An Evolutionary Basis for Pollination Ecology

David W Inouye,S C Willemstein

doi:10.2307/2409474

Abstract

In the introduction and chapter 2 the incentives and way of reasoning are given for the description of an evolutionary basis of pollination ecology. Starting from the until recently rather anecdotical character of the study of pollination ecology as a whole, and in the absence of large-scale correlations of flowerecologically important character states with angiosperm and insect phylogeny (in the sense of Hennig, 1966), an attempt is made to derive directed evolutionary lines (transformation series) of floral character states. Because the fossil record of flowers is very restricted and the study of angiosperm phylogeny in the sense of Hennig (1966) is only at its very beginning, the only possibilities to achieve this, can be based on the comparatively well-known fossil history of insects and insect phylogeny, the least anecdotically compiled survey of insect visits to flowers, whether resulting in pollination or not, by Knuth (1898a and 1899) as far as it concerns the central European area (most thoroughly known area concerning insect fauna and angiosperm flora), and the fossil record of extant angiosperm taxa. The insect visits to flowers are correlated with the pollination-ecologically important floral character states as they are found in Hegi (1906-1931; 1963, etc.; 1966, etc.) and Knuth (1898a and 1899) by statistical analyses on an extensive data base. These analyses, based on a geographically restricted area, are correlated with the evolution of insect-feeding (and corresponding morphology) based on insect phylogeny and fossil record. These correlations require two presuppositions: “horizontal” uniformitarianism (Recent insect behaviour and physiology in taxa of lower rank are supposed to be rather constant over the world); and ”vertical” uniformitarianism (as it is used in historical geology). The results of these correlations form a series of functionally and stratigraphically/phylogenetically directed floral transformation series, dated by the fossil record of insects. The transformation series are compared w

Highlights

Reciprocal averaging or correspondence analysis is a technique for displaying the rows and columns of a two-way contingency table as points in space
For the description of an evolutionary basis for pollination ecology the following tools are available: a) insect phylogeny based on Recent comparative morphology and fossil history; b) Recent feeding-habits of insects and their relationships with flowers; c) angiosperm phylogeny based on Recent comparative morphology and fossil history
If we compare in the quantitative analysis the frequencies of the insect groups visiting their corresponding facultative and obligatory pollination types with the higher frequencies within the pollination types, it is striking that in the butterfly- or moth-pollinated flowers the frequency of the Lepidoptera is almost double of that of the Apoidea

Summary

Introduction

Reciprocal averaging or correspondence analysis is a technique for displaying the rows and columns of a two-way contingency table as points in (lowdimensional) space. We can either choose to make separate displays for rows and for columns, or we can make a joint display for both of them. By interpreting the geometrical relations within and among the joint representation of row and column profiles, we hope to arrive at a more comprehensive overview of associations among insect taxa and the colours of the flowers visited by them, than can be attained by breaking up the data matrix into numerous 2x2 chi-square tests. In correspondence analysis the displays are representations of the data in a form which is more convenient for interpretation. We will only give an informal account on interpretative guidelines

Methods

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Discussion

Conclusion