permaculture

[Lawrence London <lfljvenaura@gmail.com>]

http://www.npr.org/blogs/thesalt/2014/07/09/329994522/biologist-says-promoting-diversity-is-key-to-keeping-the-bees
https://www.uoguelph.ca/cpa/wp/2014/07/bee-foraging-chronically-impaired-by-pesticide-exposure-study/

Bee Foraging Chronically Impaired by Pesticide Exposure: Study

July 8, 2014 – News Release

A study co-authored by a University of Guelph scientist that involved
fitting bumblebees with tiny radio frequency tags shows long-term exposure
to a neonicotinoid pesticide hampers bees’ ability to forage for pollen.

The research by Nigel Raine, a professor in Guelph’s School of
Environmental Sciences, and Richard Gill of Imperial College London was
published today in the British Ecological Society’s journal *Functional
Ecology*.

The study
<http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.12292/abstract;jsessionid=8494B0511C09DB49BE4C36F1BE8D5662.f03t01>
shows how long-term pesticide exposure affects individual bees’ day-to-day
behaviour, including pollen collection and which flowers worker bees chose
to visit.

“Bees have to learn many things about their environment, including how to
collect pollen from flowers,” said Raine, who holds the Rebanks Family
Chair in Pollinator Conservation, a Canadian first.

“Exposure to this neonicotinoid pesticide seems to prevent bees from being
able to learn these essential skills.”

The researchers monitored bee activity using radio frequency identification
(RFID) tags similar to those used by courier firms to track parcels. They
tracked when individual bees left and returned to the colony, how much
pollen they collected and from which flowers.

Bees from untreated colonies got better at collecting pollen as they
learned to forage. But bees exposed to neonicotinoid insecticides became
less successful over time at collecting pollen.

Neonicotinoid-treated colonies even sent out more foragers to try to
compensate for lack of pollen from individual bees.

Besides collecting less pollen, said Raine, “the flower preferences of
neonicotinoid-exposed bees were different to those of foraging bees from
untreated colonies.”

Raine and Gill studied the effects of two pesticides – imidacloprid, one of
three neonicotinoid pesticides currently banned for use on crops attractive
to bees by the European Commission, and pyrethroid  (lambda cyhalothrin) –
used alone or together, on the behaviour of individual bumblebees from 40
colonies over four weeks.

“Although pesticide exposure has been implicated as a possible cause for
bee decline, until now we had limited understanding of the risk these
chemicals pose, especially how it affects natural foraging behaviour,”
Raine said.

Neonicotinoids make up about 30 per cent of the global pesticide market.
Plants grown from neonicotinoid-treated seed have the pesticide in all
their tissues, including the nectar and pollen.

“If pesticides are affecting the normal behaviour of individual bees, this
could have serious knock-on consequences for the growth and survival of
colonies,” explained Raine.

The researchers suggest reform of pesticide regulations, including adding
bumblebees and solitary bees to risk assessments that currently cover only
honeybees.

“Bumblebees may be much more sensitive to pesticide impacts as their
colonies contain a few hundred workers at most, compared to tens of
thousands in a honeybee colony,” Raine said.