Semiochemicals pheromones

Semiochemicals pheromones Allomones

1. SEMIOCHEMICALS Pheromones & Allelochemicals BALWANT SINGH [email protected] BY

2. SEMIOCHEMICALS Chemicals that modify behavior in any way are referred to as semiochemicals. Not only chemicals stimulate but they might also inhibit certain behaviors. Semiochemicals can be divided in two main classes: Pheromones: Chemicals that operate intra-specifically. That is, among members of the same species. Allelochemicals: Chemicals that operate inter-specifically. That is among members from different species.

3. Introduction Semiochemicals Pheromones Allelochemicals

4. Semiochemicals Pheromones Allelochemicals

5. What is a Pheromone? Defined chemical signal between members of the same species , eliciting a particular behavior or physiological change...”

6. Pheromone A pheromone is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting outside the body of the secreting individual to impact the behavior of the receiving individual. Their use among insects has been particularly well documented. In addition, some vertebrates and plants communicate by using pheromones.

7. Background The term "pheromone" was introduced by Peter Karlson and Martin Lüscher in 1959. Pheromone is the Greek word pherein (to transport) and hormone (to stimulate). It is also called as ecto -hormones. German biochemist Adolf Butenandt had characterized the first such chemical, bombykol , a chemically well-characterized pheromone released by the female silkworm to attract mates

8. Classification of Pheromones Pheromones are classified based on their function- 1) Aggregation pheromone 2) Alarm pheromone 3) Epideictic pheromone 4) Releaser pheromone 5) Signal pheromone 6) Primer pheromone 7) Territorial pheromone 8) Trail pheromone 9) Sex pheromone 10) Others pheromone

9. Sex pheromone Sex pheromones are involved in reproduction by attracting the opposite sex. In some species female pheromones are used to attract the male. In other species male pheromones are used to attract the female.

10. Pheromones Sex pheromone

11. Alarm pheromone Alarm pheromones are used to warn members of the same species about imminent danger. For example the aphids were using an alarm pheromone to inform other members of their species that they were attacked by a lady bug! As soon as aphids smell this alarm pheromone they drop from the plant. In this way, even aphids that are not being attacked by the lady beetle fall to the ground.

12. Pheromones Alarm pheromone

13. Aggregation pheromone Aggregation pheromones are use to congregate members of the same species in relatively big numbers. They are used by organisms that need help to invade a new area or habitat or plant. These conifer beetles for example do a better job, or have a higher fitness when feeding in group than when feeding individually.

14. Pheromones Aggregation pheromone

15. Trail pheromone Trail pheromones are used by ants to mark their trails so they can follow each other. Have you ever scratch the soil under an ant trail? Do it and you will see how the ants get confuse and lost for a while.

16. Pheromones Trail pheromone

17. Host-marking pheromone Host marking pheromones are used by parasitoids to avoid ovipositing on hosts they or somebody else have oviposit already. Hyper parasitoids may use these marking pheromones to find their hosts.

18. Pheromones Host-marking pheromone

19. 1) Aggregation Aggregation pheromones function in mate selection, overcoming host resistance by mass attack, and defense against predators. A group of individuals at one location is referred to as an aggregation, whether consisting of one sex or both sexes. Aggregation pheromones have been found in members of the Arthropods. Aggregation of bug nymphs

20. 1) Aggregation Aggregation pheromones are among the most ecologically selective pest suppression methods. They are nontoxic and effective at very low concentrations Aggregation of bug nymphs

21. 2) Alarm Some species release a volatile substance when attacked by a predator that can trigger flight or aggression in members of the same species. Pheromones also exist in plants: Certain plants emit alarm pheromones when grazed upon, resulting in tannin production in neighboring plants. These tannins make the plants less appetizing for the herbivore. Exm . : ants, bees, termites.

22. 4) Releaser Releaser pheromones are pheromones that cause an alteration in the behavior of the recipient. In general, this type of pheromone elicits a rapid response, but is quickly degraded. For example, some organisms use powerful attractant molecules to attract mates from a distance of two miles or more.

23. 5) Signal Signal pheromones cause short-term changes, such as the neurotransmitter release that activates a response. For instance, GnRH molecule functions as a neurotransmitter in rats to elicit lordosis behavior.

24. 6) Primer Primer pheromones trigger a change of developmental events (in which they differ from all the other pheromones, which trigger a change in behavior).

25. 7) Territorial Pheromones mark the boundaries and identity of an organism's territory. In cats and dogs, these hormones are present in the urine, which they deposit on landmarks serving to mark the perimeter of the claimed territory.

26. 8) Trail Trail pheromones are common in social insects. As long as the food source remains, the pheromone trail will be continuously renewed. The pheromone must be continuously renewed because it evaporates quickly. For example, ants mark their paths with these pheromones, which are volatile hydrocarbons. Certain ants lay down an initial trail of pheromones as they return to the nest with food. This trail attracts other ants and serves as a guide.

27. 9) Sex In animals, sex pheromones indicate the availability of the female for breeding. Male animals may also emit pheromones that convey information about their species and genotype.

28. Allelochemicals Alomones-benefit sender Kairomones-benefit the receiver Synomones-benefit both Thank You