Fish become pessimistic and lovesick if they’re torn apart from their true lover, researchers find
- Female cichlids were sad and lovesick after their chosen partner was removed
- They were less likely to be interested in food and were not likely to reproduce
- Study shows humans aren’t the only species that becomes attached to a lover
Humans aren’t the only species whose mental state is affected when they lose their lover.
Female cichlids, a type of monogamous fish that primarily dwells in South America, become depressed and lovesick when their mate is removed and they’re placed with a non-preferred male partner, a new study has found.
Researchers came to this conclusion after the female fish took longer to investigate boxes that either contained food or were empty, demonstrating symptoms of apathy.
Female cichlids, a type of fish that primarily dwells in South America, become depressed and lovesick when their mate is removed and they’re placed with a non-preferred male partner
DO FISH FORM EMOTIONAL BONDS?
In what’s believed to be a first-of-its-kind study, researchers say they’ve determined fish can form attachments to sexual partners.
Through a series of cognitive tests, they found that female fish were more likely to take on a ‘glass half-full’ mental state when they remained with their chosen partners.
In addition, they spawned more quickly and tended to their eggs more often.
The study, published Tuesday in the journal Proceedings of the Royal Society B, was conducted by researchers from the University of Burgundy in Dijon, France.
It’s also believed to be the first study that shows non-human species can also form attachments to sexual partners.
‘It is, as far as we know, the very first demonstration of emotional bonds between partners in non-human species,’ Francois-Xavier Dechaume-Moncharmont, one of the study’s co-authors, told Inside Science.
In order to prove this hypothesis, the researchers carried out a series of cognitive tests in a group of 33 female cichlids.
Over the course of two weeks, they closely studied how the female fish behaviors changed when they were paired with a male fish that they had not picked themselves.
When females were paired up with a male fish they preferred, they spawned faster, tended to their eggs and were more likely to look at their environment with a ‘glass half-full’ perspective.
By contrast, a female fish who was paired with an non-preferred male fish was less likely to spawn.
Scientists then gauged the female fishes’ mood further with another round of experiments.
Over the course of two weeks, researchers closely studied how the female fish behaviors changed when they were paired with a male fish that they had not picked themselves
They placed two different types of containers in the fishtank: Ones with a black lid that were empty and another with a white lid that contained a treat.
Over time, the fish were meant to learn through trial and error which containers held a treat and which ones did not.
Researchers found that females who were paired with the male they rejected either paused when investigating the containers, or didn’t investigate them at all.
This asserts that females who are torn away from their true love are more likely to take on a ‘pessimistic bias,’ or depressed outlook.
Meanwhile, their female counterparts who remained with their chosen male discovered the white containers more quickly, demonstrating again that glass half-full perspective.
‘When we are removing the partner from the female, she is exhibiting pessimistic behavior,’ Dechaume-Moncharmont told Inside Science.
‘We have shown in this study that in the sexual context, the presence or absence of the partner may affect the emotion of the female.’
CAN FISH FEEL PAIN JUST LIKE HUMANS?
People who joke about having the memory of a goldfish may have to think again, after scientists have found fish can remember events for up to a fortnight.
Canadian researchers trained fish to locate food before removing them from the tank for 12 days.
When the fish were later reintroduced, motion-tracking software revealed they could identify the precise location of the food.
The study looked at African Cichlids, a popular aquarium species which has previously been shown to demonstrate complex behaviours, including aggression.
Working on the assumption they could be capable of advanced memory tasks, each fish was trained to enter a particular zone of an aquarium to be fed, with each training session lasting twenty minutes.
After three days, the fish were given a 12-day rest period.
They were later reintroduced into their training arena, and their movements recorded with motion-tracking software.
This software revealed the fish returned to the spot where it found food.
Scientists believe the fish recalled the previous training experiences and were able to reverse this association, after further training sessions where the food reward was associated with a different stimulus.
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