Harvest of evidence

The last entry I posted was premature in its prediction that autumn is here and for the past week we’ve enjoyed some bright, warm weather: an Indian Summer before autumn proper envelops us.  Sunday afternoon was spent in the garden, digging up potatoes and planting the garlic we bought on the Isle if Wight.  Neither of these crops requires pollinators, but others we’ve been harvesting this month do, including squashes, runner beans and greengages.  The latter are from a mature tree that, when we took over the house in 2012, I assumed was a bog standard Victoria plum.  The tree did not crop last year but has more than compensated this season with abundant deliciously sweet fruit.

All of this provides useful anecdotes for public lectures.  Since appearing on Bees, Butterflies and Blooms I’ve regularly been asked to give talks to gardening societies and  I try not to refuse because they are usually fun with attentive, knowledgeable audiences.  At one such event earlier this year I was asked: “Is there any evidence that declining pollinators are resulting in lower crop yields in Britain?”  It’s a great question that goes to the heart of evidence-based conservation and the notion that science should be informing such policies as strategies to conserve biodiversity.

As far as I’m aware there is no indication that British insect pollinated crop yields have declined.  And if the evidence of our greengages, runner beans and squashes is anything to go by, there’s currently plenty of wild bees, hoverflies and other insects (we get few honeybees in this garden) to service those food plants that require their pollinating activities.  But that doesn’t mean we should be complacent and monitoring is required, because the evidence from other countries is that yields are down for insect pollinated crops and hand pollination is required in some places.

Evidence should inform everything that we do and believe as scientists, gardeners, informed members of the public, whatever label we choose for ourselves.  This is especially true of currently controversial issue such as the causes of global climate change or the effects of neonicotinoid pesticides on pollinator health (see Dave Goulson’s slides from a recent conference talk, for example).  But we should also understand that a basic tenet of science is that it can never “prove” anything:  new evidence may appear at any time that refutes our cherished notions, or disproves that pet hypothesis.  We make decisions on weight of evidence not on proof.  So it was depressing to read a widely publicised article about a Nigerian postgraduate student’s claims that he has “proved” that homosexual relationships are “unnatural” because only the opposite poles of magnets are attractive to one another, the same chemical compounds do not react together, and roosters only love hens.   At first I thought it was a spoof but it appears that the research student is perfectly serious and, more, has been tipped to win a Nobel Prize by his equally deluded supervisors.

It’s easy to scorn the guy’s findings and point out that people aren’t magnets or simple chemical compounds and that homosexual activity is widespread in the animal world (so how do we define “unnatural”?)   But Karin, as always, had a deeper and more nuanced view of this story than did I.  Perhaps it’s her training in psychotherapy but whatever the reason, she gave an alternative perspective and pointed out a sad possibility.  Karin suspects that the student has been manipulated by academic and political powers that have a vested interest in such “proof” because of threatened sanctions on aid.  Under this scenario the student has been encouraged by the academics at the university to pursue this misguided work, which can only support the Nigerian government’s anti-gay stance.  Of course the research will never be published by any reputable scientific journal and the story has harmed the University of Lagos’s international reputation.  But for the narrow minded and biblically fundamentalist, the story itself will be evidence enough to shore up their own prejudices.  One person’s crackpot claims is another’s decisive evidence.