[Pollinator] Fwd: [New post] Honeybees and Corn 2016

Mon Sep 12 11:07:44 PDT 2016

Hi Peter,

Actually, in a corn agroecological system, pollen from the treated corn
would probably pose the lowest risk for honey bees. The bees at greatest
risk would be those exposed to the blowing neonic-laden dust and nearby
water sources. Very low levels of neonicotinoids end up in corn pollen
because it is seed-treated. If it were a different system, i.e. fruit
orchards, contaminated pollen and nectar would be a much greater problem,
because orchard trees are treated with soil and trunk injections rather
than seed treatments. Soil and trunk treatment results in much higher
concentrations (and we might assume persistent concentrations, based off
the data from ash trees, but there are no data on persistence in orchard
trees)  in the crop plant tissues, pollen, and nectar.

You are correct that honey bees visit corn to collect pollen, mostly
because it is the most abundant source in the area and not because it
provides any ample nutrition. If there were sufficient amounts of
alternative forage nearby that provides both nectar and pollen, in high
quantities, there may be less foraging on corn (I say may because at this
time it does not look like bees select pollen based off nutritional
quality--they only do this with nectar).

With that said, a study based on one site and one season is pretty much
guaranteed to fail to detect any real patterns in colony health and
mortality.

John, I would take the weight gain results with a grain of salt for another
reason. Weight is not the best measure of colony health because there is no
way to separate weight from honey from weight of bees, brood, or pollen.
You can have a failing colony from any given cause (mites, viruses, or
pesticides) with few bees because many of the bees died, but these colonies
may still lot of honey that makes up most of the weight in the colony
because there are fewer bees to eat it. A healthier and more populated
colony might weigh a little less because there are more bees eating honey
(also keep in mind that the bees:honey ratio is going may mean very
different things at different times of the year).

I would also advise against using residues of neonics in the bees
themselves to determine whether they have been poisoned. Neonics like
imidacloprid are metabolized very quickly and will not be present in the
bees after a few hours, unless they consumed a ridiculously high (not
field-realistic) amount. It is far more useful to take samples of pollen
and nectar of forage flowers, stored pollen, and nectar to really
understand colony pesticide exposure. Not enough studies have done this,
and the studied that do don't do the best job at getting a representative
sample from the colony. If you do sample honey and pollen from inside the
colony, several samples should be taken from several frames and then
combined for analysis, rather than removing a little square from one frame
and assuming that it represents all pollen in the colony. (Personally, I
think we really need a study that determines how pesticide residues differ
in different parts of the colony--this would be extremely useful to
sampling in other studies).

Another note about the vanEngelsdorp et al. (2015) study (I think this is
the one you are referring to but I may be wrong--if you aren't discussing
the neonic feeding experiment then disregard this comment) is that colonies
exposed to neonicotinoids had higher levels of *Varroa* mites, and colonies
at the higher concentrations of 20 ppb and 100 ppb had higher mortality
than those in the control group and 5 ppb treatment group. I did not like
that the authors concluded that those results were irrelevant because the
concentrations were high--the maximum concentration detected bee bread in
Mullin et al. (2010) was 206 ppb, which is over double the highest
concentration used in the experiment.

Wow, I got a little long-winded there. Sorry folks.

Stephanie

On Mon, Sep 12, 2016 at 10:10 AM, Peter Bernhardt <bernhap2 at slu.edu> wrote:

> Very good.  Let's consider a little detective work.  "Neonics" are most
> likely to harm those honeybees collecting pollen produced by systemically
> treated corn seeds, right?  Why would honeybees visit male flowers of a
> wind-pollinated plant in which grains are packed with starch instead of
> amino acids and lipids?  The usual answer, based on a long history of
> literature, is that honeybees only visit corn tassels when there's little
> else on which to forage.  Townsend's bees had a "good year" in which forage
> plants were plenty and the workers did not have to seek out what
> anthropologists call "famine foods" when studying human populations. That's
> why can't always predict success of failure in a multi-factorial system in
> agriculture (like bee-keeping) restricted to one site and season.
>
> Peter
>
> On Sat, Sep 10, 2016 at 1:28 AM, Kit Prendergast <
> kitprendergast21 at gmail.com> wrote:
>
>> I fully support Stephanie's conclusion and could hardly have put it
>> better myself. One needs to actually measure bee keeper practices ( and one
>> has to ask how reliable are self-reports? How consistent are the behaviour
>> of beekeepers across seasons?), pesticide exposure, pathogen exposure,
>> climatic variables, foraging resources available in the environment (pollen
>> and nectar resource abundance, and their distribution across the
>> landscape), perhaps even competition between different bee populations
>> (managed, wild, and native), or predators, to parse out the effects of
>> various factors that might contribute to honeybee health. What has been
>> recently shown in both lab and field studies is that pesticides do
>> negatively affect honeybee survival and foraging ability at concentrations
>> experienced in nature. It is also consistently shown that loss of flowering
>> plants has a negative effect on pollinators, including on pollinator
>> health. Pesticides also can stress bees, interacting with other stressors
>> like nutritional limitations, adverse weather, and pathogens.
>> Given that pesticides are known to affect other pollinators and insects,
>> it is parsimonious to conclude that honeybees are also affected, whereas
>> anecdotal reports of bad beekeeper management based on single examples that
>> do not stand up to scientific rigour (replication, controls etc.) cannot be
>> considered to be reliable.
>> Regards
>>
>> On 10 September 2016 at 05:42, Stephanie Parreira <
>> parreirastephanie at gmail.com> wrote:
>>
>>> This is a highly over-simplified opinion about the neonicotinoid
>>> problem. I would have further questions for the above person, such as, are
>>> there weather differences between the region where the colonies died and
>>> the place your colonies are (windy conditions can blow neonic-laden dust
>>> into colonies and onto foraging bees, so if one place is windier than the
>>> other, bee exposure and response may be different)? Is the area of planted
>>> corn significantly different from the area of corn in Ontario (more corn
>>> planted = more potential exposure to neonics and less alternative forage)?
>>>
>>> Anecdotal evidence will do no one any good, whether that anecdotal
>>> evidence argues against neonicotinoid use or for it. We should take things
>>> like this with a grain of salt and understand that there are many factors
>>> at play that may increase the potential of pesticides to severely affect
>>> honey bee colonies.  I am not saying that beekeeper practices cannot be
>>> improved to increase colony survival, but to blame beekeeping practices
>>> without any comparison or contrast between beekeeping practices, landscape
>>> and foraging environment, and pesticide exposure (in-hive or forager
>>> residues), it is irresponsible to jump to this conclusion.
>>>
>>> (Furthermore, even if neonicotinoids are not the issue for honey bee
>>> colonies specifically, we should still be concerned about their many
>>> detrimental effects on native bee populations, which have been demonstrated
>>> in the scientific literature time and time again.)
>>>
>>> On Thu, Sep 8, 2016 at 7:24 AM, Laurie Adams <lda at pollinator.org> wrote:
>>>
>>>>
>>>>
>>>> ---------- Forwarded message ----------
>>>> From: John Purdy <johnrpurdy at gmail.com>
>>>> Date: Thu, Sep 8, 2016 at 6:59 AM
>>>> Subject: Fwd: [New post] Honeybees and Corn 2016
>>>> To: Laurie Adams <LDA at pollinator.org>
>>>>
>>>>
>>>> Here is an important observation from a beekeeper in western Canada.
>>>> It helps to build confidence in what I found in my recent bee health study.
>>>> perhaps it is worth posting. (a section is a mile square or 640 acres)
>>>>
>>>> John
>>>> ---------- Forwarded message ----------
>>>> From: Alberta Buzzing <donotreply at wordpress.com>
>>>> Date: Sun, Sep 4, 2016 at 10:40 PM
>>>> Subject: [New post] Honeybees and Corn 2016
>>>> To: johnrpurdy at gmail.com
>>>>
>>>>
>>>> Lee Townsend posted: "I had a yard of 40 hives on a quarter section of
>>>> treated corn this year, and it is interesting as I am not seeing any of the
>>>> effects on the bees that groups like the Ontario Beekeepers Association
>>>> claims to take place in this situation.  My bees are of th"
>>>>
>>>> New post on *Alberta Buzzing*
>>>> <http://albertabuzzing.com/?author=1> Honeybees and Corn 2016
>>>> <http://albertabuzzing.com/2016/09/honeybees-and-corn-2016/> by Lee
>>>> Townsend <http://albertabuzzing.com/?author=1>
>>>>
>>>> I had a yard of 40 hives on a quarter section of treated corn this
>>>> year, and it is interesting as I am not seeing any of the effects on the
>>>> bees that groups like the Ontario Beekeepers Association claims to take
>>>> place in this situation.  My bees are of the same species that are in
>>>> Ontario, the corn is treated the same way as it is in Ontario, and the
>>>> planting was done the same as in Ontario.
>>>>
>>>> Leads me to think the problem is not neonics, but beekeeper
>>>> management.  It is truly unfortunate that the Ontario Beekeepers
>>>> Association and groups like it refuse to admit what exactly they are doing
>>>> with their colonies, with proof to back up their claims.
>>>>
>>>>
>>>> *Lee Townsend <http://albertabuzzing.com/?author=1>* | September 4,
>>>> 2016 at 8:40 pm | URL: http://wp.me/p5JjBC-1X
>>>>
>>>> Comment
>>>> <http://albertabuzzing.com/2016/09/honeybees-and-corn-2016/#respond>
>>>>    See all comments
>>>> <http://albertabuzzing.com/2016/09/honeybees-and-corn-2016/#comments>
>>>>
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>>>>
>>>>
>>>>
>>>> --
>>>> John Purdy PhD
>>>> Environmental Scientist
>>>> Abacus Consulting Services Ltd
>>>>
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