Burrowing mammals actively change their environment, and provide valuable microhabitats used by other species. These burrows offer other animals vital thermal refuges from temperature extremes and environmental fluctuations particularly in hot arid and semi-arid habitats.

The architects of the burrow

All structures have stories to tell. At Wolwekraal Nature Reserve in the arid succulent Karoo region of South Africa, three wild honeybee nests were located in aardvark burrows. Aardvarks (Orycteropus afer) are extensive burrowers in sub-Saharan ecosystems, actively modifying their environment in the construction of shelters and in excavating termitaria for food. This, in turn, generates nest sites and unique habitats that support a variety of other species, amongst them also cavity-dwelling honeybees and the numerous other creatures that co-exist in a wild nest. This article looks at the ecology of the honeybee nest site, and the dependence on the honeybee for numerous creatures as a source of food.

Honeybees are cavity dwellers

Nest 1, an aardvark burrow with a colony under a sandy rim

Honeybees are cavity dwellers. At Wolwekraal trees are scarce and rock cavities are a rare sight. Dwellings, much like the food supply, are transient. Wolwekraal is situated in the  Karoo Basin which once formed a deep, inland sea. Through the erosion of the mountains to its south and of the landscape towards the north, a cycle of sedimentation began. Over hundreds of millions of years layers of sediment were deposited some 3km deep, and later tilted to form the seemingly endless horizons north of the village of Prince Albert. This area supports many different and unique plants, adapting to extreme climatic conditions together with their pollinators, including the honeybee. This is also where the aardvark roams. 

It has been suggested that the limiting factor on the number of wild honeybee colonies in any area is determined by the worst month when there is little forage. In this desert region, not only is forage challenging and limited in the hot summer months with very little other than the Vachellia karroo in flower, but also the availability of nest sites. The three wild honeybee nests located at Wolwekraal all lie along a single north flowing minor drainage line west of the Dorps river in aardvark burrows situated on deep alluvial sediments. Aardvarks avoid areas of solid or rocky ground, preferring a sandy, loose soil optimal for digging. Aardvarks are skilled burrowers, and their tunnels provide crucial thermal refuges in the extreme temperatures of the Karoo, where summer highs often exceed 40°C and rainfall is scarce. These burrows help maintain a more stable climate, with internal temperatures ranging from 25°C to 32°C, offering a respite for many species. For honeybees, whose ideal brood temperature is around 35°C, these burrows provide an ideal nesting environment. 35°C is also an ideal temperature for the moulding of wax comb by honeybees.

A small colony situated in an aardvark hole

Nest 3, a small colony situated between two aardvark diggings that are connected

The importance of shade

One of the key benefits of these aardvark burrows is the shade they provide. The relentless heat of the Karoo can make the ground scorching—often 10°C to 20°C hotter than the air.  Even the sparse shade from the branches of the Vachellia karroo trees offer some relief from the heat. It is therefore not surprising to see a vast diversity of other creatures sharing the dwellings which honeybees inhabit. 

Co-habitants of the nest

Termites were the first co-habitants noted in the documented nest sites. Aardvarks, in excavating these cavities, were, of course burrowing for termites upon which they feed. Over the current study period of 12 weeks, only twice did it appear as though one of the three honeybee colonies had been attacked by termites. The skirmish with the guard bees was short-lived and within a day dead termites and honeybees were removed from the nest by worker bees and dropped at distances of 20m – 50m from the colony. In environments where food is limited, it does not take long for the dead to be predated on. Immediately Pheidole and other ants arrive on the scene to carry off the bodies, as do beetles such as the Eurychora sp., commonly known as mouldy beetles. Several mouldy beetles have been documented living side-by-side with honeybees in two of the three aardvark burrows. If bees detect incursions by chemical means, it would appear as if these beetles, by covering themselves with soil and nest debris and by rubbing soil particles on each other—as documented at one of the nests—would possibly use this form of camouflage to be able to move around the periphery of the nest largely unhindered by the honeybees. Soil and vegetative debris is adhered by bristles and waxy filaments on these beetles’ backs. Mouldy beetles are detritivores, feeding on dead plant and animal litter. Such detritus is an important component of food reserves in desert regions. As such, honeybee nests offer a constant concentration of detritus to support this population. Other beetles documented in these nests include the tortoise darkling beetle (Epiphysa flavicollis) which scavenge plant and animal material at night and live for many years. 

The role of wax moths and other detritivores

Other detritus feeders are the larvae of the greater and lesser wax moth, Galleria mellonella and Achroia grisella respectively. These larvae are mostly tolerated by wild honeybees as they play an important role in maintaining nest hygiene. They help by cleaning out sections of old wax comb and are frequently found feeding on leaf litter, beeswax particles, and pollen present in the nest debris. 

On the Cape Peninsula an abandoned honeybee nest in a cavity situated under rock was documented. In the nest were numerous wax moths and the deserted wax comb was writhing with wax moth larvae. In addition, two shrews made their home in the nest, benefiting from the plentiful food source provided by both the larvae and the moths. Once the larvae have cleaned the comb and both they and the shrews have departed, the nest becomes ready for re-occupation, illustrating the ingenious cycle of nature. The role of the wax moth is thought to be that of a scavenger, helping therefore to control potential diseases much like hyenas do in their ecosystems. Interestingly, the moths and the larvae continue to play a role even while the bees occupy the nest.

Shrews on the Cape Peninsula feeding on wax moth larvae

A diverse community

Skinks, too, are found feeding on wax moth in honeybee nests. In addition, the variegated skink (Trachylepis variegata) was seen feeding on small invertebrates like ants and flies. Flies abound at every honeybee nest site. Rondanioestrus apivorous, a bee tachinid, lays eggs on bees in the air as they fly into their nest. The egg almost immediately hatches into a larva which feeds on the soft tissue of the honeybee until it is ready to pupate. The bee conopid, Physocephala fascipennis with its distinctive hourglass abdomen does the same. In addition, the Blue-green bottle fly of the Lucilla sp. is also a regular visitor to the nest as are the robber flies of the family Asilidae.

When a small number of Banded bee pirate wasps (Palarus latifrons) were documented at two of the three nest sites, the wasp, upon catching a returning forager flying into the entrance of the burrow, would fly off in the direction of its nest followed by a scurry of small jackal flies. These kleptoparasitic milichiid flies (Desmometopa spp.) feed on :haemolymph rich in nutrients, and they typically steal food from other insects. They are thought to be attracted by a chemical pheromone given off by the injured or stressed honeybee, and they need to be fast to keep up with the flight of the much larger predatory wasp. Banded bee pirates are most active when temperatures are between 24C and 40C. Their diet consists largely of honeybees. The wasps compete with each other for prey, each vying to catch a honeybee, darting back and forth across the nest entrance and diving at each other. The captured honeybee is stung and paralysed by the female wasp and taken to its burrow where she lays an egg on the bee. The egg hatches into a larva and consumes the bee. Other wasps, such as the Bembix wasp, have also been noted flying higher above the nest site. Bembix hunt their prey on the wing, often catching forager bees flying off or returning to the nest. Bembix typically prey on flies of various families, however not exclusively, as seen at the wild honeybee nests and where honeybees are foraging on the sweet thorn (V. karroo).

Top row: Banded bee pirate wasp carrying off a honeybee caught on the fly. Bottom row: numerous fly species wait at the nest entrance to lay eggs on returning foragers

Ants are so important in the ecology of a wild honeybee nest and are ever present in the nest. They are constantly contributing to nest hygiene by carrying away dead bees and other organic matter including seeds blown into the burrows. Seeds are also carried out by the bees themselves, thus both ants and honeybees are vital to seed dispersal, with ants playing a much larger role. While ants are tiny, they have a really large ecological impact. In the wild certain species may be tolerated by honeybees and we have documented ant nests side by side with wild honeybee nests, separated by a good portion of propolis. As long as there is a healthy balance, ants and bees, which are related, both being of the order Hymenoptera, coexist in close proximity, as do the termites and the honeybees at the nest site at Wolwekraal.

A balbyter ant (Camponotus rufopilosis) carrying a dead honeybee into its nest

Spiders, too, find their place within these burrows. Some spiders tunnel into the walls, and Pholcid spiders (daddy-longlegs, cellar spiders) hang upside-down in their haphazard webs. They rely more on the irregular structure of the web to trap honeybees returning to the nest, rather than it having adhesive properties. Upon detecting struggling prey these spiders swiftly wrap their prey with silk-like material, either eating it immediately or storing it for later. Jumping spiders (Salticidae) do not spin webs, but are free-running and actively stalk any prey they detect, and are often found on the soil surface. They are known to have the sharpest vision of all spiders, along with tactile chemoreceptors on their pedipalps. They mostly specialise in preying on ants which are usually plentiful, but generally prey on a wide range of insects and other spiders, and prey may sometimes include a honeybee.

Observing nature’s complexity

The diversity in these extreme environments is surprising. So often one is reminded of the extraordinary privilege of being able to still wander in such untouched spaces; or in areas that were once farmed but have been allowed to bounce back again boasting bygone beauty. This phenomenon is particularly evident in the case of wild honeybee colonies established within burrows, where the bees thrive abundantly and do not perceive humans as threats to their resources or existence. Instead, observers are presented with the unique opportunity to engage in passive observation, immersing themselves in an alternative ecosystem characterised by intricate ecological interconnections that often transcend human comprehension. It is as if one enters a state of mindfulness previously unexplored.

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Dippenaar-Schoeman A.S., Van den Berg M.A. & Van den Berg A.M. (2001). Salticid spiders in macadamia orchards in the Mpumalanga Lowveld of South Africa (Arachnida: Araneae). African Plant Protection 7(1): 47–51.

Gess, S.K.& Gess, F.W. (2014). Wasps and bees in southern Africa. SANBI Biodiversity Series 24.

Haddad, C.R. & Dippenaar-Schoeman A.S. (2002). The influence of mound structure on the diversity of spiders (Araneae) inhabiting the abandoned mounds of the snouted harvest termite Trinervitermes trinervoides (Sjöstedt). Journal of Arachnology, August 2002.

Heiduk, A., Brake, I., Shuttleworth, A. and Johnson, S.D. (2023) “‘Bleeding’ flowers of Ceropegia gerrardii (Apocynaceae-Asclepiadoideae) mimic wounded insects to attract kleptoparasitic fly pollinators,” New Phytologist.

Henschel, J. R. (2021).Long-Term Population Dynamics of Namib Desert Tenebrionid Beetles Reveal Complex Relationships to Pulse-Reserve Conditions. Insects 2021 Sep; 12(9): 804.

Hepburn, H.R. (1986). Honeybees and Wax, An Experimental Natural History. Springer Verlag, 205 pgs.

Knöthig, J. (2005). Biology of the Aardvark (Orycteropus afer). Diplomarbeit, Fakultät für Biowissenschaften der Ruprecht-Karls-Universität Heidelberg.

Milton, S. J., Short, S., & Dean, W. R. J., 2022. Decline in whistling rat (Parotomys brantsii) density: Possible response to climate change in the Karoo, South Africa. African Journal of Ecology, 60, 969–979.

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Should we keep bees?

Arid to semi-arid environments are surprisingly rich in bee diversity. When most people think of bees, they often picture the honeybee (Apis mellifera). However, the reality is far more complex. Globally, there are over 23,000 bee species, the majority of which are solitary rather than social, as seen in honeybee colonies. In these solitary species, each female constructs her own nest, gathers pollen and nectar to provision her young, and lays her eggs before her brief life of sometimes just 6 to 8 weeks comes to an end. Each season often hosts its own unique bee species. This contrasts with honeybees, which remain active throughout the year in most regions of South Africa. Many of the solitary bees have co-evolved together with the flora of each region. This intricate tapestry of adaptation and survival has unfolded over millennia, leading to a remarkable diversity that thrives even in the harsh climates of areas like the Karoo. It’s astonishing to think that such diversity exists in seemingly desolate landscapes. 

As I observe the bees at Wolwekraal Nature Reserve in the arid Karoo, I often feel a sense of urgency; there simply aren’t enough hours in the day to document the incredible ecology and behaviour of solitary bees currently emerging with the spring flowers. In SA we have over 1300 species of solitary bees, but many remain to be both discovered and described. So little is known about them. 

Wolwekraal is a paradise for bees, but bees don’t thrive in isolation. Their presence also transforms Wolwekraal into a haven for all life that relies on them. As examples of what exists, for the past three weeks I have been engrossed in a bare patch of hardened ground surrounded by vygies, daisies, and other typical Karoo flora. Currently annuals like Gazania lichtensteinii are flowering in swathes of yellow. At first glance this sandy deflation hollow appears desolate. But I have been incredulous at the life on it! It is home to a nest aggregation of solitary bees. I counted 114 nests in just twelve square metres. The males hatch first, engaging in frantic competition to mate with the newly emerging females. Once mated, she flies off in search of a new nest site and begins her foraging for pollen and nectar to start reproducing and to ensure the survival of future generations. 

The abandoned nests are then repurposed by other solitary bees, such as those in the Osmiine tribe, which includes leaf-cutting, mason, and resin bees. These female bees utilise diverse nesting techniques, often lining their burrows with remarkable reddish-pink pulp made from chewed plant material. Others use leaves and petals to construct thimble-like chambers. After foraging for nectar and pollen on flowers close by, each burrow is meticulously sealed with a mixture of sand, tiny stones or leaves, and a secretion from a special gland. Some even place stones on top for additional protection. Once her work is complete, the female dies, leaving her young to develop underground until they hatch in a year, if conditions are right. 

However, the nests are not always safe from other threats. Wingless velvet ants (a kind of wasp) are able to push out the stones and lay eggs within. Moreover, bee-flies can parasitise open nests, further complicating the lives of solitary bees. Amidst this all, balbyter ants carry off any organic debris, frantic surface beetles and sand lizards scurry by, grasshoppers leap across the terrain, and robber flies, birds and barking geckos are all in the neighbourhood.

Beyond this deflation hollow, I discovered an extraordinary mud nest in the shallow of a stone. A bee known as Chalicodoma builds her nest in a hollow in a rock sealed over by sand cemented with a secretion from her mouth. And just a short distance away, along the ancient riverbank of the Dorps, exists another active bee nesting site with a multitude of bee nests; here root and burrow fossils create extraordinary patterns between nest entrance holes. This is merely a glimpse into the myriad stories waiting to be uncovered at Wolwekraal.

Many aspects in nature remain undocumented. For example, the fly I filmed parasitising the solitary bee nests may represent a new host record. Some solitary bee species are highly specialised, acting as the sole pollinators for specific flower species. This fragile interplay highlights the delicate nature of plant-pollinator relationships. Our landscapes are vastly under-documented, and with many species facing extinction due to habitat loss and human encroachment, we must act quickly to better understand and protect these vital ecosystems.

Wild honeybees are equally fascinating, and again so little is known about them. In most places honeybees have become a commodity and are typically associated with hives (and honey), and traded as pollination units. In South Africa, fortunately, more than 90% of honeybee colonies remain wild residing in natural habitats. Contrary to common belief, we have no shortage of bees. This natural abundance fosters adaptation in micro-habitats, and to changing environments and climates. In both our solitary bees and wild honeybees, SA has a huge natural pool of excellent pollinators. In Europe, most wild honeybee populations have been lost, with the majority of western European nations seeing almost total domestication and hybridisation of their once indigenous honeybee species. As a result, many colonies succumb annually to disease and other stressors. In contrast, wild honeybees in their natural cavities create habitats conducive to survival. Their use of abundant, local, site-specific plant resins, mostly in the form of propolis, and their interactions with many other creatures, organisms and microbes within the nest, is what keeps their environment healthy. 

Human activity can disrupt this delicate balance. Introducing hives to a new area can drastically alter the local ecosystem. A single hive can house up to 60,000 bees, all of which require substantial amounts of forage to thrive. The ecological consequences can be severe, especially when unaware of the existing species. Besides the risk of disease and microbial shifts, and the introduction of different strains of honeybees into an area, honeybees can outcompete solitary bees for nectar and pollen, further stressing already vulnerable populations. Wild honeybees living naturally in an area are equally affected by such increases in honeybee numbers. During periods of extreme heat or drought, wild honeybees can enter a state of dormancy, relying on stored honey to survive. It’s been suggested that the number of wild honeybee colonies in an area is limited by the worst month for forage availability. 

Nature possesses a remarkable intelligence and a fragile balance that we must strive to protect. We should be cautious not to unintentionally contribute to ecological loss through changes like hive introductions in finely tuned environments. Instead, by planting indigenous flowers and veld types and allowing some areas of our gardens to remain wild, we can invite nature in and help create vibrant ecosystems. Just as Wolwekraal serves as a unique ‘laboratory’ for observing nature, our gardens can also become spaces for wild bees and other creatures, revealing the wonders of biodiversity season after season, and allowing us all to become bee-keepers of a different kind. Who knows what bees we may yet discover.