Abundance of Philaenus spumarius in relation to types of plant community in the Tvärminne archipelago, southern Finland

Abstract

Eight main types of plant community capable of supporting populations of the meadow spittlebug (Philaenus spumarius (L.), Homoptera), were distinguished on the islands of the Tvärminne archipelago, off the south coast of Finland. The area is subject to land upheaval amounting to about 42 cm in 100 years. The flora and vegetation of the island meadows develop through successive stages determined by edaphic, climatic and biotic factors which themselves are changed by land upheaval. The meadows are mostly very small. The secular succession of the vegetation is rendered irregular by yearly and longer-term fluctuations in climate. Changes in the vegetation affect the choice of food-plants available and so cause fluctuations in the size of the spittlebug populations. The amplitude of these fluctuations, depends on the type and constancy of the various plant communities.