Long life is common among bird parents that get help with childcare. This
finding comes from researchers at the universities of Lund and Oxford who
reviewed data from more than 9,000 studies.
Being a parent can be tough. In general, animals that care for many
offspring die young, at least in species where parents are not helped by
others. However, in some species things are different and parents recruit
'helpers' to assist with childcare. In such group-living species, parents
often produce lots of young and also live an exceptionally long time. This
new research now shows that this happens because helpers reduce the burden
of care on parents.
"A common pattern in group-living species is that parents do not care very
much for their own young. Instead, the helpers are responsible for feeding
and protecting the young and performing the other tasks that are usually
associated with being a parent", says Philip Downing at Lund University.
The fact that the parents avoid this work-load means that they can reproduce
again and again and still live a long time.
Some group-living species take this to the extreme with parents always
relying on helpers for offspring care. For example, breeding individuals in
ants, termites and naked mole rats live for many decades, producing
thousands of offspring without ever caring for a single offspring. While
these species are fascinating, it is impossible to tell if the secret to
breeders living for such a long time is outsourcing parental care as all
breeders have helpers.
Instead Philip Downing, his Lund colleague Charlie Cornwallis, and Ashleigh
Griffin from Oxford University, focused their review on 23 bird species
where some parents get help raising their young, while other parents take
care of their young on their own. Such species occur throughout the world
and include long-tailed tits in Sweden, sociable weavers in Southern Africa
and the Seychelles warbler that occurs on a few islands in the Indian Ocean.
"It is within these 23 species that we see clear differences in longevity.
Parents who get help with caring for young live, on average, one to two
years longer than parents who don't. This may not sound like a lot, but in
human terms it equates to about six and a half glorious years", says Charlie
Cornwallis.
However, the researchers add a twist: Not all helpers take their job
seriously. If the helpers are lazy, parents are forced into putting more
effort into raising their young, something that shortens their lives.
So what is the secret behind living a long time and having many offspring at
the same time? Philip Downing has the answer:
"As a parent, make sure you have hard-working helpers".
Reference:
Philip A. Downing et al, Hard-working helpers contribute to long breeder
lifespans in cooperative birds, Philosophical Transactions of the Royal
Society B: Biological Sciences (2021). DOI:
10.1098/rstb.2019.0742
Tags:
Plants & Animals