The following points highlight the five major effects of allelochemicals on various organisms. The effects are: 1. Repellents 2. Escape from Predators 3. Suppressant 4. Attracants 5. Avoidance.
Effect of Allelochemical # 1. Repellents:
Repellents are distasteful and poisonous compounds present in buttercup leaves or mustards or the noxious butyl mercaptan (butanethiol) sprayed by the skunk. The bombardier beetle sprays boiling hot p-benzoquinones from a nozzle present on its posterior end. These repellents are thus used for escape.
Effect of Allelochemical # 2. Escape from Predators:
Some insects live on the surface film of water. They release detergent-like chemical to reduce the surface tension, so that they are whisked rapidly forward and away from a predator.
Effect of Allelochemical # 3. Suppressant:
Suppressant are chemicals that suppresses the activities of other organisms. Chaparral shrubs produces materials that inhibit herbaceous growth around them. Certain phytoplankton releases substances that slows down the feeding rate of some herbivorous zooplankton.
ADVERTISEMENTS:
Fungi releases antibiotics in the soil where they live, to inhibit the growth of competitors. In some cases, the suppressant produced by the species, sometimes have inhibitory effect on themselves, called autotoxins.
Effect of Allelochemical # 4. Attracants:
Attracants may be aggressive or non-aggressive in function. Aggressive attracants are released by carnivorous plants to lure insects towards them. Non-aggressive attracants are a case of mutualism where the attracant smell benefits both the flower that is pollinated and the insect that obtains pollen or nectar.
Effect of Allelochemical # 5. Avoidance:
These attracants may serve to avoid organisms. Some poisonous plants have odour that potential foragers can detect and avoid. The broad-headed skink (lizard) of southern United States, can distinguish between the scent of king cobra that eat lizards, and hognose snakes that do not.