Connectivity of green and blue infrastructures: living veins for biodiverse and healthy cities

Its World Bee Day!

Every day that the world keeps on ticking is a global acknolwedgement of the importance of bees.

Honey bees have been associated with humanity for a long time. A lot of emphasis is put on their roles as pollinators, which we absolutely need in order to grow most of our food crops. But let’s not forget that they also make honey and wax. Honey is not only nice to eat, and a direct way to taste the landscape, but also has a number of very useful antiseptic properties. Honey can be used at home or in hospitals to prevent infection and scarring. Wax is also more important than you might think—it isn’t just used for candles (of course, if you live in Scandinavia candles will practically save your mental health in winter). Beeswax is also used in common products like cosmetics and pharmaceuticals. Pure beeswax, without contamination from agricultural chemicals, sells at a premium price for this market, and is mainly now found in rural Africa. Honey bees, as eusocial species, have lessons to teach us about evolution, and also provide us one of the most fascinating methods of abstract communication in the animal kingdom, with their ability to communicate the angle and distance to a resource through the “waggle dance.”

BIOVEINS is researching the bees that nested in our bee hotels, as a way to understand how wild bees use green spaces in cities. Thus, we are focusing on all the non-honeybee (Apis mellifera) bees. These bees may include bumblebees (Bombus), and other solitary bees like Coletes, fuzzy bees that you might mistake for honeybees but that generally have less-distinct yellow bands on the thorax, or Andrena, the silvery fuzzy sand bees, which make colonies of nest-burrows in sandy banks and dunes. The genus Osmia nests in straws and other hollows, including snail shells! The Nomada genus consists of small, brightly colored, smooth bees. And there are many more. If perhaps slightly less incredible in form that flies (, they are also diverse and beautiful, and they also play vital roles in helping plants of all kind reproduce. Without bees, we would still have pollinators like flies and butterflies, birds, bats and even ants—but ecosystem processes might start to fall apart in surprising ways. According to Winfree et al. (2011), 87% of plants are pollinated by animals. Bees are thought to be the most prolific pollinators, since all bees eat nectar, pollen and other plant products throughout their life stages. Flies, specifically beeflies, hover flies and tachinid flies, are the second most important pollinators, while butteflies come in third with only some actually taking nectar and pollinating flowers. No butterflies actually eat pollen and thus they don’t collect it on purpose, but they may act as long-distance dispersers of accidentally-transported pollen. Birds, bats, beetles, ants and other species have specific mutualisms with a relatively narrow range of flowering species.

Honeybees can create stiff competition for flower resources due to the large sizes of commercial colonies, which can have negative consequences for wild bee (and other pollinator) populations. But, according to our understanding of biodiversity, we need the combination of all the diverse ways of being pollinators to ensure that crops, flowers, and other plants survive the wide range of possible impediments that climate change can throw up, as well as other more normal risks and minor disasters that occur in nature. One particular way of carrying out pollination (seasonal timing, frequency, visitation routes and distances, network of plants visited, techniques for getting into complicated flowers, etc.), or a couple of ways in combination, might just be the right strategy to survive problems that come up. We should thus think about favoring wild native bees in our gardens whenever possible, for example by making nesting materials available for them, or planting plants they can feed on. We can also avoid using pesticides in our gardens. This has already been outlawed in French public and private gardens, which sets a good example for other countries. Of course, the vast majority of the landscape is still awash in pesticides and other contaminants used to produce industrial food crops, that may kill bees, and that render their wax too impure for human use. Ironically, perhaps, cities might be able to become oases for healthy bee diversity.

Also, here are my personal tips for cohabiting with bees (and wasps). (1) You can pet bees while they are on a flower, feeding. They won't notice, and they won't sting you. You get to enjoy how fuzzy they are. (2) Avoid bees that look lost, in other words wandering around walking on their legs rather than flying. They may get confused, crawl in your clothing, and sting you in a panic. (3) If a wasp starts making a small nest in the wrong place, you may be able to slowly displace it to another location. The female, when she comes back to provision her eggs, will probably find the nest if it is not too far away and memorize the new location after a few trips. You can avoid killing the wasp, and also recreate a version of famous experiments by Niko Tinbergen! (4) Yellowjackets (Vespula and Dolichovespula) sometimes annoying want to eat your food during a picnic, especially in the fall. You can often satisfy them and keep them out of your own sandwich by giving them a little tiny piece of meat or other food just for them. Honestly, we can all live together with just a little attention and learning.

Are you BEE-wildered? Are you BEE-guiled? Have you BEE-wilded you garden? Look at some of the resources below!

Winfree, R., Bartomeus, I., & Cariveau, D. P. (2011). Native pollinators in anthropogenic habitats. Annual Review of Ecology, Evolution, and Systematics, 42, 1-22.

IPBES assessment report on pollination services:

in French:

--Meredith Root-Bernstein 20 May 2019