CHROMOSOME NUMBERS OF SOME EAST AFRICAN GRASSES

Chromosome numbers of 133 collections of grasses belonging to 51 genera and 105 species are reported here for material from East Africa. These include first counts for 5 genera and 51 species. The basic chromsome number of x = 6 has been found in Sporobolus; x = 10 in Loudetia and x = 13 in Pentaschistis have been confirmed. It is pointed out that chromosomes of Eragrostis vary considerably in size. The genera Harpachne, Commelinidium, Acritochaete, Pseudechinolaena and Exotheca, which are cytologically examined for the first time, have chromosomes with the socalled “panicoid” features, viz., chromosomes with small size and x = 9 or 10.     

SOARING BEHAVIOUR AND PERFORMANCE OF SOME EAST AFRICAN BIRDS, OBSERVED FROM A MOTOR-GLIDER

Various species of soaring birds were studied by following them in a motor-glider, mainly over the Serengeti National Park, Tanzania. The characteristics of thermal convection in the study area are described in general terms. The two vulture species of the genus Gyps live by scavenging among the herds of migratory ungulates, especially Wildebeest. They are not territorial, and gather in large numbers on kills. When raising young they may be obliged by game movements to forage at long distances from their nests. Their cross-country performance is adequate for a foraging radius of over 100 km in dry-season conditions. Their ability to compete with Spotted Hyaenas is thought to depend partly on this factor and partly on an advantage in arriving early at kills. These two species appear to find food more by watching other vultures than by searching for it directly. The Lappet-faced and White-headed Vultures are thought to be sedentary, and to depend on thorough searching of a fixed foraging territory, rather than on following migratory game. They have lower wing loadings than the Gyps vultures, and were not seen cross-country flying. They never gather in large numbers. The Hooded Vulture is a solitary nester, but it does fly across country, and does gather at kills. Vultures soar individually, and seem to be good at exploiting such phenomena as thermal streets. They do not travel in flocks. Tawny and Martial Eagles react positively to the glider, and are suspected of regarding it as potential prey. White Storks migrate between Europe and Africa, and also travel about within East Africa, by thermal soaring. They soar in flocks, and unlike vultures rely on co-ordinated social behaviour to locate thermals. In choosing their route, they often fail to react to obvious weather signs. They enter cumulus clouds from the bottom when thermalling, but probably do not climb far above cloudbase. Marabou Storks soar individually, but also sometimes travel in flocks. When doing so, they show less lateral spreading than White Storks, which reduces the effectiveness of the flock as a thermal-finding unit; on the other hand, they do seem to react to visible weather signs, like vultures or glider pilots. White Pelicans, which travel by thermal soaring between different lakes in the Rift Valley, show the most highly co-ordinated social soaring behaviour. Unlike White Storks, they fly in formation even when circling. Storks and pelicans showed more signs of alarm when approached by the glider than did the vultures or birds of prey. This could be due to their being preyed upon in flight, for instance by Martial Eagles. The basis of conventional thermal cross-country flying is outlined, and it is explained why the high wing loadings of the Gyps vultures are appropriate to their peripatetic habits. A method of thermal soaring without circling is discussed, and shown to be more readily feasible for small than for large birds. Some differences in soaring techniques between birds and glider pilots are interpreted in the light of this calculation. A case in which Black Kites apparently used this technique to soar in random turbulence is described. The cross-country speed attainable by thermal soaring should be similar to the cruising speed under power in both large and small birds. Rough calculations of the energy costs suggest that a large bird (White Stork) should reduce its fuel consumption by a factor of 23 by soaring rather than flying under power, whereas this factor would be only 2–4 for a small bird (Bonelli's Warbler). Other reasons why thermal soaring is an advantageous means of travel for large but not for small birds are also indicated.     

山东省几种林果害虫病毒记述

近几年来,山东省一些林场的赤松毛虫自然发生流行性病毒病,当地进行人工喷洒病毒防治松毛虫大面积试验获得良好效果。继后我们又发现山东省其它一些林果业害虫也有类似的自然死亡现象,现将采集到的几种昆虫病毒进行研究鉴定,简报如下。 1.赤松毛虫(Dendrolimus spectabilis Butler)细胞质型多角体病毒(CPV)及颗粒体病毒(GV) 1973年以来,山东省沂南县东风林场的赤松毛虫经常发生流行病而大量死亡;经调查此病分为萎     

THE RESPONSE TO ‘BLACK-LIGHT’ RADIATION OF SOME COMMON FLIES OF ECONOMIC IMPORTANCE

The responses towards black-light traps of Musca domestica, Fannia canicularis, Lucilia sericata, Calliphora erythrocephala, Phormia terrae-novae and Stomoxys calcitrans were observed by recording the recapture rates of groups of flies released in the laboratory under standardised conditions. Five species showed more than 90% recapture in 3–6 hours, but significantly different response patterns were demonstrated. These differences did not persist beyond a period of 2 1/2 hours from the time of release.

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Zusammenfassung Die Reaktionen von Musca domestica, Fannia canicularis, Lucilia sericata, Calliphora erythrocephala, Phormia terraenovae und Stomoxys calcitrans auf Schwarz-Licht-Fallen wurden an den Wiederfangraten von Gruppen von Fliegen ermittelt, die unter standartisierten Bedingungen im Laboratorium freigelassen worden waren. Bei Darstellung auf einer logarithmischen Skala ergeben die Resultate näherungsweise eine Gerade. Innerhalb der ersten fünf Minuten waren beträchtliche Unterschiede in der Reaktion der einzelnen Arten festzustellen, doch nach 150 Minuten zeigte keine gegenüber anderen signifikante Verteilungsunterschiede. Fünf Arten waren nach drei bis sechs Stunden zu 90%, Fannia nur zu 80% wiedergefangen. Im Inneren von Gebäuden können deshalb Fallen dieses Typs als fast gleichmäßig wirkungsvoll gegenüber beliebigen Fliegenarten bei Routine-Kontrollfängen betrachtet werden.

     

若干有争议的直立人头骨特征在周口店和东非人科成员中的出现情况(英文)

多年来,直立人被看作是一个公认的物种;它曾分布于亚洲和非洲,也可能还曾分布于欧洲。这个物种包括了从距今180万年至距今大约20万年的人科成员。直立人标本彼此之间有着许许多多的相似之处,因此,归属于同一个物种已为众所认可(Howells 1980,Rightmire 1984)。 然而,这一观点好几年来受到一些研究者的质疑(Andrews 1984,Stringer 1984,Wood 1984)。这些研究者使用的是分支系统学方法。使用这种方法是试图复原出演化谱系中分裂出新种和其它分类单元的过程。该方法并不涉及全部相似之点,而是着重于单一的形态性状状态及其变化和分裂情况。依据这一方法,共有的衍生特征或独有的衍生特征对复原物种之间的关系才是有用的。亚洲的与非洲的直立人之间的许多共有性状常只被当作在其它分类单元里也存在的原始性状而已。 根据分支系统学方法,一些研究者(Stringer 1984,Wood 1984)强调:若干0独有的衍生性状状态或特化性仅存在于东亚的直立人之中。Andrews(1984)对原始特征作了进一步地剔除,表列出东亚直立人具有的7个近裔自性:额矢状嵴、顶矢状嵴、厚的颅盖骨、顶骨的角圆枕、枕外隆突点远离枕内隆突点、乳突裂、以及盂内突与鼓板之间的隐窝。 Andrews(1984)根据这些特征提出了一个假说,认为“人类的演化绕过了亚洲     

医学昆虫防制研究的新发展

本文系一文献综述, 重点介绍近来防制医学昆虫研究方面的重大发展, 对今后防制研究的方向方法, 具有一定的战略战术意义。 首先介绍了新的生物学防制理论和方法。应用射线不育性方法消灭贪食美蝇已在中、北美取得成功, 而且创造了区域性灭种的范例。它进一步孕育了昆虫自灭(绝嗣)方法的理论。化学不育性方法正在研究探索中, 实验室试验已初步证明某些药物可使蚊蝇不育, 乃一新生萌芽。遗传不育性方法尚在假设阶段, 能否成功, 还待试验证明。 其次在化学防制方面, 现已出现几种新的途径。滞留熏蒸杀虫剂可在有人而通风的房舍中使用, 其蒸气能熏杀昆虫, 但对人比较安全, 现已接近应用阶段。家畜动物通过内服药物等途径以毒杀其体内外的寄生或吸血昆虫已有了开端。与上述两法有关的有机磷杀虫剂, 其慢性中毒问题。尚须进一步研究。杀虫树脂是一新的剂型, 其杀虫毒效远比一般滞留喷洒为持久, 且可在擦洗频繁的场所使用, 现已推广应用。在诱虫剂方面亦有一定的进展。看来诱虫剂加杀虫剂和化学不育剂可能成为未来防制害虫的有效方式。     

APPLIED TOPOGRAPHIC-ANATOMICAL STUDIES OF EAST AFRICAN GAME RUMINANTS

The topographic relationships of the so-called “vital centres” like the spinal chord brain, heart and major blood vessels of East African game ruminants are discussed, using the impala and the buffalo as type animals for a series of diagrams. Anatomical conditions in relation to the effect of shots in the various body regions are demonstrated with the aim of reducing irresponsible and painful wounding of game animals. Investigations and diagrams are based upon material from 59 animals of 18 species; of these, 47 animals were formalin-fixed and dissected in a natural standing position.