With the publicity surrounding bee decline, people are asking themselves how much we need to be concerned. I sometimes get asked questions such as:
Another question tends to focus on honey bees: "If honey bees (specifically) disappear, will humans starve, or will other bees or other insects merely compensate for them, by providing the pollination services we need?"
Let’s tackle these questions.
Firstly, studies have shown, that in terms of crop pollination, wild pollinators can do the job of honey bees.
For example, a study (published Feb 2013) by Garibaldi et al states that wild pollinators enhance fruit set of crops, regardless of honey bee abundance, and that pollination by managed honey bees supplemented, rather than substituted, pollination by wild insects. (You can find the study here - copy and paste the web address into a new window: http://www.sciencemag.org/content/339/6127/1608)
Thus in an agricultural system where insect pollinator abundance is promoted and can thrive, a variety of bees and pollinating insects will quite naturally pollinate crops, and will do the bulk of the pollinating.
So it seems that if honey bees disappeared off the planet tomorrow (not that we would want them to!), then in theory, other pollinators could step in to replace honey bees to pollinate at least some - and probably quite a lot of our food crops.
Such a scenario requires that wild pollinators are available on farmland. In many scenarios, this is not the case, and farmers have to take pro-active steps, sometimes purchasing bees.
Indeed, formerly wild bee species are increasingly being reared commercially and are being sold for pollination to farmers who otherwise could not guarantee the presence of these pollinators on their land.
So can we relax?
No, because to continue to rely on commercial rearing of particular pollinators for food crops, instead of addressing the problems that are causing decline, is risky for food security, and it is taking a sticking plaster approach to solving our problems.
We might be able to breed a few species, but we cannot breed one of every bee, butterfly, moth and pollinating beetle, not to mention a myriad other invertebrates.
It also ignores the importance of diversity and species abundance in the wider landscape and this inter-related ecosystem. Simply breeding a few more bee species for commercial pollination merely solves a potential glitch in preserving intense farming practices.
Unfortunately, honey bees are not the only bee species – or even pollinator or invertebrate species, to have experienced decline.
The focus on honey bees in the media may create a distorted impression of the real scenario. However, the reason honey bees have received so much focus, is because they are more closely observed by humans than any other invertebrate species. For example, commercial beekeepers providing pollination services to agriculture, as well as hobby beekeepers, have collectively raised alarm for quite some years, and especially in connection with neonicotinoid pesticides.
Nevertheless, the problems faced by honey bees and reported by beekeepers, really should raise alarm generally, because it should lead us to ask questions about what is happening to wild species of bees, pollinators and other insects, and in fact, invertebrates as a whole.
However, I think more focus and resource is needed on monitoring a larger variety of insect species.
What some research tells us is that with species decline, there occurs a corresponding degradation or decline in vegetation/the wider eco-system.
Generally, there may be some overlap in pollination of some plants by some species (i.e. multiple pollinators may provide a potential pollination service for particular plants).
However, this is not always the case.
What the evidence suggests is that loss of species does not necessarily mean that this will definitely be compensated for by other species, and that unfortunately, biodiversity foots the bill.
Indeed, we know that certain plant species can only be pollinated by a very limited number of insect species.
For example, some species of orchid and fig are only pollinated by particular wasp species.
Many reports can be found on the internet, however, here are a few examples of resources detailing decline of bees and other insects:
There are isolated areas cases where human action has contributed to declie of a particular species. For example, according to Xerces in the USA, commercially reared bumblebees may be a threat to wild bees: B. affinis, B. occidentalis, B. terricola, and B. franklini.
However, it stands to reason that some of the problems we are causing for bees, are also a problem for other species.
For example, if habitat loss and agricultural intensification, with years of pesticide use, are affecting bees, they must surely affect other insects and invertebrates too.
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