Less input same output: simplified approach for population size assessment in Lepidoptera

With the aim of creating a simplified sampling scheme that would retain the accuracy of standard mark–release–recapture (MRR) sampling, but at a greatly reduced cost, we analysed 23 capture–recapture data sets from spatially closed populations of six Lepidoptera species according to the constrained Cormack–Jolly–Seber models. Subsequently the relationships between the estimates of population parameters were investigated in order to develop a regression equation that would enable us to calculate seasonal population size without sampling the population throughout the entire flight period. The proportion of individuals flying at peak population was highly variable (CV=0.39), but the variation decreased considerably (CV=0.14) after different life span and flight period length were accounted for. Over 90% of the variance of this proportion was explained by the life span:flight period length ratio. Simulations of hypothetical sampling schemes proved that schemes covering the second and third quarter of the flight period performed much better than those restricted to the second quarter only. The accuracy of seasonal population size estimated with the regression equation developed was comparable for intensive schemes (daily sampling) and non-intensive ones (sampling once in 2 or 3 days). We propose a simplified method of surveying butterfly populations that should be based on checking the presence of flying adults at the beginning and end of the flight period to assess its length, and MRR sampling covering its middle part, with intervals between capture days corresponding to the average life span of investigated butterflies.     

栽培川西獐牙菜中6种药用成分的测定方法和动态积累研究

采用反相高效液相色谱法对川西獐牙菜中6种药用成分不同生长期的含量进行了测定.色谱柱为Kro-masilC18 250mm×4.60mm,5μm ,流动相为甲醇-0.02%的磷酸水溶液,检测波长260nm.该方法具有很好的线性关系和回收率.结果显示,川西獐牙菜全草的最佳采收期为9月中旬 花果期 .     

土壤水分对温室春黄瓜苗期生长与生理特性的影响

以津优1号黄瓜为试验材料．研究了土壤不同水分含量对温室春黄瓜苗期生长与生理特性的影响。结果表明,在土壤水分为田间持水量90％时．黄瓜幼苗长势健壮,茎粗大,根系活力强,叶绿素含量和光合速率高．与其它处理差异显著,说明土壤含水量过高或过低均不利于培育黄瓜壮苗。株高和叶面积随土壤含水量的升高而增加;细胞汁液浓度随土壤含水量的升高而降低．且对植株水分状况反应十分敏感,可以用来作为判断植株水分盈亏状况的生理指标。     

Testing predictions of the critical period for survival concept using experiments with stocked Atlantic salmon

Two separate field experiments were performed in the U.S.A. and Norway with stocked Atlantic salmon Salmo salar . In the Norwegian experiment, the offspring of early‐spawning fish which had larger eggs and emerged a few days before offspring of later spawning fish had consistently higher survival rates. In the U.S.A. experiment, stream sections with higher proportions of favourable foraging locations during the critical period (the transition from dependence on maternally‐derived yolk reserves to independent feeding) had lower loss rates of fish stocked as unfed fry. These results provide support for the critical period concept (CPC) in Atlantic salmon, underscores the utility of a manipulative approach to achieve further advances in knowledge of Atlantic salmon ecology and provide additional guidance to management and restoration. A mechanistic, conceptual model for density dependence is presented to identify important knowledge gaps that remain to further evaluate the importance of the CPC for Atlantic salmon population regulation.     

Phylogeography of five Polytrichum species within Europe

Using allozymes and microsatellites we have analysed the genetic structure among European populations for several Polytrichum species to infer relevant factors, such as historical events or gene flow, that have shaped their genetic structure. As we observed low levels of genetic differentiation among populations, and no decreasing levels of genetic variation with increasing latitude within most of the examined species, no genetic evidence was obtained for a step-wise recolonization of Europe from southern refugia after the latest glacial period for P. commune , P. uliginosum , P. formosum and P. piliferum . The near absence of population substructuring within these species does indicate that extensive spore dispersal is the most important factor determining the genetic structure among European Polytrichum populations. Gene flow levels have apparently been sufficient to prevent genetic differentiation among populations caused by genetic drift, and to wipe out any genetic structure caused by the postglacial recolonization process. On the other hand, increased genetic differentiation of alpine P. formosum populations suggests that mountain ranges might restrict gene flow significantly among Polytrichum populations. In contrast to most examined Polytrichum species, P. juniperinum showed high levels of genetic differentiation and a profound genetic structure. Assuming that gene flow is not more restricted in P. juniperinum , these findings suggest that this species has recolonized Europe after the latest glacial period from two different refugia, one possibly being the British Isles.  © 2003 The Linnean Society of London, Biological Journal of the Linnean Society 2003, 78, 203–213.     

Early sea mortality of mark-recaptured juvenile chum salmon in open coastal waters

Estimates of instantaneous mortality rate of mark-recaptured chum salmon Oncorhynchus keta juveniles in coastal waters of the Sea of Japan ranged from 0·033 to 0·268 day⁻¹ in the 14–43 days after release. High mortality rate may have been caused by size-selective mortality or poor ability to adapt to the coastal environment inhabited by chum salmon juveniles soon after release. The results indicated that large-scale mark-recapture experiments are useful for estimating mortality during the early sea life that is considered to be a critical period for Pacific salmon.     

Maturation, spawning and growth of rock soles off Kodiak Island in the Gulf of Alaska

Northern rock sole Lepidopsetta polyxystra females from the Kodiak Island area, Alaska, reached 50% maturity at 328 mm L _T and an average age of 7 years. In contrast, southern rock sole Lepidopsetta bilineata females reached 50% maturity at 347 mm L _T and an average age of 9 years. Spawning started in midwinter for northern rock sole and peaked during the spring, while spawning for southern rock sole occurred during the summer. The bottom depth for spawning northern rock sole ranged from 43 to 61 m and averaged 45 m; spawning depth for southern rock sole ranged from 35 to 120m and averaged 78m. Both species appeared to develop a single stock of oocytes and to ovulate them in a single spawning. Northern rock sole females grew faster overall ( K =0.24) than southern rock sole females ( K =0.12) but reached a smaller maximum length ( L _∞=430 mm) than southern rock sole ( L _∞=520mm). Males of both species grew more slowly than females after 5 years of age and reached a smaller maximum length.     

Modifications of Visual Evoked Potentials in Patients with Glaucoma

We compared the visual evoked EEG potentials (VEP) elicited by presentation of a reversal chess pattern in patients with glaucoma and in the control group. Amplitudes, peak latencies of the main VEP components (N75, P100, and N145), interpeak intervals, and interpeak magnitudes were measured, and a spectral analysis of the averaged VEP was performed. In patients suffering from glaucoma, the latencies of the N75 and P100 components were greater, while the interpeak intervals P100-N145 and N75-N145 were shorter, than those in the control group. Glaucoma-related changes in the VEP spectral characteristics, in particular a drop in the spectral power of oscillations corresponding to the alpha rhythm, were observed.     

Domestic burnt offerings and sacrifices at Roman and pre-Roman Pompeii, Italy

Excavations below the A.D. 79 destruction levels in two houses at the Roman town of Pompeii, Italy included programmes of sieving and flotation for the recovery of biological remains. In addition to the usual finds of charred plant material and bones representing crop processing or food waste, and mineralised remains from sewage, were numerous burnt offerings. Cones and seeds of stone pine, fruit such as fig and grape and nuts such as walnut and hazel were present in many of them. Some of the offerings contained burnt bone, with the heads and feet of cocks (male domestic fowl) being particularly well represented. There was some change in the plants and animals used for the burnt offerings with time. These offerings could be related to domestic worship described in literary sources and depicted as offerings on altars in Pompeiian wall paintings at shrines to the Lares (household gods). The burnt offerings resulted in the preservation by charring of fruit that are not usually burnt during their processing for consumption. They also presented a taphonomic problem because re-worked charred material from burnt offerings was likely to have been a major component of other charred assemblages from the sites. Received November 22, 2001 / Accepted February 26, 2002