Comments on: Male Frog Extracts and Fertilises Eggs From Dead Female

By: Malcolm

Malcolm — Sun, 19 May 2013 07:43:53 +0000

I cant see any benefit for this species, because these females would have only one chance of passing on their genes, whereas females of other species could lay multiple batch of eggs.

By: Sola Oludiji

Sola Oludiji — Sat, 16 Mar 2013 12:56:45 +0000

I guess Never say die”. the species must continue

By: Kevin McCurdy

Kevin McCurdy — Mon, 04 Mar 2013 00:35:14 +0000

Where to begin…

As far as this behavior contributing to a skewed sex ratio in the general population, did you read the article? The article states that males are found dead at a rate of 10:1 to 20:1 over that of females after these mating events. If anything, this should skew the population towards females. Something else is going on here.

I, too, am fascinated by the overlay of equity and equality, uniquely human ideals, on biological processes.

By: kcurtain

kcurtain — Sat, 02 Mar 2013 04:26:07 +0000

I’m not sure why these findings are surprising at all. Many male frogs squeeze females during amplexus to either encourage the female to initiate ovipositing or to physically push the eggs out of her. The males probably have no idea that the females are dead – they are just following their normal instinct to grab a female in amplexus and squeeze. To identify this as if it is some sort of newly discovered behavior is a stretch. And naming it functional necrophilia? This is external fertilization we’re talking about! In frogs! It’s not as if they’re picking corpses on purpose.

By: W.Benson

W.Benson — Sat, 02 Mar 2013 01:03:02 +0000

Ed:
Izzo is probably looking at the operational sex ratio: the number of males ready to mate when gravid females show up at mating sites. Females spawn all their eggs rather quickly and, if they survive, return to the forest; males stick around and mob each female as she arrives. In two or three nights, as many females may arrive individually as there are males waiting. Also, there is no guarantee that all females will be ready to mate in a given mating session. This would further skew the operational sex ratio even if males and females were equally numerous.
That said, it seems reasonable to assume that female deaths further skew the operational sex ratio towards males.

By: amphiox

amphiox — Thu, 28 Feb 2013 03:12:54 +0000

WIth respect to trying to actively meddle in the natural biology of amphibians, does anyone recall the Australian Bullfrog?

By: Ed Yong

Ed Yong — Wed, 27 Feb 2013 23:43:34 +0000

Okay several things.

1) Misogyny. The last paragraph is meant to be read in a deadpan, tongue-in-cheek way. Also, these are frogs. And yes, in a situation where the female has a high chance of dying, she gets reproductive benefits from having her eggs fertilised post-mortem. Just as, for example, this male spider (http://phenomena.nationalgeographic.com/2012/06/12/male-spider-castrates-himself-and-gets-more-stamina/) gets reproductive benefits from ripping his penis off.

2) The sex ratio thing – it’s really not that unusual! All sorts of factors contribute to massively skewed sex ratios in the wild, including parasites, predators, differing investment by parents, differing competition between the sexes.

The bizarre thing is mapping human values onto this (“psychotic”??), seeing skewed sex ratios as a problem to be fixed, and actually suggesting that we deliberately skew the sex ratios back to what we think is appropriate.

By: Caitlyn Johnston

Caitlyn Johnston — Wed, 27 Feb 2013 21:39:51 +0000

The sex ratio thing could easily be solved by breeding them in captivity and only releasing females. We (humans) could flood the population with females so they aren’t so gruesomely massacred and the males aren’t so desperately psychotic.

By: Christopher Moore

Christopher Moore — Wed, 27 Feb 2013 21:33:24 +0000

Not surprising, but REALLY cool!

For those of you interested in sex ratios, the original paper has no quantitative foundation. I bet it’d be an interesting problem if you have the mathematical tools.

By: Caitlyn Johnston

Caitlyn Johnston — Wed, 27 Feb 2013 20:42:57 +0000

Clearly, it’s because they keep killing off the females.