behavioral ecology
DESCRIPTION
Behavioral Ecology. Photo from Wikimedia Commons. Ethological Underpinnings of Behavioral Ecology. Konrad Lorenz. Instinct , imprinting , etc. Photo from http://www.dabase.org/lorenz.htm. Ethological Underpinnings of Behavioral Ecology. Niko Tinbergen. - PowerPoint PPT PresentationTRANSCRIPT
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
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?
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 & Orgin (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 individuals in the colony the benefits to helping the queen 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…