An interaction where the actor and recipient both suffer a cost is referred to as
Spite is an interaction between species where both suffer a cost (option 4).
There are six basic types of interactions between species, defined by whether it helps or harms one or both parties.
- Mutualism is an interaction where there is mutual benefit to both parties. A classical example is nitrogen fixation by rhizobia bacteria in the root nodules of legumes – the plant receives usable nitrogen compounds in the form of ammonia or amino acids, and the bacteria get organic acids for their carbon and energy needs.
- Spite is an interaction where there is harm to both parties. An example of this behaviour can be seen in two strains of the bacterium Photorhabdus luminescens: if they are plated in close proximity, bacteria from one strain with explode in a shower of toxins to kill the other strain.
- Predation is when one species eats another species – so it harms one species but benefits the other. A sparrow eating a grain or a lion eating a giraffe are both predations.
- Parasitism is similar to predation in the sense that one species is harmed and the other is benefited, but in this case the association is long-term. So rather than straight up eating the prey, the parasite lives with, on, or inside the host, consuming resources without providing any return. These are often the cause of diseases, such as tapeworm, wuscheria, and Plasmodium (the protozoa that cause malaria).
- In commensalism, one species benefits, while the other is neither harmed nor benefited. An example would be barnacles growing on whales. The barnacle uses the movement of the whale to capture food by passive filtration, while the whale is not affected either way.
- Amensalism is an interaction where one species is harmed, and the other is neither harmed nor benefited. Some bacteria, for instance, produce antibiotics that kill other microbes.