Summary from the authors: Extra‐pair mating in a socially monogamous and paternal mouth‐brooding cardinalfish by Theresa Rueger

Rueger, Theresa, Hugo B. Harrison, Naomi M. Gardiner, Michael L. Berumen, and Geoffrey P. Jones. “Extra‐pair mating in a socially monogamous and paternal mouth‐brooding cardinalfish.” Molecular Ecology. 2019. 28-10: 2625-2635

Link to paper: https://onlinelibrary.wiley.com/doi/full/10.1111/mec.15103

In this study, we followed more than 500 Pajama cardinalfish on reefs in Papua New Guinea. Cardinalfish stay close to each other in pairs for long periods of time, often for several years. Looking at the babies they produce with genetic markers, we found that most of them do exclusively breed with that partner. However, contrary to expectations, we also saw some sneaking behaviour. When presented the chance, both males and females take the opportunity to mate with other individuals.

Photo by Chris Hamilton

The findings are remarkable because the males brood the eggs in their mouths. They can’t feed during that time and their swimming ability is compromised, so brooding is very costly for them. That puts females in an advantageous position, because they can produce eggs quicker than the male can brood them and they can go and give eggs to another male. The males can offset that advantage by eating some or all of the eggs and accept eggs from another female. Also, in some rare cases males can fertilize eggs that another male is brooding, saving all the energy they would need to use to brood them themselves.

Photo by Chris Hamilton

It’s a complicated mating system, which is something we can only find out by spending lots of time observing the fish and using genetic analysis to identify parentage. Our tests reveal the complex nature of social groups in fishes and how promiscuity could upturn theories for how monogamy arose. – Theresa Rueger

Check out other media cover of the paper at ScienceDaily and follow on Theresa on twitter @TheresaRueger

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s