Pollination of Platanthera chlorantha (Orchidaceae): new video registration of a hawkmoth (Sphingidae)


R. Steen, Dept of Ecology and Natural Resource Management, Norwegian Univ. of Life Science, NO-1432 Ås, Norway. E-mail: ronny.steen@umb.no


Documenting species interactions is a time consuming enterprise, in particular for rare interaction events and interactions taking place at night. Pollinators foraging on orchids have traditionally been monitored by discovering pollen vectors on collected insects, recording traces left by moths on the orchid, direct observations and recently by continuous video monitoring. Direct observations in the wild of orchids with low visitation rates is time demanding. In the present study I monitored greater butterfly-orchids (Platanthera chlorantha), by using a event triggered video monitoring system. A total of 23 nights of monitoring were conducted, whereas only 6 nights had visits by one moth species, namely the pine hawk-moth (Hyloicus pinastri). The total numbers of pine hawk-moths registered were 18. In addition to species identification, the video recordings also enabled detection of pollinaria on the pine hawk-moths. Most of the pine hawk-moth visits took place around midnight. The visit lasted on average for 38.0 sec and the average number of flowers visited was 9.6. In future studies, this video system could give more details on interactions between orchids and insects and even link it to environmental factors (e.g. varying weather conditions).