1

Interspecific Relationships

2

AS Explanatory note• interspecific relationships (predation,

parasitism, mutualism, commensalism, competition for resources)

3

Mutualism (+,+)= a close, co-operative association between

individuals of two species from which both benefit, often characterised by communication between the participants; a form of symbiosis.

e.g. pollination

4

• Co-evolution is the evolution of two species to become totally dependent on each other. Each of the species involved exerts selective pressure on the other, so they evolve together. Co-evolution is an extreme example of mutualism

5

• Some examples of co-evolution :

Acacia ants and acacia trees Acacias are small, Central

American trees in the Leguminosae. They have large, hollow thorns. The acacia ants

live in the thorns. On the tips of its leaflets, the plant makes a substance used by the ants as food. The ants defend the tree

from herbivores by attacking/stinging any animal

that even accidentally brushes up against the plant. The ants also prune off seedlings of any other plants that sprout under “their”

tree

6

Lichens Lichens are composed of a mixture of fungi and algae. In each “species” of lichen, the alga and fungus are so

closely intertwined that whole lichens are classified as species, rather than the component fungus/alga.

The type of fungus and alga are species-specific. The alga does photosynthesis

and produces sugars as fuel for both. The fungus

attaches the whole lichen to its substrate (tree, rock) and

holds in water needed by the alga.

7

3 Main Types of exploitation

• Predation

• Parasitism

• GrazingExploitation is when one organism gains benefit at

the expense of another which is harmed.

(+,-)

8

• http://www.youtube.com/watch?v=c81bcjyfn6U&feature=PlayList&p=A0AD6A14E53D2CCE&playnext=1&playnext_from=PL&index=90

9

Predation• Predation = predator kills prey

(+/-)

• Short term effect = p+p affect each others numbers

10

Two species of mites demonstrate the coupled

oscillations of predator and prey densities

Interpretation: It is apparent from the graph that both populations showed cyclical behaviour, and that the predator population generally tracked (lagged) the peaks in the prey population.

11

Predator – prey numbers

• Predators can only reproduce if they eat enough prey.

predator numbers are influenced by prey numbers

Mostly found in simple ecosystems – tropical ecosystems have complex food webs

12

• Kiore numbers increase when more grass seed available

13

• Canadian Lynx mainly prey on Snowshoe Hare. An increase in hare numbers is soon followed by an increase in lynx numbers

14

Ladybeetle larvae eating an aphid

15

• Long term effect = p+p shape each others evolution

The idea of an arms race between a prey animal evolving better ways to defend itself against a predator that is improving its own offensive abilities

Predator prey evolution explanation

In this snowy environment, the polar bear is white to avoid being noticed as it approaches the seal, and the seal pup is white to avoid being noticed by the bear.

16

• Belonging to a group - can increase food intake via:

-locating food-catching food

Predator Strategies

17

• Snares eg spider webs; glow worms lure and trap prey.

18

• Mimicry = Resemblance of an organism (the mimic) in color, pattern, form, behavior, or a combination of these to another organism or object (the model).

• The taking on by an animal of the look of another sort of animal or thing for the purpose of:

• keeping itself safe (traditional sense)

• enhancing predation

19

Female fireflies of the genus Photuris

• Photuris females mimic the signal of other firefly species.

• Responding male firefly is captured and eaten.

20

• http://www.youtube.com/watch?v=EqJzuc9pE00

21

While the cleaner Labroides dimidiatus (top) is a symbiont to other marine fish, removing their ectoparasites, the mimic Aspidontus taeniatus (below) bites off parts of other fishes'

skin and fins

•(Cleaner Fish + host = mutualism). A Cleaner Fish look-alike is able to get close to bite chunks off fin and gill.

22

• Speed e.g. cheetahhttp://www.planetarkive.org/topics/attack2.html

23

• Camouflage• http://www.planetarkive.org/topics/attack2.html

• http://www.ryanphotographic.com/crypsis.htm

24

• http://www.youtube.com/watch?v=fSdICt60ZDA&feature=related

25

• Poisonhttp://www.planetarkive.org/topics/attack2.html

26

• Sensitive senses Great white sharks use their amazing sense of smell to track down their prey underwater. They can detect a speck of blood, no bigger than a pinprick, that is floating around in over 100 litres of water from more than 4km away!

http://www.planetarkive.org/topics/attack2.html

27

• Stalking

28

Prey Defences

• Living in Groups

• - greater vigilance (may be further enhanced by combining sensory capabilities of another species).

29

• Sensitive senses e.g. impala - keen sense of smell+ baboon - excellent colour vision)

30

• -increased armament – more teeth to deter predators e.g. a group of baboons can kill a leopard

31

• -dilution effect - more for predator to choose from = less impact if one is lost

• -confusion effect – difficult for predator to focus on one individual

32

• Deception• camouflage + appropriate behaviour, e.g.

ground-nesting chicks ‘freeze’.

33

• counter-shading e.g. pelagic (open water) fish (e.g. Kahawai) silvery underside, dark top

34

Batesian Mimicry - a palatable animal mimics an unpalatable one e.g. viceroy resembles toxic monarch butterfly

35

Don’t eat the monarch – it’s chunderous!

36

One of the snakes in the picture below is poisonous and the other one is a mimic. Coral snakes are very easy to see because of their bright red, yellow, and black stripes. They are colored this way so that other animals know they are poisonous and will leave them alone. The Scarlet Kingsnake looks almost EXACTLY like the Coral snake, but it is perfectly harmless!

The scarlet king snake on the left is the mimic, and the coral snake on the right is the poisonous one. The scarlet king snake is hoping that its enemies will think it is poisonous and not eat it! If you couldn't tell the difference, don't worry about it! The Kingsnake, or the mimic, would be really happy that you couldn't! If you ever see one of these snakes, here is a rhyme to help you remember the difference between the two. "Red on yellow, kill a fellow. Red on black, won't hurt Jack."

37

• Mullerian Mimicry - several unpalatable species resemble one another – yellow and black stripes warn of danger – used by wasps, snakes, bees, frogs

38

                                   

                                 

  

                                

   

                                   

                                

   

                                 

  

Müllerian mimicry in Dendrobates frogs near Tarapoto, Peru (a - c) The three frogs are all putative members of a single species,

Dendrobates imitator. Each of these different morphs is sympatric with a different species in a different geographical region. The species with which each morph is sympatric is shown directly below that morph. From left to right, the species in (d - f ) are: Dendrobates variabilis

(Tarapoto), Dendrobates fantasticus (Huallaga Canyon) and `Dendrobates ventrimaculatus’ (Yurimaguas).

39

• diversion of attack - eg ‘eyespots’ on butterfly and moth wings. Predator diverted away from body, or scared away.

40

• autotomy - shedding of a body part when attacked eg NZ lizards and Tuatara can lose their tails.

41

• Synchronised Breeding

-shortens breeding season therefore less

offspring lost to predators e.g.

Gannets-saturates feeding capacity e.g. coral.

42

ParasitismA parasite is any organism that feeds at a host’s

expense. The host is harmed but not killed. Parasites are always smaller than their host. One host may support many parasites of the same species.

• Host specific = when a parasite depends for its food on one organism.

• Parasites may weaken the host so that it becomes more vulnerable to other hazards.

• There are more parasitic than free-living sp.

43

• Ectoparasites live on the outside of the host e.g. mosquitoes, lice.

44

• Endoparasites live inside the host e.g. liver flukes, tapeworm.

Beef tapeworm = 7½ m – world’s biggest ‘microbe’

Ascarids or roundworm infections are primarily a problem of young horses. They seldom cause significant damage in animals that are 11 years or more old. They are primarily found in the small intestine.

45

– They have reduced structures (inc sensory, muscular, & nervous systems)

– ‘Holding-on’ structures eg hooks

• Reproduction based on transmission of offspring to a new host. Adults cannot survive outside the host.

46

• http://www.youtube.com/watch?v=vMG-LWyNcAs

• http://www.youtube.com/watch?v=dy4cQON7-JU

47

– produce many eggs though getting them to a new host is often difficult.

– complex lifecycle with several different young stages, each in a different host.

48

• Social Parasitese.g. cuckoo - a brood parasite.e.g. ants ‘slave-making’ of other ants nests.

The picture shows a queen of a social parasite, Acromyrmex insinuator, being harassed by a worker of its host species, Acromyrmex echinatior. Socially parasitic ants use the nests and workforce of other ant species to raise their own offspring. The queens of social parasites need to get inside the nests of other ants, where they will lay eggs which are reared by the workers of their host.

49

50

• Plant parasites. Connect with vascular tissue of host. Total Parasites rely fully on their host e.g. wood rose has no roots, no chlorophyll.

51

• Partial parasites (hemiparasite) have chlorophyll and only get water and minerals from host e.g. mistletoe.

52

Grazing

A grazer consumes part of many organisms which are not killed. Like predators, grazers feed off

populations.

53

• Chemical Defences of plants

• toxic and distasteful. Cyanogenic glycosides release hydrogen cyanide when plant damaged e.g. clover leaves and karaka seedsCardiac glycosides e.g. Tutu, Swan plantTannins are bitter e.g. Tea leaves.

54

Allelopathy

Odours may discourage browsing by big and little animals. Another reason, however, is to suppress the growth of a nearby plant. These toxins, called allelochemicals, permeate the soil around a plant and act as germination inhibitors. Because these allelochemicals are present, seeds from a nearby plant, although spread over a large area, can remain dormant for decades. Since the toxins are hydrocarbons, they are burned when a fire roars through the area.

55

• interruptive. ferns and conifers produce chemicals similar to insect hormones which disrupt insect growth e.g. inhibit metamorphosis. Toxicity: Known to be poisonous to livestock throughout

the US, Canada, and Europe. Simple stomach animals like horses, pigs, and rats develop a thiamine deficiency within a month. Acute bracken poisoning affects the bone marrow of both cattle and sheep, causing anemia and hemorrhaging which is often fatal. Blindness and tumors of the jaws, rumen, intestine, and liver are found in sheep feeding on bracken fern. Toxicity: All parts of brackenfern, including rootstocks, fresh or dry leaves, fiddleheads and spores, contain toxic compounds, and are poisonous to livestock and humans. Consumption of brackenfern causes vitamin B1 deficiency in horses, and toxins can pass into the milk of cattle. Young leaves of brackenfern have been used as a human food source, especially in Japan, and may be linked to increased incidence of stomach cancer. Humans working outdoors near abundant stands of the plant may be at risk from cancer-causing compounds in the spores

Also allelopathic

56

• deadly e.g. alkaloids of Hemlock, Deadly Nightshade (extremely toxic to mammals but not to birds – disperse seed) and strychnine plant of Asia.

All parts of deadly nightshade plant, especially berries, are venomous and responsible of toxicologic symptoms, typical indeed for all members of Solanaceous family, the so-called “anticholinergic syndrome”, whose symptoms are synthesized in an old english rhyme:“hot as a hare” (increase in body temperature)“blind as a bat” (pupillary dilatation and accomodation paralysis)“dry as a bone” (block on perspiration and salivation)“red as a beetroot” (face and neck congestion)“crazy as a hen” ( psychomotor excitement, hallucinations).

57

Mechanical Defences• Spines – e.g. sea

urchins, cacti, hedgehogs, roses

58

• Shells – e.g. barnacles, shellfish, hermit crabs, nuts

59

Animal counter-measures

• Sheep can detoxify clover

• Monarch butterfly caterpillars accumulate poisons from food (e.g. nettles) to be used for their own defence; poison retained in adults as protection against birds

60

PestsIntroduced animals often

become pests because there are few or no predators e.g. rabbits, goats, wasps, gorse, possums in NZ

61

Biocontrol

• An introduced predator can control an introduced pest

E.g. parasitoid wasps have brought cabbage white butterfly under control

adult of Apanteles sp. (parasitoid of Pieris sp.)

Larvae of Apanteles sp. (parasitoid) emerging from Pieris sp. larva

62

Argentinian moth controls prickly pear cactus in Australia

63

Abiotic pop’n control• Barnacles compete for

space• Muskrats without

territory starve or get eaten