卵数来增加繁殖输出。这些结果表明,宁波滑蜥是雌雄个体大小同形的两性异形模式,性选择使得雄性有着较大的头长,以具有较高的交配成功率,生育力选择使得雌性有着较大的腹长,以具有较大的生育力和繁殖输出。     

Subsociality and female reproductive success in a mycophagous thrips: An observational and experimental analysis

Oviparous females of the haplodiploid, facultatively viviparous thrips Elaphrothrips tuberculatus(Thysanoptera: Phlaeothripidae) guard their eggs against female conspecifics and other egg predators. The intensity of maternal defense increases with clutch size. Field and laboratory observations indicate that cannibalism by females is an important selective pressure favoring maternal care. Experimental removals of guarding females showed that egg guarding substantially increases egg survivorship and that the survivorship of undefended eggs is higher in the absence of nonguarding female conspecifics than in their presence. The fecundity of viviparous females increases with the number of eggs cannibalized. The reproductive success of oviparous females increases with body size and local food density and decreases with local density of breeding females. Social behavior may not have advanced beyond maternal care in Elaphrothrips tuberculatusbecause, relative to Hymenoptera, capabilities for helping relatives are few or nonexistent, and the causes of variation in female reproductive success are not influenced easily by cooperation among females.     

Measuring temporal variation in reproductive output reveals optimal resource allocation to reproduction in the northern grass lizard, Takydromus septentrionalis

We measured the reproductive output of Takydromus septentrionalis collected over 5 years between 1997 and 2005 to test the hypothesis that reproductive females should allocate an optimal fraction of accessible resources in a particular clutch and to individual eggs. Females laid 1–7 clutches per breeding season, with large females producing more, as well as larger clutches, than did small females. Clutch size, clutch mass, annual fecundity, and annual reproductive output were all positively related to female size (snout–vent length). Females switched from producing more, but smaller eggs in the first clutch to fewer, but larger eggs in the subsequent clutches. The mass-specific clutch mass was greater in the first clutch than in the subsequent clutches, but it did not differ among the subsequent clutches. Post-oviposition body mass, clutch size, and egg size showed differing degrees of annual variation, but clutch mass of either the first or the second clutch remained unchanged across the sampling years. The regression line describing the size–number trade-off was higher in the subsequent clutch than in the first clutch, but neither the line for first clutch, nor the line for the second clutch varied among years. Reproduction retarded growth more markedly in small females than in large ones. Our data show that: (1) trade-offs between size and number of eggs and between reproduction and growth (and thus, future reproduction) are evident in T. septentrionalis ; (2) females allocate an optimal fraction of accessible resources in current reproduction and to individual eggs; and (3) seasonal shifts in reproductive output and egg size are determined ultimately by natural selection.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 91 , 315–324.     

Cross‐generational costs of compensatory growth in nine‐spined sticklebacks

Compensatory growth (CG) is a form of phenotypic plasticity allowing individuals’ growth trajectories to rebound after a period of resource limitation, but little is known about the reproductive and cross‐generational costs of CG. We studied the potential costs of CG by exposing female nine‐spined sticklebacks Pungitius pungitius to 1) high (favourable), 2) low (stressful), and 3) recovery (initially stressful, subsequently favourable) feeding treatments, and quantified the effects of these treatments on female reproductive traits (clutch, egg and yolk size), and on the size of their offspring. The low feeding treatment reduced female size relative to the high and recovery feeding treatments, which produced equally large females. Hence, females from the recovery treatment demonstrated CG and full growth compensation. Feeding treatments had significant effects on clutch, yolk, egg and larval size, also when the effect of female size was controlled for. However, these effects came about mostly because females from the low feeding treatment produced small clutches with large eggs (containing little yolk) and larvae, whereas females from the recovery feeding treatment produced as large clutches, eggs (with similar amounts of yolk) and larvae as females from the high feeding treatment. Yet, structural equation modelling revealed that while a direct effect of female size on offspring size was positive in the low and high feeding treatments, it was negative in the recovery feeding treatment, independently of egg and clutch size. This indicates a cross‐generational tradeoff between female and offspring sizes in the recovery feeding treatment. Also the tradeoff between clutch and larval size was more pronounced in recovery than in low or high feeding treatments. Hence, apart from demonstrating that environmental influences experienced by females during their development have the potential to influence their size, fecundity and reproductive traits, the results also provide evidence for complex cross‐generational costs of recovery growth.     

Life-history variation within a three-spined stickleback population in the Camargue

Among individuals of female three-spined sticklebacks Gasterosteus aculeatus from a population in the Camargue, southern France, studied in 12 successive years, adult L _T ranged from 31–64 mm, clutch size ranged from 33–660 eggs, and mean egg diameter per clutch ranged from 1.15–1.67 mm. Because the population was strictly annual, inter-annual variation corresponded to variation among generations having experienced different environmental conditions. Body mass varied significantly among years, suggesting an effect of varying environmental conditions. Gonad mass and clutch size increased with body mass, but mean egg diameter was not correlated to body mass. Body mass-adjusted gonad mass, interpreted as reproductive effort per clutch, did not vary significantly among years, suggesting that this trait was not influenced by environmental conditions. Body mass-adjusted clutch size and egg size varied significantly among years. Inter-annual variation in body length at breeding, clutch size and egg size was of the same order of magnitude as inter-population variation reported by other authors for this species. During the breeding season, reproductive effort and clutch size tended to increase. Egg size tended to decrease during the breeding season but this seasonal pattern varied among years. Observed life-history variation is discussed both in terms of its evolutionary significance and methodological implications in the study of life-history variation among populations.     

Two eggs,two different constraints: a potential explanation for the puzzling intraclutch egg size dimorphism in Eudyptes penguins

Phenotypic plasticity and phenotypic stability are major components of the adaptive evolution of organisms to environmental variation. The invariant two-egg clutch size of Eudyptes penguins has recently been proposed to be a unique example of a maladaptive phenotypic stability, while their egg mass is a plastic trait. We tested whether this phenotypic plasticity during reproduction might result from constraints imposed by migration (migratory carry-over effect) and breeding (due to the depletion of female body reserves). For the first time, we examined whether these constraints differ between eggs within clutches and between egg components (yolk and albumen). The interval between colony return and clutch initiation positively influenced the yolk mass, the albumen mass, and the subsequent total egg mass of first-laid eggs. This time interval had only a slight negative influence on the yolk mass of second-laid eggs and no influence on their albumen and subsequent total masses. For both eggs, female body mass at laying positively influenced albumen and total egg masses. Female investment into the entire clutch was not related to the time in the colony before laying but increased with female body mass. These novel results suggest that the unique intraclutch egg size dimorphism exhibited in Eudyptes penguins, with first-laid eggs being consistently smaller than second-laid eggs, might be due to a combination of constraints: a migratory carry-over effect on the first-laid egg and a body reserve depletion effect on the second-laid egg. Both these constraints might explain why the timing of reproduction, especially egg formation, is narrow in migratory capital breeders.     

Reproductive Flexibility: Genetic Variation,Genetic Costs and Long-Term Evolution in a Collembola

In a variable yet predictable world, organisms may use environmental cues to make adaptive adjustments to their phenotype. Such phenotypic flexibility is expected commonly to evolve in life history traits, which are closely tied to Darwinian fitness. Yet adaptive life history flexibility remains poorly documented. Here we introduce the collembolan Folsomia candida, a soil-dweller, parthenogenetic (all-female) microarthropod, as a model organism to study the phenotypic expression, genetic variation, fitness consequences and long-term evolution of life history flexibility. We demonstrate that collembola have a remarkable adaptive ability for adjusting their reproductive phenotype: when transferred from harsh to good conditions (in terms of food ration and crowding), a mother can fine-tune the number and the size of her eggs from one clutch to the next. The comparative analysis of eleven clonal populations of worldwide origins reveals (i) genetic variation in mean egg size under both good and bad conditions; (ii) no genetic variation in egg size flexibility, consistent with convergent evolution to a common physiological limit; (iii) genetic variation of both mean reproductive investment and reproductive investment flexibility, associated with a reversal of the genetic correlation between egg size and clutch size between environmental conditions ; (iv) a negative genetic correlation between reproductive investment flexibility and adult lifespan. Phylogenetic reconstruction shows that two life history strategies, called HIFLEX and LOFLEX, evolved early in evolutionary history. HIFLEX includes six of our 11 clones, and is characterized by large mean egg size and reproductive investment, high reproductive investment flexibility, and low adult survival. LOFLEX (the other five clones) has small mean egg size and low reproductive investment, low reproductive investment flexibility, and high adult survival. The divergence of HIFLEX and LOFLEX could represent different adaptations to environments differing in mean quality and variability, or indicate that a genetic polymorphism of reproductive investment reaction norms has evolved under a physiological tradeoff between reproductive investment flexibility and adult lifespan.     

Reproductive tradeoffs and yolk steroids in female leopard geckos, Eublepharis macularius

Life history theory predicts tradeoffs among reproductive traits, but the physiological mechanisms underlying such tradeoffs remain unclear. Here we examine reproductive tradeoffs and their association with yolk steroids in an oviparous lizard. Female leopard geckos lay two eggs in a clutch, produce multiple clutches in a breeding season, and reproduce for several years. We detected a significant tradeoff between egg size and the number of clutches laid by females during their first two breeding seasons. Total reproductive effort was strongly condition-dependent in the first season, but much less so in the second season. Although these and other tradeoffs were unmistakable, they were not associated with levels of androstenedione, oestradiol, or testosterone in egg yolk. Female condition and egg size, however, were inversely related to dihydrotestosterone (DHT) levels in egg yolk. Finally, steroid levels in egg yolk were not directly related to steroid levels in the maternal circulation when follicles were developing, indicating that steroid transfer to eggs is regulated. These findings suggest that maternal allocation of DHT could mitigate tradeoffs that lead to poor offspring quality (i.e. poor female condition) and small offspring size (i.e. small egg size).     

Intra‐clutch pattern of albumen δ13C and δ15N in yellow‐legged gulls Larus michahellis: female dietary shift or resource allocation strategy?

Energy or nutritional constraints associated to female dietary shifts during the clutch production period may play a role in generating intra‐clutch egg size variation in yellow‐legged gulls Larus michahellis. To explore this possibility, we determined albumen δ¹³C and δ¹⁵N values in three‐egg clutches (modal clutch size) from three different breeding episodes: Ebro Delta 2004 and 2006, and Columbretes Islands 2004. Rather than a shift in females’ diet, consistent intra‐clutch patterns of variation in egg size and albumen isotopic values (particularly in the case of albumen δ¹³C, which values held constant throughout the laying sequence) pointed to an intrinsic mechanism as the most feasible cause for the relatively smaller size of third/last‐laid eggs. However, diet “quality” for breeding females seemed to affect intra‐clutch egg size variation. In particular, a deficit of specific nutrients for egg formation associated to refuse scraps exploitation (as suggested by depleted albumen isotopic values) likely resulted in the more apparent intra‐clutch egg size profile for the Ebro Delta 2004. In the absence of dietary shifts, the observation of consistently higher δ¹⁵N values for third‐albumens suggested a greater contribution of endogenous resources to their synthesis, as conversion of stored reserves into egg proteins results in greater isotopic fractionation, thereby yielding enriched isotopic signatures (particularly for δ¹⁵N that shows greater isotopic fractionation with respect to that commonly assumed for δ¹³C). We point to reabsorbed material derived from the hormonally‐mediated regression of the female reproductive system (which is likely the intrinsic mechanisms resulting in the intra‐clutch pattern of egg size variation: the hormonal hypothesis) as the most feasible endogenous source of nutrients for the synthesis of last‐laid eggs, as optimize reproductive investment and maximize female fitness.     

Geographical variation in egg size of the Great Tit Parus major: a new perspective

A recent study on geographical variation in egg size of Great Tits Parus major concluded that: (1) mean egg size tended to increase with increasing latitude; and (2) mean egg size was positively correlated with mean clutch size. Including new data on both egg and clutch size, we reanalysed the relationships between egg size, clutch size and latitude, and investigated the possible effects of habitat type, female body size and egg shape on these relationships. We found that (1) egg volume showed minimum values around 51°N, increasing both north and southwards; (2) female body size increased linearly with increasing latitude; (3) female body size was positively correlated with egg breadth, but not with egg length or egg volume; (4) the sphericity index of the eggs (breadth to length ratio) was largest at medium latitudes, and eggs were more elongated towards the north and the south; (5) the relationship between clutch size and latitude was curvilinear, with the largest clutch sizes at intermediate latitudes; (6) egg size was not correlated with clutch size when the complete latitudinal range was considered, but egg size was negatively correlated with clutch size between 40 and 51°N; and (7) egg size did not differ among habitat types. We suggest that female body size (which probably limits egg breadth), and the pressure for producing large eggs (which in turn increases the reproductive success) are the main determinants of geographical variation in egg size and shape. Populations of small-bodied Great Tits seem to escape from the limits of their size, producing relatively elongated eggs, so that from a certain latitude southwards, egg volume does not decrease in spite of a decrease in female body size. Moreover, the negative relationship between egg and clutch size at low latitudes suggests that energetic trade-offs may also contribute to determine egg size in the south.     

Reproductive parameters in relation to food supply in the whiskered tern ( Chlidonias hybrida )

It is generally accepted that breeding terns are sensitive to food supply and that their reproductive effort could be substantially affected by the availability and access to resources. In this study we examined reproductive parameters in the whiskered tern Chlidonias hybrida in relation to food supply during the courtship feeding period (food brought by males to females) over a 2-year period (2004–2005). We also studied whether the condition of the nestlings [body condition index (BCI)] was related to a proxy of the reproductive investment of the adults (the clutch size) during a season of food shortage. Behavioural observations showed a decrease in the intensity of male courtship feeding between years (2004 > 2005), and a strong shift in the relative abundance of the two prey groups (invertebrates/fish; invertebrate prey dropped from 88.0 to 49.3%) brought by males. This change in food delivery rates did not result in a delay in laying, but there was a significant difference in mean clutch size between years (2.71 ± 0.49 eggs in 2004 and 2.05 ± 0.78 eggs in 2005) without any within-year variation in relation to the laying dates. The egg size (volume and length) was related to the year (2004 < 2005), suggesting a trade-off in the quantity and the quality of eggs between the two seasons. We also found no evidence that the investment in a large clutch affected nestling BCI in the course of the food shortage season. Since many pairs (about 60%) interrupted breeding during the incubation stage, we assumed that parents that succeeded in rearing nestlings in these conditions were probably ‘high-quality’ individuals. Our results therefore showed that whiskered terns are sensitive to the varying food conditions they experienced throughout the courtship period. The diversity of prey types could be a key factor in the reproductive investment of this tern species.     

A hierarchical response to differences in ration size in the reproductive performance of female three-spined sticklebacks

The response of female three-spined sticklebacks ( Gasterosteus aculeatus ) to differences in food ration during the breeding season was quantified for several variables related to reproductive performance. The measured protein and lipid contents (mg g⁻¹) of eggs were unaffected by ration. Egg size increased with an increase in both ration and female size, but the proportional increase in egg size was much smaller than the proportional increase in ration. The best predictor of mean batch (clutch) fecundity and weight was female size. There was a small but significant increase in batch fecundity with ration, but the increase was not directly proportional to the increase in ration. The rate of spawning, total breeding season fecundity and total weight of eggs spawned over the breeding season were sensitive to ration with breeding season fecundity and weight increasing in direct proportion to ration. Thus, in female sticklebacks, there is a hierarchy of sensitivity to ration in the response of variables related to reproduction.     

Geographic variation in reproductive traits and trade-offs between size and number of eggs of the Chinese cobra (Naja atra)

We collected gravid Chinese cobras (Naja atra) from one island (Dinghai) and three mainland (Yiwu, Lishui and Quanzhou) populations in south‐eastern China to study geographical variation in female reproductive traits and the trade‐off between the size and number of eggs. We then conducted an common experiment on cobras from two of the four populations to further identify factors contributing to the observed trade‐offs. The mean size (snout–vent length) of the smallest five reproductive females increased with increasing latitude. Oviposition occurred between late June and early August, with females from the warmer localities laying eggs earlier than those from the colder localities. Maternal size was a major determinant of the reproductive investment in all populations, with larger females producing not only more but also larger eggs. Clutch size was more variable than egg size within and among populations. The observed geographical variation in clutch size, egg size, clutch mass and post‐oviposition body condition was not a simple consequence of variation in maternal size among populations, because interpopulation differences in these traits were still evident when the influence of maternal size was removed. The upper limit to reproductive investment was more likely to be set by the space availability in the island population, but by the resource availability in the three mainland populations. Trade‐offs between size and number of eggs were detected in all populations, with females that had larger clutches for their size having smaller eggs. Egg size at any given level of relative fecundity differed among populations, primarily because of interpopulation differences in the resource availability rather than the space availability. Except for the timing date of oviposition and the mean size of the smallest five reproductive females, all other examined traits did not vary in a geographically continuous trend. The common garden experiment, which standardized environmental factors, synchronized the timing date of oviposition, but it did not modify the conclusion drawn from the gravid females collected from the field. The observed geographical variation in the female reproductive traits could be attributed to the consequence of the effects of either proximate or ultimate factors. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 85 , 27–40.     

蜡皮蜥的两性异形和繁殖输出

为研究蜡皮蜥(Leiolepis reevesii)两性异形和繁殖输出,于2002、2003年4月下旬从海南乐东一种群捕获423头蜡皮蜥。经检测得到繁殖雌体的最小体长为89．0mm,据此判定≥89．0mm的个体为性成熟。研究结果表明：①蜡皮蜥具有两性异形,雄性大于雌性且具有较大的头部。成体雄性头长和头宽随体长的增长速率大于雌性,幼体头长和头宽随体长的增长速率无显著的两性差异。以性别和年龄(成、幼体)为因子的双因子ANOVA比较两性头长和头宽与体长的回归剩余值发现,雄性头部大于雌性,幼体头部相对大于成体。②饲养于实验室的母体中有42头于2002、2003年5月22日～7月16日产出正常卵,这些繁殖雌体具有年产多窝卵的潜力。窝卵数和卵重的变异系数分别为0．18和0．13,前者变异度大于后者。窝卵数、窝卵重和卵重均与母体体长无关。卵重与相对生育力之间无显著的负相关性,表明蜡皮蜥缺乏卵数量与卵大小之间的权衡。相对窝卵重与母体体长呈显著的负相关,表明较小的母体具有相对较大的繁殖输出。因雌体繁殖会滞缓其生长,小母体具有相对较大的繁殖输出,至少部分地解释了雌性蜡皮蜥的成体为什么个体较小。     

Female reproductive characteristics of the Balkan wall lizard (<Emphasis Type="Italic">Podarcis taurica</Emphasis>) in the northwestern periphery of its range

We present data on the female reproductive traits of the Balkan wall lizard in the Deliblato Sand, a large continental sandland in the Pannonian area in the northwestern periphery of the species range. The clutch and egg characteristics of the population were investigated on the basis of clutches laid in laboratory conditions by gravid females captured in one locality. Balkan wall lizards produced at least two clutches in a breeding season. Individual females laid clutches of commonly two (range 1–4) eggs. The female body size had no effect on clutch and egg size. There was no trade-off between egg size and clutch size.     

The trade‐off between clutch size and egg mass in tree swallows Tachycineta bicolor is modulated by female body mass

Egg production is a costly component of reproduction for female birds in terms of energy expenditure and maternal investment. Because resources are typically limited, clutch size and egg mass are expected to be constrained, and this putative trade‐off between offspring number and size is at the core of life history theory. Nevertheless, empirical evidence for this trade‐off is equivocal at best, as individual heterogeneity in resource acquisition and allocation may hamper the detection of the negative correlation between egg number and mass within populations. Here, we investigated how female body mass and landscape composition influences clutch size, egg mass, and the relationship between these two traits. To do so, we fitted linear mixed models using data from tree swallows Tachycineta bicolor breeding in a network of 400 nestboxes located along a gradient of agricultural intensity between 2004 and 2011. Our dataset comprised 1463 broods for clutch size analyses and 4371 eggs (from 847 broods laid between 2005–2008) for egg mass analyses. Our results showed that agricultural intensity negatively impacted clutch size, but not egg mass nor the relationship between these two traits. Female mass, on the other hand, modulated the trade‐off between clutch size and egg mass. For heavier females, both traits increased jointly, without evidence of a trade‐off. However, for lighter females, there was a clear negative relationship between clutch size and egg mass. This work shows that accounting for individual heterogeneity in body mass allows the detection of a clutch size/egg mass trade‐off that would have remained undetected otherwise. Identifying habitat and individual effects on resource allocation towards reproductive traits may help bridging the gap between predictions from theory and empirical evidence on life history trade‐offs.     

中国石龙子雌体繁殖特征和卵孵化的地理变异

浙江丽水和广东韶关中国石龙子均年产单窝卵,窝卵数,窝卵重和卵重均与雌体SVL呈正相关,雌体头部形态,繁殖特征,产卵起始时间和孵孵化的热依赖性等有显著的地理变异;韶关石龙子产卵起始时间为5月中旬,比丽水经子约早两周,韶关石龙子窝卵数较大,卵较小,窝卵重与丽水石龙子无显著差异。韶关石龙子特定SVL的窝卵数比丽水石龙子多2．8枚卵,中国经子卵数量和大小之间有种群间权衡,无种数内权衡,同一种群内卵数量与卵大小无关,孵化温度影响石龙子孵出幼体的一些特征,24℃孵出细幼体比32℃孵出幼体大,躯干发育好,剩余卵黄少,韶关24℃孵出幼体的体重,躯干干重小于丽水幼体,韶关32℃孵出幼体的SVL小于丽水幼体,剩余卵黄大于丽水幼体,表明适宜卵孵化温度范围有地理变异。丽水石龙子卵对极端高温和低温的耐受性较强,适宜卵孵化温度范围较宽。