Native and exotic flower visitors in the Christchurch Botanic Gardens and their contrasting plant preferences

Abstract

The Christchurch Botanic Gardens in New Zealand provide a landscape of closely intermixed native and exotic plants. This site was ideal for the study of bird and insect flower visitors and their relative importance for plant regeneration. Thirty-seven species of native and exotic plants were chosen to determine the frequency of bird and insect visitation rates. From these data, plant preferences of native and exotic flower visitors were investigated. A total of 24 insect species from 5 orders were observed. Over 50% of all insect visits were made by the native bee Lasioglossum sordidum. Native insects were found to prefer native plants (70.1% of visits), whereas exotic insects preferred exotic plants (70.4% of visits). Silvereyes (Zosterops lateralis) were the main bird flower visitors, and showed no preferences for native vs exotic plants. Exotic birds made up less than 5% of all plant visits, consistent with their relative unimportance to pollination in other New Zealand studies.