Research

Anne Gaskett

PhD project      Behavioural Ecology Lab, Dept. Biological Sciences, 
                          Macquarie University, NSW

Supervisor:      Dr Marie Herberstein,
Collaborators:  Prof Rod Peakall (ANU), Dr Florian Schiestl (ETH Zurich)

Project Title:    Sexually deceptive pollination and
                          multiple signal mimicry in orchids (2005-2008)

Sexually deceptive orchids, such as Australian Cryptostylis spp., have floral structures, colours, scents and textures thought to mimic female insects. Male insects that respond by attempting to mate with the orchids' flowers, inadvertently collect and distribute the pollinia. In sexually deceptive systems, a pollinator is usually specific to only one orchid species. Cryptostylis is unique because although the five Australian species look remarkably different, they are thought to share a single pollinator, a male Ichneumonid wasp species. I am using Cryptostylis orchids to examine the functions of multiple signals (chemical, visual, structural and tactile) in mate choice by the fooled male wasps. I am also interested in the potential costs of sexual deception for pollinators, and the evolution and maintenance of deceptive relationships. This research is supported by a Furniss Foundation/American Orchid Society Fellowship.

John Siemons

Research Project  The Botanic Gardens Trust,
                               Sydney at Mount Annan Botanic Garden

Supervisors:         John Siemon and Cathy Offord

Project Title:        Storage of rare and threatened NSW orchid species
                              and their associated mycorrhizae

Website:               http://www.hermonslade.org.au/projects/HSF_04_8/hsf_04_8.htm

Zoe Smith

PhD project         Burnley College, The University of Melbourne, 
                             and The Royal Botanic Gardens Melbourne, VIC.

Supervisors:       Dr. Cassandra McLean, Senior Lecturer,
                             The University of Melbourne, and
                            Elizabeth James, Conservation Geneticist,
                             The Royal Botanic Gardens Melbourne.

Project Title:      Developing a reintroduction plan for the Sunshine Diuris,
                            Diuris fragrantissima. (2003-2006)

Diuris fragrantissima has declined so severely in the last 100 years that only six plants are now known to exist at a single site. A flourishing ex situ collection of plants has been cultivated asymbiotically for reintroduction. In order to successfully reintroduce D. fragrantissima to the wild, a suitable fungal partner must be located either in situ, ex situ or from closely related species. Germination trials will determine whether isolates form mycorrhizal symbionts with D. fragrantissima. Fungal isolates will be genetically identified by direct sequencing of the ITS region of nuclear DNA. A suitable isolate will be utilised in reintroduction trials. The taxonomic status of D. fragrantissima will be investigated using direct sequencing of the nuclear ITS and chloroplast trnT-F and matK regions of DNA, and population genetics and gene flow among D. fragrantissima and its closest relatives investigated using AFLPs. Evolutionary relationships between fungal isolates and plant hosts will be investigated as well as fungal persistence in situ.

Magali Wright

PhD project     Burnley College, The University of Melbourne, and
                         The Royal Botanic Gardens Melbourne, VIC.

Supervisors:    Dr. Cassandra McLean, Senior Lecturer, 
                          The University of Melbourne, 
                         Rob Cross, Horticultural Botanist, 
                          The Royal Botanic Gardens Melbourne, and 
                         Prof. Roger Cousens, 
                          The University of Melbourne.

Project Title:    Maximising mycorrhizal efficacy for improved cultivation 
                          and reintroduction of Caladenia tentaculata (2004-2007) 

Michaela Walsh

Honours Project   Burnley College, The University of Melbourne, and
                               The Royal Botanic Gardens Melbourne, VIC.

Supervisors:         Dr. Cassandra McLean, Senior Lecturer, 
                               The University of Melbourne, 
                              Rob Cross, Horticultural Botanist, 
                               The Royal Botanic Gardens Melbourne.  

Project Title:         Effect of media and fertilisers on the growth of Pterostylis spp. 
                               and their mycorrhiza (2004)

Tien Huynh

PhD project         Burnley College, The University of Melbourne, and 
                             The Royal Botanic Gardens Melbourne, VIC.

Supervisors:       Dr. Cassandra McLean, Senior Lecturer, 
                             The University of Melbourne,
                            Prof. Ann Lawrie, 
                             RMIT University, Bundoora, VIC. 

Project Title:      Mycorrhizal fungi in Caladenia species (2000-2003)

Nick Porch

Geography and Environmental Science, Monash University, Clayton, Vic. 3800.
Email: Nick.Porch@arts.monash.edu.au   Phone (Home): 9531-5311.

Project Title: Weevils feeding on orchids: The amycterine genus Tetralophus

The Amycterine Weevils
This large group of distinctive, flightless weevils is endemic to Australia.  It is widely distributed with the majority of taxa found in southwestern Australia, the arid centre and drier parts of eastern Australia.  This distribution is partly a consequence of the habits of the species.  As far as we know, all species feed as larvae as adults, on monocotyledons.  Primary food sources include a wide range of grasses, sedges, lilies and relatives, and even the grasstrees (Howden, 1986).  The fauna contains 39 genera and more than 400 species (Zimmerman, 1993), although there has been little modern work on the group since Zimmerman’s overview.

The Genus Tetralophus
The genus Tetralophus Waterhouse currently contains two similar species that are apparently restricted to south-eastern Australia (Zimmerman, 1991): T. sculpuratus (see below) and T. excurusus.  Like many genera of amycterine weevils nothing was known of the hosts of this small genus.  Recently ll records of the genus in the Australian National Insect Collection (ANIC) and the Museum of Victoria were examined for distribution and host data.  Of several dozen records only one had any indication of collection circumstances beyond location.  This record “found on flower of orchid” confirmed the suspicion that the genus is restricted to Orchidaceae.

Distribution
Museum records and the few published records show both taxa are restricted to SA, VIC, TAS and southern NSW (see map).  Within this region the species are probably only found in lowland eucalypt woodlands and open forests although they occur in other habitats where the hosts occur in sufficient numbers.

Hosts and Habits
Larvae of amycterine weevils almost exclusively feed on the underground parts of their host and the adults generally feed on the above-ground part of the same species.  Often the larvae form small ‘cells’ in the soil adjacent to the roots, rhizomes, stems, tubers etc. of the host.  Less commonly they burrow through the rhizomes.

Until recently there were 5 records of adult T. sculpturatus on Thelymitra from a locality near Driffield, central Gippland.  These observations occurred over a period of 4 years and occurred from August-October.  Somewhat unusually for the family, all these records are from during the day.  Four of the records were of individuals consuming leaves, generally from the leaf tip along the blade, the fifth was of an individual consuming a stem that had presumably yet to flower.  It was assumed, and stillmay be the case, that T. sculpturatus was restricted to Thelymitra. 

The most recent record from the same locality (2 Oct. 2005) is of an individual feeding on a Microtis leaf.  What does this mean?  There are a couple of possibilities.  One, it is not the same species – I haven’t seen the specimen yet.  Two, the adult is feeding on a taxon related to the larval host, but the larvae wouldn’t utilise the tubers of Mictotis for development.  Three, the taxon has a broader range of hosts than is currently recognised.

Of the 14 museum records that have dates, the months of collection are: August (2), September (1), October (4), November (2), December (2), January (3), February (1), and May (1) correlating nicely with the growing season of most terrestrial orchids.

How Can You Help?
There are a number of ways.  We really know relatively little about the distribution and ecology of these beetles.  I’m particularly interested in records of the distribution, hosts and habits of these (and other) beetles on terrestrial orchids.  It is possible that other  genera of amycterine weevils feed on orchids – we don’t know the hosts of most of the genera let alone the species.
1. Specimens – if you can, collect the specimen, record the date and time, the detailed location and notes on the host and what the beetle was doing.  This information will help build a detailed picture of the ecology of these weevils.
2. Photographs – I know there are plenty of photographers out there.  I have no images of these beetles on their hosts and these would be greatly appreciated if you can get them.
3.  Anecdotes about past observations that may have been of these or other beetles would also be useful.
4. Finally, and I shudder at the suggestion knowing the way in which growers treasure their charges, it would be interesting to attempt rearing these weevils on cultivated orchids.  First we would need a number of live captured adults (this may be difficult enough to make this an unlikely exercise) and a pot of suitable hosts (probably Thelymitra).  I’m happy to chat about this to anyone who would even consider this exercise.

Distribution of Tetralophus scultutatus and T. excursus.  Shading represents areas predicted to have suitable climate for the genus based upon known collection localities.

References:
Howden, A. T. (1986). Notes on the biology of adult and immature Amycterinae (Coleoptera, Curculionidae). Proceedings Linnean Society of New South Wales 109, 91-105.
Zimmerman, E. C. (1991). "Australian Weevils (Coleoptera: Curculionoidea. Vol V (Colour Plates 1-304)." CSIRO, Melbourne.
Zimmerman, E. C. (1993). "Australian Weevils Coleoptera: Curculionoidea. Vols III." CSIRO, Melbourne.

A male wasp (Lissopimpla excelsa, Ichneumonidae) attempting to mate with a flower of Cryptostylis subulata. Photo taken by Katy Dika

Anne smelling Nigritella rubra in Switzerland. N. rubra smells like chocolate, which is very appropriate for Swiss flora! Photo taken by Florian Schiestl.