Project update: Contrasting bird and insect pollination through use of novel camera and genetic technologies.

I recently put together some material on my work for the University of Melbourne open day. As a teaser for the papers in current preparation, here’s an abstract and some visuals on the project.

While we simply do not know what pollinates many of Australia’s plants, there is good evidence emerging showing Australia to be a global hotspot for bird-pollination. This raises questions about what ecological and evolutionary factors might encourage plant lineages to adapt to use birds as couriers for their pollen. As well, we might ask what the outcomes are when a plant species ties its reproductive fortunes to a bird, rather than an insect.

My project employs custom cameras designed for motion-capture data capture of insect visitors to flowers, in order to demonstrate contrasting bird versus insect visitation in pairs of closely related native shrubs. Fine-scale population genetic analysis in these plants is revealing evidence for systemic differences in the movement of pollen under these different pollinator regimes.

IMG1 Stomarrhena

Styphelia stomarrhena is pollinated exclusively by birds.

The video below shows bird visitation by a number of honeyeater species, as well as the way in which floral morphology excludes bee pollinators from accessing pollen or nectar in Styphelia stomarrhena.

IMG2 Xerophyllum

Styphelia xerophylla is the sister species to S. stomarrhena and has evolved a tight relationship with a single species of native bee: Leioproctus macmillanii.

 

The videos below show motion-captured footage of the native pollinator of Styphelia xerophyllum, a female native bee (Leioproctus macmillani).

However the flowers are also visited by introduced honeybees (Apis mellifera).

 

A quick note on plant names: These species recently underwent taxonomic revision, moving them from genus Astroloma to Styphelia. It is rather new, hence the confusion over these shrubs apparently having two names.

First video of bird pollination in Astroloma stomarrhena

I’m thrilled to share this never-before seen sequence of birds feeding on Astroloma stomarrhena, a winter-flowering shrub endemic to Western Australia.

Earlier this year, I decided A. stomarrhena looked like a perfect candidate for my new study on pollinators and gene flow. What I needed was a bird-pollinated species of plant, closely related to an insect-pollinated species. This one seemed to match all the criteria I needed, except there was no evidence that it was bird-pollinated. But with those long, tapered corolla tubes, and that pink-red coloration, I believed that birds absolutely had to be the pollinator.

The danger was, that while birds might be visitors, the plant could be somewhat “generalized”, and also use insects. This is pretty common, especially in places like Australia where European Honeybees (Apis mellifera) have invaded ecosystems that evolved in their absence, and honeybees will visit absolutely everything whether the plants are adapted to bees or not.

By deploying a new camera-trapping method that I am developing to record insect visitation, I was able to gather several days of pollinator observations, despite some very bad weather. After initially being baffled as to what honeyeater might visit such a low ground-hugging shrub, I got my answer after day one, when I captured video of my new favourite bird: the Tawny-crowned Honeyeater (Gliciphila melanops) feeding on the flowers. Furthermore, the recordings of honeybee fly-bys are sufficient to rule them out as pollinators.

This little result is a win on two fronts: a successful trial of new pollinator-monitoring cameras, and vindication of predicting pollinators from flower morphology.

Click here for the full HD video.

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