Download Behavioral Ecology for November 21

Be sure to read these sections along with the notes. Come to lecture Tuesday with
any questions. We will also begin General Ecology Ch. 50 on Tuesday. Have a
great holiday.
BEHAVIORAL ECOLOGY – CHAPTER 51
C. Learning
2. Spatial Learning
a. Every environment shows spatial variation.
b. Animals must modify their behavior based on experience with the spatial structure of
the environment, including nest locations, hazards, food and possible mates.
c. Many animals use landmarks as location indicators
i. Digger wasps use landmarks to locate their nests.
ii. Many migrating species use landmarks. (only works over short distances).
3.
a.
b.
c.
Cognitive maps
Cognitive maps: internal representations of objects in the environment.
Can be used to: locate previously stored caches of food.
Some migration behavior depends on cognitive maps.
4. Associative learning: learning to associate one stimulus with another
Two common types of associative learning: classical conditioning and operant
conditioning.
a. Classical conditioning - learning in which an arbitrary stimulus is associated with a
reward or punishment.
• Russian physiologist Ivan Pavlov - induced dogs to salivate when they heard a bell by
learning to associate it with powdered meat.
b. Operant conditioning (trial-and-error learning) - learning in which an animal
learns to associate one of its own behaviors with a reward or punishment and then tends
to repeat or avoid that behavior.
i. Psychologist B.F. Skinner - put lab animals in a box with a variety of levers. Test
animals learned to choose only those levers that yielded food.
ii. English birds learned to open milk bottles left on doorsteps and drink the cream when
one or more of the birds discovered its probing behavior was rewarded when directed at
the bottles.
c. Operant conditioning is common in nature.
• Predators learn to associate certain kinds of prey with painful experiences and modify
their behavior accordingly.
5. Cognition and problem solving
Animal cognition includes information processing on many levels. Complex nervous
system activities underlie sophisticated behavior, such as problem solving. Some
animals have internal representations of physical objects in their environment. The
study of cognition connects nervous system function with behavior
a. Cognition - The ability of an animal's nervous system to perceive, store, process, and
use information gathered by sensory receptors. Cognition is synonymous with
consciousness or awareness.
b. Cognitive ethology - The study of animal cognition. It attempts to illustrate the link
between data processing by nervous systems and animal behavior. It includes problem
solving behavior.
6. Genotype/Environment interactions
Varying degrees of genetic and environmental factors contribute to the learning of
complex behavior. The development of songs in birds is an excellent example.
a. In some species, learning plays only a small part in the development of song.
• New World flycatchers that are reared away from adults of their own species will sing
the song characteristic of their own species without ever having heard it.
b. Some songbirds have a sensitive period for developing their songs.
• Individual white-crowned sparrows reared in silence perform abnormal songs, but if
recordings of the proper songs are played early in the life of the bird, normal songs
develop. Although the young bird does not sing during the sensitive period, it memorizes
the song of its own species by listening to other white-crowned sparrows sing.
c. Canaries may learn new song “syllables” each year, adding to their song during a
yearly plastic song stage.
IV. Behavioral traits can evolve by natural selection
Behavior varies in natural populations. Because of the influence of genes on
behavior, natural selection can result in the evolution of behavioral traits in
populations.
A. Behavioral differences between closely related species are common.
1. Males of different Drosophila species sing different courtship songs.
2. Species of voles differ in paternal care.
B. Significant differences in behavior also can be found within species.
1. When behavioral variation within a species corresponds to variation in environmental
conditions, it may be evidence of past evolution.
2. Genetically based variation in prey selection by garter snakes Thamnophis
elegans.
a. Coastal garter snakes eat salamanders, frogs, and toads, but mainly slugs.
b. Inland snakes eat frogs, leeches, and fish, but do not eat slugs.
c. It is thought that when inland snakes colonized coastal environments 10,000
years ago, a small fraction of the population had the ability to recognize slugs by
chemoreception.
i. These snakes took advantage of this abundant food source and had higher fitness than
snakes that ignored slugs.
ii. The ability to recognize slugs as prey increased in frequency in coastal populations.
3. Genetically based variation in aggressive behavior in funnel web spiders
Agelenopsis aperta
a. The funnel web spider lives in riparian zones and the surrounding arid
environment in the western United States.
i. The spider’s web is a silken sheet ending in a hidden funnel, where the spider sits and
watches for food while foraging.
ii. When prey strikes the web, the spider runs out across the web to make its capture.
b. There is a striking difference between the behavior of spiders in riparian forests
and those in arid habitats.
----In arid, food-poor habitats, A. aperta is more aggressive to potential prey and to other
spiders in defense of its web, and it returns to foraging more quickly following
disturbance.
c. The differences in aggressiveness between desert and riparian spiders are genetic.
i. Highly productive riparian sites are rich in prey for spiders, but the density of bird
predators is also high.
ii. The timid behavior of A. aperta in riparian habitats was selected for by predation risk.
Natural selection favors behaviors that increase survival and reproductive success