wanted to know how relatedness and kin selection in cichlid fish affected their
predator inspection behaviour, or more generally, whether relatedness would
affect cooperation between individuals.
many previous studies have explored the effects of kin selection on cooperation
between individuals of the same species in theory, only a select few explored
these concepts as experiments, particularly on cooperation outside of breeding.
(Hesse et al. 2015) Thus, to explore the practical validity of these theories
as well as demonstrate cooperation and kin selection among non-mating
individuals, Hesse et. al. conducted this experiment on cichlid fish.
experimental fish were raised artificially apart in small tanks before the
experiment proper, with 15 of each raised from two separate pairs of mating
experiment was conducted within a tank which was divided into three
compartments which were initially hidden from one another, with one housing the
predator, another for acclimatization, and the last for the actual experiment
cichlid fish, which were either related or not, were introduced into the acclimatization
compartment to familiarize themselves with the tank
predator was introduced to its compartment, where it would be separated from
the cichlid fish by a transparent barrier. The area near the predator across
the barrier was referred to as the inspection zone
barrier between the acclimatization and experimental compartments was removed
and the behaviour of the fish regarding the predator was observed
inspections by both fish as well as solitary inspection by a single fish were
observed and recorded, signalled by the entry and exiting of fish to and from
the inspection zone
authors ultimately concluded that more closely related cichlid fish were more
likely to cooperate with one another by performing anti-predatory behaviour, as
related cichlid fish on average spent significantly more time in the inspection
zone together compared to non-related individuals, while also spending less
time in the inspection zone alone.