The Amphibification of Fertility

Originally published April 2015

Hello everyone! Before we explore the reason behind my flagrant decimation of the English language in this month’s title, let us have a brief look at some exciting developments across the Welsh border. On the 17th March the National Assembly for Wales passed the Well-Being of Future Generations (WFG) Bill. This exciting piece of legislation (a term I rarely use) places duty of sustainable development on the public sector including the Welsh Government and Local Authorities. Of course we have yet to see how well it will be implemented but it is a positive step that recognises the correlation between ‘quality of life’ and the natural environment. We await the publication of the Welsh Government’s Environment (Wales) Bill which, it is hoped, will give substance to the commitment of halting the decline in biodiversity. Bravo Cymru, wake up Whitehall!

Sadly, our wildlife needs as much protection as the legislative bodies can afford. Thousands of species in the UK are in decline. I am sure it is not an ageing auditory system that is the cause of my hardly noticing the dawn chorus this year. We are blessed to be surrounded by birdsong in our corner of the Isles but the avian proms are not the glorious crescendo of years past.

On the subject of mating calls, it was in the weeks leading up to Christmas that I found myself pausing in mid flow to listen to an unexpected sound coming from the garden pond; a frog in full courtship mode, croaking loud enough for the world to hear. I do not know if that particular frog struck it lucky, given that it was the middle of winter and by rights the amorous croaker should have been hibernating, but if he didn’t, those frogs who mated this spring have made up for his loss. My garden pond, along with the Quarry Wood pond is awash with gelatinous clouds of frogspawn so redolent of my school desserts (see Aliens that Laugh in the Night, May 2010).

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Our common native frog, aptly named the Common Frog (Rana temporaria), is the one people are likely to see in their gardens and woodlands. With their characteristic dark patch behind the eye and preference for jumping rather than walking they are easily distinguished from the recently reintroduced Pool Frog (Pelophylax lessonae) or our local, cackling invader the Marsh Frog (Pelophylax ridibundus).

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Those sensible members of the species who do hibernate usually emerge in late February ready to spawn in March, although a mild winter may see them in the water as early as December. The few weeks following the hibernation period is a noisy, flurry of orgiastic behaviour. Pond watchers will often see two and three frogs in amplexus (Latin – embrace), the mating embrace of frogs, toads, newts and, bizarrely, horseshoe crabs. Before long, clumps of 3-400, black-dotted eggs are adorning, ponds, ditches and even puddles. R. temporaria is not known for great parenting skills and its Latin name reflects the fact that their presence in the ponds is on a temporary basis only. After spawning they disperse and the eggs are left unguarded. Incredibly, only around five out of the three thousand eggs that one female usually lays will develop into adult frogs. Temporary sites may dry up, frost and ice will damage the spawn and tadpoles provide a readily available meal for a whole host of aquatic predators such as Herons and dragonfly larvae. It is not uncommon for the tadpoles to turn on each other once their diet becomes more carnivorous and the numbers soon dwindle.

TQW Apr 2015 tadpoles

Clearly, if this were not the case and tadpole mortality was lower, we would be swamped with the numbers of frogs associated with biblical plagues. Most of the ancient cultures reflected the fecundity of this ubiquitous animal. In reality, the Egyptians were very used to seeing large numbers of frogs along the Nile. It is no coincidence that the hieroglyph for a large number, 100,000 was a tadpole and that Heket, was their frog-headed goddess of fertility and childbirth. The Greeks and Romans also associated frogs with fertility and good fortune and it seems that it was only in Christianity they were deemed as evil and demonic; often associated with witchcraft.

There is no doubt that the few weeks of frantic and prolific mating is essential in the ecology of our common croakers; the odds are definitely stacked against them. Adult frogs are subject to predation, disease and pollution stress. Any one of these factors can cause mass mortality events, the latest on record being in County Kildare, Ireland. Last year hundreds of R. temporaria were found dead or dying in a breeding pool near the Curragh. Post mortems were carried out for the deadly, amphibian diseases Chytridiomycosis and  Ranavirus but came back negative. The prevailing theory is that the frogs succumbed to the attentions of a flock of birds, such as Crows. Thankfully the frogs have, literally, bounced back this year and the pond is being monitored by the ever-vigilant Herpetological Society of Ireland.

TQW Apr 15 Jap frog

A POOL was once congeal’d with frost;
The frogs, in its deep waters lost,

No longer dared to croak or spring;
But promised, being half asleep,
If suffer’d to the air to creep,

As very nightingales to sing.

A thaw dissolved the ice so strong,–
They proudly steer’d themselves along,
When landed, squatted on the shore,
And croak’d as loudly as before. 

Johann Wolfgang von Goethe (1821)

Let us hope that the Welsh Government uses the legislation it has put in place to promote sustainable development and biodiversity and become a role model to the rest of the powers that be both in the UK, and beyond. No matter how abundant the wildlife may seem around us, the natural world is a dangerous place for all its denizens for none of us know what is around the next corner or, indeed, in the next pond.

Paul Johnson

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Image 2: Rana Temporaria by Tom Blackwell, used under Creative Commons License 2.0 / Image 3: European Frog – rear legs only by Mark Stevens, used under CC2.0


 

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