Dick Marron  wrote:

>If mites just cloned themselves, there would be no variation and they could
>not adapt. Since it's obviously true that mites DO adapt, especially to our
>pesticides then they are not just clones of each other. Variance can take
>place in the formation of an egg, and does. Pieces of DNA get dropped and
>others picked up. Recombination of existing DNA yields new phenotypes. I
>don't pretend to be up on the details but it is obvious that they are not
>"basically clones." Stop saying that. People actually read this list for
>information.

Right. Clone is a bad choice of word. However, the varroa life cycle
is a closed circuit, where the female mates with her own offspring.
But I think it is an error to describe resistance as a response to
pesticides as much as it is a weeding out of susceptible individuals.

> Varroa enters the prepupal cells one to two days prior to capping and hides from the nurse bees by submerging in the remaining liquid brood food, lying upside down.

> Varroa produces its first egg 60 hours after the cell is sealed. The first egg is usually a haploid male, and the subsequent female eggs are laid at 30-hour intervals. (1)

* * *

> Resistance occurs when a pest population -- insects, for instance -- is exposed to a pesticide. When this happens, not all insects are killed. Those individuals that survive frequently have done so because they are genetically predisposed to be resistant to the pesticide.

> Repeated applications and higher rates of the insecticide will kill increasing numbers of individuals, but some resistant insects will survive. The offspring of these survivors will carry the genetic makeup of their parents. These offspring, many of which will inherit the ability to survive the exposure to the insecticide, will become a greater proportion with each succeeding generation of the population. (2)


references

1. PARASITIC MITES OF HONEY BEES: Life History, Implications, and Impact
Diana Sammataro, Uri Gerson, and Glen Needham

2. Pest Resistance to Pesticides
Robert G. Bellinger, Department of Entomology, Clemson University

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