Week 11.2

Animal Behaviour - Bio3436 Study Notes

How Does Behaviour Develop?

Interaction of Genes and Environment

• Genes and Phenotype

  • Genes and the environment interact during development, leading to the production of the phenotype.

  • Differences in genes lead to differences in phenotype.

  • Differences in the environment produce differences in phenotype.

Phenotype Variants

• Phenotype 1

• Phenotype 2

• Phenotype 3

Phenotypic Plasticity and Norm of Reaction

• Phenotypic Plasticity: The genome enables the organism to produce a range of anatomical and behavioral phenotypes based on environmental conditions.

• Norm of Reaction: Refers to the spectrum of phenotypes produced across a range of environmental conditions, highlighting the adaptability of organisms to different environments.

• development covers all changes that happen across the lifespan of an organism, encompassing growth, learning, and responses to environmental stimuli.

Role of Experience in Development

• Experience-Independent Development: Changes driven largely by genetics and not shaped by experience.

  • sometimes development is independent from experiences (not independent from environmental experience) talking about stimuli

• Experience-Dependent Development: Changes determined by the lived experiences of the individual.

  • unique life experiences will affect their phenotype on a particular trait

Example: Coastal vs Inland Garter Snakes

• Comparison of dietary preferences shows that the differences are genetic, indicating experience-independent behavior.

• costal: eat large banana slugs → specialized trait bcs slugs tend to be hard to eat and are often poisonous

• inland: eat small fishes dont eat banana slug

Daphnia cucullata Case Study

• Defenses in Multi-predator Environments

  • Comparative Scanning Electron Micrographs: Show variations during different life stages; traits include helmet length (HL), body length (BL), and tail spine length (SL).

• Juvenile Daphnia: Develop helmets in the presence of a specific predator (larvae of the fly Chaoborus), which reduces their predation risk.

• Kairomone: An interspecific chemical messenger that benefits the receiver (the prey) rather than the sender (the predator); used by prey to avoid capture.

  • special chemical signal that is eavesdropped on… sender producing that receiver is benefiting from… daphnia detect it in the water and devlope helmets to protect them from it…only develop the helmets if they sense the presence of this chemical signal, allowing them to adaptively respond to predation threats. This process illustrates the profound impact of chemical communication in shaping the morphology and survival strategies of prey species in aquatic ecosystems.

Social Insects Development

• Eusociality: Characterized by three features:

  1. Cooperative care of young

  2. Sterile castes

  3. Overlapping generations

• Common classes include Hymenoptera (ants, bees, wasps).

• different members of the same colony will specialize in different fields by developing different characteristics, allowing for efficient division of labor and enhanced survival of the colony as a whole.

Age Polyethism in Honeybees

• Task Distribution Based on Age:

  • Just Emerged Bees (1-2 weeks): Clean out dirty honeycomb.

  • Forager Bees (3-5/7 weeks): Forage for nectar, pollen, and water.

  • Guard Bees (2-3 weeks): Protect the hive. remove deceased bees

  • Nurse Bees (0-1 weeks): Feed larvae, receive food from foragers.

  • Lifespan for honeybees ranges from 5 to 7 weeks.

  • have different jobs throughout their lifespan

  • development goes throughout entire lifetime

table

→ took of all young nurse and other colony took out old foragers

• take out old foragers causes there to be more young foragers

• take out young nurse causes old nurses

• while the changes are age dependent but it is also experience dependant… have to compensate for lack of young nurse / old forager

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Development in the Honeybee Brain

• dramatic structure = mushroom body… different to human neurons lighter blue are dendrites that are taking in info… dark blue is axons

  • part we care about for bee development are the dendrites… there are 3 different sections

  • 
    

• Neuronal Changes Over Time: Study shows the development concerning experience, where the volume of specific brain structures changes.

• Neuropil Volume: Data demonstrates age-related changes in the honeybee brain development when related to tasks performed:

  • as honeybees develope the volume in the structures gets largers

    • D1 → when they first hatch

    • First Flight →

    • Fifth Flight

    • First Foraging

Experience Dependent in Honeybee Brain Development

• Polyethism: Honeybee behavior is not entirely experience-independent as it is influenced by task performance and learning through experiences.

• Experience-Expectant Growth: Changes in the mushroom bodies of the honeybee brain as a result of age and expected environmental stimuli.

  • experience doesn’t come before the change the change comes in anticipation of the experience to prepare them for the new stimuli of becoming a forager and having to take in so much visual stimuli

Ontogenetic Adaptation

• Maturational vs. Adaptational Changes

  • Development is not solely about maturation but involves continual adaptation to environmental challenges and opportunities.

  • at each developmental stage there are particular things that are really adaptive that arent as adaptive at other stages…. some things might be more beneficial as infant than as adult

Learned Taste Aversions in Rats

• Study Design of Taste Aversion: Pairing a novel flavor with an illness-inducing drug, such as lithium chloride (LiCl), results in a learned aversion to that flavor.

• wanted to learn taste adversions in rat pups

• when paring stimulus with certain outcome there needs to be some type of temporal contiguity, which refers to the timing between the presentation of the flavor and the administration of the drug to effectively establish the association.

• taste aversion can happen hours after the food had already been eaten

  • Flavor A Reaction:

  • Flavor A mixed with LiCl leads to illness > Creates learned aversion.

    • makes them feel ill… won’t want to eat anything with that flavour again

  • Flavor B with Na (control) shows no adverse effect.

  • when preferences are taken they should prefer flavour B and should be averted towards flavour A bcs it was previously associated with negative experiences. This demonstrates the impact of conditioned taste aversion on food choices among animals.

  • wanted to know how taste aversion changes over lifetime

  • wanted to compare how the rats would develop aversion while they were nursing vs. when they were no nursing

• Nursing Influence: Learned aversion can be suppressed if the novel flavor is experienced while nursing.

Specific Example of Flavor Aversion

• Geraniol (G): A rose-like odor used in experiments.

• Flavors Tested:

  • G-Li: Geraniol-flavored milk with lithium chloride.

    • should expect to be paired with sickness and shouldn’t want to eat it later on

  • G-Sal: Geraniol-flavored milk with saline.

  • rat pups that are actively nursing: see no difference between G-Li and G-Sal even though we should

  • rat pups that are not actively nursing… drop in % of rat pups that will take flavour that was associated with sickness showing learned aversion

  • rat pups that are weening drastically don’t want to consume the flavour indicating learned food aversion

  • if pups learn aversion to their mothers milk it would me certain death even if other milk is making them sick … they need their mothers milk

  • adversion when they no longer need mothers milk, taste aversion is prominante because they no longer need their mothers milk for su

  • Learning Dynamics: The learned aversion is heavily influenced by immediate experiences during sensitive developmental periods.