天然次生林群落中刺五加种群生态学的研究 Ⅲ 刺五加种群生殖力表的编制与分析

本文以无性系小株为基础,编制了无性系植物刺五加种群的生殖力表,计算并分析了刺五加种群的几个重要生殖参数。最后,对一般植物种群的生殖力表的编制进行了讨论。     

Insecticide-induced resurgence of the whitebacked planthopper Sogatella furcifera (Horvath) (Hemiptera: Delphacidae) on rice varieties with different levels of resistance

The influences of the insecticides quinalphos, chlorpyriphos, methyl parathion, endosulfan, imidacloprid and deltamethrin applied three times at 10 days intervals at half of their recommended field concentrations to potted plants of a planthopper-susceptible and a planthopper-resistant rice variety, on reproduction and survival of whitebacked planthopper, Sogatella furcifera (Horvath), and on the chemistry of its host plant, were investigated. Methyl parathion, deltamethrin and quinalphos enhanced the fecundity of the hopper (164-211 vs. 131 for the control) and consequently the resurgence ratio (increased up to 1.75 fold). Methyl parathion and deltamethrin significantly increased nymphal survival (59.3 vs. 52.2% for the control) and the growth index (4.8 vs. 4.2 for the control) of the hopper. The sex ratios of adults emerging on methyl parathion- and deltamethrin-treated rice plants increased in favour of females (1.51 vs. 1.15 for the control) on the susceptible variety but was not altered on the resistant variety. Biochemical analyses of the rice leaves revealed significantly higher quantities of reducing sugars, proteins and amino acids, but lower amounts of total phenols in leaf sheaths and blades of methyl parathion-, deltamethrin- and quinalphos-treated plants of the two varieties. The leaf sheaths and blades of the resistant variety contained more than twice the total phenols present in those of the susceptible variety. The results showed a positive correlation between increased levels of reducing sugars, amino acids and proteins in the rice plants and the fecundity of S. furcifera and a negative correlation between phenol contents of the rice plants and fecundity.     

Ruffed grouse population dynamics in the central and southern Appalachians

Ruffed grouse (Bonasa umbellus; hereafter grouse) populations in the central and southern Appalachians are in decline. However, limited information on the dynamics of these populations prevents the development of effective management strategies to reverse these trends. We used radiotelemetry data collected on grouse to parameterize 6 models of population growth to: (1) determine the pattern of growth in these populations, and (2) identify the demographic rates most important to growth. Trend estimates from population models were most similar to trend estimates derived from Breeding Bird Survey and Christmas Bird Count data when models incorporated either a reproductive or survival event. These events randomly increased fecundity or survival, respectively, to their empirical maxima on average once every 5 years. Reproductive events improved estimates on areas dominated by mixed mesophytic forest, while survival events characterized population growth on oak (Quercus spp.)-dominated sites. The finite rate of increase (λ) was most sensitive to brood survival followed by adult and juvenile non-breeding survival on most sites. However, brood survival was low (<0.35 female chicks/hen survived to week 5), and elasticity analyses indicated λ responded more strongly to proportionate change in non-breeding and breeding survival rates of adults and juveniles than any reproductive variable. Life stage analyses corroborated this result. At baseline values, survival of adults and juveniles may be the main determinants of growth in these populations, and reproduction may not be adequate to compensate for these losses. Therefore, population growth above baseline levels may be regularly needed to restock these populations. Researchers have hypothesized that population dynamics may differ between mixed mesopytic and oak-dominated sites due to differences in forage quality and quantity. Thus, a potential mechanism for the increases in λ needed to sustain populations on mixed mesophytic forest sites is the greater fecundity observed during years with high oak or beech (Fagus grandifolia) mast abundance. The availability of this high quality forage allows hens to enter the breeding season in better condition and realize higher fertility. Alternatively, on oak-dominated sites, population growth increases may also be a product of higher non-breeding survival of birds in mast years, when birds do not need to range as far to forage and can limit their exposure to predators.     

Woodpeckers increase in abundance but maintain fecundity in response to an outbreak of mountain pine bark beetles

Many temperate woodpecker species are thought to be highly conservative in their fecundity with little response to fluctuations in availability of resources. In a 15-year field study in interior British Columbia, we evaluated responses in abundance and fecundity of six species of resident and migrant woodpeckers (downy woodpecker [Picoides pubescens], hairy woodpecker [Picoides villosus], American three-toed woodpecker [Picoides dorsalis], pileated woodpecker [Drycopus pileatus], northern flicker [Colaptes auratus], and red-naped sapsucker [Sphyrapicus nuchalis]) to a large-scale outbreak of mountain pine bark beetles that resulted in a strong positive pulse in food supply. Population densities of woodpecker species increased during outbreak years. Despite the year-round multi-annual increase in food resources, and in contrast to the strong increases in fecundity shown by nuthatches and chickadees, annual fecundity (as indicated by clutch size and number of nestlings that fledged) did not change for any woodpecker species over the study. Similarly, we found no changes in fecundity in response to selective forest harvesting despite numerical increases for woodpeckers at these sites. Our study confirms that these woodpecker species are conservative in their reproductive investment patterns even during strong multi-annual increases in food. Our findings indicate woodpecker populations are regulated numerically through variable survival and/or greater immigration rates, which can result in higher breeding densities temporarily during resource pulses.     

批次化生产与定时输精对母猪利用率的影响

文章主要探讨批次化生产与定时输精技术对母猪利用及淘汰的关系。结果显示,2019-2020年该场母猪淘汰率为36.63%,而0-2胎占全部淘汰母猪比例的65.76%。结果表明,批次化生产和定时输精确实有利于生物安全防控,提高工作效率,但储备大量后备猪是必要前提。     

玉米截形叶螨实验种群生殖力表

在28℃±0.5℃的条件下,应用叶盘法组建了玉米截形叶螨实验种群生殖力表。结果表明,截形叶螨各螨态发育历期分别为:卵3.56d～3.77d,幼螨2.08d～2.52d,若螨2.15d～3.44d,成螨16.85d～21.00d;完成1代需8.00d～10.52d,寿命24.85d～32.76d。t检验表明,除卵期、幼螨期外,雌螨和雄螨在其它虫态历期间均存在显著(t0.05=2.03,df=36,p<0.05)或极显著(t0.01=2.72,df=36,p<0.01)的差异。单雌总产卵量为89.72粒,日均产卵量5.64粒;雌成螨羽化后平均1.24d开始产卵,产卵率曲线表现为单峰型,日均产卵率在羽化后6d～10d达到高峰,此后迅速下降。截形叶螨在玉米上的存活曲线属于Ⅰ型曲线,死亡多发生于发育后期;净增殖率(R0)为37.5628,周限增长率(λ)为1.2221,内禀增长率(rm)为0.2006,世代平均周期(T)为18.0755d,种群加倍时间(DDP)为3.4554d。     

蚕豆上南美斑潜蝇的成虫寿命及繁殖力研究

 在恒温20.1 ℃,RH 48.9%的条件下,用蚕豆苗和用吸足15%的蔗糖水的棉球饲养南美斑潜蝇,测得雌、雄成虫的最长寿命、平均寿命及在蚕豆苗上的最高产卵量、平均产卵量。15%蔗糖水棉球饲养雌、雄成虫最长寿命及平均寿命是17 d,7 d,5.3 d,3 d。蚕豆苗饲养雌、雄成虫的最长寿命及平均寿命分别是19 d,6 d,10.6 d,3.5 d。在相同条件下,测得每对成虫在蚕豆苗上的最多产卵量及平均产卵量分别是316粒、214.5粒;产卵的高峰期是羽化的6～9 d。     

饵料对鲎虫生长·寿命·生殖的影响

[目的]探索不同饵料对鲎虫生长、寿命、生殖的影响。[方法]用7类饵料投喂鲎虫幼体进行饲养试验,研究鲎虫背甲长、相对增长率、特定生长率、寿命、产卵量。[结果]不同饵料饲养条件下,雌性个体背甲长为6.1～9.8mm、相对增长率为113.9%～302.9%、特定生长率为0.043%/d～0.067%/d、寿命为15.5～33.8d、产卵量为51.7～457.5;雄性个体背甲长为5.3～8.9mm、相对增长率为141.6%～267.5%、特定生长率为0.038%/d～0.055%/d、寿命为18.8～34.7d。3种饵料混合组背甲长、相对增长率、寿命、产卵量最高,其次为2种饵料混合组、单一饵料组。[结论]投喂不同饵料对鲎虫幼体的生长、寿命、产卵量影响显著。     

芦笋饲养甜菜夜蛾对其种群生长发育、繁殖力和存活的影响

研究了室内以芦笋为饲料饲养对甜菜夜蛾生长发育、繁殖力和存活的影响。结果表明,取食芦笋的甜菜夜蛾幼虫历期显著缩短1.72d,历期的天数主要集中在13d左右;蛹历期差异不显著,蛹重显著减少34.2mg,羽化率下降1.07%;雄成虫的平均寿命增加约1.47d,总的产卵前期长了0.82d;单雌产卵量下降了196.06粒,成虫雌雄比率分别为1：1.22和1：0.82;幼虫、蛹、成虫的存活率均下降;种群参数中内禀增长率分别为0.14和0.21,说明甜菜夜蛾种群数量都为上升趋势,但以芦笋饲养的种群上升趋势显著慢于人工饲料种群。     

寄主龄期对马尼拉陡胸茧蜂繁殖力和寿命的影响

研究了甜菜夜蛾和斜纹夜蛾不同龄期对马尼拉陡胸茧蜂繁殖力、寿命的影响。结果表明,马尼拉陡胸茧蜂寄生甜菜夜蛾和斜纹夜蛾2龄幼虫时,繁殖力最高;当寄主虫龄大于2龄时,马尼拉陡胸茧蜂繁殖力随着虫龄的增大而降低。在寄生甜菜夜蛾和斜纹夜蛾的各个龄期中,马尼拉陡胸茧蜂的雌蜂寿命均长于雄蜂寿命。在寄生甜菜夜蛾和斜纹夜蛾2龄幼虫时,雌雄蜂寿命均最长;随着龄期的增长,雌雄蜂寿命逐渐缩短。