Nerve activates contraction

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Population InteractionsPredation
Fig. 14.X Smith Smith, 6th ed. (p. 283)
2
From the introductory remarks to Predation, Ch.
14 in your text Although the very term predator
brings to mind images of lions on the savannas of
Africa or the great white shark cruising coastal
waters, predation is defined more generally as
the consumption of all or part of one living
organism by another. Although all heterotrophic
organisms derive their energy from the
consumption of organic matter, predators are
distinguished from scavengers and decomposers in
that they feed on living organisms. As such,
they function as agents of mortality with the
potential to regulate prey populations.
Likewise, being the food resource, the prey
population has the potential to influence the
growth rate of the predator population. These
interactions between predator and prey species
can have consequences on community structure and
serve as agents of natural selection, influencing
the evolution of both predator and prey.
Smith Smith, 6th ed. (p. 283)
3
Predation is one of several types of
consumer-resource interactions between species
Table 53.1 in Campbell Reece, 7th ed. (p. 1180)
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Fig. 14.2, Smith Smith, 7th ed (p. 284)
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Population cycles in the snowshoe hare and lynx
Fig. 52.19, Campbell Reece (6th ed)
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Fig. 14.26, Smith Smith (6th ed), p. 306
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• Two aspects of the response of a predator
  population to changes in prey density
• functional response the relationship between
  density of the prey population and the number of
  prey consumed per predator largely determined by
  the relative demands of
• a. search time, and
• b. handling time
• 2. numerical response the change in the
  population of the predator in response to a
  change in prey density

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Functional response curves
Type I Prey taken per predator increases
linearly with increasing prey density.
Proportion of prey consumed is constant. Type II
Predation rate rises at a decreasing rate as prey
density increases, eventually reaching a maximum.
Thus, the proportion of the prey population
taken declines with increasing density. Type III
Predation rate is low initially, then increases
in a sigmoid curve, finally maximizing. The
proportion of the prey population taken is low at
first, rises to a maximum, then declines with
further increases in prey density.
Fig. 14.3, Smith Smith, 6th ed. (p. 287)
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Functional response curves
European kestrel (Falco tinnunculus)
Voles (Microtus sp.)
Fig. 14.4 in Smith Smith, 6th ed. (p. 288)
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Functional response curves
Fig. 14.4 in Smith Smith, 6th ed. (p. 288)
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Functional response curves
Fig. 14.4 in Smith Smith, 6th ed. (p. 288)
12

Testing optimal foraging theory Prey-dropping
behavior by crows on Mondarte Island,
BCExperimental results (Zach. 1978. Behaviour
67134147)
Northwestern crow (Corvus caurinus)
whelk (Thais lamellosa)
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(No Transcript)
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Test of the optimal foraging hypothesis Feeding
behavior of mule deer (Odocoileus hemionus)
Response to predation risk
Fig. 51.24, Campbell Reece (7th ed)
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More on optimal foraging theory Natural
selection should favor efficient foraging
strategies. Optimal foraging behavior is thus a
compromise between maximizing benefit while
minimizing investment and/or risk.
16

Some considerations in optimal foraging Where
to forage? How long to hunt there? How to
search? Which prey to go after?
17
Test of optimal foraging by bluegill sunfish
feeding on Daphnia (a laboratory experiment by
Werner Hall 1974)
Fig. 51.23, Campbell Reece, 7th ed (p. 1123)
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• Other aspects of foraging
• 1. search image
• 2. prey switching
• 3. aggregative behavior in predators
• 4. plant defenses against predation (herbivory)
• physical protection
• chemical defenses
• mutualistic partners, e.g.,
• endophytic fungi
• ants

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There is great diversity in predator-prey
interactions a couple of less-familiar examples
20
Pond ecosystem Giant water bugs (right) prey on
polliwogs (left)
21
Stream ecosystem Fishing spidersa couple of
species from Kentucky
Dolomedes tenebrosuslargest fishing spider of
KY, with a legpsan of 3 inches.  Commonly found
on the trunks of trees near water.
Six-Spotted Fishing Spider (Dolomedes
triton)Slightly smaller.  Often seen hunting on
the water's surface in ponds and slow-moving
streams.
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Stream ecosystem Fishing spidersother species
Some fishing spiders can go underwater for brief
periods of time to catch aquatic prey and to
escape danger.
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Predation on plants by animals
Intense predation on oaks by gypsy moths in
eastern forests of North America
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Predation on plants by animals
Intense predation on oaks by gypsy moths in
eastern forests of North America
Fig. 14.24 in Smith Smith, 6th ed (p. 303)
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Predation on plants by animals
Intense grazing on grassland plants by large
herbivores in southeast Africa (left of fence),
compared to exclosure area (right)
Fig. 14.24 in Smith Smith, 6th ed (p. 303)
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Some adaptive responses to predation
27
Crypsis in a flounder (Paralichthys) and in a
walking stick (Phasmatidae)
Fig. 14.14 in Smith Smith, 6th ed (p. 296)
Fig. 14.15, Smith Smith, 6th ed (p. 297)
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Crypsis in two insect species
Miller, 2nd ed., Figure 8-11, p. 177
Miller, 2nd ed., Figure 8-11, p. 177
Span worm
Wandering leaf insect
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An example of Batesian mimicry
Miller, 2nd ed., Figure 8-11, p. 177
Viceroy butterfly (the mimic)
Monarch butterfly (the model)
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Another example of Batesian mimicry When
disturbed, the hawkmoth larva (left) resembles a
snake (right).
Fig. 53.7, Campbell Reece, 7th ed (p. 1162)
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Müllerian mimicry among unrelated species (a)
social wasps (Vespidae), (b) solitary digger
wasps (Sphecidae), and (c) the caterpillar of the
cinnabar moth (Callimorpha jacobaeae)
Fig. 14.19, Smith Smith, 6th ed (p. 299)
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Aposematism (warning coloration)
Fig. 14.17, Smith Smith, 6th ed (p. 298)
black-legged poison frog
monarch butterfly
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Aposematic coloration in the poisonous coral
snake (Micrurus fulvius) ...
... and its Batesian mimic, the nonvenomous
scarlet king snake (Lampropeltis triangulum)
Fig. 14.18, Smith Smith, 6th ed (p. 298)
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Another defenseChemical defenses in two insect
species
Miller, 2nd ed., Figure 8-11, p. 177
Bombardier beetle
Monarch butterfly
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Additional defense strategies (read about these
in text) 1. protective armor (e.g., clams,
turtles) 2. behavioral defenses (e.g., hiding,
fleeing, grouping) 3. predator satiation (e.g.,
periodic cicadas, masting in oaks)
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Aggressive mimicry by a predator The robber fly
(Laphria sp.) mimics its prey, the bumblebee
(Megabombus pennsylvanicus)
Fig. 14.23, Smith Smith, 6th ed (p. 302)
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Crypsis and aggressive mimicry by the alligator
snapping turtle
Fig. 14.22, Smith Smith, 6th ed (p. 302)
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ParasitoidismIs it predation? or parasitism?
A cicada-killer wasp with its paralyzed but
living prey, a mature cicada
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Plants as predatorsthe Venus flytrap
Fig. 37.16, Campbell Reece (6th ed)
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Plants as predatorsthe pitcher plant
Fig. 37.16, Campbell Reece (6th ed)
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Plants as predatorsthe sundew
Fig. 37.16, Campbell Reece (6th ed)
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Testing questions about predation A laboratory
experiment by C.B. Huffaker (1958)
Carl Barton Huffaker
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Predation A laboratory experiment by C.B.
Huffaker (1958) Experimental set-up with oranges
and rubber balls in a tray
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Predation A laboratory experiment by C.B.
Huffaker (1958) An orange, partially
papered-over to limit food availability Two mite
species were introduced (1) Eotetranychus, the
6-spotted mite, eats orange peel and is a serious
pest of citrus orchards. (2) Typhlodromus preys
on the 6-spotted mite.
Eotetranychus sexmaculatus
Typhlodromus occidentalis
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• Predation a laboratory experiment by C.B.
  Huffaker (1958)
• Huffaker started with a simple system,
  introducing 20 prey mites (Eotetranychus) on each
  orange.
• In the absence of predators, prey populations
  increased and leveled off at about 4700 mites per
  orange area (an area equivalent to that of a
  whole orange).
• Huffaker then tried introducing 2 predatory
  mites (Typhlodromus) after giving the prey
  population an 11-day head start.
• In these experiments, the predator populations
  increased , eventually killing off all the prey,
  then dying off themselves.
• The rate of this process depended on the
  relative proximity of the oranges. If oranges
  were adjacent, prey populations reached about 350
  individuals before being exterminated at day 27.
  If the oranges were scattered randomly throughout
  the 40-position tray, prey reached about 3000
  individuals and lasted 36 d before being wiped
  out.
• Huffaker then introduced further complexity...

46
Predation A laboratory experiment by C.B.
Huffaker (1958) He added Vaseline barriers to
retard migration and the spread of pedestrian
Typhlodromus (the predator). He also introduced
ballooning-sticks to help Eotetranychus (the
prey) disperse better. The results
47
Parasitoidism A laboratory experiment by
Pimentel (1968)
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Coevolution in a parasitoid-host system The wasp
Nasonia vitripennis is a parasitoid of several
fly species. Here a female Nasonia is laying a
clutch of eggs into the pupa of a blowfly
(Phormia regina)
Fig. 53.x2, Campbell Reece (6th ed)
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Coevolution in a parasitoid-host system An adult
blowfly (Phormia regina)
Fig. 20.9 in Ricklefs, Economy of Nature 5th ed.
(p. 388)
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Coevolution in a parasitoid-host system Another
female Nasonia laying eggs into a housefly pupa
Fig. 20.3 in Ricklefs, Economy of Nature 5th ed.
(p. 384)
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Coevolution in a parasitoid-host
system Pimentels lab experiment testing for
evolutionary response by a host to a
parasitoid. In this cage, host progeny were
removed and replaced by naive pupae.
Fig. 20.4 in Ricklefs, Economy of Nature 5th ed.
(p. 384)
52
Coevolution in a parasitoid-host
system Pimentels lab experiment testing for
evolutionary response by a host to a
parasitoid. In this cage, host progeny remained
in cage.
Fig. 20.4 in Ricklefs, Economy of Nature 5th ed.
(p. 384)
53
Coevolution in a parasitoid-host
system Pimentels lab experiment testing for
evolutionary response by a host to a
parasitoid. Response of naive houseflies (left)
vs. previously-exposed houseflies (right)
Fig. 20.5 in Ricklefs, Economy of Nature 5th ed.
(p. 385)
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Two examples of predation by animals used as
biological controls for invasive plant
species
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Predation on plants by animals Cactoblastis and
the prickly pear
Fig. 17.1, Ricklefs 5th ed. (p. 330)
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Population regulation by predatorsKlamath weed
Chrysomelid beetles