This is a delicate topic for me, as I study pollination services in agriculture and the answer to this question can directly impact the funding and interest in my research. It’s also a very complex issue; the answer varies globally and even within countries. This is a very US centric post because that is where I have researched bees and pollination services, but feel free to chime in below with a comment about pollination services in other countries!
I’m going to divide this issue into two chunks because there are two major groups of insects that contribute to crop pollination: domesticated bees (mainly the honeybee), and wild bees that already exist in the environment and provide “free” pollination services to agricultural crops.
Humans have had a long association with the honeybees; there is evidence that they were domesticated over 4,000 years ago in ancient Egypt and they have followed humans ever since (Buchmann 2006). The original purpose of their domestication was honey production, but modern agriculture relies more on the pollination services provided by the bees. In the US alone, the pollination services of honeybees are valued at over 15 billion dollars a year (Morse and Calderone 2000) (19.3–40.3 billion US$ when adjusted for inflation in 2012).
Widespread attention was brought to the honeybees after Colony Collapse Disorder was first reported in 2006 (vanEngelsdorp et al. 2006). The case of the “disappearing bees” was alarming because we didn’t know what caused it and because we couldn’t study the dead bees…they simply never returned to the hive.
The result of this original scare was twofold. First, a huge amount of research was funded to find the cause of Colony Collapse Disorder and to combat it (that’s a whole other post). Second, we realized just how fragile depending on a single species for all of our pollination services could be.
Though bee keepers are still experiencing large losses every winter, there is convincing evidence to show that there are more honeybees than ever before (Aizen et al. 2008). How can this be called a pollination crisis? Actually, though the number of honeybees has increased, our dependence on them has outpaced their growth. The number of pollinator dependent crops is increasing at a rapid rate (Aizen and Harder 2009).
Wild and Native Bees
This issue gets more complex. Because of the threats to the honeybee, researchers started looking for alternative pollinators. After all, there are more than 20,000 bee species worldwide! We’ve learned so much about native bees just in the past few years, and the research community is buzzing*, so to speak, about their potential to provide all of the pollination services that crops require.
Are those native and wild bees in decline? We don’t really know (Ghazoul 2005). There is some evidence to suggest that some groups of wild bees are declining (Bartomeus et al. 2013), but we really don’t know enough about their past abundance and distribution to say for sure. We only started really studying them when the honeybees began to suffer! As a result, we don’t have a baseline to judge.
We’re searching for species that can be domesticated (such as the mason bees (esp. Osmia spp.) and bumblebees (especially Bombus impatiens)) and ways to improve nesting habitat for mining bees. Farmers have even begun to invest in floral provisioning strips to boost native bee abundance within their fields.
And we know that native and wild bees can provide all of the pollination services that agricultural crops require…IF they have enough habitat (Garibaldi et al 2013).
So that’s all great, right? It sounds like we have resources we can rely on, spreading out our dependence to many species, and strategies for encouraging them are well on their way.
Threats to Pollination Services
But the elephant in the room is big agriculture. The wild bees can’t survive in monocultures of almonds spanning hundreds of hectares in California (Klein et al. 2007). And in the meantime the bees (and all other insects at the same time) are being pounded by pesticides. And not just the insecticides made to kill insects, but fungicides and herbicides. They are not only toxic themselves to the bees, but the herbicides also have a huge impact on non-crop floral resources on field edges.
Recent work by Chris Mullin shows that there are more than 98 different pesticides in honeybee pollen (Mullin et al. 2010). And a recent paper that came out this year shows that most of the pollen in honeybee hives is from weedy field edges (Pettis et al. 2013). Those edges are strongly impacted by pesticide use.
So what do you think? Is there a pollination crisis? Is it imminent? We can’t say for sure, but there are plenty of reasons to invest in pollination services. After all, we owe the diversity and colour of our diet to the pollination services provided by insects. And that diversity and colour is directly linked to our health and longevity.
As I once heard May Berenbaum say, “If we lost bees, we wouldn’t starve**, but we’d all get scurvy pretty fast!”
** Staples like wheat, rice, and corn do not require insect pollination.