1 Symbiosis Insect-Plant Interactions 3 rd Lecture

2 First Discussion Session (This message had sent to you) The first discussion topic will be about symbiosis Date: Monday of next week, 30/3/2009 You should collect enough materials from primary references and books (but not from net), write outline and notes. In the end of discussion, you will submit your notes and the copy of references that you would use.

3 Definition of Symbiosis The term symbiosis (from the Greek: συμ, sym, "with"; and βίοσίς, biosis, "living") GreekwithlivingGreekwithliving The term was first used in 1879 by the German mycologist, Heinrich Anton de Bary, who defined it as: "the living together of unlike organisms" GermanmycologistHeinrich Anton de Bary1879 GermanmycologistHeinrich Anton de Bary

4 Definition of Symbiosis Symbiosis is simply defined as living together. Scientists use this term to describe intimate relationships between members of different species. By definition there are at least two species in a symbiotic relationship; it is unknown the maximum number.

5 Definition of Symbiosis The relation between two different species of organisms that are interdependent; each gains benefits from the other

6 Definition of Symbiosis There is no single universally agreed upon definition of symbiosis. Some[attribution needed] define symbiosis in the sense that De Bary intended, describing a close relationship between organisms in which the outcome for each is highly dependent upon the other. There is no single universally agreed upon definition of symbiosis. Some[attribution needed] define symbiosis in the sense that De Bary intended, describing a close relationship between organisms in which the outcome for each is highly dependent upon the other.

7 Definition of Symbiosis The interdependent relationships between living things, called symbiosis A general rule is that the partners must spend a significant amount of time together (part or all of their life cycles). In this case…….some of

8 Terminologies SymbiosisSymbiosesSymbioticSymbiontHost

9 Types (Categories) of Symbiosis It depends on the definition! must spend a significant amount of time together (part or all of their life cycles).

10 + Species "A" Species "B" MutualismCommensalismParasitismCommensalismNeutralism Parasitism Competition Types of Symbiosis HM

11 Types of Symbiosis 1-Symbiotic relationships may involve an organism living on another(ectosymbiosis), ectosymbiosis inside another (endosymbiosis), inside another (endosymbiosis),endosymbiosis 2-Symbiotic relationships, may be either obligate, which is to say necessary to the survival of at least one organism, or facultative, where the relationship is useful but not vital

12 Types of Symbiosis EctosymbiosisEctosymbiosis, also referred to as exosymbiosis, is any symbiotic relationship in which the symbiont lives on the body surface of the host, including the inner surface of the digestive tract or the ducts of exocrine glands HM digestiveexocrine Ectosymbiosisdigestiveexocrine Examples of this include ectoparasites such as lice, commensal ectosymbionts, such as the barnacles that attach themselves to the jaw of baleen whales, and mutualist ectosymbionts such as cleaner fish. ectoparasites licecommensal barnacles baleen whalesmutualistcleaner fishectoparasites licecommensal barnacles baleen whalesmutualistcleaner fish

13 Types of Symbiosis EndosymbiosisEndosymbiosis is any symbiotic relationship in which the symbiont lives within the tissues of the host; either in the intracellular space or extracellularly. Examples are nitrogen-fixing bacteria (called rhizobia) which live in root nodules on legume roots, single-celled algae inside reef-building corals, and bacterial endosymbionts that provide essential nutrients to about 10%–15% of insects bacteriarhizobiaroot noduleslegumealgaecorals Endosymbiosis bacteriarhizobiaroot noduleslegumealgaecorals

14 Lichens One example of beneficial symbiosis (called mutualism) is that found between algae and the fungus of lichens. While fungi provide vital protection and moisture to algae, the algae nourish the fungi with photosynthetic nutrients that keep them alive. As a biology textbook puts it: "Neither population could exist without the other, and hence the size of each is determined by that of the other"

15 Lichens

16 Lichens So which came first, the alga or the fungus? Since neither could exist without the other, according to evolution for both to survive they had to evolve independently of each other, yet appear at exactly the same time and with precisely the right functions.

17 Bees and Plant Consider next the relationship between bees and plants. While collecting the precious nectar that provides their hives with food, bees pollinate dozens of species of flowers and agricultural crops. Without this vital pollination, orchards could produce little if any fruit, and fruit trees would not survive for long. How can these plants exist without first being pollinated by bees? On the other hand, how could bees exist without first being provided with the necessary nectar as food?

18 Bees and Plants In addition, the bee has to carry out pollination in a precisely specific way for the process to work. If the bee visited other species of flowers at random, pollination could not occur, since the pollen of one species of flower does not fertilize another species. Somehow the bee knows to visit only one plant species at a time and at the right season.

19 Yucca plant and the yucca moth One of the most amazing examples of symbiosis is that between the yucca plant and the yucca moth. The yucca plant is incapable of pollinating itself to grow more seeds and perpetuate. The yucca moth (Tegeticula, formerly Pronuba) pollinates the yucca plant while laying its eggs inside the plant.

20 Yucca plant and the yucca moth

21 Yucca plant and the yucca moth After hatching, the moth larvae feed on the seeds of the yucca. Remarkably, the moth carefully calibrates the number of its larvae growing inside each flower so the larvae will not consume all the seeds of the yucca—because if they ate all the seeds the yucca plants would stop reproducing, thus eventually dooming the yucca moths as well!

22 Yucca plant and the yucca moth By pollinating the plant, the moth develops food (yucca seeds) for its larvae while ensuring that the plant can perpetuate its own kind as well. But that's not all. The life cycle of the yucca moth is timed so the adult moths emerge in early summer—exactly when the yucca plants are in flower. How could this remarkable relationship have developed by random minor changes in both plant and insect over eons? It is obvious that it appeared abruptly or it never could have developed at all.

23 Cleaning symbiosis It is common for large fish such as sharks, after consuming smaller fish, to have food remains and parasites imbedded around their teeth. Eventually these particles can produce disease or a dangerous build-up of matter that can hinder eating. But certain types of small fish exist that function as biological toothbrushes, safely cleaning the teeth of the larger predators.

24 Cleaning symbiosis The cleaning fish fearlessly swim inside the open mouth of the larger fish and carefully eat the debris and parasites from the teeth. How can a predator fish restrain his instincts of getting a free meal by just closing his mouth and chewing, or avoid lashing out because of the irritating cleaning process? These actions go directly against the self- preservation instincts of both animals, yet they methodically carry out this sanitizing procedure. Some species even set up the equivalent of cleaning stations, where the larger fish patiently wait for their turn while others ahead of them have their mouths cleaned.

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26 Such cleaning symbiosis is also found among a species of bird and a reptile. In Egypt the Egyptian plover hops right into the open mouth of the Nile crocodile to remove parasites. After the job is done, whether the crocodile is hungry or not the bird always leaves unscathed.

27 How could such diverse animals, which normally have a predator-victim relationship, become partners in a cleanup operation? If these procedures evolved, as evolutionists contend must have happened, how many birds would have been eaten alive before the crocodile decided it was in his interest to let one clean its mouth, then proceed to let it escape? In contrast, how many birds would have continued picking crocodile teeth when they saw some of their feathery cousins eaten alive by crocodiles? They certainly are instinctively aware that better and safer ways of getting a meal are available to them.

28 Such sophisticated relationships among diverse creatures show an underlying intelligent design and forethought at work. Symbiotic relationships are clearly a great challenge to Darwinism, providing solid evidence of a Designer and Creator.

29 Competition or Cooperation: How Symbiosis Defies Darwin

30 Cleaning Symbiosis The drawing shows the Nile crocodile opening its mouth to permit the Egyptian plover to feed on any leeches attached to its gums.

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32 Symbiotic nitrogen fixation One of the most important examples of mutualism in the overall economy of the biosphere is the symbiotic relationship between certain nitrogen-fixing bacteria and their legume hosts.

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34 Bullhorn Acacia is best known for its symbiotic relationship with a species of ant () that lives in its hollowed out thorns. Unlike other acacias, Bullhorn acacias are deficient in the bitter alkaloids usually located in the leaves that defend against ravaging insects and animals. Bullhorn acacia ants fulfill that role. symbioticantalkaloids symbioticantalkaloids

35 The ants act as a defense mechanism for the tree, protecting it against harmful insects, animals or humans that may come into contact with it. The ants live in the hollowed-out thorns for which the tree is named. In return, the tree supplies the ants with protein-lipid nodules called Beltian bodies from its leaflet tips and carbohydrate- rich nectar from glands on its leaf stalk. These Beltian bodies have no known function other than to provide food for the symbiotic ants. The aggressive ants release an alarm pheromone and rush out of their thorn "barracks" in great numbers. proteinlipidBeltian bodiescarbohydrateglandssymbioticpheromoneproteinlipidBeltian bodiescarbohydrateglandssymbioticpheromone According to Daniel Janzen (Costa Rican Natural History, 1983), livestock can apparently smell the pheromone and avoid these acacias day and night. Getting stung in the mouth and tongue is an effective deterrent to browsing on the tender foliage. In addition to protecting A. conigera from leaf-cutting ants and other unwanted herbivores, the ants also clear away invasive seedlings around the base of the tree that might overgrow it and block out vital sunlight. Daniel JanzenCosta Rican livestockpheromoneleaf-cutting ants herbivoresDaniel JanzenCosta Rican livestockpheromoneleaf-cutting ants herbivores

36 Epiphytes Epiphytes are plants that live perched on sturdier plants. They do not take nourishment from their host as parasitic plants do. Because their roots do not reach the ground, they depend on the air to bring them moisture and inorganic nutrients. Epiphytes are plants that live perched on sturdier plants. They do not take nourishment from their host as parasitic plants do. Because their roots do not reach the ground, they depend on the air to bring them moisture and inorganic nutrients.

37 Epiphytes

38 Epiphytes

39 Interaction vs symbiosis These interactions are often brief. There are many cases, however, where two species live in close association for long periods. Such associations are called symbiotic