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From:
Peter Loring Borst <[log in to unmask]>
Reply To:
Informed Discussion of Beekeeping Issues and Bee Biology <[log in to unmask]>
Date:
Tue, 9 Jun 2015 06:31:39 -0400
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Hi all
What we are talking about here is the complex intersection of behavior and evolution. This is a highly debated topic among evolutionary biologists, so it is no wonder there is ample disagreement here at Bee-L

Quoted Material Follows:

Behavior has been viewed as a pacemaker of evolutionary change because changes in behavior are thought to expose organisms to novel selection pressures and result in rapid evolution of morphological, life history and physiological traits. However, the idea that behavior primarily drives evolutionary change has been challenged by an alternative view of behavior as an inhibitor of evolution. According to this view, a high level of behavioral plasticity shields organisms from strong directional selection by allowing individuals to exploit new resources or move to a less stressful environment.

Duckworth 2009

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A perfect example of this is the difference between temperate honey bees and tropical honey bees. The two types of bees evolved two different responses to environmental adversity. The temperate zone bee hoards and goes into a dormant state when resources fail whereas the tropical ones migrate to better conditions. In a sense, the migratory behavior allows the tropical bee to avoid becoming closely adapted to a particular environment by being able to get out of it. 

Almost like human behavior, it avoids the evolutionary imperative to adapt. The temperate bee in a sense does the same thing by creating a suitable environment (the nest) in which to protect itself until better conditions arise. Most other bees and wasps simply allow the colony to die and the queen hibernates alone in the ground. So the ability to change one's environment sidesteps the necessity for adaptation. 

More complex behaviors such as learning, intelligence, and behavioral plasticity also allow organisms to avoid genetic change. How does this apply to honey bees? If they can quickly acquire behaviors to rid themselves of parasites, then the species doesn't need to wait for genetic mutation to produce novel traits, which can be a slow and uncertain process. This is the principal of the acquired immune system, whereby an organism responds in real time to attacks and retains that response for the lifetime of the organism. 

It can even pass this response to the offspring, as we mentioned earlier. Mammals pass antibodies to their offspring in utero; social organisms can pass beneficial microbes from parents to offspring. In a sense, this is a technique of modifying one's internal environment to avoid succumbing to challenges from the external environment (disease)

P

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Quoted Material:

The traditional view states that the rate of evolution is determined by a combination of mutation rate that generates variation and the intensity of natural selection that sorts this variation. Changes in the intensity of natural selection are often assumed to be solely a function of the rate of environmental change; however, the intensity of selection is determined by the interaction of an organism with its environment. Behavior is at the forefront of this interaction because it determines where organisms live and reproduce and how they obtain resources, avoid predators, choose mates, maintain homeostasis, and respond to conspecific and heterospecific competitors. Thus, changes in either the environment or an organisms’ behavior can alter selection pressures. This places behavioral change on equal footing with environmental change as a potential cause of evolutionary change.

The foundation for arguments that behavior plays a unique role in evolution—whether that role is as a driver or as an inhibitor of evolutionary change—is that behavioral traits are distinct from other aspects of the phenotype. I suggest that it is not high developmental plasticity which makes behaviors unique but instead is their reactive nature. Active organisms are shaped by their environment and these same organisms also shape their environment. Yet, recognizing that behavior can play a causal role in evolution does not mean that all types of behavior and all types of behavioral shifts should affect evolutionary processes in the same way. Instead, the challenge for future studies in this area is to determine how different types of behaviors (e.g., social behaviors versus habitat selection) and different types of behavioral shifts (e.g., shifts due to learning versus shifts due to selection) affect selection pressures in the short term to ultimately impact the rate of evolutionary diversification.

Duckworth 2009

* * *

Honey bee has a variety of behaviors which fit into the above discussion. She mentions learning and its effect of foraging behavior, but there may be other learned behaviors as well, such as response to parasites or environmental cues. Honey bee is not strictly bound by instinctive behaviors. 

Organisms that are tend to be tethered to a particular niche, while organisms like honey bees and people, which are adaptable in real time (vs evolutionary adaptation) can succeed in a variety of environments, and respond to a variety of challenges. 

To be able to change and adapt in real time is in the final analysis a product of evolution, but in a sense, it is a defense against the need for further genetic change, which as we know is based on random mutation, or to put it more plainly: luck.

P

* * *

ref:
Renée A. Duckworth (2009) The role of behavior in evolution: a search for mechanism. Evol Ecol 23:513–531

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