横纹金蛛多次产卵生物量分配初步研究

卵袋是雌蛛产卵、若蛛孵化等繁育后代的保护性场所.常见农林蜘蛛横纹金蛛(Argiopebruennichi)一般一生产卵3～6次,织制卵袋3～6个.本文对横纹金蛛的体重、卵袋生物量、卵粒数与卵粒重进行了测试研究.结果表明,随着产卵次数增加,产卵间隔时间更长,但雌蛛产卵后至下一次产卵前生物量的增量在减少,而对卵袋生物量的投...     

Egg yolk plasma can replace egg yolk in stallion freezing extenders

Hen egg yolk is normally used as a cryoprotective agent in semen freezing extenders, but its use has sanitary and practical disadvantages. Moreover the protection afforded by egg yolk has not yet been completely elucidated. The objective of this study was to compare the egg yolk plasma fraction to whole egg yolk in stallion freezing extender. Plasma contains mainly Low Density Lipoproteins (LDL), which are widely presumed to be the cryoprotective agent in egg yolk. Plasma can be produced on an industrial scale, sterilised by gamma-irradiation and incorporated in a ready-to-use extender (our ultimate objective). Plasma samples were subjected to different doses of gamma-irradiation (3, 5, 10 kGy) without dramatic chemical changes that may affect their cryoprotective properties. Stallion semen was frozen with whole egg yolk as a control and with sterilised egg yolk plasma. A fertility trial was conducted on a total of 70 mares' cycles. Fertility per cycle was 60% after insemination of semen frozen in our control extender containing egg yolk (EY), compared to 69% for the extender containing sterilised egg yolk plasma (EYP) (P > 0.05). Post-thaw motility and membrane integrity of spermatozoa were also analysed. Motility parameters were not significantly different between extenders except for the variable VAP (for EY versus EYP, VAP: 63 μm.s⁻¹ versus 59 μm.s⁻¹, a, b: P < 0.001; PROG: 41% versus 39%, RAP30: 56% versus 54%; RAP40: 51% versus 48%, P > 0.05). Membrane integrity was better preserved in EY than in EYP but the difference between extenders was small (P < 0.05). Our results demonstrated that sterilised egg yolk plasma has the potential to replace egg yolk in stallion freezing extender. This experiment led to the development of a ready-to-use extender called INRA-Freeze^® (IMV-Technologies, France).     

Species identity of geographically distinct populations of the glassy-winged sharpshooter parasitoid Gonatocerus ashmeadi: morphology, DNA sequences, and reproductive compatibility

Gonatocerus ashmeadi is a common and seemingly widespread egg parasitoid of Homalodisca coagulata, the glassy-winged sharpshooter (GWSS). Location records for G. ashmeadi indicate its natural range to be the southeastern USA and northeastern Mexico (which coincides with the presumed native range of GWSS), and possibly southern and central California (CA) (the adventive range of GWSS). The purpose of our work was to determine whether G. ashmeadi in the USA and northeastern Mexico is one species or a complex of reproductively incompatible sibling species. We used three approaches to determine the species identity of different G. ashmeadi populations: (1) reassessment of key morphological features using scanning electron microscopy (SEM) to determine if subtle morphological differences exist between G. ashmeadi populations which could indicate species differences; (2) to determine if molecular differences exist between G. ashmeadi populations collected from different regions by comparing mitochondrial and ribosomal DNA sequences; (3) mating compatibility studies to determine if different populations of G. ashmeadi are reproductively isolated, or if mating occurs, whether offspring are viable thereby defining species groups on the basis of successful interbreeding. Results from these three areas (morphology, DNA sequences, and reproductive compatibility) have been evaluated collectively; leading us to the conclusion that G. ashmeadi as it is currently viewed is a valid species and not an aggregate of morphologically indistinguishable cryptic species.     

Host suitability and thermal requirements of Lathromeris ovicida Risbec (Hymenoptera: Trichogrammatidae), an egg parasitoid of cereal stemborers in Africa

Factors affecting the bionomics of the trichogrammatid egg parasitoid Lathromeris ovicida and its association with the two sympatric scelionid egg parasitoids Telenomus busseolae and Telenomus isis were studied in the laboratory. The potential host species employed were the noctuids Sesamia calamistis and Sesamia botanephaga, and the pyralids Eldana saccharina and Mussidia nigrivenella. Using eggs of S. calamistis Hampson as hosts, the lower and upper thresholds for development were estimated at 14.8 and 34 °C, respectively. The percent parasitism, total progeny, and sex ratio decreased gradually from 42.0 to 10.2, from 56.4 to 10.8, and from 0.74 to 0.61, respectively, with host age. The intrinsic rate of increase and female fecundity was highest on the two noctuids, followed by E. saccharina and M. nigrivenella. Lathromeris ovicida preferentially attacked eggs already parasitised by either Telenomus busseolae or Telenomus isis. Thus, L. ovicida is probably a facultative hyperparasitoid.     

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].     

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]。     

A test of three hypotheses for ovariole number determination in the grasshopper Romalea microptera

Ovariole number in insects determines potential fecundity and can be influenced by genes, environmental conditions during development and parental effects. In the present study, three hypotheses are tested for ovariole number determination in the grasshopper Romalea microptera (Beauvois), which exhibits both intra‐ and interpopulation variation in ovariole number. In hypothesis 1, variation in ovariole number is a result of genetic variation. In hypothesis 2, ovariole number is influenced by nutrition during development. In hypothesis 3, ovariole number is influenced by maternal nutritional status. Females from four treatments are compared: low‐food, high‐food, daughters of low‐food, and daughters of high‐food. There is a relationship between parent and offspring ovariole number despite different environments, supporting hypothesis 1. Also, ovariole numbers are slightly, but significantly lower in individuals fed a low‐food diet compared with a high‐food diet, supporting hypothesis 2. Hypothesis 3 is not supported: starved and well‐fed females produce eggs of similar mass, as well as offspring with similar numbers of ovarioles, suggesting that the nutritional status of mothers does not influence offspring mass or offspring ovariole number. The results imply that genetic variation and developmental conditions determine ovariole number in this species but maternal environment does not. These results conflict with previous studies of ovariole determination in grasshoppers and locusts.     

维生素B12对萼花臂尾轮虫种群的影响

温度为15℃时,添加20,40,80和100μg/mL维生素B12后,萼花臂尾轮虫(Brachionuscalyciflorus)种群密度随时间增加而增长,其回归方程依次为:y=e(0.1757+0.2974x),y=4.6765x1.2079,y=7.7798x1.0175和y=e(0.6117+0.3469x),密度显著高于对照组(t=4.56,8.15,8.53和9.86;P1.4366,y=7.7461x1.6533,y=6.3611x1.7790和y=9.064x1.6872,对照为y=7.5902x1.50192。各添加组的密度均显著高于对照组(t值分别为16.12,10.17,5.83和5.86;P(0.1376+0.4395x),y=e(0.2032+0.4856x),y=3.4615x1.9522和y=e(0.0220+0.48074x)。对照组除了和20ng/mL组间没有统计差异外(t=0.34,P>0.05),其他各实验组密度显著高出对照组(t值分别为3.66,10.23和2.13)。最高混交率分别为18.18%,7.60%,18.18%和16.67%,对照为66.70%。最大卵雌比依次为0.70,1.90,0.91,1.09,对照组为0.95。       

不同克隆萼花臂尾轮虫的后代质量及其相关因素分析

在4个温度(15 ℃、20 ℃、25 ℃和30 ℃)下对4个不同生化遗传特征的萼花臂尾轮虫克隆(A、B、C和D)所产幼体的耐饥饿时间及其与温度、轮虫个体大小和卵大小等的关系进行研究.结果表明,15 ℃下克隆B幼体耐饥饿时间最短,为45.67 h;20 ℃和25 ℃下克隆C幼体耐饥饿时间均最长,分别为61.33 h和72.01 h;30 ℃下克隆A幼体耐饥饿时间最长,为40.11 h.4个温度间,克隆A轮虫幼体的耐饥饿时间在15 ℃下最长,克隆B和C轮虫幼体的耐饥饿时间在30 ℃下均最短,克隆D轮虫幼体的耐饥饿时间随培养温度的升高而逐步显著缩短.4个克隆轮虫的幼体耐饥饿时间均与温度呈显著负相关关系.克隆A轮虫的幼体耐饥饿时间还与卵体积呈显著负相关,克隆C相反;克隆B和克隆D轮虫幼体耐饥饿时间与个体体积呈显著正相关关系.