麦双尾蚜发生数量与小麦播种期的关系

新疆伊犁和塔城冬、春麦田的麦双尾蚜Diuraphis noxia (Mordvilko) 有虫株率和百株蚜量,与小麦播种时间密切相关。在小麦正常播种期内,冬小麦晚播可以显著减少麦双尾蚜数量,每晚播种10天,第二年麦双尾蚜有虫株率可以下降40%～70%;春小麦每晚播种10天,麦双尾蚜有虫株率增加30%～88%。     

不同湖泊演替过程中浮游动物数量及多样性的研究

作者对长江中下游的湖北省保安湖的扁担塘、桥墩湖区、青菱湖的有草区(称南青菱湖)和无草区(称北青菱湖)及黄家湖等五个湖泊(区)浮游动物的种类组成、密度、多样性进行了研究。扁担塘常见浮游动物104种,桥墩湖107种,南青菱湖89种,北青菱湖73种,黄家湖88种,浮游动物的种类均随着水草生物量的减少而下降。浮游动物的密度均随着水草生物量的减少而增多。上述湖泊(区)浮游动物无论是种类组成还是密度均以小型的原生动物和轮虫占绝对优势。浮游动物多样性指数的变化与水草的丰度密切相关。随着湖泊水草生物量的增加,浮游动物的多样性指数也随之而增加。       

甘肃省冬小麦生长发育对暖冬现象的响应

运用甘肃省天水、西峰两地1951-2005年的气温资料及天水、西峰农业气象试验站1981-2003年冬小麦物候观测资料,分析探讨了甘肃冬小麦种植区50多年的冬季气温变暖趋势及冬小麦生长发育过程对气候变暖的响应．结果表明：冬季气温升高对冬小麦生长发育产生了较大影响．在最近20多年,冬小麦越冬死亡率下降到2％以下,越冬天数减少了7～8d,整个生育期缩短8～10d,返青一开花期天数延长7d,这有利于冬小麦生产及气候资源的利用-同时,冬季气温升高及降水减少也使冬小麦产量稳定性变差,麦田病、虫危害发生率增加,给冬小麦的安全生产增加了不确定因素．     

高家镇旧石器遗址1998年出土的石制品

高家镇遗址是三峡地区一处重要的旧石器时代遗址。遗址埋藏于长江右岸第Ⅲ级基座阶地内。1995年和1998年经过两次发掘,揭露面积456m2,出土石制品2500余件,其中1998年在B区发掘出土石制品719件。石制品类型包括石器、石核、石片和断块等。古人类选取河卵石为原料运用锤击法剥片和加工石器;石器以大型为主,毛坯多为石核和完整石片,砍砸器是石器的主要类型;石器加工较简单,多数单向加工。石器工业具有中国南方旧石器时代主工业鲜明特点。地貌和地层对比,显示该遗址可能与冉家路口遗址同时,处于中更新世晚期。     

Characteristics of the Later Hoocene Epoch Sporo-pollen Assemblage and Their Significance in Dabusu Lake,Qianan County,Jilin Province

According to the sporo-pollen analysis of the ten localities in Dabusu lake, it could be divided into two sporo-pollen assemblage zones from bottom to top: the lower series (1–2 bed) of Equisetum, lsoites sporo-pollen zone and upper series (3–6 bed) of Ranunculaceae, Chenopodiaceae, Aritemisia sporo-pollen zone. This paper deals also with the course that in the middle later period of the later Holocene Epoch the obvious change of paleogeographic environment is no less than twice in the area surounding Dabusu lake. As for the vegetation, the wet grassy marshland of temperate zone in which the pteridophyta Predominated turned towards meadow -steppe in which herbs predominated. While the wet climate turned towards arid climate and the fresh water lake turned towards salt lake.     

Study on the Fossil Woods Found in Zigong,Sichuan, China

This paper describes three fossil woods, which were firstly found in Zigong city, Sichuan Province, China. The localities of the fossil woods are close to the locality of the famous Dashanpu dinosaur quarry of Zigong. The strata of the fossil woods beating are Xiashaximiao Formation and Xintiangou Formation of the Middle Jurassic, approximately match the strata of the Dashanpu dinosaurs. According to the structures of the secondary xylem, the fossil woods belonged to the primitive conifer genus-Araucarioxylon. Because it was comparatively and obviously different from the other species in this genus, it is assigned as a new species: A. zigongensis. As there was neither fossil leaf nor fossil pollen or spore found in the dinosaur bearing strata before, the discovery of these fossil woods might bear some important significance in the dinosaur research.     

Change of Sulfur Content in the Bark and Its Application in Monitoring the Air SO2 Pollution in Winter

The sulfur content in different parts of the twig the same year is different, i.e. leaf bark wood. Variation exists in different tree species in seasons and appears to be in positive retation with atmospheric SO2 concentration. The bark of hibernal twig of the deciduous leaves possesses significant capacity of sulfur absorption which is interrelated with the total opening of lenticelle and is also influenced by the surface structure of stems as well. This paper presents a regression equation and a calculation chart for monitoring SO2 pollution by sulfur content detected in the bark in winter at some regions in Shenyang. The results are in concert with those determinated by the physical-chemical methods.     

Foraging ecology drives social information reliance in an avian eavesdropping community

Vertebrates obtain social information about predation risk by eavesdropping on the alarm calls of sympatric species. In the Holarctic, birds in the family Paridae function as sentinel species; however, factors shaping eavesdroppers' reliance on their alarm calls are unknown. We compared three hypothesized drivers of eavesdropper reliance: (a) foraging ecology, (b) degree of sociality, and (c) call relevance (caller‐to‐eavesdropper body‐size difference). In a rigorous causal‐comparative design, we presented Tufted Titmouse (Baeolophus bicolor) alarm calls to 242 individuals of 31 ecologically diverse bird species in Florida forests and recorded presence/absence and type (diving for cover or freezing in place) of response. Playback response was near universal, as individuals responded to 87% of presentations (N = 211). As an exception to this trend, the sit‐and‐wait flycatcher Eastern Phoebe (Sayornis phoebe) represented 48% of the nonresponses. We tested 12 predictor variables representing measures relevant to the three hypothesized drivers, distance to playback speaker, and vulnerability at time of playback (eavesdropper's microhabitat when alarm call is detected). Using model‐averaged generalized linear models, we determined that foraging ecology best predicted playback response, with aerial foragers responding less often. Foraging ecology (distance from trunk) and microhabitat occupied during playback (distance to escape cover) best predicted escape behavior type. We encountered a sparsity of sit‐and‐wait flycatchers (3 spp.), yet their contrasting responses relative to other foraging behaviors clearly identified foraging ecology as a driver of species‐specific antipredator escape behavior. Our findings align well with known links between the exceptional visual acuity and other phenotypic traits of flycatchers that allow them to rely more heavily on personal rather than social information while foraging. Our results suggest that foraging ecology drives species‐specific antipredator behavior based on the availability and type of escape cover.