The threat of pollinators: What happened to the swarming insects?

pic (2).

I remember with nostalgia growing up in the village. There were many trees, lots of grass, plenty of fruits from the farm, bees, and numerous types of birds. I particularly loved the sunbird, for I found its beak amusing. Their beautiful colors and loud chirping made me very happy. Bee stings were also not uncommon, and swarms of insects attracted by the light during the darkness annoyed me when I tried to read. A couple of decades later, the birds are gone, quite literally! I do not remember the last time I saw a sunbird in my village. Bees too are as rare as desert rain and night readings around the light are quiet. What happened?
What are pollinators?
This particular incidence may not be peculiar to my village, it is all too common. But what are pollinators? Pollinators are species that facilitate the pollination process in plants. A plant can be pollinated by self-pollination, wind pollination or by pollinators in order to reproduce and in order to create yield.
Bees are the most popular types of pollinators but did you know that birds, bats, butterflies, moths, wasps, flies, and some mammals also pollinate? Bees in East Africa include carpenter bees, Amegilla bees, stingless bees, longhorn bees, and honeybees (Martins, 2014).

A German study found a reduction in the biomass of flying insects by 76% within the last 27 years.

There has been an enormous reduction in pollinators across the world, a matter that is potentially cataclysmic! A German study found a reduction in the biomass of flying insects by 76% in a span of 3 decades (Hallmann et al., 2017). pic5Another study analyzed data from over 1 million arthropods, from about 2700 species, in a period that lasted from 2008-2017. The results of this study showed a decline in species across the study regions. Moreover, the biomass, abundance, and number of species showed a decline of 67%, 78%, and 34%, respectively. Further, a report by IPBES shows that despite there being a 300% increase in the volume of pollinator-dependent foods globally; the population of pollinators is decreasing rapidly. Additionally, 16.5% of vertebrate pollinators are threatened by extinction (Potts et al., 2016).

Why do we need pollinators?

A decline in pollinators can certainly threaten food sovereignty, as the yields of over 2/3 of all crops are dependent on pollinators.

Paw Paw, watermelon, pumpkin, cucumber, and others are 100% dependent on pollinators and would not carry any fruits at all if there is no insect around. Only 1/3 of all crops are totally independent of pollinators and uses self – or wind pollination. pic4This needs to be taken into account when governments are talking about the issue of food insecurity and pushing for increased food production only instead of taking the protection of pollinators into account.

 

Why are pollinators’ biomass and diversity decreasing?
Urbanization, climate change, and deforestation are contributing factors to the decrease in insect decline but intensive agriculture is certainly the main factor. The problematic practices within intensive agriculture are monoculture and intensive weed control (lack of habitat for insects) and the application of pesticides. In Kenya, 32% of all products show high or very high toxicity towards bees. pic1Of most concern is the effect of neonicotinoid pesticides on pollinator populations. Neonicotinoid pesticides are modern insecticides that are very toxic to bees and bumblebees and have been linked to a reduction on bees as well as other pollinators (Nicolopoulou-Stamati, Maipas, Kotampasi, Stamatis, & Hens, 2016). In Kenya active ingredients such as imidacloprid, thiamethoxam, fipronil and thiacloprid are in use and can be found in 54 different products in Kenya as e.g. Confidor (imidacloprid), Actellic (thiamethoxam), Sword (fipronil) and Calypso (thiacloprid).
However, in Kenya there is no awareness creation about the toxicity of these products towards pollinators; as a result, farmers apply regularly during times when pollinators are out for foraging.

It’s important to point out, that in Europe three of the active ingredients are already withdrawn from the market (thiamethoxam, fipronil, thiacloprid) and one is heavily restricted to close areas (imidacloprid).

How do these neonicotinoids act on the health of pollinators?
When sprayed on plants, the chemicals are absorbed and transported through the vascular system and find their way in pollen, and nectar. As bees forage, they are exposed to neonicotinoid pesticides either indirectly via pollen and nectar or directly through spray drift. Inasmuch as these chemicals are more toxic when in high amounts, they are also quite harmful to pollinators when in chronic low amounts. pic2Effects on bees include memory disruptions, mobility challenges, foraging, feeding habits, and also hive activity (Henry et al., 2012). This eventually affects the health of the pollinators hive and the pollination capacities of these bees, and consequently a reduction in crop yield. A study done in 2012 on neonicotinoid pesticide thiamethoxam and its effect on the European honey bee showed that sublethal exposure to thiamethoxam lead to increase in hive death rate of foraging bees through homing failure. Bees that were exposed to thiamethoxam did not make it to their hives, but those in the control sample that were not exposed to thiamethoxam made it (Henry et al., 2012). Another study on large earth bumblebee found that exposure of these bees to imidaclopid affected their ability to forage (Gill, & Raine, 2014).

In Kenya, there are not many studies done to show the decline in pollinators, but one particular study done in the Lake Victoria region revealed that farmers in that region observed a decline in bees and bird over time (Abong’o, Wandiga, Jumba, Madadi, & Kylin, 2014). The study may not have identified specific population changes in terms of percentages but the observation of decline over years is significant. beeeeFurther, data from the National Bee Keeping Station, as well as observational evidence shows there has been a decline in wild bee populations, migratory swarms, and honey production in Kenya (Muli et al., 2014). In South Africa, a nationwide survey showed a decline in managed bee populations with losses of 29.6% from 2009-2010, and 46.2% from 2010-2011 (Pirk et al. 2014).
What shall we do now?
To reverse this process of pollinator decline, world governments must put any effort into the withdrawal and/or restriction of those pesticides, which are toxic to bees. The EU is leading the way in putting the health of the population first and took various neonicotinoids already from the market. pic3There needs to be awareness creation amongst the farmers, to inform farmers not to spray during the flowering season, when the pollinators are out and especially not during the morning, as pollinators are most active during this time of the day. Farmers could also adopt integrated pest control methods that do not give priority to pesticides. To attract bees, flower strips with bright colors should be grown. Such flowers include dandelion, goldenrod, lavender, marigold, milkweed, snapdragon, and sunflower. Habitat for wild bees should be created as they nest in the soil and wild bees nest should not be destroyed as it is practiced by many farmers.
What can I do as an individual?

Being aware of the impact of how you consume is a good start, although, that is often difficult to navigate. It’s always a good idea to make sure you’ve got a diversity of flowering plants around your home, space doesn’t matter. Did you know that Berlin has more bees than the surrounding agricultural fields, as many people grow flowers on their balconies and window benches? Even just getting in touch with nature is good.
Clearly, we cannot afford to have declining pollinators as this will threaten our food security. It is already too difficult feeding the current population especially in Africa yet most African governments are silent on this concern. We need to recreate our beautiful nature with beautiful smelling soils, chirping birds and stinging bees. It’s our responsibility to spread awareness. Let’s start now before it’s too late.

 

References

Abong’o, D., Wandiga, S., Jumba, I., Madadi, V., & Kylin, H. (2014). Impacts of pesticides on human health and environment in the River Nyando catchment, Kenya. International Journal of Humanities, Arts, Medicine and Sciences, 2(3), 1-14.

Gill, R. J., & Raine, N. E. (2014). Chronic impairment of bumblebee natural foraging behaviour induced by sublethal pesticide exposure. Functional Ecology, 28(6), 1459-1471.

Hallmann, C. A., Sorg, M., Jongejans, E., Siepel, H., Hofland, N., Schwan, H., … Kroon, H. D. (2017). More than 75 percent decline over 27 years in total flying insect biomass in protected areas. Plos One, 12(10). doi: 10.1371/journal.pone.0185809

Henry, M., Beguin, M., Requier, F., Rollin, O., Odoux, J. F., Aupinel, P., … & Decourtye, A. (2012). A common pesticide decreases foraging success and survival in honey bees. Science, 336(6079), 348-350.
https://www.dw.com/en/to-stop-an-insect-die-out-the-world-needs-pollinator-friendly-policies-scientist-warns/a-50682992
Martins, D. J. (2014). Our friends the pollinators: A handbook of pollinator diversity and conservation in East Africa. Nature Kenya, the East Africa Natural History Society.
Nicolopoulou-Stamati, P., Maipas, S., Kotampasi, C., Stamatis, P., & Hens, L. (2016). Chemical pesticides and human health: the urgent need for a new concept in agriculture. Frontiers in public health, 4, 148.
Pirk, C. W., Human, H., Crewe, R. M., & VanEngelsdorp, D. (2014). A survey of managed honey bee colony losses in the Republic of South Africa–2009 to 2011. Journal of Apicultural Research, 53(1), 35-42.
Potts, S. G., Imperatriz-Fonseca, V., Ngo, H. T., Biesmeijer, J. C., Breeze, T. D., Dicks, L. V., … & Vanbergen, A. J. (2016). The assessment report on pollinators, pollination and food production: summary for policymakers. Secretariat of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services.

 

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s