Pete, it's impossible to "grow" an unhealthy colony.  Unless larval and
adult survivorship, and adult productivity are high, a colony cannot grow
its population.  Good colony growth is the signature of good nutrition.

I don't think that gets at the heart of the matter. We know that growth in plants and animals can be stimulated by the use of nutrients, fertilizers, etc. and that synthetic feeds and amendments cannot adequately substitute for natural ones. Growth may be stimulated at the expense of other aspects of organism health. My comments were prompted by the paper by Gloria DeGrandi Hoffman and Judy Chen, edited by Christina Grozinger and Jay Evans. These are the best people in the field, I don't feel as if we can dismiss their work. They write

This review will focus on the role of nutrition in immune
response to viral pathogens. We briefly describe the
connections between nutrition and individual immunity,
and speculate on the possible changing nutritional
requirements of colonies throughout the year. These
changes might revolve around trade-offs between colony
growth and immune defense. Within this framework, we
include the effects of parasitism by Varroa because when
the mite is present, optimal nutrition alone might not be
sufficient to keep virus levels low.

In their references they cite:

Cotter SC, Raubenheimer SS, Wilson DK: Macronutrient balance
mediates trade-offs between immune function and life history
traits. Func Ecol 2011, 25:186-198.

Reports findings from a study that simultaneously manipulated diet
composition and caloric density in healthy and immune challenged
insects to determine how diet quality and quantity affect immune
response.

From that paper:

Our results show that both constitutive and induced immune responses are not limited by the total quantity of nutrients consumed, but rather different traits respond differently to variation in the ratios of macronutrients (diet quality), and peak in different regions of macronutrient space. The preferred dietary composition therefore represents a compromise between the nutritional requirements of growth and immune responses. We also show that a non-pathogenic immune challenge does not affect diet choice, rather immune-challenged insects modify their allocation of nutrients to improve their immune response.

Our results indicate that immune traits are affected by the macronutrient content of the diet and that no diet can simultaneously optimize all components of the immune system. To date the emphasis has been on the effects of micronutrients in improving immunity, our findings indicate that this must be widened to include the neglected impact of macronutrients on defence against disease.

Finally, Marla Spivak stated 

Because of the bee die-offs that we’re seeing, many researchers are saying, let’s give
them things that are more aligned with what bees eat naturally. In fact, Purina just put
out a big job description – they’re looking for a researcher to study a better bee food,
derived more from plant pollen and other plant ingredients. This is going to happen,
and it’s going to happen fairly soon.

In other words, the work on nutrition is ongoing, and it's generally agreed that nutrition encompasses a lot more than simple rapid growth. I don't think anyone believes that bees would do just as well on cane sugar and yeast/soy mixtures than they would in pastures of abundant nectar and pollen. Granted, if you are stuck in an area without forage, you can use synthetic feedstuffs, and it might even be cost effective, but historically have always preferred to have their bees on good pasture if they can access it. 

PLB

             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html