multiple paternity frogspawn ?

[Will Atkins]

Just a thought that I had when watching the frog orgy (frorgy?) of Rana temporaria in my garden pond today.

I noticed that several of the males, which greatly outnumber the females, made a scramble to jump on top of some fresh laid clumps of spawn once the pair had moved away. Are they trying to fertilise at least some of the eggs once the male in amplexus has had his go? does anyone know of research into this? Thanks, Will

[Jeroen Speybroeck]

http://onlinelibrary.wiley.com/doi/10.1 ... x/abstract

https://kops.ub.uni-konstanz.de/xmlui/b ... sequence=1

[Will Atkins]

Thanks Jeroen, that ties in nicely with the behaviour I saw today.

[Mario Schweiger]

Just will remind you on the vipersgarden databases.
Both papers are in the DB now.
Laurila & Seppä, Biol. J. Linn. Soc. 1998 = PDF-6524
Vieites et al., Nature 2004 = PDF-6527

Mario

[Niklas Ban]

Thank you for sharing, very interesting!

[Will Atkins]

thanks again guys. I am wondering if the male frogs in my pond are resorting to jumping on fresh laid spawn because this year there is currently an imbalance between males and females - we have had around 10 days of dry, cold nights which meant that most of the males (around 150) are in the pond, but have only been joined by about 30 - 40 females (and these, of course, leave the pond as soon as they have spawned). So there's always a large majority of lone males. In more normal years, I would expect a sex ratio closer to 1:1.

[Jeroen Speybroeck]

In general, sex ratio often appear more skewed than they actually are. Females tend to behave more secretively to avoid being molested too much. This might seriously hamper establishing a decent "true" sex-ratio estimate.

[Jeroen Speybroeck]

In case you're interested, there's some work been done on sex reversal in this species too, as (like in many amphibians) they seem to lack obvious sex chromosomes etc. Complex but interesting stuff.

[Will Atkins]

Thanks again, amazing what our 'common' frog (in the UK) still has to offer!

[Ilian Velikov]

Interesting stuff!

In case you're interested, there's some work been done on sex reversal in this species too, as (like in many amphibians) they seem to lack obvious sex chromosomes etc. Complex but interesting stuff.

Anything published yet or is the work done at the moment?