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Showing papers in "Journal of Animal Ecology in 1943"


Journal ArticleDOI
TL;DR: It is shown that in a large collection of Lepidoptera captured in Malaya the frequency of the number of species represented by different numbers of individuals fitted somewhat closely to a hyperbola type of curve, so long as only the rarer species were considered.
Abstract: Part 1. It is shown that in a large collection of Lepidoptera captured in Malaya the frequency of the number of species represented by different numbers of individuals fitted somewhat closely to a hyperbola type of curve, so long as only the rarer species were considered. The data for the commoner species was not so strictly `randomized', but the whole series could be closely fitted by a series of the logarithmic type as described by Fisher in Part 3. Other data for random collections of insects in the field were also shown to fit fairly well to this series. Part 2. Extensive data on the capture of about 1500 Macrolepidoptera of about 240 species in a light-trap at Harpenden is analysed in relation to Fisher's mathematical theory and is shown to fit extremely closely to the calculations. The calculations are applied first to the frequency of occurrence of species represented by different numbers of individuals--and secondly to the number of species in samples of different sizes from the same population. The parameter ` alpha ', which it is suggested should be called the `index of diversity', is shown to have a regular seasonal change in the case of the Macrolepidoptera in the trap. In addition, samples from two traps which overlooked somewhat different vegetation are shown to have ` alpha ' values which are significantly different. It is shown that, provided the samples are not small, ` alpha ' is the increase in the number of species obtained by increasing the size of a sample by e (2.718). A diagram is given (Fig. 8) from which any one of the values, total number of species, total number of individuals and index of diversity (alpha), can be obtained approximately if the other two are known. The standard error of alpha is also indicated on the same diagram. Part 3. A theoretical distribution is developed which appears to be suitable for the frequencies with which different species occur in a random collection, in the common case in which many species are so rare that their chance of inclusion is small. The relationships of the new distribution with the negative binomial and the Poisson series are established. Numerical processes are exhibited for fitting the series to observations containing given numbers of species and individuals, and for estimating the parameter alpha representing the richness in species of the material sampled; secondly, for calculating the standard error of alpha, and thirdly, for testing whether the series exhibits a significant deviation from the limiting form used. Special tables are presented for facilitating these calculations.

3,121 citations






Journal ArticleDOI
TL;DR: The consistency of the sand and the salinity and pH of the interstitial water were the main factors examined and what correlation, if any, existed between them and the distribution of the fauna was discovered.
Abstract: The main object of the investigations was to determine the distribution of the fauna at various levels of the beach at different localities on the Northumberland coast. In addition, some of the more inportant factors of the environment of the animals collected were investigated, partly with the object of discovering what correlation, if any, existed between them and the distribution of the fauna, and partly to determine the existence of any unusual conditions. The consistency of the sand and the salinity and pH of the interstitial water were the main factors examined. The laboratory work connected with the tesearch was carried out at the Cullercoats Dove Marine Laboratory, and I am indebted to Prof. A. Meek, Mr B. Storrow, Dr H. 0. Bull and Mrs Cowan for much encouragement and advice. I am also grateful to Prof. A. D. Hobson for valuable suggestions regarding the preparation of this paper.

32 citations




Journal ArticleDOI
TL;DR: Although the Corixidae are to be found in almost any pond and pool throughout the country, yet very little has been written about the factors responsible for the distribution of the various species, it is shown that there is a close relationship between the percentage of organic matter in the soil and the species of Corixids living there.
Abstract: Although the Corixidae (Hemiptera, Heteroptera) are to be found in almost any pond and pool throughout the country, yet very little has been written about the factors responsible for the distribution of the various species. By far the most important paper is that of Macan (1938) who has made a detailed analysis of a large number of habitats in the Lake District, and shown that there is a close relationship between the percentage of organic matter in the soil (% o.m.s.) and the species of Corixids living there. On a previous occasion the writer (Popham, 1941) has shown that certain species of Corixidae not only vary in colour, but that they tend to agree with that of the pond in which they occur. This agreement was thought to be due to the following factors: (I) the action of predators in destroying those insectF not adapted to the background; (2) the action of the background in controlling the intensity of pigmentation of nymphs and young adults, and (3) choice by the adults of a background with which they harmonize. Studies on the last two are recorded in the present paper. At the time of writing (I942), the classification of the Corixidae is in a state of flux. Mr China of the British Museum has drawn my attention to a classification by Walton (in Hutchinson, 1940) who has divided the genus 'Corixa' into some nine subgenera; but until this system has been confirmed by other authorities, it has been decided to follow the nomenclature of Macan (1939). The generic name 'Arctocorisa' is therefore used for 'Sigara'. The Ostwald Colour Chart has again been used as a standard and the percentages of white in the various standards are:

20 citations