Eristalis tenax is claimed to be a honeybee mimic. Indeed, when I started working on Eristalis tenax I occasionally (more than once) brought back bees from the field, instead of hoverflies. Apparently, even beekeepers struggle to tell the difference, as evidenced by the post below from the Kangaroo Island Beehive, with the heading "Busy bee" but the photo shows an Eristalis male hoverfly. Hoverflies are good pollinators, so the flower probably doesn't mind, but I doubt the Beehive people will get any honey out of this little guy.
I found myself staring at my electrophysiology setup this morning, lacking my usual motivation and enthusiasm for it. I started justifying to myself why I shouldn’t do an experiment today; I’m tired, it’s been a hectic week, it’s Friday, I’ve got other things I could do instead. The list of excuses I could have used goes on and on.
So why did I setup an experiment? Mostly because of advice I was given years ago. When you find yourself procrastinating with a list of tasks, pick the one you feel like doing the least and just get it done. Even if you achieve nothing else for the day, it forces you to stop the procrastination cycle.
Of course, it was one of the best recordings I’ve ever got, even though; I’m tired, it’s been a hectic week, it’s Friday and I had other things I could have done instead.
- By Richard
Some disturbing news has come out recently, in the form of a paper in Biological Conservation, reviewing evidence that insect populations around the world are falling at a shockingly high rate (https://doi.org/10.1016/j.biocon.2019.01.020). In a survey of 73 studies on insect populations world-wide, the authors show that according to the papers surveyed, 41% of all insect species are in decline, with a 2.5% loss in total insect biomass every year.
On land, the biggest losses in biodiversity are in dung beetles, followed by moths, butterflies and bees (the authors note that "the fate of other pollinators such as hoverflies is ... largely unknown"). However, the situation is even worse among aquatic insects (33% of species are endangered vs. 28% of terrestrial species), with major losses among dragonflies, mayflies, stoneflies and caddisflies.
The authors identify the main causes as originating in intensive agriculture during the last century, leading to habitat loss and pollution from pesticides and fertilisers. A smaller role is also played by various biological factors including diseases and the effects of other introduced species, as well as by climate change.
Plummeting insect numbers are of course highly concerning because of their fundamental position in ecosystems, playing a role in pollination, recycling nutrients and decomposition (see also Kevin's recent post) and importantly as food for many vertebrate species.
Species that have evolved as specialists in one ecological niche are the most susceptible to loss. In many cases, these species are being replaced by other generalist species, which some could argue could start to fill the roles vacated by the specialists. But as the authors point out, just as import as the loss of insects in general is the fact that the loss of individual species compromises the long-term resilience of ecosystems.
Some caveats may exist on the conclusions drawn in the paper. In some quarters there has been criticism of the search methodology used to select papers for inclusion in the survey, which may have biased the pool of papers towards ones showing declining numbers only. Also, many major species of insects were not included in the study, due to a lack of data, and vast areas of the globe were not included for the same reason.
In fact, one possible glimmer of hope is that the vast majority of the surveyed studies were based in the highly industrialised and developed countries of North America and Europe, with some evidence from the remaining studies that the rate of decline may be lower in other regions of the world.
In response to the paper, some news sites have offered suggestions for actions that people can take locally to help to alleviate the problem. For two such examples, see here and here.
I am not very used to meet compatriots here in Australia. What a surprise, that my colleagues from Prague (Dr Petr Janšta, Bc. Julie Böhmová and Bc. Ondřej Barda) decided to come to Adelaide this January! This coincidence ended up in a fieldtrip to Moorunde Wildlife Reserve. We were invited there by our local colleague, Dr Gary Taylor, from Adelaide University.
We had a wonderful time. Collecting, installing a Malaise trap and - of course, looking for wombats! Unfortunately, we left too early to meet them. Instead, we came across myriads of Yellow Jewel Beetles (Temognatha heros). Yellow Jewel Beetles use their vision to locate conspecifics. They were strongly attracted to my pinkish-orange t-shirt, and a few of them even landed on me!
South Australia is a perfect place to live for a zoologist, with all the unique and beautiful creatures!
However, my internship is slowly coming to the end. Hopefully, this is not my last time working with people from Motion Vision Lab, as I love both the team & the topics that are being studied here. I encourage everybody, who fell in love with motion vision research, to consider coming, too - there is a post doc offer (see post below). Don't miss your chance.
The hoverfly vision group can be found at 2 locations: At Flinders University in Adelaide, Australia, and at Uppsala University in Sweden. To find out more about us and our research, browse through the pages.