[Pollinator] Fwd: Alfalfa and Its Pollinators- some more refs

[Kimberley Fellows]

Jim Cane asked me to share his references with you ... an Easter egg of the
academic kind! KiM

---------- Forwarded message ----------
From: Cane, Jim <Jim.Cane at ars.usda.gov>
Date: 28 March 2013 19:38
Subject: RE: [Pollinator] Alfalfa and Its Pollinators- some more refs
To: Kimberley Fellows <kimberley.fellows at gmail.com>


 Kim- there are some additional papers of use to you, I believe.  One
practical question to consider is your level of tolerance.  Resistance to
the herbicide Round-Up exists naturally in plant populations.  A beautiful
study in Australia documented the degree of gene flow for this trait in the
first year that GMO canola was grown there, replicated over a huge
geographic range, and with sufficient sensitivity that they detected the
fraction of a percent that was naturally resistant before introduction.
With most GMO traits, one could not afford that kind of replication.





Below is a summary of experiments focused on gene flow with alfalfa and its
different prevalent pollinators.  Honey bees are used in the California
Central Valley, but it takes tricky water management to water stress the
plant to weaken the tripping mechanism so that a honey bee does not mind
it, then restore water before you kill the plant, then repeat.





Van Deynze, A. E., Fitzpatrick, S. M., Hammon, B., McCaslin, M. H., Putnam,
D. H., Teuber, L. R., and Undersander, D. J. Gene flow in alfalfa: biology,
mitigation, and potential impact on production. Special Publ.[28], -30pp.
2008. Ames, Iowa, Council for Agricultural Science and Technology.
Ref Type: Serial (Book,Monograph)

Another is this insightful field study, which shows that alfalfa foragers
travel out into a field, then forage very locally, then fly home.  Foraging
distance does not equate with flight distance.



St.Armand P. C., D. Z. Skinner, and R. N. Peaden. 2000. Risk of alfalfa
transgene dissemination and scale-dependent effects. Theoretical and
Applied Genetics, *101:*107-114.
Ref Type: Journal
Abstract: Pollen can function as a vehicle to disseminate introduced,
genetically engineered genes throughout a plant population or into a
related species. The measurement of the risk of inadvertent dispersal of
transgenes must include the assessment of accidental dispersion of pollen.
Factors to be considered include the rate of pollen spread, the maximal
dispersion distance of pollen, and the spatial dynamics of pollen movement
within seed production fields; none of which are known for alfalfa
(Medicago sativa L.), an insect-pollinated crop species. Using a rare,
naturally occurring molecular marker, alfalfa pollen movement was tracked
from seed and hay production fields. Results indicated that leafcutter bees
((Megachile spp.) used in commercial seed production show a directional,
non-random bias when pollinating within fields, primarily resulting in the
movement of pollen directly towards and away from the bee domicile.
Within-field pollen movement was detected only over distances of 4 m or
less. Dispersal of pollen from alfalfa hay and seed production fields
occurs at distances up to 1000 m. By examining widely dispersed, individual
escaped alfalfa plants and their progeny using RAPD markers, gene movement
among escaped alfalfa plants has been confirmed for distances up to 230 m.
The outcrossing frequency for large fields was nearly 10-times greater than
that of research-sized plots. A minimum isolation distance of 1557 m may be
required to prevent gene flow in alfalfa. Data suggest that complete
containment of transgenes within alfalfa seed or hay production fields
would be highly unlikely using current production practices

And last, for pollination efficacies, there is my own little comparative
study.  Basically, tripping rate predicts everything that follows (pod set
and seed set).



Cane J. H. 2002. Pollinating bees (Hymenoptera: Apiformes) of U.S. alfalfa
compared for rates of pod and seed set. Journal of Economic Entomology, *95:
*22-27.
Ref Type: Journal
Abstract: Alfalfa (=lucerne) flowers require visiting bees to trip the
sexual column, thereby providing pollination and subsequent pod and seed
set. Previous studies have compared the pollination values of different bee
species solely by the speed with which they handle flowers and the
proportion of visited flowers tripped. In this greenhouse study, five
species of bees, including the three commercially managed U.S alfalfa
pollinators, are likewise compared for their floral tripping frequencies.
These bee species are also compared for the pod set and mature seed that
results from their single visits to virgin flowers. Regardless of the
identity of the pollinating bee, tripped flowers had the same probabilities
of pod set and seed set. Thus, differences in the single-visit pollination
efficiencies of the various bee species are entirely attributable to the
proportion of visited flowers that they trip. Females of the alkali bee,
Nomia melanderi Cockerell, and the alfalfa leafcutting bee, Megachile
rotundata F, tripped 81 and 78% of visited flowers, respectively. Males of
these species are significantly less effective (61 and 51%, respectively),
but still significantly superior to the honey bee, Apis mellifera L. (22%
of visited flowers tripped). These relationships are supported





Jim



===============================

James H. Cane

USDA-ARS Bee Biology and Systematics Lab

Utah State University, Logan, UT 84322 USA

tel: 435-797-3879   FAX: 435-797-0461

email: Jim.Cane at ars.usda.gov

web page: *www.ars.usda.gov/npa/beelab*

publications:* http://digitalcommons.usu.edu/piru/*

Gardening for Bees:
http://extension.usu.edu/files/publications/factsheet/plants-pollinators09.pdf






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