Times have changed.
When I was a young boy, we used to have a small and not too special garden, located in a small town in the East of The Netherlands. (Some readers may think ‘argh shut up Robin, you’re still a fucking child’ and although that may have some truth to it, it also makes this story all the more worrisome) I took care of the garden most of the time that our family lived in that place. It was a simple garden, mostly already there when we moved in. A patch of grass lawn (or moss, daisies and dandelions?), a small pond, a very large paved terrace. Some color was provided by a few disproportionally small raised beds that had a bunch of horticultural plants here and there. My favorite plant present at the time was a huge Buddleja davidii, better known as a butterfly-bush. (I did not know then that they’re also horribly invasive, and since learning this about a decade or so ago, I have been on the fence about it) This butterfly-bush, as the name implied, was ALWAYS full of butterflies. They loved drinking the sweet nectar from its many many flower heads. The bush admittedly was huge, and must have had several hundred flower heads at a time, but it was no exception that the plant was entirely covered by insects; bees and bumblebees, hoverflies, and most obviously butterflies. The Netherlands is not a place with great diversity, it has been species poor for decades, probably centuries. However, some butterflies were abundant. Among the most abundant were small and large cabbage white butterflies, peacock butterflies, small tortoiseshells and red admirals. It may not have been the most impressive list of species, but nevertheless was a wonderful and impressive sight.
Flash-forward to ten years later. Roughly 2011. By this time, I had started studying Biology and was about to finish my Bachelor’s thesis (on insects, of course). I no longer lived in the place with the garden, and my family, too, had since moved a couple of times. I did live in a student house, which, although lacking a garden, provided a good home – in the form of cracks in the concrete slabs surrounding the house – to several invasive trees and bushes. The dominant tree here was Robinia pseudoacacia, a beautiful tree, but also a brutally invasive beast. Some cracks were occupied by other plants, among which my old friend, the butterfly-bush. There was something different about the butterfly-bush. Insects still seemed to like it, but clearly, they were not around in the numbers that I had seen in my youth. Sure, sure, I studied 75 kilometres from the place I grew up, and that may have explained part of it. It is all anecdotal, but I would not be surprised that numbers had been much greater a decade before in this town as well.
Now we jump forward to the present time. What has changed? I have finished a PhD degree in ecology/entomology at the Netherlands Institute of Ecology. In this time, I have worked on several species of butterfly and moth. I certainly kept an eye out for them whenever I would be outside and wherever I would go. Except the odd cabbage white, there was not much flying around in the fields or (organic vegetable) gardens. Today, I don’t live in The Netherlands any longer. My job has brought me a few hundred kilometres South-East. I am currently working with a small team of plant-insect researchers at the Technical University of Munich. My first observation after moving to Southern Bavaria was that insect diversity and abundance were still a bit healthier here than what I had seen in the Netherlands in the years before. Flower strips in agriculture are widely used in Bavaria, and in these strips, you can see quite a few butterflies flutter by. (Yes, I did that) However, I also noted that nothing ever came close to every summer in the ’90’s on that huge butterfly-bush.
Today, I observed something that I found so noteworthy that I spent almost ten minutes trying to get a good picture of it. I saw two butterflies that had woken up from hibernatio and were warming up their weathered wings and bodies in the springtime sun. They were the small tortoiseshell (Aglais urticae) and the peacock butterfly (Inachis io).
What was so noteworthy about this? Well, I have spent the last twenty years of my life being enamoured by insects. I find them among the most fascinating creatures on the planet. I have chosen a career path in which the red thread has always been entomology. I think my opinion in the matter has some weight to it. This moment was noteworthy because I found it noteworthy. I found it noteworthy because I could and cannot remember a single moment in the past five to ten years where I saw two different but considered very common species of butterfly in the same close area, let alone in the same shot.
What happened? Good question. You might think that we took their host plants away. Without food, no eggs, no caterpillars, no butterflies, right? True. Except – and I’ll save you a quick google – the larvae of these two butterflies feed on stinging nettle. Females deposit small clusters of eggs, and the groups of larvae gregariously feed on stands of nettle until they are about to pupate. At this time, they tend to spread out and disperse to find a suitable place to form a pupa and transform into an adult butterfly. Stinging nettle, as we all know, is pretty much everywhere. Sure, most of us don’t want it in our gardens, and we may pull it out, but there is plenty of nettle in other areas, including road sides, forest edges and agricultural field margins. Nettle quite likes these nitrogen-rich soils. So, what is it then? It’s another good question. Pesticides, pollution, loss of habitat, climate warming, reduced quality of host and nectar plants. We know that all these things (among a much longer list) may have a role to play, and it is hard to give a clear answer. But one thing is quite clear, the presence of the human species is wiping out species at rates that greatly exceed the natural rate of extinction.
It’s not pretty.
There are many entomologists out there working hard on finding the reasons for insect declines, and thinking hard about solutions. I am trying to do my fair share, but sometimes wonder if it is enough. It is about time that we turn the tide for our little friends. Insects are tough bastards. They have been around for a long time and can be hugely prolific. Populations could increase. It may not be too late for many species. But we may have little time left. I believe that if we truly want to make a change for nature’s biodiversity, we can do this. I also think that we should. I could write ten more paragraphs about all the processes that NEED insects (and biodiversity in the broader sense), but I won’t, because it is not the point I’m trying to make. I don’t think we should protect diversity only because of function. I think we should protect it because it is worthy of protection. I think we should protect it because every child in the future should be able to have fond memories of a bush filled with butterflies.