Insect, arthropod, and insectivore population crash

[jim mcnamara]

Popular science version: (Let me know if the link has problems)
https://www.washingtonpost.com/scie...s-massive-insect-loss/?utm_term=.f9b8006df72b

Long term sampling from the 1970's to 2017/2018 shows losses of insect, arthropod, and insectivore populations in tropical and European ecosystems. The authors comments were not at all positive about the implications of the population crashes they saw in long term data.

The losses ranged from 75% (1/4 survivorship) to >98% (1/60 survivorship for glue trap samples) from the start of the studies (1970's) until recent census data.

Edited percents.

 

[fresh_42]

$3/4$ are also the figures European media report.
https://www.nabu.de/news/2017/10/23291.html
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0185809

 

[gleem]

This is most likely not a good sign even though bugs can be a problem. Are the insect the canary in the mine? What is this telling us? Global warming it would seem would be too slow to explain such a dramatic change. Some crops show a 6% drop in yield for every 1 deg C increase. Since the 70's it has only been about a 0.5 deg or so increase. Could such a small increase in temp cause this? What about pesticides having some slow effect or some other environmental pollutant? Insect might have some common metabolic architecture that could be susceptible to some foreign agent across many species.

A mass extinction has been followed for some decades in the amphibian population around the world too. https://www.vox.com/science-and-health/2016/10/14/13147056/amphibian-extinction-frog-bd . A fungus being the culprit at least for some species. Temperature/humidity is a factor for fungus and mold isn't it? But in the tropics the humidity is very high as well as the temperature.

I would not be surprised if it is found attributable to human activity. Humans change the environment much more quickly than nature. This challenges the adaptability of various species.

 

[pinball1970]

Popular science version: (Let me know if the link has problems)
https://www.washingtonpost.com/scie...s-massive-insect-loss/?utm_term=.f9b8006df72b

Long term sampling from the 1970's to 2017/2018 shows losses of insect, arthropod, and insectivore populations in tropical and European ecosystems. The authors comments were not at all positive about the implications of the population crashes they saw in long term data.

The losses ranged from 75% (1/4 survivorship) to <2% (1/60 survivorship for glue trap samples) from the start of the studies (1970's) until recent census data.

Yes, Bees have been hard hit in the UK – I found thishttps://dspace.stir.ac.uk/bitstream/1893/862/1/Conservation%20Review6.pdfIntensive farming and fertilizers have been discussed but I don’t think there is anything definitive.Many chemicals have the below biocides are now restricted in the EU under REACh – too late for our Bees though if this is the main reason.https://en.wikipedia.org/wiki/Organotin_chemistry#Biological_applicationsAny entomologists on the site? Any viral research links?

 

[BillTre]

Here is a short article from Science magazine news that discusses the same issues in tropical forests (which are among the most bio-diverse regions in the world).
Not only do they find reductions in insect/arthropod populations but also in the populations of their predators.

 

[fresh_42]

Here is another related study, this time Puerto Rico:
https://phys.org/news/2018-10-degrees-decimated-puerto-rico-insect.html (magazine)
http://www.pnas.org/content/early/2018/10/09/1722477115 (paper)

 

[Buzz Bloom]

The losses ranged from 75% (1/4 survivorship) to <2% (1/60 survivorship for glue trap samples)

Hi Jim:

I think you intended to say that the small survivorship of 1/60 corresponds to losses of >98% rather than <2%.

Regards,
Buzz

 

[Laroxe]

There are a number of problems with the research into this, the first is with the fact that the issue is linked to some popular causes, you have groups promoting the idea that we are in a man made extinction event, the Anthropocene and the decline in insects is entirely consistent with this, then we have the global warming prediction that we face a huge increase in insect populations. Some of the figures given like last years German study with suggested a decline of 75% seem to be rather ridiculous and severely underestimates the importance of insects in an ecosystem, but studies around the globe do suggest there is something unusual happening and many species are experiencing a decline.
The biggest problem in the research is that there simply isn't enough of it, good baseline measures of populations and the population dynamics simply don't exist, scientists are simply playing catchup. It also seems that many of the suggested culprits don't stand up to close examination, there have been some good examples of how fairly small changes in the environment, like introducing new species of trees can have a massive effect on local insect populations. Studies on colony collapse in honey bees have suggested a transmittable disease in the presence of a particular parasite is the usual finding and it seems it isn't a new phenomena, people have speculated that some insecticides might have compounded the problem. However once the problem became widely recognised Bee Keepers took action and have maintained the population and of course honey production.
A major issue is that many of the suggested causes simply wouldn't have the sort of rapid global effect that seems to be taking place, honey bees represent an important resource and so attracted considerable sums of money for research but its difficult to know how much more will be invested before the problem starts to impact on our own well being. If this decline does turn out to be progressive and the losses increase it certainly will have a significant impact and not just on birds.