Support the Arctic Sea Ice Forum and Blog

Author Topic: Decline in insect populations  (Read 41872 times)

kassy

  • Moderator
  • Nilas ice
  • Posts: 2373
    • View Profile
  • Liked: 1142
  • Likes Given: 982
Re: Decline in insect populations
« Reply #250 on: July 02, 2020, 02:54:25 PM »
Alarming long-term effects of insecticides weaken ant colonies

...

But so far, no data existed to show how exposure to low concentrations, which do not induce direct mortality, affect ants in the long run. The data, collected at the University of Bern in cooperation with Agroscope and the University of Neuchâtel, clearly demonstrate previously overlooked long-term effects, which are not detectable during the first year of colony development. The results are published in "Communications Biology", an Open-Access Journal of Nature. According to the authors, this study highlights the importance to develop sustainable agricultural practices that incorporate reduced use of agro-chemicals to prevent irreparable damages to natural ecosystems.

Worrying long-term impacts

Thiamethoxam has a clear negative impact on the health of ants. Thiamethoxam is a neonicotinoid insecticide used to combat pest insects that threaten our harvest. Unfortunately, there is more and more evidence showing that thiamethoxam and similar agro-chemicals have negative consequences for other beneficial insects, including ants and honey bees.

...

In the present work, colonies of black garden ants were chronically exposed to field realistic concentrations of thiamethoxam over 64 weeks. Colonies were raised in the laboratory from queens that were captured in the field. Before the first overwintering of the colonies no effect of neonicotinoid exposure on colony strength was visible. However, until the second overwintering it became apparent that colonies exposed to thiamethoxam were significantly smaller than control colonies. Because the number of workers is a very important factor for the success of an ant colony, the observed effects are most likely to compromise colony survivorship. Considering the important role of ants in natural ecosystems, our results indicate that neonicotinoids impose a threat to ecosystem functioning.

...

https://www.eurekalert.org/pub_releases/2020-07/uob-ale070120.php

Long-term effects of neonicotinoid insecticides on ants
https://www.nature.com/articles/s42003-020-1066-2
Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.

kassy

  • Moderator
  • Nilas ice
  • Posts: 2373
    • View Profile
  • Liked: 1142
  • Likes Given: 982
Re: Decline in insect populations
« Reply #251 on: July 18, 2020, 10:40:09 PM »
About 94 per cent of wild bee and native plant species networks lost


Climate change and an increase in disturbed bee habitats from expanding agriculture and development in northeastern North America over the last 30 years are likely responsible for a 94 per cent loss of plant-pollinator networks, York University researchers found.

The researchers, corresponding author Professor Sandra Rehan of the Faculty of Science and grad student Minna Mathiasson of the University of New Hampshire, looked at plant-pollinator networks from 125 years ago through present day. The networks are comprised of wild bees and the native plants they historically rely on, although most of those have now been disrupted.

About 30 per cent of plant-pollinator networks were completely lost, which translates to a disappearance of either the bees, the plants or both. In another 64 per cent of the network loss, the wild bees, such as sweat or miner bees, or native plants, such as sumac and willow, are still present in the eco-system, but the bees no longer visit those plants. The association is gone.

The remaining six per cent of the plant-pollinator networks are stable or even thriving with pollinators such as small carpenter bees, which like broken stems for nest making.

"There are several reasons for the losses in the networks. Climate change is likely the biggest driver. We know that over the last 100 years or so annual temperatures have changed by two and a half degrees. This is enough to alter the time when certain native plants bloom," says Rehan.

"For a bee that's out for months on end or is a generalist pollinator, this isn't such a critical mismatch, but for a bee that's only out for two weeks of the year and only has a few floral hosts, this could be devastating." An increase in non-native species of bees and invasive species of plants, which have displaced some of the native species, is another reason for the decline in networks.

...

https://www.sciencedaily.com/releases/2020/07/200716144740.htm
Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.

Alexander555

  • Nilas ice
  • Posts: 1244
    • View Profile
  • Liked: 128
  • Likes Given: 44
Re: Decline in insect populations
« Reply #252 on: August 02, 2020, 09:54:55 PM »
Some more stuff about te bees. I'm going to see if i can get some more bees over here. https://watchers.news/2020/07/30/bee-population-decline-threatens-major-crop-yields-in-u-s-and-global-food-security/

Alexander555

  • Nilas ice
  • Posts: 1244
    • View Profile
  • Liked: 128
  • Likes Given: 44
Re: Decline in insect populations
« Reply #253 on: August 02, 2020, 10:02:09 PM »
I placed a home like this for the humblebees. What could i do extra for them, besides extra flowers ? https://www.tuinadvies.be/tuinwinkel/product/2256/hommel-kweekbak-professioneel

vox_mundi

  • Young ice
  • Posts: 3867
    • View Profile
  • Liked: 2273
  • Likes Given: 300
Re: Decline in insect populations
« Reply #254 on: August 02, 2020, 10:40:47 PM »
Bumblebee Habitats and Diets Change Over Their Lifecycle
https://phys.org/news/2020-07-bumblebee-habitats-diets-lifecycle.html

Bumblebees change their home ranges and dietary preferences after establishing nests, suggesting that diversified landscapes help support bee populations as their needs change during different phases of their lifecycle.

Cavigliasso P, Phifer CC, Adams EM, Flaspohler D, Gennari GP, Licata JA, et al. (2020) Spatio-temporal dynamics of landscape use by the bumblebee Bombus pauloensis (Hymenoptera: Apidae) and its relationship with pollen provisioning. PLoS ONE 15(7): e0216190
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0216190

-------------------------------

Observe what the bee's preference are.

Provide blooms during each season

Here in Connecticut these are the flowers most visited by bumblebees at our community garden

Blueberries - spring
Grape hyacinth - spring
Catmint - Spring
Thyme - spring
Borage - summer
Salvia - late spring
Echinacea - summer
Tomatoes - summer
Squash, cucumbers - summer
St John's wort - summer
Agastache - summer, fall
Joe Pye weed - summer
Milkweed - summer
Sunflowers - summer
Butterfly bush - summer fall
Oregano summer fall
Mint - summer fall
Zinnias - summer fall
Goldenrod - fall
Asters - fall

Don't expect the bumblebee queen to stay in the box if your winters are freezing.

I was a beekeeper in the 90's and 00's
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

Insensible before the wave so soon released by callous fate. Affected most, they understand the least, and understanding, when it comes, invariably arrives too late

Alexander555

  • Nilas ice
  • Posts: 1244
    • View Profile
  • Liked: 128
  • Likes Given: 44
Re: Decline in insect populations
« Reply #255 on: August 03, 2020, 10:19:21 PM »
We do have freezing in winter. But for what i can find on the internet the bumblebees are  the bees that can handle the cold the best. Do you maybe know when they use a tunnel below the surface as a nest. Do they have like several tunnels for ventilation, or would it just be one tunnel. Or is the nest a little more sophisticated ? The box is developed by bumblebees specialists, and they made a few little holes in the back for ventilation. I was thinking about doing a little experiment. I buy a 2th box, and i dig him in as much as possible. I put sand on top of it, and only keep the entree open. That should protect it a little better against the cold. But should i do something with the ventilation holes ? Maybe straws to the surface.

vox_mundi

  • Young ice
  • Posts: 3867
    • View Profile
  • Liked: 2273
  • Likes Given: 300
Re: Decline in insect populations
« Reply #256 on: August 03, 2020, 11:10:40 PM »
Bumblebees are tough, but not invincible.

A bumblebee queen does not overwinter in the nest. They overwinter in burrows beneath leaf litter or in brush piles. They will be several cm deep, near or below the frost line in dry soil. They may use abandoned mice/vole nests. Their metabolism is so slow during winter that ventalation is usually not a problem.

In spring, a mated queen emerges from her overwintering site, searches for a spot to nest, and works alone to raise a first cohort of worker daughters. The colony grows over several months, producing successive cohorts of workers before switching to produce males and new queens. In mid‐ to late summer, newly mated queens seek sheltered sites where they overwinter.

Rinse; repeat.

Habitat determines both location.

Nectar and pollen near the colony nest
Dry, unfrozen, leaf litter for overwinter site.

Bumblebees start their year early. I've seen them at flowers early march, anytime it's above 8-10°C.

Honeybees will be out earlier because they can return to the colony and warm up. I've seen honeybees on my Snowdrops on clear sunny days in January
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

Insensible before the wave so soon released by callous fate. Affected most, they understand the least, and understanding, when it comes, invariably arrives too late