The Gregarious associations Are those relationships within the same species in which their individuals have a life in common, whether within a short or prolonged period of time.
Usually, these associations have three essential purposes and each predominates according to the species in question: one, the search and obtaining of food; Two, migrations to more hospitable lands; And three, the reproduction, defense and survival of the animal.
More generally, gregarious associations are those who practice gregariousness, which is the tendency of certain types of animals to live in groups, with others of their own kind.
This group can have different levels of complexity and their relations vary according to the objective of the group, which can be a herd, a shoal or a flock. In any case, it follows a principle of cooperation in which individuals help the collective.
However, gregarious associations can come with other types of associations, such as colonial or hierarchical associations, which are also based on cooperativism but have very specific characteristics.
Fortunately, the peculiar features of various animals allow it not to be very difficult to make a distinction between a species of the otr, and therefore among its various intraspecific relations.
Differences with other types of gregarious associations
As already stated, a gregarious association is not the same as a colonial or hierarchical association, or any other. Lots of animals in nature need their co-religionists to live and survive in their environment, or to avoid being eaten by predators.
However, these associations have several points by which they differ; Points with which the species is defined in its totality, beyond the exceptions to the norms that may have.
By definition, colonial associations involve a group as in gregarias. However, the colonial ones have individuals that leave from the same progenitor, with which they share their habitat and their physical space (their bodies are united to each other).
In marine corals, for example, these associations are colonial and not gregarious because this species lives on the same seabed, they have the same source of reproduction and their specimens are not separated.
The same can be observed with sexual associations. Here the group does not exist but to reproduce itself, but it is a group so small that it can not therefore be a gregarious association since it constitutes a pair.
A sample of this is with the lions, in which the male mates with the female to later have their offspring. Sexual union, therefore, is not multitudinous, but only between a male (alpha) that meets the female to perpetuate its species.
In the case of family associations, the group is not as in gregarious associations, because the nucleus makes a family and not the convergence of them or their individuals; Family that by the way is usually constituted by the father, the mother and the young in a defined space that is separated from the other families within the same species.
This is frequent in many birds, which mark the territory where their nest is, which they defend and in which they hatch the eggs.
In this way, hierarchical associations come into play because they can be easily confused with gregarias. It is true that both focus on the group, but only in the hierarchy there is division of labor, chain of command and anatomical differences in its members that are observable to the naked eye.
This happens with bees, where the workers work for the colony and are presided over by a queen whose physical appearance is very different from theirs, both in size and function.
Thus, and taking into account what has been said above, the gregarious relations proper are group relations such as colonial, sexual, family relations and hierarchical relations.
However, only a relationship can be strictly gregarious as long as its individuals do not have physical union with each other, are not reduced to the mere reproductive act, are not enclosed in isolated nuclei and, above all, do not have a society ruled by castes or Ladders
Examples of gregarious species
Insects
The Monarch Butterfly ( Danaus plexippus ) Is a clear demonstration and one of the exceptional cases of gregariousness in insects (often many of them have hierarchical relationships, such as ants and various coleopteran species).
This butterfly is famous for its annual emigration, which travels long distances in its flight and is realized by millions of individuals, in a cyclical process that has its swings between the territories of Mexico, the United States and Canada.
Birds
Migratory birds are an excellent example of what gregarious associations are; Some have a short distance migration, while others have a long distance migration.
One of them is the Caribbean white barnacla ( Branta leucopsis ). This species of goose, belonging to the chordates that inhabit the North Atlantic, emigrates in autumn and, as happens with those of its species, makes a flight to a determined destination that is carried out in a group.
Mammals
Some mammals serve to explain gregarious associations, since they belong to this category. The African elephant ( Loxodonta africana ), Although it has an isolated behavior among adults, it gives the opportunity to move in groups to distant regions where there is water to withstand the shortage of the dry season.
In humans this categorization has been much debated and writers like Richard Dawkins have pointed out that it behaves like a"selfish cooperator."
Fishes
At this point learn migratory fish and all who move in shoals (or banks of fish) for various purposes. Among them is common herring ( Clupea harengus ), A fish of the family of clupeidos that moves in very large groups.
It is believed that they do so in order to make the most of energy and also to maximize the amount of food consumed, which could not be captured by a single herring.
References
- Allaby, Michael (2003). A Dictionary of Zoology. Oxford: Oxford University Press.
- Batra, Suzanne W. T. (1968). "Behavior of Some Social and Solitary Halicone Bees Within Their Nests: A Comparative Study (Hymenoptera: Halictidae)." Journal of the Kansas Entomological Society, 41 (1), pp. 120-133.
- Burton, Maurice and Burton, Robert (1969). International Wildlife Encyclopedia (21 vols.). Singapore: Marshall Cavendish.
- Crespi, Bernard J. and Yanega, Douglas (1995). "The Definition of Eusociality". Behavioral Ecology, 6 (1), pp. 109-115.
- Dawkins, Richard (2006). The Selfish Gene. Oxford: Oxford University Press.
- Russell, Bertrand (2002). Human society: ethics and politics, 3rd edition. Cambridge: Oxford University Press.
- Verma, Ashok (2015). Principles of Animal Taxonomy. Oxford: Alpha Science International Limited.
- Wilson, Edward O. (1971). The Insect Societies. Massachusetts: Belknap Press, Harvard University Press.