Native pollinator management may be a key to improving fruit set in Tasmanian Mountain Pepper, Tasmannia lanceolata (Winteraceae), an emerging spice resource

ABSTRACT

Tasmanian Mountain Pepper is a new crop that produces a valuable flavoring agent derived from its fruit. However, annual yields are unpredictable and its commercial prospects depend upon a reliable fruit set. As poor pollination is a possible cause, the pollination biology of this dioecious plant was examined in natural and plantation settings using direct observations, sticky traps, gas chromatography, and microscopy. A community of small insects visits the flowers, and the insect species represent at least seven families of small flies, three families of beetles, and various wasps and moths. Pollen grains were observed on the bodies of bibionid flies (Bibionidae), syrphid flies (Syrphidae), and snail-flies (Sciomyzidae). The tetrahedral tetrad pollen grains are unlikely to be suitable for dispersal by wind. Similar volatiles were emitted by both males and females; several ocimene compounds are attractants for insect pollen vectors. The female flowers also emitted indole, a known fly attractant. It is therefore likely that Tasmannia lanceolata is dependent on the services of diverse insects, especially Diptera, for promoting fruit set. Plantations should be established in the vicinity of biodiverse native vegetation that supports a wide variety of native flying insects capable of transferring pollen.

KEYWORDS:

• Biodiversity
• Diptera
• floral head-space
• new crop development
• pollination

Acknowledgements

The authors thank Geoff Allen and Stephen Quarrell for assistance with insect identification and for suggesting potential methods and areas of enquiry, Chris Read and Diemen Pepper for material assistance and financial support, and Karsten Gömann and Gustaaf Hallegraeff for assistance with microscopy. We would like to thank to David Nichols for assistance with the GC and GC-MS and Dugald Close for assistance with research and writing. Essential oils of Tasmania, the Rural Industries Research and Development Corporation (RIRDC), and the Natural Plant Extracts Cooperative Society provided funding for the project and RIRDC awarded the Tony Byrne PhD scholarship to M. Wilson.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Rural Industries Research and Development Corporation [PRJ-008346];