Pollination relationships of a shrub community in a Maltese 'wied'

Abstract

This study is the first on the ecology of pollination in the Maltese Islands. Pollination relationships were investigated over a period of two years for a shrub community, consisting of 12 species, at Wied Ghollieqa, Kappara, Malta. In 1990, the shrubs flowered from May till December. Distinct seasonal changes in both the number and identity of insect taxa, and in the blooming patterns of the shrubs, were apparent; maximum blooming and insect species richness and abundance occurred in summer. The main insect visitors were members of the Coleoptera, Lepidoptera, Diptera, and Hymenoptera, the latter two orders grossly outnumbering the others, both in species richness and abundance. Plant species with specialised pollination mechanisms were not present. The majority had non-restrictive regular flowers which were either small but produced in large numbers, or else larger and produced in relatively lower numbers. The shrub community appeared to have a flexible pattern of pollinator use with the most abundant ·insects tending to visit all the coflowering shrubs irrespective of their floral features. This overlap in pollinator use implies a degree of competition provided that pollinators represent a limited resource. Staggered flowering and different lengths of flowering seasons are two main mechanisms to reduce this competition.