by Neil Rusch, South Africa. No.20 Summer 2021
Wild honeybees have shown themselves to be highly adaptive. If left to their own devices they colonise and thrive in niche environments, endure extremes of heat and cold, and miraculously survive if challenged by fickle nectar flows, influenced by climate shift and drought. These and other insights are the focus of a project that has entailed working with bees in the Nama Karoo, a dryland region in South Africa known as !Ka Gariep in the indigenous language.
In this article I hope to convey something of my experience and awe, inspired by the resilience and adaptability of African honeybees (Apis mellifera scutellata). Woven into the study I will include the unfolding story of the Agave Honey Bee (LOG) Hive that is being built and deployed in the Nama Karoo and elsewhere with the aim of habitat-creation and regenerative purposes.
The conception and development of the Agave Honey Bee (LOG) Hive was written about in NBH, No.18 Winter 2021. Project details appear on the freelivingbees platform [1] whilst the hive – vertical and horizontal versions – is described at length in Bee World [2]. The Agave log hive project is currently collaborating with the Sustainability Institute, affiliated to the University of Stellenbosch. The purpose is to establish an ongoing teaching and skills-share programme in-line with the Agave log hive philosophy, that is: (a) minimal to no intervention, (b) bee-centred habitat creation before honey production, and (c) re-wilding, or re-nature-ing as some prefer to call it.
Pursuing these ideals we began in August 2020 deploying Agave log hives on a 4000 hectare farm in the Nama Karoo where farm management had begun to implement a range of regenerative farming practices. As plans unfolded we discovered immediately that the bee project would not be a simple case of placing prepared logs in select locations and then waiting for wild swarms to colonise the hives, no matter how bee-friendly the new hive was. There were no wild bees obviously visible in the arid environment at that time. The depleted wild honeybee population can plausibly be explained by the paucity of rain, over a seven year period, variously attributed to the El Niño phenomenon, climate shift, or both.
The study began with a survey in which we systematically investigated rocky outcrops and cavities for any sign of bees, including hollow quiver tree trunks (Aloidendron dichotomum, formerly Aloe dichotoma). Our search was successful in locating remnant honeycomb where wild bees had previously lived but there were no living bees, only their traces. Either the colonies had absconded or died out. Results of the survey revealed that the long-term drought had seriously impacted the veld and vegetation with stark consequences for the honeybee population.
In anticipation of rain at some future date we set about restoring the previously occupied cavities. Mostly this entailed reducing cavity entrances to assist thermoregulation but also to aid hive protection against predators like the Death’s Head Hawk Moth (Acherontia atropos), Agama Lizards (Agama hispida) and Bee Pirates (Philanthus triangulum, and Palarus latifrons), the most destructive bee-predators in the hotter parts of southern Africa. Temperatures in the project area can exceed 40°C, day-after-day in Summer, yet plummet below 0°C overnight in Winter.
The mean annual effective rainfall in the Nama Karoo varies from less than 50 to 150 mm per annum. Water availability is critical to colony survival as is a temperature-efficient cavity. The semi-desert day-night temperature differentials are in any case extreme. The long-term survival of any colony in these conditions depends hugely on the cavity they occupy. A thermally-efficient cavity can improve the energy expenditure of the colony. Having done what we could to restore the wild bee places we then hung one Agave log hive in a kameel doring tree (Vachellia erioloba) to await the arrival of a swarm. This all relied on rainfall to break the drought.
Five months later the southern hemisphere Summer rain finally arrived. We returned to the project area intent on continuing our survey now that the veld was festooned with blossoms in abundance, as only a dryland ecology can produce. To fully immerse ourselves in the environment we decided to camp near a naturally occurring spring, or oog (Afrikaans: eye). Right away we were rewarded. On the first day before sunrise we awoke to the sound of bees clamouring among the yellow-green blossoms, flowering on the bushes (Zygophyllum morgsana, Afrikaans: skilpadbos) next to our tent. The sound of bees before sunrise made the connection between bees and plants vividly obvious: resilient bees living in arid conditions require resilient plants that thrive with minimal moisture.
Soon after sunrise as the temperature began to climb the bees suddenly disappeared, as if a switch was flicked. Apparently the skilpadbos had shut down its nectar flow in order to prevent unnecessary and wasteful nectar loss caused by evaporation. This interaction between the plant and the bees was repeated the following morning and the morning after that for as long as there were blossoms on the bush. It’s at moments like this that I stand in awe of the wild African bees. As we had witnessed there is a symbiotic intelligence that connects Apis mellifera scutellata to the tough plants. Both are elegantly adapted to their niche environment. But there was something else we had learned through this experience, and that was to be patient, to watch, and to listen.
Knowing that there was a colony of bees in the vicinity we paid particular attention to the spring in the days that followed. We anticipated the arrival of specialist water-foragers from the colony at the water source. With day-time temperatures 35°C or more, it was reasonable to expect bees to collect water for the purpose of cooling their hive, wherever that was. From the spring we hoped we might trace their flight direction by follow beelines in the low-angle evening light. Thus we thought that we might discover the location of their hive but in practice it didn’t work out like that. The order was, first we heard humming and only then did we see the beelines converging on the spot where the colony nest was situated, 170m distant from the spring. In the days that followed we found another two colonies, having established what we were looking for, or should I say listening for (3). The three colonies were strong and vibrant and were all situated within a 350 metre radius, relative to the spring.
Meantime we received a message from the farmhouse, 7km distant, saying that a swarm of bees had moved into the Agave log hive; the one we had deployed five months earlier. On inspection it turned out to be a tiny swarm. We also discovered that a Death’s Head Hawk Moth had moved into the hive together with the bees. The colony was under extreme duress not only because of the moth but in addition the foragers arriving and departing from the hive were being predated upon by a dozen, or more Banded Bee Pirates. Sadly, this small colony did not survive but it was the first A. m. scutellata swarm to colonise an Agave log hive. Inspired by this we have deployed a further four Agave log hives of the vertical type and one horizontal log hive in the vicinity of the spring, figuring that the wild bee population will in time produce swarms that will occupy the Agave log hives. This confidence is based on the expectation of a good nectar flow from the Winter-flowering quiver trees, watered by Summer rains in excess of 140mm. The indigenous KhoeSan people believed in what they call “the rain’s magic power” (4). From our experiences in the drylands of the Nama Karoo there seems no reason to dispute this claim.
The Agave log hive project in the Nama Karoo is ongoing but already within the start-up phase we have made several important observations, which I believe are worth reflecting upon for the benefit of NBH readers.
Early on we considered introducing bees into the project area from 50km away. The idea behind this was two-fold: (a) kick-start the regenerative process, and (b) fast-forward an increase in the bee population. When we first contemplated this idea there was no knowing for certain that we would find a resident, foundational bee population. The impulse to “do something” is so in-built and powerful. It takes an equal force to stop, watch and listen. In our case patience paid off. It would have been so wrong to bring bees into the project area from outside. Of course, on paper and theoretically speaking, we are dealing with a single sub-species, A. m. scutellata but such reasoning overlooks an important factor: the interactions that take place between species and environment. In other words we must consider the integrity of both genotype and phenotype. This can be represented in the following relationship: genotype + environment + random variation → phenotype. It’s reasonable to suppose that if we had gone ahead and introduced “foreign” colonies into the area it might well have compromised the phenotype characteristic of the three wild colonies living close to the spring, and any others in the vicinity we may yet discover.
Water is necessary at colony level for temperature regulation but equally so for the individual bee, notably because of in-flight evaporation and excretory moisture losses. In short, bees and the bee biome has a high water turnover (5). The location of the three wild colonies near the spring is therefore likely no accident but rather a causal consequence, key to their survival. Observations over a 15-year period at a site 100km to the South suggests the same mechanism. When conditions are good the bee population is widely distributed. During periods of water-stress the population retracts to a reliable water source. In dryland conditions the bee population grows and shrinks according to the patterns of intermittent yet cyclical rainfall. The fluctuating bee demographic provides a proxy, indicative of water availability; vital for thermoregulation and for the maintenance of hive humidity. Both temperature and humidity are conditions that must be maintained for successful larval and pupal development, and also for nectar concentration (6). In other words when brood rearing is taking place water is collected and if water is scarce the colony is compromised.
Is bee behaviour dictated to by environmental conditions, or does bee intelligence inform adaption to niche conditions? This project provides us with an opportunity to contemplate such questions since the conditions in the Nama Karoo are so extreme and stark. I don’t believe that the mechanistic scenario is entirely correct, rather I see bees capable of responding beyond the boundaries of the mechanistic model in ways that are astonishing. For example, there’s research that tells us that A. m. scutellata have an unusual, perhaps unique, behaviour. Foragers begin the nectar desiccation process by regurgitating dilute nectar onto their tongues, which initiates the nectar-to-honey transformation. What is atypical is that A. m. scutellata begins this process early while the foragers are in the field amongst the flowers and on their return flight to the hive. Previously it was thought that nectar desiccation only begun back at the hive. The critical point is that A. m. scutellata foragers, taking advantage of the high ambient temperature, have adapted their behaviour and the nectar desiccation function. From this example it would appear that we are witnessing a “smart” response to the hot, dry conditions. Moreover, this behaviour has direct bearing on “honeybee thermoregulation, water balance and energetics during foraging, and for the communication of nectar quality to recruits” (7).