The press has recently been filled with reports of a new global environmental crisis creeping up on us day by day. A study in Germany has concluded that general insect numbers are decreasing year on year. The study makes no conclusions as to the cause but is observational only but does show a clear trend at these sites. Many environmentalists have seized on this report as proof that conventional agriculture is entirely to blame for this decline which,if true, has serious repercussions for the entire ecosystem. The so called windscreen effect (whereby car windows seem to be less ‘bug splattered’ than they used to be) has also be linked as further evidence that everyone can relate to. Combined this is being used to further condemn the use of insecticides. Should farming foot the blame for this? The report this is based on does not make this assumption but suggests a possible link.
I would confess another observation. It’s the time of year when flies come into the house to die before the winter. I would say this year the number of ‘attendees’ is lower than previous years in my house but a single year observation could be caused by all sorts of things. Contrary to that working the tractors late into the night recently seemed to attract as many swarms around the worklights as usual. The Swallow population (insect eaters) also appeared to have a good year with successful breeding.
I would make the following additional comments on the subject :
Insect populations numbers fluctuate annually quite naturally depending on each season’s climate variation. In the UK we have had a series of very mild winters in recent years and this will have affected insect lifecycles. Do hibernating insects struggle in a wet winter period? Some years there are swarms of wasps; other years there are less. May flies and horseflies (or as we call them; “stouts”) seem to be flourishing.
Artificial light sources are known to be detrimental to nocturnal insects such as moths. How many insect populations have been crippled by artificial light interfering with breeding cycles? Modern street lights are now going white with LED bulbs; is this further damaging populations?
Insects love livestock and the waste they make! How have insect populations changed purely as a result of a decline in livestock numbers across Europe?
We are using less insecticides now than we used to. The highest load is on the Spring Bean fields and yet these are still insect havens most of the year. We successfully applied targeted insecticides to our beans, following pest threshold triggers, in close proximity to active bee hives (with keeper’s cooperation) without any issue by spraying post-dusk. The products we use now are much better than those of the past and much more targeted.
On our farm in recent years agri-environment areas have continued to grow giving new insect-rich nature habitats such as field corners, field margins, stone curlew plots and wild bird covers. These must be having a positive effect for the ecosystem and insect numbers.
How does air pollution affect insect populations and has encroaching urbanization escalated this effect? Perhaps in the UK a move to a service economy and away from a manufacturing base has had a positive effect.
Habitats continue to be lost to residential and non-residential development which will surely only have reduced insect populations.
The trend for sterile urban gardens (decking and paving) over natural garden areas will have damaged insect populations by removing habitats. Homeowners need to make more ‘hotels’ to help do their bit.
In conclusion this subject is really complex and more study is needed. One study in Germany should not be extrapolated to the entire globe and simply jumping on the pesticide-bashing bandwagon is over-simplistic! Insects are undoubtedly a key base to the food chain and the canaries in the coal mine; let’s please see more research before leaping to conclusions and find out what’s really happening!