Why does female infidelity occur so frequently throughout the animal kingdom? A 10-year study from the University of East Anglia published today shows that female birds may increase their offspring's survival through their infidelity.
Although in many animals females may pair up with a specific 'social' mate who helps raise the pairs' offspring, DNA fingerprinting studies across a wide range of animals reveals that offspring may often be sired by males other than the pair male.
What has perplexed scientists is why females engage in such infidelity – what is the benefit of being fertilised by these other males – males which do not contribute towards raising the offspring.
Despite pairing with the same male for life, female Seychelles warbler birds often prefer to be fertilised by other males, and this appears to increase the genetic quality of their offspring.
The study has shown that these extra-pair fertilisations can result in a higher diversity of specific genes which detect disease and trigger an immune response in offspring. As a consequence, the offspring survive longer probably as a result of having greater resistance to a wider range of diseases.
The research 'MHC-dependent survival in a wild population: evidence for hidden genetic benefits gained through extra-pair fertilisations' has been lead by Dr David Richardson (UEA) and is published today in Molecular Ecology.
Since 1997 more than 97 per cent of warblers on the tiny island of Cousin in the Seychelles were ringed, blood sampled, and their breeding attempts followed. The researchers monitored the fate of 160 birds hatched on the island between 1997 and 1999, over 10 years.
They found that females paired to males with a low diversity of disease-detecting genes (major histocompatibility complex or MHC) elevate the gene diversity of their offspring by gaining extra-pair fertilisations from males with higher diversity. This extra pair fertility was found to be common – accounting for 40 per cent of offspring.
Importantly, the offspring born as a result of this female infidelity have higher genetic diversity at these disease-detecting genes than they would have had if sired by the cuckolded pair male. However they were not found to be higher than the population average.
The researchers then found a positive association between diversity of MHC genes and juvenile survival. A higher than median MHC diversity was found to increase lifespan more than two-fold.
They also found that offspring with a specific rare gene variant (Ase-ua4) had a five times longer life-expectancy than offspring without this allele. However these birds did not necessarily have a greater MHC diversity. It is thought that individuals with this rare variant of MHC genes may survive longer because these rare variants better resist diseases that have already evolved to evade more common variants.
Dr Richardson said: "We first tested whether extra-pair offspring have a survival advantage compared to within-pair offspring. Then we tested whether there are genetic benefits to the patterns of the MHC-dependent extra-pair fertilizations observed in this species."
"We did not find any evidence for genetic benefits of extra-pair fertilisations per se, as on average extra-and within-pair offspring survived equally well.
"However, by not being faithful to a pair male with low MHC diversity, females are ensuring that their offspring do not end up with below average levels of MHC diversity and therefore lower survival.
"We have shown that the association between survival and MHC diversity levelled off with increasing diversity, so choosing males with above average MHC diversity would not have resulted in any additional fitness benefits for the offspring.
"One thing that remains unknown however, is what mechanism drives the patterns of MHC-dependent extra-pair mate choice. Experiments are needed to determine whether females actively choose more diverse MHC males or whether other factors like male-male competition or sperm competition play a role."
The study was lead by the University of East Anglia, with colleagues from the University of Sheffield, the University of Groningen and Nature Seychelles.
Lisa Horton | EurekAlert!
Study relating to materials testing Detecting damages in non-magnetic steel through magnetism
23.07.2018 | Technische Universität Kaiserslautern
Innovative genetic tests for children with developmental disorders and epilepsy
11.07.2018 | Christian-Albrechts-Universität zu Kiel
There are currently great hopes for solid-state batteries. They contain no liquid parts that could leak or catch fire. For this reason, they do not require cooling and are considered to be much safer, more reliable, and longer lasting than traditional lithium-ion batteries. Jülich scientists have now introduced a new concept that allows currents up to ten times greater during charging and discharging than previously described in the literature. The improvement was achieved by a “clever” choice of materials with a focus on consistently good compatibility. All components were made from phosphate compounds, which are well matched both chemically and mechanically.
The low current is considered one of the biggest hurdles in the development of solid-state batteries. It is the reason why the batteries take a relatively long...
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
17.08.2018 | Event News
08.08.2018 | Event News
27.07.2018 | Event News
20.08.2018 | Information Technology
20.08.2018 | Life Sciences
20.08.2018 | Information Technology