Disappearing nannies force parents to accept their duties

Apr 12, 2013
Disappearing nannies force parents to accept their duties
Cichlid (Julidochromis ornatus). Credit: Heinz Buescher

(Phys.org) —Large helpers (nannies) in a cichlid fish allow the dominant male and female to reduce their personal contribution to their offspring and territory, according to new research published today in Functional Ecology.

By removing the large helper for 30 days – which corresponds to one breeding cycle in this species – a team from the University of Bristol and the University of Bern (Switzerland) studied the investment strategies of the dominant pair and the survival of their , while checking for immigration of new helpers.

Dr Rick Bruintjes, NERC Science & Business Marine Renewable Energy Fellow at the University of Bristol described: "In the cichlid Julidochromis ornatus, one large male helper spends almost all of his time close to the breeding shelter, whereas the dominant pair is only around half of their time. By removing the large helper we found that one day after removal the dominants increased territorial duties, however, seven days after removal the initial higher investment was back to pre-removal levels."

Senior statistician Dr Dik Heg from the University of Bern said: "Already after seven days, 36 per cent of the removal groups had a new large subordinate immigrant. Only with a new immigrant large helper did dominants relax their territorial duties, showcasing the benefit of having a large subordinate for the dominant pair."

MSc Zina Heg-Bachar, research assistant at the University of Bern, explained: "Removal of the nanny did not change rates of fry and small fish, most likely because the parents and/or the new nanny compensated for the absence of the original nanny."

This study shows the importance of large helpers in allowing the dominant pair to reduce their personal contribution to their . Moreover, it highlights the importance of immigration of new helpers to relieve dominants from carrying out parental behaviours in cooperative breeding systems.

Explore further: Aphrodisiac for fish and frogs discovered

More information: Bruintjes, R. Heg-Bachar, Z. and Heg, D. Subordinate removal affects parental investment, but not offspring survival in a cooperative cichlid, Functional Ecology. onlinelibrary.wiley.com/doi/10.1111/1365-2435.12088/abstract

Related Stories

Mother's little helpers

Aug 16, 2007

An Australian bird has been found to produce smaller, less nourishing eggs when it breeds in the presence of other ‘helper’ birds that provide child-care assistance. This unique adaptation enables the ...

A helping hand from the grandparents

Dec 21, 2007

A team of scientists led by the University of East Anglia has discovered the existence of ‘grandparent’ helpers in the Seychelles warbler – the first time this behaviour, which rarely occurs except in humans, has been ...

Recommended for you

Telling the time of day by color

18 hours ago

Research by scientists at The University of Manchester has revealed that the colour of light has a major impact on how the brain clock measures time of day and on how the animals' physiology and behavior adjust accordingly. ...

Aphrodisiac for fish and frogs discovered

Apr 17, 2015

A supplement simply added to water has been shown to boost reproduction in nematodes (roundworms), molluscs, fish and frogs – and researchers believe it could work for humans too.

Evolution puts checks on virgin births

Apr 17, 2015

It seems unnatural that a species could survive without having sex. Yet over the ages, evolution has endowed females of certain species of amphibians, reptiles and fish with the ability to clone themselves, ...

Humans can't resist those puppy-dog eyes

Apr 16, 2015

When humans and their four-legged, furry best friends look into one another's eyes, there is biological evidence that their bond strengthens, researchers report.

Roundworm parasite targets canine eyes

Apr 16, 2015

(HealthDay)—A small number of dogs and cats across the United States have been infected by a roundworm parasite that targets the eye, according to a new report.

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

geokstr
1 / 5 (2) Apr 12, 2013
I'll bet disappearance of the governmental nanny would cause many parents to accept the responsibilities they've abdicated over the last 100 years with respect to their own children, too. Instead we have increasing calls for the government to take total responsibility for all children.

What could possibly go wrong with that?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.