In view of the end-of-the-world rain we had all day on Monday, I was somewhat concerned about how soggy I was going to get during yesterday's planned day of fieldwork. I needn't have worried though - the day dawned bright and sunny with very little breeze. Perfect fieldwork conditions! So I set out to my regular field site for my first Philaenus spumarius collection of the season. And a rather nice day it was too.
The field was a-buzz with all manner of invertebrates making the most of the dry weather, including this impossibly tiny and impossibly handsome weevil. I do love a weevil!
But back to business! Although there are around 18 species of froghoppers and leafhoppers that could potentially act as vectors for the Xylella bacterium should it enter the UK, Philaenus spumarius (also known as the Meadow Spittlebug) is by far the most widespread and abundant. It has also been implicated in the spread of Xylella in Italy, so it is of particular interest to the BRIGIT research project. With this in mind, one of the key aims of the project is to repeatedly sample populations of Philaenus in different habitat types in different locations around the UK throughout the field season (roughly May through to late September). We will then be able to examine their DNA which should help answer important questions like how far individuals move and how much mixing there is between populations in neighbouring habitats, which in turn will give us an idea of how far and how fast the Xylella bacterium might be transmitted if it arrives here.
So my job for the day was to collect some nymphs (juvenile bugs) from five different habitat types (e.g. open grassland, scrub, woodland etc) around my field site. Nymph collection is pretty easy - you just need to look out for the tell-tale blobs of spittle, have a root around in it, and there you go. I was a little worried that there might not be much spittle left as it is quite late in the season for nymphs still to be around in the south of England (things are a bit later further north), but again, my worries were unfounded - there was loads of the stuff!
On examining the bugs within the spittle, I found nymphs at quite a range of life stages. Froghoppers and leafhoppers don't have a larval (caterpillar) or pupating stage like we see with groups such as butterflies and moths. Instead, the nymphs look just like smaller versions of the adults, but without functioning wings. They go through five moults as nymphs, getting larger each time, before becoming adults, with each stage between moults being known as an instar. I found nymphs from what looked to be the second instar, right through to the fifth (and final) instar.
I also had one or two adults hop by to see what was going on - so clearly it was a good job I managed to fit my collection in this week - if I left it much longer there wouldn't be any nymphs left to collect!
So with my collections done, all that was left was for me to fill in my data sheet and send my specimens off to the clever people in the lab that do all the DNA stuff. And I even managed to get a bit of help with filling in my data sheet!
All in all, a very productive day. Good job too, as the rain is back today!
If you have seen any spittle when out and about, please do let us know. We have a couple of different recording options for you to use - both can be accessed here.