From Charles Snell
Your article on Lucky the frog stated that I failed in my attempt to breed
from the last remaining pool frog in captivity in Britain
(12 January, p 42).
Not wanting the scientific and conservation communities to be left with the
depressing idea that the last British pool frogs died without issue, I need to
correct this statement.
Lucky was in fact extremely keen on the opposite sex in spite of being, in
frog terms, quite geriatric. So keen was he to keep the British end up, in fact,
he had to be prised off some of the European females in his outdoor enclosure
(for their own sake) after holding onto them in amplexus for three days
continuously.
The unsuccessful matings were with females of Swedish origin. I found this
particularly disappointing as, in the name of science, I had spent some of my
1997 summer holiday chasing Swedish females around a lake with a net in the hope
of getting breeding started (with clearance from the Swedish government).
Genetic work by myself at Greenwich University and by Inga Zeisset and Trevor
Beebee at Sussex University shows that Norway and Sweden have pool frogs that
are the closest genetically to those of Britain. The Swedish females showed no
interest in laying eggs, even though Lucky was firmly attached and waiting to
fertilise them. They also showed no interest in Swedish males and vice
versa.
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My assumption is that an environmental trigger is missing when the Swedish
frogs are at British latitudes. Two females, of presumed Dutch origin, bred
quite happily with Lucky and to this day, Lucky’s genes persist in several
offspring.
Pool frogs belonging to Swedish, Norwegian and British populations seem,
however, to form a distinct genetic grouping (a “clade”). It was hoped that if a
mating with Lucky occurred with Swedish or Norwegian females, offspring of this
scientifically interesting clade could be released back into East Anglia.
Beckenham, Kent
