Introduction
Tasmania is the home of a diverse array of flora and fauna assemblages. The plants range from the diminutive, pygmy sundews to the delicate terrestrial orchids to the kaleidoscope of colourful heaths, native irises, lilies and bush peas to the robust and floriferous daisy bushes and the towering eucalypts and myrtles. The perpetuation of each of these floral species is a consequence of their flowers attracting suitable pollinating fauna. Their curious floral structures, charming colours and scents have evolved over millenniums of generational change to make them irresistible to their pollinators. Deciphering the role these stunning flowers play in their mating game to lure the desired pollinator generates a new level of interest, beyond just their visual attractiveness. This article continues to explore the many powerful relationships plants have developed with their pollinators, with particular emphasis on the furry and feathered pollinators.
Pollen is demanding to produce
As there is always adequate carbon in nature, plants can make carbohydrates in the form of very cheap sugary nectar and in appropriate amounts to meet the service costs of the more expensive pollinators (Yellow Wattle birds, Pygmy possums etc). In contrast to nectar, manufacturing of pollen demands ample moisture and precious nitrogen, plentifully available in tall forests and rainforests but limited in low nitrogen environments such as dry coastal heaths and grassy woodlands. In these areas, most of their nitrogen is obtained through healthy symbiotic relationships between fungi and plants.
Ingenuity conserves pollen and provides a competitive edge
To conserve pollen plants have evolved cunning protective processes and structures.
For example the Native Cranberry Astroloma humifusum and the Bearded Heaths
( Leucopogon spp.) flowers possess rings of hair at the throat of their flora tubes which limits their nectary accessibility to finely beaked birds, long tongued insects or very small insects. Curiously many highly floriferous shrubs, often in close proximity
(such Tea trees, Correas etc) have developed other conservation methods. Undetected by their pollinators, each shrub may only produce nectar in 20-30% of their receptive flowers. The flowers with barren nectaries frustrate the insects by displaying all the
Footprints in the Pollen – – Phil Watson 1

same attractions as the nectar laden flowers. These plants possess an uncanny ability to still engage the pollinator’s interest, whilst maintaining just enough full nectaries.
Research has revealed that in our Common Heath Epacris impressa the potential volume of conserved nectar in their deep nectaries varies from 0.1 – 0.2 millilitres under harsh conditions to 2 – 3 millilitres in lush conditions. To fill a kilogram jar of honey hard working bees must fly up to three times extra distance to visit enough nectar bearing flowers (estimated at 1,000,000 flowers across 50,000km). Individual bees work itself to death in 3 weeks contributing only 2-3 mls of pure honey in its life time.
Another method used by plants to gain a competitive edge is the clever use of darker coloured flowers and early morning peak nectar flows. By absorbing the sun’s warmth an alluring sweet scent attracts early flying pollinators. Examples include the brilliant red flowers of the Running Postman ( Kennedia prostrata ) and the warm autumn tones of Bush Pea flower Bossiaea cinerea .
Tasmania is home to a spectacularly diverse assemblage of plants. They range from the diminutive, pygmy sundew to the colourful and intricately structured terrestrial orchids to the kaleidoscope of colourful heaths, native irises, lilies and bush peas to the robust and floriferous daisy bushes and gigantic eucalypts and myrtles. As the main feature of each of these plants, their flowers have evolved to simply act as the plant’s tool in the mating game, with their intricate designs refined over millenniums of generational change. Waiting to be discovered by the nature lover is the fascinating world of curious structures, processes and complex interrelationships between these plants and their pollinators. This article explores the intriguing field of pollination ecology, which studies the interaction between plants and their pollinators.
Nectar and pollen are irresistible rewards
Although flowers appear very different, they all have the same basic structure. Their central female parts (carpels) contain the ovaries which require pollinating to form fruits and seeds. These are surrounded by the male parts (stamens) which are the pollen producers, designed to ensure the fertilization of the ovules in the ovary.
Encircling the stamens and pistils are the petals and sepals, colourful accessory structures whose roles are to protect the pollen and nectar and to promote their floral attributes as boldly as they dare.
To achieve a transfer of pollen from the stamens of one flower to the ovules of another, pollination agents are targeted, attracted by a reward of delicious body building pollen which is high in fats and protein, or energy giving nectar which is
Footprints in the Pollen – – Phil Watson 2

high in sugary carbohydrates. To maintain a competitive advantage, the flowers’ colours and scents must be as irresistible as possible. In human terms this is somewhat akin to streets lined with cake shops, cafes and restaurants displaying windows of decorated cakes and other delicacies. Like the flower-scented breezes, these are made even more tempting by fans wafting mouth watering aromas into the street.
No footprints required
There are many self pollinating flowers that do not need pollinators. Of these, a few practise the bizarre process called cleistogamony, which allows flowers such as Viola sp, Wahlenbergia sp . a few species of Leek Orchids Prasophyllum sp and small flowered Caladenia sp.
to self pollinate without opening.
The honeyeaters are the largest family of birds in Australia with a staggering 80% of all bird species in forest communities belonging to this diverse family. Records indicate that over 100 species of Australian honeyeaters frequent well over 1000 indigenous species, with many developing close mutual relations with indigenous flora. The flora benefits significantly from pollination and seed dispersal. Unlike the numerous 1:1 bird:plant relationships formed between their overseas counterparts,
Australian Honeyeaters have no true 1:1 relationships although there are some which are very close (such as that between Swift Parrots and Blue Gums).
Honeyeaters have unique features
Our honeyeaters are much larger and more robust than the overseas equivalents such as the very energetic, but tiny, American humming birds or the small, colourful South
African sunbirds. Unexpectedly, the largest of all the world’s specialised nectar feeders is Tasmania’s Yellow Wattle Bird ( Anthochaera paradoxa ) some 10 times larger than the hummers or sun birds.
1
With this substantial size and robustness, honey eaters offer a superior pollination service relative to the insect pollinators. They have the capacity to feed and hence transfer pollen during wet periods or remain active in adverse weather conditions including hot, cold or windy conditions. They are also capable of transferring larger pollen loads over longer distances and can frequent many more flowers in a working
1 Low T. Our Sweet Country a Celebration Australian Geographic Jan- Mar 2006 Edition
Footprints in the Pollen – – Phil Watson 3

day than insects.
2
As efficient nectar feeders, they have evolved elaborate tongues which are prolonged and protrude well beyond their bill tips enabling collection from deep nectaries. The front edges of their tongues are delicately frayed to form a brush for licking up the nectar. By lapping up nectar at the rate of 10 licks per second, nectaries can be emptied within a second or two.
Mutual benefits for honey eaters and gum flowers
In Tasmanian forests where moisture and plant nutrients are in luxurious amounts, members of the Myrtle family ( Myrtaceae ) including Gums ( Eucalyptus sp ), Bottle
Brushes ( Callistemon sp ) and Paper Barks ( Melaleuca sp ) etc, have abundant nectar.
Each brushy or fluffy flower can pump nectar for over 2 to 3 weeks to satisfy the birds (also bats and agile arboreal marsupials) addictive behaviour. Fortunately their flowers have been sturdily constructed to support the honeyeater’s bulky bodies whilst busily feeding. Given insects are blind to colours on the infra red end of the light spectrum (reds, oranges, yellows etc) their vibrant red and orange coloured flowers provide them with further competitive advantages.
It is not unexpected that the more pugnacious honey eaters, particularly the little wattle bird, Yellow wattle bird, New Holland Honeyeaters ( Phylidonyris novaehollandiae ) and Noisy miners become extremely boisterous and territorial, as they boldly defend, their flower clusters. This defensive behaviour has been linked to defoliating insect-derived dieback in stands of flowering Gums, as a result of both the small foliage insect gleaners (Black headed, Strong billed and Crescent Honey eaters,
Pardalotes Thornbills etc) and the large foliage and trunk gleaners (Golden Whistlers,
Black-faced Cuckoo-shrike, Grey Shrike-thrush etc) being frightened away.
Fortuitously their dominance diminishes as the flowering period closes forcing the aggressors to leave the area in search of protein rich staple foods such as fruits, honeydew seeds, lerp and manna.
2 Rowe M.T. RAOU Honeyeaters of Hawks Nest & Tea Gardens A Guide National Parks NSW
Footprints in the Pollen – – Phil Watson 4

Swift Parrot and the Blue Gum partnership
The close relationship between the Swift parrot and Blue gum is a captivating example of flora and fauna adaptation resulting in outstanding mutual benefits.
Taking advantage of the Blue Gum’s ( Eucalyptus globulus ) nectar–laden cups surrounded by shaving brush-like pollen tipped stamen, the Swift parrot ( Lathamus discolor ) migrates to breed within the Blue Gum dominated communities. This dependence by Swift parrot on the gum is reflected by the gum on the parrot. As a consequence of the swift’s short, stout bill it needs to not only brush many of the stamens but also dabs the stigma of each flower in its endeavours to empty the nectar cup. The resultant dusting over the facial region of the parrot, achieves the flower’s goal of transferring its pollen to the other flower. Although the swift’s mutual relationship produces remarkable pollination service for the gum, the musk lorikeet
( Glossopsitta concinna ) with its similar attributes also provides a valuable contribution.
Swift Parrot being dusted whilst feeding on Blue Gum flower 3
In contrast to these stout billed birds, the finer billed honey eaters such as the New
Holland Honeyeater, Crescent Honeyeater and Eastern Spine Bills which also feed on the Blue gum’s nectar. However they rarely brush the stamens or stigma and consequently are considered as ineffective pollinators.
Pollen presenter – an example of intelligent design
The Australian Protea family ( Proteaceae ) are ideally suited to bird and mammal
3 Hingston A. B, Gartrell B.D. & Pinchbeck G. How specialised is the plant-pollinator association between Eucalyptus globulus ssp. globulus and the swift parrot Lathamus discolour Austral Ecology
(2004) 29, 624-630
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pollination as a consequence of their cunningly designed pollen presenter . This long stalk-like structure collects pollen on its stigmatic tip as it brushes past the internal anthers once it starts to open out. This flower’s pollen presenter continues to unfurl from the body of the flower before finally prominently positioning itself above the main body of the flower. With the bird’s arrival and subsequent desire to probe into the flower’s nectary, the honeyeater is dusted by the pollen presenter on its forehead, before departing. Having successfully off-loaded the pollen, the pollen presenter’s stigmatic tip is now free to receive pollen carried by the next appropriately dusted honeyeater. The spectacular, nectar filled Spider Flowers ( Grevillea sp.) are the best known flowers with pollen presenters. However, the Hakea ( Hakea sp.), Waratah
( Telopea sp.), and Guitar Plant ( Lomatia sp.) amongst others all have similar attributes.
Kangaroo Paws are not just a pretty flower
In Western Australia, the famous Kangaroo Paws Anigosanthus sp. provide an attention grabbing example of floral charisma and superb design for bird pollination.
Not only do they form sturdy landing platforms for honeyeaters to exploit their nectaries, but during their flowering period each flower spike is architecturally designed to offer one solitary receptive bloom at a time. Daily one flower pivots boldly into position while the spent flowers continue to hinge out of prominence.
Their multi coloured flowers have pollen laden frilly tips perfectly poised to transfer pollen onto the foreheads of nectar seeking birds. Since the bird’s fine bills accurately reflect the curvature of the tubular corollas leading to their deep nectary, this adaptation has granted them privileged access otherwise denied to pollen raiders.
Honey eaters love tubular bells
Fine billed honey eaters rely on reddish coloured, tubular flowers for nectar supplies during winter and early spring when their staple food sources are diminished. Many native flowers benefits from this bird pollination service include the brilliant redorange Christmas Bells ( Blandfordia punicea ) and the exquisite red bells of the
Climbing Heath ( Prionotes cerinthiodes ), Native Fuchsias ( Correa sp.), Candle
Heaths ( Richea spp) and Native Heaths ( Epacris spp). All of these have evolved the necessary key bird-alluring attributes which feature odourless, pendant, tubular corollas, with the peaking of their diurnal nectar flows in winter and early spring.
One of the most outstanding Tasmanian examples uncovered by recent research of birds pollinating tubular flowers is that of the dry sclerophyll understorey shrub from
Footprints in the Pollen – – Phil Watson 6

eastern Tasmania known as the Spreading Pink berry Leptecophylla divaricata
(Epacridaceae). This has the honour of being the first recorded bird-pollinated dioecious plant in the Australian flora. The tubular pendant corolla of its flower “ has evolved in a clade otherwise conforming to the typical dioecious pollination syndrome of small white flowers serviced by small insects ” 4
It is reported that characteristically their male flowers are larger and earlier flowering and produce much more nectar than the female flowers. The researchers also noted that the species had a high level of self–fertility and suggested that this dioecism assisted their outcrossing chances.
Reflecting again on the overseas honey eaters, these sunbirds, humming birds etc, they have highly specialised 1:1 relationships based on their long curved beaks being perfectly adapted to access the deep nectaries. Due to these flower’s showy nature and desirability, some of these plants have now become environmental weeds although luckily in Tasmania they cannot be open-pollinated by birds. These include the gorgeous red bells of the Chilean Bellflower, Lapageria rosea, old garden favourite
Agapanthus Agapanthus africanus , Bugle Lily, Watsonia meriana , African Cornflag,
Chasmanthe floribunda and Montbretia, Crocosmia x crocosmiiflora .
Eastern Spinebill feeding on Epacris sp.
5
Current estimates indicate over 25 species of mammals actively feeding on nectar pumped from flowers of Australian trees. Of these there are 7 or more species of possums, arboreal marsupials and gliders involved in pollination as well as a number
4 Higham R.K and McQuillan P.B. Cyathodes divaricata (Epacridaceae) the first record of a birdpollinated dioecious plant in the Australian flora Australian Journal of Botany 48 (1) 93 - 99
5 Rowe M.T. RAOU Honeyeaters of Hawks Nest & Tea Gardens A Guide National Parks NSW
Footprints in the Pollen – – Phil Watson 7

of bats and rodents. Interestingly one important furry pollinator is the smallest glider in the world, known as the feather tail or pygmy glider ( Acrobates pymaeues ). It feeds on pollen, nectar and insects in the eastern Australian coastal forests. Like the mountain pygmy possum ( Burramys parvus ), little pygmy possum and eastern pygmy possum ( Cercatetus lepidus & C.nanus
) they are recognised as valuable contributors to pollination of dry woodlands trees from the myrtle and protea families.
Another engrossing species is the Western Australian mouse sized, honey possum
( Tarsipes spenserae ) known by the aboriginal name of Noolbenger . It has a very slender, long whip-like, tapering prehensile tail giving it remarkable agility amongst the nectar bearing flower clusters. It is ideally suited to suck up blossoms, nectar, pollen and microscopic insects with its very elongated, tubular snout and a brush-like tongue similar to that of a honey eater. Akin to the other gliders and possums strong smell receptors allow it feed nocturnally on nectareous flowers. In the day it hides in nests of grass and fur constructed in dense foliage such as found in grass tree tops.
Bats and flying foxes also play a significant role in pollination and seed dispersal for both native and exotic trees. For example, the Grey-headed flying Fox, like other flying foxes, flies long distances across cleared and urban landscapes to forage and subsequently transfer pollen amid flowering gums such as the Spotted Gum Corymbia maculata ). Of note is that these furry pollinators, bats and flying foxes do not require nectar to survive, but rather, enjoy nectar as a junk food in an opportunistic way.
The Southern Snow Skink’s contribution
The key role which the Southern Snow Skink plays in the pollination of the alpine scoparia ( Richea scoparia ) is another enthralling example of mutual benefits being received as part of the mating game.
In order to protect its stamens and stigmas against torrid alpine conditions the flowers surrounds its delicate reproductive parts with a fused petal capsule. In doing so, it restricts access by seed dispersers and insect pollinators. During summer, the mature flowers produce large amounts of nectar which worryingly remains trapped within the capsule. Slithering to the rescue is the Southern Snow Skink which aggressively tears apart the capsule in order to satisfy its voracious appetite for the nectar. With the floral parts finally exposed, the opportunistic pollinating insects can do their job and its seeds can subsequently be dispersed.
Everything is being affected by global warming’s environmental changes.
It is already established that over the past 30 years the world’s alpine and subalpine
Footprints in the Pollen – – Phil Watson 8

flora is flowering on average 2 to 3 weeks earlier. The current rate of change is more rapid than the life cycles of their insect pollinators.
Equally concerning is the progressive contraction of cold adapted flora’s range to both higher altitudes and higher latitudes. Disastrously, this movement is not matched by the adaptive capacity of their pollinator. Today across the SE Australia and Tasmania alpine and subalpine regions there is a major loss of snow patches coupled with early spring thaws. This affects bird migration and breeding patterns, which is now often compounded when followed by a late snow dumps and killing frosts that disrupt bird and marsupial breeding, winter hibernation and access to nectar sources. A graphic example of this is in the Mt Kosciusko National Park 6 where populations of the endangered mountain pygmy possum have crashed. In concert with this, the higher levels of ultraviolet radiation has cause the loss of rare alpine plants and their pollinators, whilst the warmer, drier conditions are causing a steady demise of others such as the Alpine Sky Lily ( Herpolirion novae-zelandiae ) and its pollinators.
It is obvious that all these environmental impacts will disrupt synchronies in the timing of important biological events such as the flora and fauna interrelationships.
On this premise, it could be anticipated that pollination ecology may well become one of the key harbingers of Climate Change.
Given the finely tuned time and space interrelationships occurring between the many and varied symbiotic and 1:1 relationships, major impacts can be expected. For example the flowering of up to 500 terrestrial orchids are perfectly time and located to match the life cycle of their one and only species of thynnid wasp pollinator. Global warming is decoupling these relationships with resulting extinctions!
This disruption of synchrony will act to amplify the more subtle changes to well known environmental indicators. Consequently, pollination ecology will become a more sensitive indicator of climate change than the environmental variables themselves.
Positively speaking, there is better news in relation to our bird and mammal pollinators. These less specialist relationships will provide an inherent robustness against the predicted global warming impacts compared to the sensitive mutual relationships entertained by their overseas counterparts.
The many other Pollinators
It is obvious that during peak flowering season, wildflowers are enveloped in clouds
6 Roslyn Beeby 8/4/06 Kosciuzko’s climate crisis Canberra Times (ACT)
Footprints in the Pollen – – Phil Watson 9

of other pollinating insects such as flies, wasps, gnats, beetles, moths and butterflies, all busily leaving their footprints in the pollen. Another article will explore their important contributions to pollination ecology.
Recommended Readings
1.
Ford, H.A. (1989) Ecology of Birds - An Australian Perspective Surrey
Beattie and Sons Pty. Ltd. Chipping Norton
2.
Encyclopaedia of Australian Wildlife (1997) Readers Digest
3.
Gilbreath A. (1979) Creatures of the Night David Mc Kay
4.
Forshaw, J.M
.
(2002) Australian Parrots Alexander Editions, Qld
5.
Micah Visoiu & Sarah Lloyd (2003), Bugs, Birds, Bettongs & Bush, maintaining habitats for fauna in Tasmania Nature Conservation Report 03/4
6.
S.L.Buchmann and G.P.Nabhan (1996) The Forgotten Pollinators ; Island press, USA
7.
K.Faegri and Van der Pijl (1973) The Principles of Pollination Ecology ;
Collins London
8.
Churchill, Sue (1998) Australian Bats – New Holland Publishers, Sydney
Phil Watson
Footprints in the Pollen – – Phil Watson 10

It is not until one sees the diversity of different insects busily working the sweetly scented blooms of plants like Native Box Bursaria spinosa that it is realised there is a whole new world of insect pollinators awaiting exploration.
Following Part 1 of this article detailing the fascinating roles that water, wind, birds and animals play in the plant’s mating game; Part 2 will expose the equally enthralling interrelationships played out by a diversity of insects.
Bees are nectar and pollen addicts
Whereas other pollinators only require nectar and/or pollen for part of their life cycles bees are addicted to these honey ingredients throughout their adult and larval stages.
To accumulate one kilogram of honey, bees will have pollinated a million individual flowers and flown over 50,000 kilometres.
Sadly, native bees are declining or have gradually been displaced since the introduction of the commercial honey bee and more recently the bumble bee. This has lead to a reduction in native flora pollination and an increase in the pollination of weeds. Hence weeds like Lupins, Agapathus, Genista, exotic Solanum sp and
Foxgloves populations are flourishing amongst our indigenous plants. Recent studies of the Bush pea Gompholobium huegelii report a large reduction in flower visits by the native megachilid bees where they competed with the bumble bee. The hairy body
Footprints in the Pollen – – Phil Watson 11

parts of this native bee perfectly match the location of the flower’s anthers and stigma, whilst the equivalent areas on the bumble bee are smooth and unable to attach pollen.
In general, our native bees favour the blue and purple flowered Sun Orchids,
Thelymitra spp ., Blue Iris Patersonia sp. Blue Bush Pea, Hovea sp., and Happy
Wanderers, Hardenbergia sp ., although they are happy to add their footprints in the pollen of yellow, mauve, pink and white blooms.
Pollination by long tongues, short tongues or buzzing wings
Bees are very capable of manipulating a variety of floral constructions to gain access to the nectaries; some flowers have developed finely tuned relationships so that only a few species of bee can decode the cryptic clues leading them to the flower’s rewards.
A classic example is the Bloodroot Haemodorum spp, where specialised bees are able to enter and pollinate their closed flowers, thus eliminating other nectar competitors.
The largest and most commonly seen bees are the sparsely hairy short tongued species that have evolved in parallel with the Myrtaceae family; gums Eucalyptus spp ., tea trees, Leptospermum spp ., paperbarks, Melaleuca spp ., and heath myrtles
Baeckea sp.
etc . have shallow cup-like nectaries ideally suited for lapping by short tongues. Prolific nectar producers such as Native Box Bursaria spinosa , and Fairy
Waxflower Eriostemon sp . are also suited for short tongued bees, although there are numerous other insect competitors.
Only a small number of the estimated 700 species of solitary bees are long tongued.
One, the leaf cutter bee, confine their foraging to flowers with deep floral tubes such as Native Fuchsia, Correa spp. Native Rosemary , Westringa sp, Native Heath Epacris spp.
and hence benefit from the lack of competition for the nectar. As they feed the pollen is dusted onto their bodies or hairy legs and is carried to the stigma of another flower so accomplishing pollination. This process has recently been short circuited by the ubiquitous bumble bee which has learnt to thieve the nectar by drilling into the base of the Epacrid’s corolla tube
Of horticultural importance to commercial growers for pollinating glass house tomatoes is the bumble bee’s buzz pollination technique . However it is also feasible that native buzz pollinators such as the large, hairy, metallic green Carpenter Bee and smaller Blue Banded Bee could fulfil this role. These bees collect the pollen that is
Footprints in the Pollen – – Phil Watson 12

flung from vibrating flower anthers. They carry it to their nesting holes bored in the soft wood of Grass-trees’ Xanthorrhoea flower shafts or old Banksia trunks. Here, an egg in each cell is provided with a feed of pollen and nectar porridge before it is closed off with wax and frass.
Spur Velleia protects its nectary with a spur at the base of the petals
Species such as the golden Guinea Flower Hibbertia riparia, Kangaroo Apple
Solanum laciniatum, Fringe lilies Thysanotos sp and Flax lilies Dianella sp, rely on buzz pollination but are often inundated by ineffective raiders such as the honey bees.
Interestingly, Hibbertia spp, have no nectary, but instead rely on its pollen to attract bees foraging for high protein food to feed their larva.
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Members of the
Goodeniaceae family such as Goodenia lanata Native Primrose, and Velleia paradoxa
Spur Velleia also have buzz-pollinated flowers, but they are designed differently to protect them from self pollinating. With the aid of a cup-like structure (indusium) they catch maturing pollen that is ready for dispersal. Once the pollen is dispersed or becomes non viable, the stigma will change to become receptive for pollination. Most Goodeniaceae have the nectary spur hidden at the base of the petals which restricts nectar access only to long tongued pollinators
Bush peas are a bee’s favourite
The Bush Peas ( Fabaceae ) with their functionally designed wing and keel structure
(eg. Showy Bossiaea Bossiaea cinerea, Bitter Peas Daviesia sp., Golden pea Aotus ericoides ) along with the pea-like flowers of the Polygalaceae (Blue Love Creeper
Comesperma volubile ) etc, have evolved an ingenuous system suited for bee pollination.
With the anther and stigma protected below the flexible lower keel petal, only the landing of appropriately sized bees attracted by nectar guides and its deep nectary can part the petals and trip the spring loaded organs to tickle the bee’s hairy belly.
The wing and keel form of the Bossiaea flowers protects its nectary from raiders
Nectar Guides
Intriguing associations have evolved with native bees and other insects whose eye receptors are strongest in the far blue end of the UV spectrum. This allows flowers
Footprints in the Pollen – – Phil Watson 14

that appear white to mammals and birds to display distinctive UV colour patterns which act as nectar guides. Common UV patterns include light blues with darker maroon or violet streaks and patches. Coupled with the flower’s ability to emit romantic pheromone attractants, the guides become magnets for bees and other insects. Numerous examples include the vivid set of spots and streaks on Donkey orchids Diuris spp. and Bush peas, the rosy red streaks on the petals of Native
Pelagonium Pelagonium australe and the prominent purple veins on the floral throats of Native Flax Linum marginale.
Linum sp. purple veins act as nectar guides
The bee and orchid love story
Due to the lack of a nectary, many of our native terrestrial orchid’s pollination needs are contingent on their ability to mimic nectar bearing flowers found within their vegetation communities. The Tiger and Leopard Orchids ( Diuris sulpurea and D. paradina ) mimic numerous bush peas, by replicating their timing of opening, structure and colours. This enticement, coupled with their ability to emit the female bee’s pheromones, lures the male bee into attempting to mate with the labellum, which results in pollen transfer.
Similarly, the blue-flowered species such as Sun Orchids Thelymitra spp .
Small flowered Caladenias and Wax Lip Orchid Glossodia sp., all have modified labella that are similar in size and shape to their petals. This has enabled them with their strong aromatic scents to mimic blue flowered irises &/or lilies (Blue Iris, Patersonia sp.
,
Flax Lily Dianella sp etc) and attract a similar suite of pollinating insects, mostly native bees.
Pollen Clogging
As insects rapidly learn to recognise the flowers that provide key food supplies, these flowers’ colour, shape and overall appearance are soon retained in their memory.
Specialised native bees, like many other insects, indiscriminately visit flowers that fit within the same group or “guild” (eg blue lilies and sun orchids). Hence they often accumulate pollen on their bodies from several different species. With this mix of pollen types scattered over their bodies, foreign pollen can be inadvertently placed on the stigma of a flower preventing pollen of its own species reaching the stigma. This pollen clogging is cunningly avoided by some highly evolved inter-relationships as a result of the anthers positioning the pollen consistently on one point of the bee’s hairy
Footprints in the Pollen – – Phil Watson 15

body, so that only the perfectly poised stigma receives a brushing of this pollen.
Flies, gnats, midges and mosquitos
As quiet achievers in the pollination game fly species frequent flowers ranging from complex orchid blooms to simple radial flowers. Remarkable in the extreme are the specialised long-proboscis South African flies whose needle-like mouth part is up to
70mm or 4 times their body length. Without the ability to retract its prodigious appendage, it must fly with it extended forward or tucked loosely below its body.
They have co-evolved with purple, red or bluish flowers of Pelargonium sp. which exhibit intensely coloured nectar guides and long–floral tubes containing deep nectar pools. While this intricate symbiotic relationship excludes nectar raiders, the impacts of climate change or habitat loss could easily result in extinction. Other typical examples are from the Irioids , including Babiana sp., Sparaxis sp. Homeria sp. and
Ixia sp.
Some of these species are flower garden favourites in SE Australia, but with no specialised flies, they lack the ability to be open-pollinated.
Commonly known for their biting and uncouth behaviour are the short–tongued flies such as blow flies, carrion flies and march flies. These species have lapping mouth parts and are attracted to decaying putrid scents and livid-coloured flowers such as the
Milkweeds Asclepiaceae . An excellent example in WA is the brown and yellow
Stinking Roger flower Hakea denticulata which smells of rotting wallaby. Pollination is carried out when blowflies, attracted by the smell, seek egg laying sites.
Using a similar style of smelly attractant, the Helmet Orchid Corybus recurvus entices flies and gnats to their dull, ground hugging fungus–like flowers. Once pollinated the fungus-scented flower shrivels and then rises on an elongated stalk blocking further pollination.
Interestingly the cryptic orchid-like, ground-dwelling Fairy lanterns Thismia sp., which also emit a fleshy odour, are considered to be pollinated by a gnats, midges, as well as beetles and other invertebrates.
The well known Greenhoods, Pterostylis spp emit alluring pheromones of the female fungus gnats or, less commonly, of a mosquito species. This is intended to entice the male onto the cocked elastic labellum. Once triggered the labellum flips inwards encapsulating the insect inside the flower. In its frantic attempts to escape, the gnat initially brushes its pollen load onto the stigma before being directed by columnar wings to be pollen dusted and finally set free. As a testament to their very short
Footprints in the Pollen – – Phil Watson 16

memories and the power of the pollination process, they will soon forget the experience and suffer a repeat episode. For those who have been attacked near wetlands by swarms of blood thirsty female midges, flies and mosquitos, one can be consoled in the knowledge their blood is fuelling these pollinators to skim around the flowers on the wetlands’ surface.
Wasps, sawflies and ants
One can only but be amazed by recent reports indicating that over 500 species of male thynnid wasps have evolved close relationships, some 1:1, with indigenous terrestrial orchids eg Duck orchids Caleana sp. Hammer orchids Arthrochilus sp.
Spider
Orchids Caladenia sp.
and Mosquito Orchids Acianthus sp.
. In contrast, ants are poor pollinators, due to their lack of body hair and tendency to damage the pollen during its transport.
In recognition of the importance of thynnids in the pollination game, some species of
Hammer or Elbow Orchids have been renamed Thynninorchis sp.
to highlight their symbiotic relationship. Two species of Thynninorchis, namely T. huntianus and T nothofagicola , are able to mimic in shape and scent the flightless female wasps after she emerges from her underground cell and climbs up on a grass stalk or low shrub.
Here, posing with erect antennae, she releases a pheromone unique to her species.
Mistaking the orchid for a female, with which he expects to fly off and mate on the wing, the male wasp seizes the elasticised labellum only to be thrown into the pollen presenter. Records indicate that many of these thynnid wasp pollinated orchids are at their peak of flowering just before the females emerges. Interestingly, after mating the male relocates the female to her original site where she parasitises corby or curl grubs by using her long proboscis to inject her eggs.
Hammer Orchid’s mimics the female thynnid wasp
A similar scenario occurs between the male
Scoliid Wasp and the
Bearded Orchids
Calochilus herbaceous.
The strikingly big hairy labellum with its pair of
Footprints in the Pollen – – Phil Watson 17

eye-like glands at its base combines with the pheromone scent to lure the male wasp.
Sawflies, a variety of wasp, are also active pollinators of plants such as the large
Flying Duck Orchid Caleana major . Their upside down flowers, with broad columnar wings, presented on a wiry scape mimics the female wasp sufficiently to entice the male to attempt pseudo copulation.
Beetles
Although beetles may have pollinated some of the very earliest of flowers, their contribution is mostly limited to the diverse Myrtaceae and Asteraceae families.
Some, such as gum beetles and cockchafers, are more prone to eat and damage the flower rather than pollinate them and their larvae also damage the plant’s root system.
Typically, Myrtaceae benefit mostly from beetles especially the jewel beetles whose footprints are common in the pollen of the gums, ti-trees, Baeckeas, and paperbarks.
Importantly the gregarious behaviour of some brightly coloured hairy beetles has been used to advantage by open flowered daisies including Billy Buttons Craspedia glauca and C alpina, Dolly Bushes Cassinia sp . and Daisy Bushes Ozothamnus spp.
where they feed on the pollen or gather to mate. During their frolicking the beetles become dusted with pollen ready to transfer to the next species. The beetle pollinated plants have shallow, broadly concave or convex brightly coloured flowers held erect with short sturdy exposed organs. These make attractive landing platforms. Some flowers even have ornamental beetle–like markings to lure passing mates with the promise of company, and hence participate in the pollination process.
Butterflies and Moths
Since most of the 22,000 Australian moths are active after dark, plants adapted to moth pollination have white or pale colours, with little scent during the day. These help to camouflage them from other insects in the day. Some moth-pollinated plants remain fully closed during the day further minimising impacts from raiders. In the evenings majestic transformations occur, including alluring perfumes and luminescing colour patterns. By first light they begin reverting to their neutral day time forms.
Typical native examples include Boronia Boronia sp , White Candles Stackhousia sp. and Hounds tongue, Cynoglossum sp., while the strongly scented cottage garden favourite Cestrum nocturum exemplifies the moth pollination features found in some of the exotic weeds.
Footprints in the Pollen – – Phil Watson 18

Both the larva and their adult moth or butterfly depends totally on living plants or their associated decaying organic matter. Subsequently they have a major effect on plants by either aiding with pollination and organic matter breakdown for nutrient supply or by destructively feeding on the plant parts
Bursaria spinosa is a butterfly favourite and is well known for attracting the
Tasmanian butterflies Bright Copper and Shouldered Brown to its prolific nectar- bearing flowers.
Indigenous plants such as Rice flowers Pimelea sp, have adapted their form and structure by positioning their nectaries at the base of long thin corollas. Whilst the moth is probing deeply for nectar, the prominently exserted anthers and stigmas transfer the pollen to and from their hairy bellies. As one of the earliest emerging spring butterfly, the Hobart Brown is strongly attracted to Rice flowers, P. humilis &
P. linifolia whilst the Tassie species of Macleay’s Swallowtail, whose larva feed on the foliage of Sassafras Atherosperma moschatum , seek out Pimelea spp, on forest margins and road sides.
Alpine Pollinators
In the alpine zone the meandering low flying Leprea Brown butterfly is strongly reliant on the prostrate alpine heath Pentachronda pumila .
The Mountain Blue is the most alpine-adapted butterfly in Australia and is an important pollinator of alpine daises such as Alpine buttons Cotula alpina Mountain
Daisy, Erigeron sp, and Silver Snow Daisy, Celmisia saxifraga. To protect itself from predation the undersides of its wings blend well with the grey lichens and dead twigs common in alpine areas. The Dominula Skipper, White Grass Dart and the Yellow
Banded Dart also feed and help pollinate the herbaceous daisies in montane woodlands.
They have low whirring flight patterns ideal for seeking out the ground hugging Snow
Everlasting Helichrysum milliganii, Paper Daisy Leucochrysum albicans and
Everlasting Daisies Craspedia alpina . Whilst feeding they adopt a distinctive profile at rest with their forewings held erect over their bodies and hind-wings held horizontally.
Recommended Readings
Footprints in the Pollen – – Phil Watson 19

1 S.L.Buchmann and G.P.Nabhan (1996) The Forgotten Pollinators ; Island press, USA
2 K.Faegri and Van der Pijl (1973) The Principles of Pollination Ecology ;
Collins London)
3 Harvey, M.S. and Yen A.L. (1997) Worms to Wasps: An illustrated Guide to
Australia’s Terrestrial Invertebrates Oxford University Press, Melbourne
4 J.B. Kirkpatrick and S. Harris (1999) The Disappearing Heath Revisited
Tasmania Environment Centre Inc.
5 Simon Nevill (2001) Guide to wildflowers of South Western Australia Simon
Nevill Publications
Phil Watson
Footprints in the Pollen – – Phil Watson 20