THE ECOLOGY OF THE GREENISH WARBLER PHYLLOSCOPUS TROCHILOIDES IN ITS WINTER QUARTERS

The Greenish Warbler is an abundant entirely insectivorous Pafaearctic migrant wintering in the tropical deciduous forests of India and east Asia. A population was studied at one locality in the eastern Ghats of south India over one winter, with a short return the following winter. Individuals maintain, and annually re-occupy, territories throughout their seven or eight months stay. A general account of territorial behaviour is given.
There is much evidence that food is critically short, particularly during the months of December to February and March, which coincides with the end of the dry season. Because of the short duration of the study, there are shortcomings in data presented. Nevertheless there is evidence that territories vary severalfold in quality and individual birds' behaviour and survival probability are correlated with this. It is suggested that territorial behaviour is the best individual strategy for long-term resource management. The presence of food competitors can alter this behaviour, much as changes in food dispersion are known to. The ability to control return time to a patch as a subsidiary function for territoriality is briefly discussed.     

EVOLUTIONARY TRENDS IN THE GENUS GINKGO

Three main independent phylogenetic groups within Ginkgoales , consisting of different families, are suggested. It is considered impossible to deduce the genus Ginkgo from any other genus by means of fossil evidence known at present.
The oldest finds of Ginkgo date from the Lower Jurassic. During the Cretaceous, increasing polymorphy in foliar remains indicates the rise of new species. During the Lower Cretaceous there also appears a type of leaf known both as G. adiantoides and as G. paradiantoides. This leaf is from the gross morphological and the anatomical point of view almost identical with the Tertiary and Recent Ginkgo populations, thus making a direct ancestry between the present-day Ginkgo and those of the Lower Cretaceous likely. By Lower Tertiary times a considerable reduction has taken place leaving only one gross morphological type of leaf, that of G. adiantoides. This is suggested to be identical with G. biloba. Although there is no positive evidence, it can be assumed that the final reduction of the genus, to its present-day East Asiatic home, has taken place during the Pleistocene period.     

METABOLIC ADAPTATION IN THE POLYMORPHIC LAND SNAIL ARIANTA ARBUSTORUM

The oxygen consumption of brown and yellow morphs of autumnand winter Arianta arbustorum was determined after adaptationto several laboratory microclimatic conditions. The data onmetabolism of autumn and winter collected snails were treatedstatistically by using factorial analysis of variance for eachseason. There are highly significant differences in the metabolicrate of autumn and winter animals resulting from the influencesof microclimatic elements like adaptation temperature, relativehumidity, environmental temperature as well as the effect ofphenotypic shell colour. There are also significant differencesin the interactions of these factors which relate the animalsto natural ecological influences. The energy utilization averagedabout 25 percent less by the brown morph than the yellow oneat 20–30°C. Comparisons were made between oxygen consumptionof the animals at these two seasons. The winter snails are characterizedby a depressed respiration rate, and significant lowering ofrespiratory Q₁₀. The results are discussed in the light of physiologicalselection by different responses of metabolic rate to microclimaticfactors on the two morphs. This is important in the maintenanceof genetic diversity and polymorphism in A. arbustorum. ^*Current address: Department of Zoology, University of El-Azhar,Egypt. (Received 23 March 1983;