水热环境对白条草蜥孵化卵和孵出幼体表型特征的影响

用4×2(温度×湿度)八种水热环境孵化安徽滁州琅琊山白条草蜥(Takydromus wolteri)卵,观测孵化卵重量变化、胚胎利用卵内物质和能量以及孵出幼体的特征。卵从孵化环境中吸水导致重量增加,卵重量的增加与入孵卵重量、孵化温度和基质湿度有关。两种孵化基质湿度对孵化期、孵化成功率、孵出幼体性比和大小都无显著影响。孵化期随恒定孵化温度的升高而缩短,27℃、30℃和33℃孵化期分别为32.5、24.9和23.0d,波动温度孵化期为31.1d。33℃孵化成功率最低(42.8%)。温度对孵化成功率和孵出幼体的性别无显著影响,但显著影响胚胎对卵内物质的动用、幼体的大小和重量。33℃不适宜孵化白条草蜥卵,该温度下孵出的幼体躯干小,剩余卵黄多,运动能力差。27℃和波动温度中孵出幼体躯干发育良好,各项被测定的特征指标极其相似。     

Phase-related body-color polyphenism in hatchlings of the desert locust, Schistocerca gregaria: re-examination of the maternal and crowding effects

The mechanism controlling the body color of hatchlings was studied for the desert locust, Schistocerca gregaria. A pheromonal factor secreted by gregarious female adults into the foam plugs of egg pods has been suggested to cause darkening in their progeny. We re-examined the role of this maternal factor by washing or separating eggs at deposition. Eggs produced by crowd-reared female adults were washed with saline or separated individually without being washed immediately after deposition and the body color of the hatchlings from them was compared with that from the eggs unwashed and kept in the egg pod until hatching. Most hatchlings were dark and no significant difference was found in the proportions of dark- and light-colored hatchlings between the treatments and controls. Likewise, eggs separated before the foam plug deposition produced dark-colored hatchlings as in the un-separated controls. These results demonstrated that neither washing nor separation of eggs at deposition affected the hatchling body coloration. The variation in hatchling body color was correlated closely to the body weight at hatching, indicating that hatchling body color had been determined maternally. Green hatchlings reared under crowded conditions remained green until the second stadium at which black patterns were induced. It was concluded that body color at hatching has been determined maternally and crowding during the first nymphal stadium influences nymphal body color but its effect is not manifested until the second stadium. The present study casts doubts on the presence of a recently suggested pheromonal factor on the color of the hatchlings.     

滑鼠蛇的繁殖输出及孵化热环境对孵出幼体表型特征的影响

用15条2002年6月中旬捕自浙江丽水的怀卵滑鼠蛇研究繁殖输出及孵化热环境对孵出幼体表型特征的影响。母体在捕后3周内各产一窝柔性卵。窝卵数、窝卵重和卵大小均随母体体长增加而增大,平均值分别为13．3(枚卵)、332．4g和24．8g。窝卵数和卵大小的变异系数分别为0．18和0．13。窝卵数与产后母体状态呈正相关,卵数量和大小无关。每窝部分可孵卵分别用恒温(24、27、30、33℃)和21．0-39．0℃(平均28．3℃)范围内的波动温度孵化,每隔5d记录恒温孵化卵的重量。孵化热环境对卵与环境之间的水分交换有显著影响,并影响孵化卵重量的时间变化。24、27、30、33℃和波动温度的平均孵化期分别为105．4、78．0、57．8、51．3和58．6d。不同热环境下的孵化成功率和幼体畸形率有一定差别,但统计上不显著。24℃和30℃孵出幼体雄性比例较高,27℃、33℃和波动温度孵出幼体雌性比例较高,但没有证据表明孵化温度能决定滑鼠蛇性别。除孵出幼体灰分含量外,孵化温度对其它幼体特征均有显著影响。33℃孵出幼体SVL较小,但剩余卵黄和其中的灰分含量大于其它温度孵出的幼体。24℃和30℃孵出幼体的总干重、总能量、躯干干重、脂肪体干重总体上小于27℃和波动温度孵出幼体。24℃孵出幼体特征性具有最小的剩余卵黄,33℃孵出幼体则特征性地具有最大的剩余卵黄。24℃和30℃孵出幼体特征较为接近,27℃和波动温度孵出幼体较为接近。对9个幼体特征变量做主成分分析发现,第一和第二主成分共解释81．2％的变异。幼体SVL、湿重、干重、脂肪含量、能量、躯干干重和脂肪体干重在第一主成分有较高的正负载系数(解释56．9％变异),剩余卵黄干重在第二主成分有较高的正负载系数(解释24．3％变异),第一和第二主成分的分值均差异显著。主成分分析进一步显示,24、30和33℃孵出幼体总体上小于27℃和波动温度孵出幼体[动物学报50(4)：541-550,2004]。     

Recolonisation potential of zooplankton propagule banks in natural and agriculturally modified sections of a semiarid temporary stream (Doñana,Southwest Spain)

The viable propagule banks of a temporary stream were studied from sections with different agricultural history. Hatching of zooplankton (copepods, rotifers and cladocerans) was recorded in the laboratory under controlled temperature and light conditions from an agriculturally modified area with average hydroperiods of about a week per year and two semi-natural reference areas with average hydroperiods of more than 3 weeks per year. We found significant differences in both taxon richness and abundance of zooplankton hatching between areas, which were lower in the agriculturally modified section, compared to the reference sections. Another factor likely to have influenced hatching in our experiment was conductivity, which differed between the two reference sections and might have affected hatching at high conductivities. For restoration purposes, hydrological reconnection of stream segments is important to facilitate dispersal from the high diversity upstream segments to the depleted sites downstream.     

产卵于温暖且热稳定巢内的蜥蜴具有相对较高但较窄范围的孵化温度

作者用蜡皮蜥(Leiolepis reevesii)为模型动物,检验产卵于温暖且热稳定巢内的蜥蜴应有相对较高但较窄的孵化温度的假设。卵在三个恒定温度(27、30和33℃)、一个波动温度处理下孵化。温度的平均值而非方差影响孵化期,27、30和33℃的平均孵化期分别为101.1、69.6和55.3d。幼体性别不受孵化温度影响。不同处理孵出的幼体仅有稍许形态差异,但运动表现差异显著。27℃孵出幼体在跑道上的表现比其它处理孵出幼体差。卵能在27℃和33℃下孵化,但这两个孵化温度并不适宜。蜡皮蜥适宜的孵化温度范围可能处于最频繁的巢温变化范围(28℃-32℃)内。与其它在低温生境或温暖生境但产卵于浅巢的有鳞类爬行动物相比较,蜡皮蜥有相对较高但较窄适宜的卵孵化温度。因此,作者的数据支持上述假设。     

不同孵化湿度下的乌龟卵孵化成功率及新生幼体特征

A total of 51 Chinese three-keeled pond turtle Chinemys reevesii eggs were incubated on wet and dry substrates (water potentials of - 12 kPa and - 300 kPa, respectively) at 30℃ to assess the influence of the hydric environments on egg survival and hatchling traits. Eggs incubated in the dry condition lost weight, whereas those incubated in the wet condition did not. The hydric environments did not affect incubation lengths (60.3 vs 60.7 days) as well as hatching successes (69.2% vs 88.0% ). Except for wet body mass and carapace width, which were larger for hatchlings from the -12 kPa treatment than from the -300 kPa treatment, the hydric environments did not affect most hatchling traits. These unaffected traits included dry body mass, carapace length, tail length, limb length, hatehling components (carcass, residual yolk and fat bodies), swimming performance and critical thermal minimum. In conclusion, within the water potential of -12 to -300 kPa, hydric environments have little effect on embryonic development and hatchling traits in Chinese three-keeled pond turtles [Acta Zoologica Sinica 50 (1) : 133 - 136, 2004].     

The variance of incubation temperatures does not affect the phenotype of hatchlings in a colubrid snake, Xenochrophis piscator

It has been documented in some reptiles that fluctuating incubation temperatures influence hatchling traits differently than constant temperatures even when the means are the same between treatments; yet whether the observed effects result from the thermal variance, temperature extremes or both is largely unknown. We incubated eggs of the checkered keelback snake Xenochrophis piscator under one fluctuating (Ft) and three constant (24, 27 and 30 °C) temperatures to examine whether the variance of incubation temperatures plays an important role in influencing the phenotype of hatchlings. The thermal conditions under which eggs were incubated affected a number of hatchling traits (wet mass, SVL, tail length, carcass dry mass, fatbody dry mass and residual yolk dry mass) but not hatching success and the sex ratio of hatchlings. Body sizes were larger in hatchlings from incubation temperatures of 24 and 27 °C compared with the other two treatments. Hatchlings from the four treatments could be divided into two groups: one included hatchlings from the 24 and 27 °C treatments, and the other included hatchlings from the 30 °C and Ft treatments. In the Ft treatment, the thermal variance was not a significant predictor of all examined hatchling traits, and incubation length was not correlated with the thermal variance when holding the thermal mean constant. The results of this study show that the mean rather than the variance of incubation temperatures affects the phenotype of hatchlings.     

安徽宿州山地麻蜥卵孵化温度效应

用3个恒定温度(27、30、33℃)和波动温度(14.0～37.5℃)孵化山地麻蜥(Eremias brenchleyi)卵。结果表明,各温度处理下卵孵化成功率差异不显著,但温度对孵化期、孵出幼体表型特征及疾跑速度有显著影响;27、30℃和波动温度下孵出幼体的SVL、重量及躯干干重比33℃的要大,33℃孵出幼体的运动能力比其他3个温度处理弱。波动温度处理下山地麻蜥卵虽短期经历潜在致死的极端温度,但对孵化成功率、孵出幼体表型特征和运动表现均无负效应。     

Fuel use and corticosterone dynamics in hatchling green sea turtles (Chelonia mydas) during natal dispersal

During their natal dispersal hatchling sea turtles depart their nest, beach and inshore areas quickly to move into offshore developmental habitat using their finite energy stores. Patterns of fuel use and endocrine responses that could facilitate hatchling sea turtle dispersal activity are poorly understood. This study, examined aspects of intermediary metabolism by measuring plasma fuel use and an endocrine response of hatchling green turtles (Chelonia mydas) during terrestrial and aquatic activity coinciding with natal dispersal. Specifically, we measured plasma concentrations of glucose, non-esterised free fatty acids and protein to gauge the contributions of carbohydrate, lipid and protein metabolism for fuelling natal dispersal. In addition, we measured plasma levels of the steroid hormone corticosterone (CORT) a hormone implicated in regulating a number of metabolic events associated with migration and energy use in vertebrates. During terrestrial activity, hatchlings ascended through the sand from their nests and exhibited significant increases in plasma CORT and lactate indicating intense periods of anaerobic activity. During swimming, all plasma metabolites, with the exception of plasma protein, peaked between 1 and 4 h post-beginning swimming activity. Plasma CORT peaked at between 3 and 5 h of swimming activity. These plasma concentrations are consistent with intensive activity inducing catabolism of carbohydrate, lipid and protein stores to support prolonged activity. These results are similar to other vertebrates and suggest a relatively uniform cascade of physiological processes during such arduous migratory events.