Mr Stefano De Faveri1, Dr R Andrew Hayes2, Ms Jodie Cheesman1, Ms Mai Nantawan1, Professor Anthony Clarke3

1Department of Agriculture and Fisheries, Cleveland, Australia, 2University of the Sunshine Coast, Sippy Downs, Australia, 3Queensland University of Technology, Brisbane, Australia

Biography:

Mr Stefano De Faveri is a principal entomologist with the Department of Agriculture and Fisheries. He has 38 years’ experience in tropical pest management. He has worked on key pests such as fruit fly, fruit piercing moths and fruit spotting bugs in a range of tropical crops. He has concentrated on fruit fly field control over the past 15 years, leading several Australian and International projects.

Abstract:

Orchid pollination has fascinated biologists since at least Charles Darwin, particularly with respect to the diversity of pollinator attraction and reward syndromes. While visually apparent flowers with nectar rewards are common, another orchid pollination syndrome is the presentation of floral chemicals which act initially as an attractant and then as a pheromone reward for the pollinator. Daciniphilous orchids attract male tephritid fruit flies which feed upon the flower to obtain the chemicals which are then incorporated into the male pheromone blend. We studied the interaction between Australia’s only endemic daciniphilous orchid, Bulbophyllum baileyi and Jarvis’s fruit fly (Bactrocera jarvisi). This orchid is known to produce the phentybutanoid zingerone and its reduced form zingerol; we found that B. jarvisi responds electrophysiologically to both compounds. To better understand the role of plant chemistry in fly behaviour we used gas chromatography-mass spectrometry to sample the chemical profile of whole flowers within and across days, as well as quantifying the abundance of chemicals in different floral parts. Zingerone and zingerol levels varied between flower parts, with the highest levels for both compounds in the sepals. We did not detect methyl eugenol, raspberry ketone or cue-lure in any of the flower parts. Ten male B. jarvisi were caged with a single flower, and observed throughout the day, the number of flies on the petals was highest at 8:00 am and dropped steadily throughout the day. There were no differences in overall levels of zingerone and zingerol across time or over the three days of flowering.