It's definitely autumn

It's definitely turned very autumnal in the past month, after the summer really stretching out into September this year. Definitely my favourite thing about autumn are conkers. Even though I have absolutely no use for them whatsoever, I always find myself just instinctively bending to pick them up where-ever I go, whether they're big, small, shiny or muddy.

Stock from dreamstime.com

Amusingly, my nieces have also picked up this habit. Maybe it runs in the family. I don't think I should be quite as relieved that I'm not the only one to come home with pockets rammed with conkers when they're nine and four.

It is quite noticeable that conkers have been getting smaller over the years though. While you can still get substantial conkers that'll definitely win a game, most of them just aren't the size they used to be- the result of a few nasty diseases that have spread through the UK since 2000. One of the most uncommon, unsightly problems is the horse chestnut leaf miner.

Image from Naturespot.co.uk

This beastie (Cameraria ohridella) arrived in the UK in 2002, and has spread across pretty much the whole country since then. It's still thankfully rare in Scotland, but has become very prevalent in some parts of the country; the rate of infestation is around 40-60km per year, so it's a real threat to large parts of the country that aren't currently affected (Forestry.gov.uk, 2014). Often horse chestnuts are the first trees to take on the golden reddy colours of autumn, or look like they do from the sheer number of leaf mining burrows across their canopy.

Image from Devonmoths.org.uk

Although this obviously looks unhealthy, so far there doesn't seem to be much evidence for the moths having a detrimental effect on the trees- there are much more dangerous diseases like bleeding canker. Obviously the presence of leaf miners when other diseases attack contribute to failing health of a plant though. Going back to the conkers, smaller ones are less likely to germinate successfully. Thankfully birds are starting to learn to use the leaf miners as food though, acting as natural pest controllers to these invaders.

Image from mostlyscarce.tumblr.com

Read more about horse chestnut diseases at ConkerScience!

Britain's Larger Moths...

This week I've moved back up to London, and an extremely messy room. I shan't put pictures, because it's somewhat horrifying the amount of stuff I've accumulated over 3 years, from uni and also all the things I left behind in the first place. Anyway, long story short, with all the tidying I've been doing, I found a few interesting bits and pieces amidst the carnage of old toys, university notes, books and god-knows-what-else.

The thing that caught my eye the most was a publication from the Butterfly Conservation on "The State of Britain's Larger Moths 2013". Okay, so it's a year out of date, but still fairly recent and very relevant in ecology.

 

Image from UKButterflies.co.uk

In the past couple of years, I've started to get much better at lepidoptera identification (moths, not so much, but I can do some of the basic ones), so this is a pretty interesting read. I haven't actually gotten through it all yet, but it's not too long; 30 pages. First off, its focus is larger, macro, moths, rather than micro-moths- there are more species of micro-moth in the UK, but they're much harder to identify, and a lot less striking than some of the big macros we get like Tiger, Silver Y and Burnet moths. 

Sadly, like a lot of reports I've read over the past year (mostly for my dissertation or ecology modules at university), numbers of many species are declining. 2/3 of 337 species of larger moths declined over the 40-year study recorded in this report, which is a pretty dire situation, given the usefulness of moths in the environment, playing a key role for plant pollination, and insectivores that rely on moths as a food source. It's quite evident that habitat loss and reductions in biodiversity of many areas are not doing moths any favours at all. Agricultural intensification and changing woodland management largely seem to have negative impacts on moths, with fragmentation of habitats causing declines in species numbers.

     

Dusky Thorn, Spinach, Lackey, Garden Tiger, Grass Rivulet and Autumnal Rustic species all have declined by over 90% in the past 40 years. Images from UKmoths.org.uk

It's not all doom and gloom though; the report also shows that the 1/3 of moths that aren't declining in numbers are actually increasing. Homogenization of the moth species pool of the UK isn't great, but at least it's good news for some species, and not all are becoming rarer. As well as these moths on the increase becoming more abundant, their territories are also expanding, with species such as the Dingy Footman having a more widespread range.

I need to give this paper a bit more of a read (I'm still only halfway through clearing the piles of stuff all over the place), but a quick skim through shows it's not all bad for Britain's moths. I'll be interested to see what they suggest in the last couple of pages as ways to conserve moths, as a lot of public friendly leaflets tend to focus on small-scale changes you can make in your own back garden, rather than a larger impact that, from a glance, seems to be the focus of this paper.

Dingy Footman, Image from Suffolkmoths.org.uk

You can read the full report here.