Behavioral

EcologyPhoto from Wikimedia Commons

Ethological Underpinnings of Behavioral Ecology

Photo from http://www.dabase.org/lorenz.htm

Konrad Lorenz

Instinct, imprinting, etc.

Photo of Tinbergen from Wikimedia Commons

Niko Tinbergen

Four questions subsumed under Proximate vs. Ultimate Causes;questions concerning, respectively, how a behavior is produced

and why it evolved (i.e., evolutionary Benefit / Cost Ratio)

Ethological Underpinnings of Behavioral Ecology

Ethological Underpinnings of Behavioral Ecology

Of his chosen study organism von Frisch said:

“The honey bee is like a magic well: the more you draw from it,

the more there is to draw.”

Karl von Frisch

Photo of von Frisch from Wikimedia Commons

Waggle Dance

Photo from Wikimedia Commons

Konrad LorenzNiko TinbergenKarl von Frisch

Nobel Prize – 1973

Ethological Underpinnings of Behavioral Ecology

E.g., artificial selection experiments suggest a genetic basis for “migratory activity”

Genes can influence behavior, so behavior can evolve

Pulido (2007) BioScience, Fig. 2

Artificial Selection

For higher proportion of migrants

For lower proportion of migrants

Foraging Behavior

Photo from Wikimedia Commons

E.g., ambush predator and female fly prey (also illustrates another cost of sex)

Items with high profitability (P) are generally preferred

Optimal Foraging Theory

Photo from http://www.rspb.org.uk/community/ourwork/b/biodiversity/archive/2013/02/18/guest-blog-in-the-still-of-the-night.aspx

P = E

t

E = net energy value, i.e., energy gained minus energy invested

t = encounter time & handling time invested in obtaining &

processing the food

Conceptual model of OFT

Optimal Foraging Theory

Net energy gained = (Total energy obtained) – (Cumulative energy investment)Drops off as animal cannot carry nor ingest more

Cain, Bowman & Hacker (2014), Fig. 8.6

Marginal Value Theorem as applied to profitability of foraging patches

Cain, Bowman & Hacker (2014), Fig. 8.8

Within a patch, the marginal value for longer time has diminishing returnsSlopes of straight, solid lines = Energy gained / time

Tangent maximizes profitability (slope) & determines optimal giving up time

Optimal Foraging Theory

Foraging (and other) decisions can be modified by predators

The Ecology of Fear

Beckerman et al. (1997) Proceedings of the National Academy of Sciences, Fig. 1

E.g., caged grasshoppers foraging in the presence or absence of the risk of predation, i.e., with or without a spider (mean s.e.m. shown)

Prey sometimes communicate their awareness of predators to those predators

E.g., stotting / pronking

The Ecology of Fear

Photo from Wikimedia Commons

Social Behavior

Photo of social grooming from Wikimedia Commons

E.g., Optimal Group SizeConsider the variable Benefit / Cost Ratio

Social Behavior

Cain, Bowman & Hacker (2014), Fig. 8.22

Should an individual remain alone or join another to form a

group of 2?

What is the optimum group size?

Should an individual join a group of 2 or 5?

What are likely benefits and costs?

Reproductive Behavior

Photo from Wikimedia Commons

The Evolution of Competitive Males & Choosy Females (and sometimes the reverse)

Parental Investment is “any investment by the parent in an individual offspring that increases the offspring's chance of surviving (and hence reproductive

success) at the cost of the parent's ability to invest in other offspring” (Trivers 1972)

Photomicrograph of human egg and sperm cells from Cain, Bowman & Hacker (2014), Fig. 7.7; photo of suckling manatee from http://mammalssuck.blogspot.com/2013/11/mega-mammal-milk-analysis.html; photo of “pregnant” seahorses from http://www.scubadiveasia.com/blog/best-dad-award-goes-to-the-seahorse/

AnisogamyMaternal investment =

nursingPaternal investment =

brood-pouch “pregnancy”

Male-Male Competition

Photomicrographs from http://prometheuswiki.publish.csiro.au/tiki-index.php?page=Spikelet+sterility+and+in+vivo+pollen+germination+and+tube+growth+under+high-temperature+stress+in+rice

E.g., male pollen grains compete to fertilize female ovules

Photo of peacock spider (Maratus volans) from Wikimedia Commons

Female Choice – Courtship

E.g., courtship in the peacock spider (Maratus speciosus)

Copulatory Courtship & Cryptic Female Choice

Photo of Maria Fernanda Cardosa’s sculptures of male damselfly genitalia from http://livingwithinsects.wordpress.com/2012/04/30/insect-reproductive-morphology/

E.g., male damselfly genitalia (aedeagi, plural of aedeagus)

Monogamy

Polygyny

Polyandry

Promiscuity

Mating Systems

Photo of horseshoe crabs from Wikimedia Commons

“Polygyny occurs if environmental or behavioral conditions bring about the clumping of females, and

males have the capacity to monopolize them.”

Emlen & Oring (1977)

Mating Systems

Cain, Bowman & Hacker (2014), Fig. 8.8; schema from Emlen & Oring (1977) Science, Fig. 1

Polygyny Threshold Model

Mating Systems

Graphic model from Orians (1969) American Naturalist, Fig. 1

Pick a point on the monogamous female curve. The distance to the right to intercept the bigamous female curve is the polygyny threshold, i.e., the habitat quality increase

required to make it worthwhile for the female to share a mate.

W. D. Hamilton

Inclusive Fitness & Kin Selection

Photo of Hamilton from Wikimedia Commons

Kin selection exposes the selfish nature of altruism; helping kin can increase one’s inclusive fitness (direct plus indirect fitness)

Hamilton’s Rule: rB > CRelatedness * (Benefits to recipient) > (Costs to altruist)

Relatedness

“I would lay down my life for 2 brothers or 8 cousins”J. B. S. Haldane

r – introduced by Sewell Wright as a measure of consanguinity

Generation 1

Generation 2

Generation 3

Mother-daughter

r = 1/2

Sisterr = 1/2

Cousinr = 1/8

Eusociality in Diploid Organisms

Photos from Wikimedia Commons

For most individuals in the colony the benefits to helping the queen outweigh the costs of sacrificing their own reproduction

rB > C

Naked Mole Rat Termites

Eusociality in Haplodiploid Organisms

Photos of Hymenoptera from Wikimedia Commons

For most female individuals in the colony the benefits to helping the queen rear sisters outweigh the costs of sacrificing their own reproduction

rB > C

Generation 1

Generation 2

Mother-daughter

r = 1/2

Sisterr = 3/4

AdoptionAggression

Anti-Predator BehaviorBeggingBreeding

Brood ParasitismCannibalism

CommunicationCooperationCopulationDispersal

Dominance HierarchiesFamily Dynamics

FlockingGrooming

Habitat SelectionHerdingHoming

Behavioral Ecology

InfanticideKin RecognitionMate Guarding

MigrationNepotismNesting

Parasite AvoidanceParental Care

PlayingPredator-Prey Interactions

RoostingScent-MarkingSex Change

SchoolingSymbiotic Maintenance

TerritorialityThermoregulation

Etc…