Overview of Pterostylis Pollination (Orchidaceae) in Victoria

Posted by @dave on
Rudie Kuiter, a professional wildlife photographer living in Victoria, Australia, has devoted much of his current time to recording the pollination of native orchid species. Here is his latest publication.

Thumb of 2017-07-11/dave/ec8916Members of the large terrestrial orchid-genus Pterostylis, collectively known as greenhoods and rustyhoods, attracted only insects of the order Diptera, the flies, as their principal or primary vectors. With few exceptions, the pollinator species were part of the superfamily Sciaroidea: infraorder Bibionomorpha: families: Mycetophilidae and Sciaridae, that are commonly known as fungus-gnats and dark-winged fungus-gnats respectively.

Introduction

All information provided is based exclusively on our extensive observations. Only species that proved to be convincing pollinators were included as principal or primary vectors. Identification was limited to the genus level, primarily based on their wing-venation, using European taxonomy (sciaroidea.info). Taxa identified as vectors were assigned a number within each genus for reference purposes. Observations were made on sites during conditions when insects were expected to be active, and by watching a colony, or a small number of plants within view from one point. Many hours were devoted to common orchids to understand the insect relationships and anticipate pollinator activity. E.g. with Pterostylis nutans it took over 20 hours in the first season to learn about pollination, the vector and to photograph the procedure. Many greenhood taxa were studied over consecutive seasons and this revealed that most of the rarely seen pollinator species may only be abundant for a very short period of a few days, or even absent, in any given season.

Pollination was witnessed in about fifty Pterostylis taxa and images were taken of all the vectors. The pollinators were comprehensively published in a book (Kuiter, 2016), and with this paper our aim is to highlight the relationships between the orchids and their respective vectors, methods of attraction, and the correlation between the Victorian Pterostylis clades and insect genera.

Click here to download and read the full PDF report. (974K PDF)

 

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