Reduction in moth numbers (1 Viewer)

CJW

Hit-and-run WUM

• May 10, 2003

• #1

I spent last night huddled around my moth trap in Ballaugh Curraghs (one of northern Britain's premier moth sites) from 9pm to 11.30pm and caught two moths (a Flame carpet and a bedraggled Puss Moth)!! Alright, I actually went to the pub for a couple of hours whilst I let the catch "build up", but I don't think I missed anything.
These last couple of years seem to have been really poor in terms of species caught and the number of individual insects. My trap at home tells the same story with only a couple of species being caught in recent weeks. What's going on?

 

Michael Frankis

conehead

• May 10, 2003

• #2

Wish I knew, but I presume its the same as why you don't get bothered by flies while out walking in the country any more, why I can sleep safely with my window open without the guarantee I used to have of waking up with 5 gnat bites, why the roses in the garden never get covered in greenfly or caterpillars any more, and why car windscreens don't get plastered in insects the way they used to. ALL insects are affected, not just moths. And so too are most insect-eating birds.

Michael

 

CJW

Hit-and-run WUM

• May 10, 2003

• #3

Hmmm, something's definitely wrong......

 

Colin

Axeman (Retired)

• May 10, 2003

• #4

CJW,
I know that Portland Bird Observatory do lots of moth trapping and the warden Martin Cade is very enthusiastic. You could contact him to see what is happening there. I appreciate it is a long way from yourself. The bird migration has been poor there this year. The URL is

http://www.portlandbirdobs.btinternet.co.uk/index.htm


I will check with the reserve manager at Slimbridge who does lots of trapping and see if he is experiencing the same sort of fall in numbers and let you know.

On the general subject of insects, I have noticed over the past few years that cow pats do not degrade as quickly as they used to and they remain free of insects for months. Not sure if this is lack of insects or a result of what the cows are given to eat.

Colin

 

Michael Frankis

conehead

• May 10, 2003

• #5

Hi Colin,

Re cowpats: that's because of Ivermectin, an antihelminth drug (against parasitic worms) that is fed routinely and prophylactically to almost all non-organic livestock in Britain. It is also highly insecticidal, and leads to cow pats (and sheep droppings etc) being sterile and free of insects.

This probably plays a significant part in the decline of certain insects and insectivorous birds, particularly those which feed around livestock such as Whinchat & Yellow Wagtail. But it is far from the only cause of the decline of insects generally, as it won't affect e.g. moths which feed on tree leaves, nor the populations of insects in urban or arable areas.

Michael

 

W

winkle

Well-known member

• May 11, 2003

• #6

Ivermectin laced cowpats are a serious problem for more than just invertebrates in some habitats. For example Late Spider Orchid can survive being covered by a cowpat for a few days, but not the weeks or even years it takes for an Ivermectin cowpat to disapear.

It's hard enough to find graziers willing to put up with grazing regimes required on chalk grassland without imposing more rules. You tend to be grateful for what you can get.

There is also an animal welfare issue here. We used sheep on a wetland site that weren't dosed. They all were very seriously affected by Sheep Tick, so anaemic we were bring them back in wheelbarrows because they could not walk. Also had the RSPCA in my face over that one.

I understand it's a very serious problem in dry countries as the cowpats just build up.

 

CJW

Hit-and-run WUM

• May 11, 2003

• #7

Any information you can get Colin would be gratefully received, thanks.
As for Ivermectin, bloody farmers, eh? why can't they leave well alone?

 

W

winkle

Well-known member

• May 11, 2003

• #8

If bloody farmers had left well alone, we would not have the diversity of habitats and species we have, even after the problems modern farming is causing.

 

Michael Frankis

conehead

• May 11, 2003

• #9

Yeah, its not the farmers that are bloody, its the agrichemical industry & govt that's forcing this on farmers who don't really want it. After all, what farmer really wants half his pasture growing nothing because it is covered in cowpats? But they are told they MUST dose their animals with this stuff, whether they want to or not.

I've no problems with Ivermectin being used where a vet prescribes it for a diagnosed sick animal (or even if the farmer can diagnose it himself), but to feed it all day every day to healthy animals is what should not be happening.

Michael

 

Colin

Axeman (Retired)

• May 11, 2003

• #10

CJW,
I will try and get more info.

Michael,
Thanks for the info on Ivermectin, and I agree that healthy animals should not be give any chemical/drug as a matter of course - antibiotics in humans spring to mind and the ensuing problems of the bugs overcoming the drugs.


Colin

 

Colin

Axeman (Retired)

• May 12, 2003

• #11

CJW,
Today, I had a quick word with one of the moth enthusiasts at WWT Slimbridge and although he has been mothing most nights, his catch totals are similar to what you say. He is getting less than a dozen per night and reckons it is too cold at the moment and expects things to pick up in June.

As an aside and yes, I know it is not a moth, but last night, nearly midnight I was out and about in my garden with my outside light on when I saw what I first thought was a huge moth, winging towards me. It landed at my feet and I was pleasantly surprised to find a male Cockchafer, only the second that I have seen in my garden.


Colin

 

CJW

Hit-and-run WUM

• May 12, 2003

• #12

Thanks for that Colin.
Cockchafers eh? They're a damn nuisance over here! 50 plus in a moth trap wouldn't be unusual! Not a pleasant thing to be greeted with first thing in the morning I can tell you!

 

Michael Frankis

conehead

• May 12, 2003

• #13

Cockchafers? I thought they were nearly extinct, just like the Red-backed Shrikes that used to use them for their main food source. I've only seen one Cockchafer, ever.

Michael

 

A

alanhill

Well-known member

• May 12, 2003

• #14

Yes, from what little I know I certainly go along with the theory that extensive use of antibiotics results in less insect life on animal dung. I went to a talk recently by the chief warden at Rutland Water and he said that they were introducing traditional breeds of cattle on the pasture around the water, specifically so that the dung that was produced was antibiotic free and thus attractive to insects.

Since hearing him speak I have taken a particular interest in cow dung on my various outdoor activities, and you do notice that where farmers have traditional cattle grazing, their dung is covered in insects, and where you have your bog standard dairy herds there is little or no insect life.

Alan Hill

 

CJW

Hit-and-run WUM

• May 28, 2003

• #15

Michael, I thought you'd like to see this that I took the other morning. It was one of 24 in my moth trap (just 6 moths!).

 

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seb_seb

Well-known member

• May 28, 2003

• #16

what do they feed on?..the cockchafers that is.

 

CJW

Hit-and-run WUM

• May 28, 2003

• #17

I'm not sure the adults do feed seb-seb. The grubs are pests on cereal crops though. Apparently.

 

jeff

Well-known member

• May 28, 2003

• #18

Didn't Bill and Kate catch something like that last night on Wild in the garden. If i've learnt anything from it, it's a male.

 

CJW

Hit-and-run WUM

• May 28, 2003

• #19

I've no idea Jeff, haven't been watching

 

Edward

Umimmak

• May 28, 2003

• #20

I think one of Iceland's few records of Red-backed Shrike was found in a moth trap once, alive and well after having polished off the entire contents of the trap.

E