Restio Species as a Source of Pollen in Autumn in the Fynbos

By Geoff Tribe

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The cavity dwelling Western Honeybee inhabiting temperate regions relies on its honey stores to tide it over the seasonal dearth periods which is a feature of its natural environment. The fact that they live in cavities allows ample stores to be accumulated for this purpose. It is this behaviour of hoarding surplus honey that is exploited by commercial beekeepers to their advantage by migrating hives from one honey-flow of exotic crops to the next. In the summer rainfall highland areas a typical seasonal cycle may start with the Highveld gums (a variety of Eucalyptus species) in spring, then on to sunflowers, soya beans, Eucalyptus grandis plantations, and finally to the Aloe greatheadii var. davyana honey-flow in winter. The seasonal dearth period for the Cape bee (Apis mellifera capensis) which inhabits the winter rainfall region of South Africa occurs during the summer months from January to March when few indigenous plants are in flower under a hot cloudless sky. Yet the honeybees survive, albeit in some areas with the help of exotic plants, the most valuable being several Australian Eucalyptus species.

075 Fig. 1

Fig. 1. A view of DanielsHoogte Private Reserve nestled on the top of Aurora Mountain 800m above sea level.

An exploration of the mountain (Fig. 1) above the West Coast town of Aurora in the first week of May 2015 revealed an abundant but unexpected source of pollen for Cape honeybees in the form of a Cape reed species belonging to the Restionaceae family. Fynbos vegetation is distinguished by its constant association with these tufted reeds which have been used to provide thatching material from the time of early European settlement. In the summer rainfall regions the Restionaceae are replaced with grasses. Restio species are usually dioecious with male spikelets drooping and female spikelets erect and are wind pollinated.

The fynbos covered Aurora Mountain is surrounded below in the Sandveld by potato and wheat fields and is contiguous with the Piketberg Mountain. The mountain fynbos here comprises of at least five species of Restionaceae and five Protea species of which Protea laurifolia (fig. 2) and Protea nitida (Fig. 3) were in flower.

046 Fig. 3

Figure 3. Many insects including honeybees visited the flowers of Protea nitida.

One species of Bruniaceae (Fig. 4) had just begun to flower as a result of the heavy coastal fog which envelops the mountain in the early morning (Fig. 5). However, around the farmhouses (32° 41’ 04’’S 18° 32’ 10’’E) were some ancient Eucalyptus globulus trees which were in flower. A commercial beekeeper had placed hives (Fig. 6) in groups of three at four localities within the fynbos vegetation. They were placed on recycled plastic containers filled with sand and strapped down to prevent the honey badger from accessing them – the mountain still inhabited by leopards, lynxes, mongooses, and various antelope including klipspringers and exotic fallow deer.

Figure 5. The morning coastal fog seen through the ‘vensterklip’ which can completely envelope the mountain.

Figure 5. The morning coastal fog seen through the ‘vensterklip’ which can completely envelope the mountain.

Figure 6. Beehive placed on top of a sand-filled container and strapped down to prevent access by the honey badger.

Figure 6. Beehive placed on top of a sand-filled container and strapped down to prevent access by the honey badger.

At this time of year the fynbos was drab and the prickly undergrowth showed very few natural resources on which the bees could forage. During the hikes around the outer rim of the mountain, no natural honeybee nests were discovered – not even in the 17 aardvark holes that were inspected. However, in several small secluded valleys there was a Restio species, Elegia tectorum, growing in thick clumps which reached to one’s elbows and which released clouds of pale yellow pollen as one pushed through it. It was here that the bees were encountered in large numbers collecting pollen (Fig. 7).Only pollen collectors were observed. No bees were visiting the female flowers (Fig. 8). It was observed that pollen was not available early in the morning, especially not until the mist had lifted, but became available only during the hotter part of the afternoon when the inflorescences were dry.

Figure 7. A honeybee collecting pollen from male Elegia tectorum flowers.

Figure 7. A honeybee collecting pollen from male Elegia tectorum flowers.

Figure 8. Female Elegia tectorum flowers not visited by honeybees.

Figure 8. Female Elegia tectorum flowers not visited by honeybees.

Elegia tectorum, or Cape thatching reed (as its name tectorum = ‘roofing’ implies), may grow to over 3m in height and occurs naturally in marshes and seeps on deep sand from Clanwilliam to Port Elizabeth. Male and female flowers occur on separate plants; the flowers are small and borne in compound branched inflorescences and flower in autumn (from March to April) which lasts for about four weeks. Large areas of several metres in diameter of either just male or female plants were observed on Aurora Mountain in close proximity to each other. Small black seeds are produced with smoke greatly increasing their germination rate.

Honeybees will be found in even the most desolate desert areas throughout southern Africa in which they find the means to survive. Within the mountain fynbos of the West Coast, restios appear to play an important, if unacknowledged, role in supplying pollen to honeybees at a time of year when such resources are in short supply. More than 400 species in about 40 genera of the Restionaceae family occur in the winter rainfall regions of South Africa and Australia, with outliers in Africa, Madagascar, Indo-China and Chile. There are about 168 restio species in South Africa which are confined mainly to the fynbos biome. They appear to play a far more important role in the ecology of the Cape honeybee than that of a wind pollinated species might warrant.

References

http://www.plantzafrica.com/plantefg/elegiatectorum.htm

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A harvester termite nest found at Aurora.

The prehistoric looking 'koringkriek' or corn cricket, Hetrodes pupus, active on the mountain

The prehistoric looking ‘koringkriek’ or corn cricket, Hetrodes pupus, active on the mountain.

The presence of rock art in caves on the mountain indicates that it has been inhabited for many centuries

The presence of rock art in caves on the mountain indicates that it has been inhabited for many centuries.

 

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