Insect decline

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Lou Jost
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Post by Lou Jost »

Some of the loss in diversity and biomass of native insects has been masked (and partly caused) by invasions of non-native species. This is especially true of ladybugs, a diverse group which in some areas has been almost completely replaced by a single non-native species.

https://www.sciencedaily.com/releases/2 ... 190306.htm

https://www.theguardian.com/environment ... ng-species

In much of the US, the native ladybugs have been largely replaced by a whole suite of non-native species. Someone who is not looking closely might think ladybugs are doing just fine.

https://www.eaglehill.us/NENAonline/art ... llee.shtml

microman
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Post by microman »

Its very scary.

I pray this year was a fluke and it will get better next summer.
Very few insects compared to a couple of years ago.
Forest full of dying or dead beetles becouse it was too dry. It was not a varm summer but it didnt rain much at all.

Basicly no mosquitos and not many other flying bugs. Did not have to kill more than mayby two flys inside the house this year and i live near the forest.
Ants also low in number, many years ago they came into the house so we had to use traps.

I live in Sweden.
I hope it will get better.. :?

rjlittlefield
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Post by rjlittlefield »

In the butterflies, in U.S. areas where long-term surveys have been conducted, populations are down across the board even for invasives. See http://butterfly.ucdavis.edu/, e.g. http://butterfly.ucdavis.edu/node/457 .

--Rik

Lou Jost
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Post by Lou Jost »

I wish they had estimated change in abundances as well as change in richness. Also, their paper's p-value-based statistical methodology obscures the really important information, which is the size of the effect being measured. The decline in richness is actually somewhat less than what I would have expected; in low and middle elevation sites, between 5% and 25% of the species have been lost. This is still very bad, of course. But I was expecting worse.

Ken Ramos
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Post by Ken Ramos »

Well butterflies I have seen scant few of and ants, a number of fire ant mounds but that don't mean much for the moment. Dragonflies, damselflies, mayflies, none what so ever and I live in a rural area beside a small creek. June bugs or scarabs, maybe one but that is all. Grasshoppers, one maybe but can't be sure. Now I know I have mentioned all of this before but I first noticed a decline of insect activity in my area of southwestern North Carolina a few years ago. Now I should be seeing a lot of stink bugs, Shield bugs but I am not. Asheville is reporting quite a few but here in Rutherford county, 50 miles south, I have not noticed but only one and at the onset of cold weather they are beating down your door and walls trying to get in where it is warm. Same with the lady beetles too and speaking of lady beetles, I have only seen one. One lady beetle all year. I would say that the aphids must be elated but they have been scarce also. Mosquito's, I had one bite, that's it and not even a fly by the rest of the year. The book I just finished reading that addresses the End Permian stated that here in the Holocene we are losing approx. 70 species a day. That is quite a very large number when multiplied over the course of a year and I am assuming that, assuming mind you, that the author was referring primarily to insects, I don't know. If it were larger animals most everything we are used to seeing would be treading lightly. That book by the way is “When Life Nearly Died,” Michael J. Benton ©2003 Thames & Hudson Ltd. London LCCN 2002109744 IBSN 13: 978-0-500-28573-2 A good read but I'm still out to lunch on exactly what caused the End Permian. I suspect a great many things however, beginning with the Siberian Traps. As for our six legged friends, I'm rooting for the pollinators. Spiders seem to be treading lightly too, usually I see at least one or two Argiope hanging about but none this year here. Over in East Tennessee at my sisters, she has enough to claim as dependents on her taxes this year. Good for her . . . !

Olympusman
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Insect decline

Post by Olympusman »

Today my wife, who is an ardent gardener, commented about there are almost no insects on our property. We live on a hardwood forest mountain in Bethlehem, Pennsylvania USA and I have also noticed a significant drop in insect species. No Lacewings for over four years when they were ubiquitous, fewer beetles, fewer jumping spiders and (thankfully) fewer Shtink Bugs.

Mike
Michael Reese Much FRMS EMS Bethlehem, Pennsylvania, USA

tpe
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Post by tpe »

Here is a nice article about reduction in an unperturbed rain forest area that is open access.

https://journals.plos.org/plosone/artic ... ne.0185809

In this case put down to rising temperatures (about 2 degrees).

I have noticed it a lot in the Pyrenees in Spain, where I do not know there is any great change in temperature, but in the areas that i was it is hard to imagine it is because of loss of habitat or pesticides, mainly because there is no agriculture or human activity.

dragonblade
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Post by dragonblade »

Over here in South Australia, there's been a noticeable decline in caterpillar species. I haven't seen the so-called grapevine caterpillars in many years. I consider myself somewhat fortunate to photograph a few individuals when I had the chance.

Beatsy
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Post by Beatsy »

As if things couldn't get more depressing, WWF reports a "60% decline in wild animal populations since 1970". That's staggering. Perversely, I hope they're not exaggerating as that will only provide ammo for the inevitable "deniers" and lobbyists - for whom money is the only consideration. They don't comprehend that even if they amass all the money in the world, they still won't be able to afford the last chicken!

Most of all, what I really can't understand is why this receives so little (or no) obvious comment or concern from the general public. It's not happening over geological or even evolutionary time scales. It's happening *within* our lifetimes fer cryin' out loud!

Troels
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Post by Troels »

Beatsy wrote:
what I really can't understand is why this receives so little (or no) obvious comment or concern from the general public
I believe that part of the problem is that most people simply do not like nature. Yes, they like nice flowers, romantic sunsets and sweet, harmless and colorful animals like butterlies and Pandas. And they like to use nice landscapes for personal physical challenges and training.

But the rest of it! Most people prefer to live in a city made out of bricks, steel, glass and concrete just to get away from all the creepy, dirty, slimy, muddy, cruel and nasty nature. And if they owe some soil they fight hard to kill anything that tries to invade their private homes and gardens.

When I go to meetings in our local nature preservation society, I see a dozen old men and ladys with grey hair. We are the last generation to remember a childhood with playing along the creek, climbing trees in the wood and exploring the wilderness around us.

In the last few years I have seen some young people join us at the nature excursions and meetings. That gives me a new hope. But it looks as if we have lost almost an entire generation.
Troels Holm, biologist (retired), environmentalist, amateur photographer.
Visit my Flickr albums

dmillard
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Post by dmillard »



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