Animals that work for us
- Shaun Smillie
Bees, birds, and bats are part of an invisible workforce that supports humanity.
Since the beginning of time, humans have recruited animals and given them jobs. Oxen were drafted in early to haul the material that built our earliest civilisations, and horses found work in transportation. As for dogs, humans have just kept finding new jobs for them to do.
However, not all animals are trained or tamed for work. Some are tasked simply with going about their everyday lives providing information to their human observers that, in years to come, may prove extremely important. Until recently, a few of these animals were going about their business in typical Joburg gardens, mostly unnoticed.
That was until Dr Chevonne Reynolds in the School of Animal, Plant and Environmental Sciences (APES) at Wits came up with an idea to gauge biodiversity in a city that is undergoing rapid urbanisation. In particular, she wanted to see how some of the world’s best pollinators – solitary bees – were getting on.
City bee biodiversity
Solitary bees are the lesser known of the bee super family but there are many of them around. It is estimated that there are nearly 1 300 bee species in South Africa and of those, only two are the classic social honeybees.
“Pollination services, and insect decline are a big issue. And 70% of all our crops are pollinated by insects, mostly bees,” explains Reynolds. “The problem we have when it comes to insect work is that insect populations haven’t been well documented, and so the data are quite patchy.” The status of the world’s pollinators is a cause for concern for scientists, because if bees stop moving pollen from plant to plant to facilitate fertilisation, agriculture will collapse.
Citizen scientists and bee hotels
For her project, Reynolds enlisted the help of some 350 citizen scientists, each one of whom was given a free bee hotel to set up in a garden. Each bee hotel, a small wooden box, has little holes drilled into it in which solitary bees take up residence and rear their young. All the citizen scientists had to do was take photographs and send them to Reynolds and her team. From the sealed-up holes, scientists could work out the occupancy rates of the hotels and from there get an idea of bee abundance in the city of Johannesburg. “It was a biodiversity indicator of sorts,” says Reynolds.
What they found in the study was a strong relation between socioeconomic status and the abundance of bees, which had to do with the wealthier citizen scientists having resources to maintain large floral gardens that supported more bees. Later the researchers collected what was left in a few of the nests and sent the sample for genetic analysis, which revealed that there are at least 14 species of solitary bees found in Johannesburg.
Hot birds can’t work
Solitary bees are not the only animals that are part of this invisible workforce. Scientists have roped in other species that are adding to our knowledge of what to expect in an uncertain future. The hot birds project involves an international collaboration of scientists who are studying the effects of heat and climate change on desert birds. The project spans the arid southern US, the Australian Outback, and the Kalahari desert. Dr Matthew Noakes, also of APES, worked on the project.
In the Kalahari, researchers have found that the increased frequency of heat waves is preventing some bird species from foraging efficiently as they must spend more time trying to stay cool.
Climatologists predict that southern Africa will experience more frequent heat waves in the decades to come, and after receiving a glimpse four years ago of what this future could look like, scientists are deeply concerned.
SA's first heat-related die-off
On 8 November 2020, staff in the Pongola Nature Reserve noticed dead birds around the administration offices. A later patrol of the reserve found a further 47 dead birds. The temperature that afternoon had reached 45 degrees Celsius; this corner of northern KwaZulu-Natal had experienced South Africa’s first ever known heat-related die-off.
“It was a combination of high temperatures and humidity that led to this die-off. Birds lose heat via evaporative water loss, but if the water content of the surrounding air is already high, this limits the amount of heat they can lose from their bodies,” says Noakes. The die-off didn’t just claim birds, it killed bats too.
There has been growing concern over what effect climate change will have on bats. Just like solitary bees, bats are great pollinators on whom our food production relies, and they play key roles in seed dispersal, insect control, and nutrient recycling. Noakes is in the process of setting up a laboratory in which he will assess heat tolerance in bats across climatic gradients in South Africa. It is part of his work into investigating which species are more resilient to heat than others, and how they adapt their behaviour and physiology to cope with higher temperatures.
Understanding heat tolerance not only assists in our understanding of the effects of climate change, but Noakes believes that it can also help in guiding the establishment of protected areas and wildlife corridors.
The birds, the bees, and humanity
But there is another important job that these unlikely worker bees, bats, and birds are doing, which Reynolds discovered while working on the bee hotel project. Again, she turned to her citizen scientists, and, through interviews and social media data, she began to understand why these volunteers took on the task of installing and monitoring the free bee hotels: “There is a very strong human-nature connection that developed through supporting the project,” she says. “It shows that there are unrecognised forms of labour that animals do for us in terms of our wellbeing, even bringing us joy.”
- Shaun Smillie is a freelance writer.
- This article first appeared in?Curiosity,?a research magazine produced by?Wits Communications?and the?Research Office.
- Read more in the 18th issue, themed #Work, which delves into the evolving nature of work, shaped by societal shifts, technological advances, and equity challenges.