Download - Animal behaviour-brood parasities
-
7/29/2019 Animal behaviour-brood parasities
1/18
Parasitism
Evolutionary equilibrium or
contuining arms race?
-
7/29/2019 Animal behaviour-brood parasities
2/18
Tight coevolution and diffuse
coevolution
-
7/29/2019 Animal behaviour-brood parasities
3/18
Comparison certain ecological characteristics that vary
along a parasitepredator spectrum
-
7/29/2019 Animal behaviour-brood parasities
4/18
Brood parasitism
the surreptitious addition of eggs to another females nest, whether of the
same (intraspecific) or different (interspecific) species There are several species of fish, insect and birds that are
obligate interspecific brood parasites.
These birds lay their eggs in the nests of other birds andprovide no parental care.
Brood parasitism is an antagonistic evolutionary interaction
between species
Brood parasitism
-
7/29/2019 Animal behaviour-brood parasities
5/18
Atemeles sp.
Atemeles beetles are one of the many insects
that are parasites in ant nests. The ants respond to
the beetles as if to other ants, feeding them.
-
7/29/2019 Animal behaviour-brood parasities
6/18
Atemeles sp.
(a) Offering food by a Formica worker-
ant to a beetle-larva
(Atemeles pubicollis) that parasitically
lives in the ant nest.(b)Atemeles-larva with position of the
cutaneus glands (k) producing baits for
the host ants.
After Hlldobler, from Hadorn andWehner, 1977)
-
7/29/2019 Animal behaviour-brood parasities
7/18
Atemeles sp.
Atemeles emigrate from the ant nest (Formica) where theyhave been raised during the summer, to the nests ofanother ant genus (Myrmica). After wintering there, theyreturn to their original nest to breed in the springtime.
There is of course a reason for these moves:
In the Formica nests, the immature stages disappear duringthe winter, and consequently social food flow is reduced.
In contrast, the Myrmica colony maintains brood
throughout the winter and high-grade food sources areavailable for theAtemeles.
-
7/29/2019 Animal behaviour-brood parasities
8/18
Cuculus canorus
Common Cuckoos are unrivaled
at laying eggs that resemble
their hosts.
Eurasian cuckoo chicks
maneuver under host eggs and
chicks and dump them over the
edge of the nest. Their backs
have a neatly designeddepression that just fits their
potential competitor.
-
7/29/2019 Animal behaviour-brood parasities
9/18
(1)Eggs matched for size
(2) thicker egg shells
(3) Egg color and pattern
(Cuckoos and in the more
host specific cowbirds),Nestling mimicry is absent in
Host-intolerant spp (Cuckoos)
Host adaptations and
mimicry
-
7/29/2019 Animal behaviour-brood parasities
10/18
Young cuckoo mimicry
-
7/29/2019 Animal behaviour-brood parasities
11/18
Cryptic egg coloration
-
7/29/2019 Animal behaviour-brood parasities
12/18
Whereas the Brown-headed Cowbird,
a recently encounter parasite species
for many hosts, does not use cryptic
egg coloration
Parasitized Red-eyed Vireo nestParasitized Wood Thrush nest
-
7/29/2019 Animal behaviour-brood parasities
13/18
Brood parasites exploit the host parents'
tendency to feed the largest young in a
brood and the one that can reach highest
most.
By laying in the nests of smaller birds,
cuckoos give their young an advantage in
the competition for food. So do
cowbirds whose eggs hatch after a
shorter incubation period which allowsthem to hatch before the hosts young.
Effect of brood parasites
-
7/29/2019 Animal behaviour-brood parasities
14/18
Contuining arms race
Why tolerate parasites eggs?
Accepting a parasites egg is even more likely to be adaptive
when the host is too small to remove the parasitic egg.
Such hosts must either accept the egg or abandon the nest,which is an expensive option, especially if nest sites are scarce
(e.g. as in cavity nesters).
Some birds do recognize parasitic eggs and remove them from
the nest. However, there is a risk that the host will discard one
or more of its own eggs in error.
Reed Warblers have been shown to make this mistake.
-
7/29/2019 Animal behaviour-brood parasities
15/18
-
7/29/2019 Animal behaviour-brood parasities
16/18
Evolutionary equilibrium
Hosts can be acceptors or rejecters actually acontinuum, and a function of time of sympatry
Egg removal e.g., catbird
Egg smashing e.g., orioles
Nest abandonment many passerines in NA
Build a second nest on top the original Yellowwarbler
-
7/29/2019 Animal behaviour-brood parasities
17/18
Conclusion
As selection operates on both hosts and parasites
the differing selection pressures have resulted in
an arms race between hosts and parasites.
Brood parasites have a significant effect on the
reproductive success of the hosts. So, with many
other species the arms-race between parasites
and hosts is ongoing.
Bener ga sih? Tolong dikoreksi ya
-
7/29/2019 Animal behaviour-brood parasities
18/18
Thank you
Coevolutionary arms race
it takes all the running you can do, just to
keep in the same place. -The Red Queen
(from Alice in Wonderland)