Gender Distributions

Is anyone aware if the ratio of males:females in newt species is anything other than 50:50. I ask as over the past few weeks there seem to be a noticably larger number of males than females visible in my ponds (Triturus spp)

Neil

In Triturus the sex ratio is generally around 50:50. The males however usually reach sexual maturity a year or two earlier than females, so you might find more males than females in a breeding pond.

In all Triturus species that I have reared from eggs, I would definately say that females outnumber males. I was discussing the subject of T vulgaris in garden ponds with a friend, who informed me that this year in his ponds he has counted twenty one females ,and only nine males.
I was interested to read Neils observations.
What have other forum users with garden ponds found?

I agree with morg.In my experience,breeding sites with vulgaris,carnifex and italicus,I've always found more females than males.

After the original posting, I feel somewhat embarrased to admit all I saw last night were female T. helvatica, no males at all.

Neil

I've almost always found more males than females. In my experience, males tend to arrive at ponds earlier in the year than the females, and leave later. This means that even if you have a 50:50 sex ratio in the population, you're likely to see more males at any one time.

are you asking about breeding age adults in the wild, or are you talking sex ratio at hatching?

It's adults returning to breed I was referring to. Calebs point about males spending longer in the aquatic stage may be the answer to the question. Also, I suppose, if the males remain hidden, their breeding success my be affected, although they are more likely to live to breed, than be eaten.

Neil

Neil
Since your original post I have been pond watching in my garden, and although I know the amount of newts in the ponds, it is indeed the males who are out of hiding and on show the most.
The females tend to stick to areas of heavy plant growth, while the males spend a lot of time in the open.
I have also taken to putting a few blocks of frozen bloodworm into the pond some evenings, and again it is the males who arrive first to feed, the females [if at all], turn up a lot later, feed then hide again.
The males will stay in the open for quite a while.

I have just heard back from two more people who I had asked to take a look at their garden pond newt numbers.
One said that he had many more males in both T vulgaris and cristatus.
The other said that this year in her small pond there was only the one male returned along with four females.

Well, here goes my contribution from Spain. Species such as Euproctus asper you will find females outnumber, normally by a proportion of 2 males for every female or even more all year around.
Also, the proportion varies from region to region. T.boscai females normally outnumber t.boscai males from August to February in Gallicia. When the breeding season comes the ratio is quite balance. Those females that stay all year around in water seem to be quite larvae and egg cannibalistic. More over, they are very old of age. This is very easy to identify in t.boscai since their belly coloration fades and their green olive colour fades to something similar to copper. Those females seem much experimented in egg and larvae hunting. That may explain their prolong stay in water.
On t.marmoratus the proportion out of the breeding season is higher in males. You could find breeding males in autumn and winter but no females at all. Normally, those males are old too. While in the breeding season this proportion get balance with a decrease of males during summer. While some females keep folding leafs for their eggs.
T.helveticus males normally outnumber females during the breeding season. I have not enough experiences on t.alpestris cyreni, t.pygmeus and p.waltl.

I have just been reading the book
Newts of the British isles by Patrick J Wisniewski.
I came accross a passage, which reminded me of this thread.
The sex ratio of newts is often biased in favour of females, though in common frogs and toads the reverse is frequently true.
Several workers have reported ratios of two or three females to every male in smooth and palmate newts.

Now I know that because the information is in a book does not make it correct, but thought I should post it.

I have that book as well, although is small I think it's exellent.

From what I've seen in my pond some years ago, and in a ditch now, T. Vulgaris definatly has more females than males, i'd say 30 males in 70 females

Francesco
I have to agree about the book, it is very good.
I would advise anybody with an interest in newts to buy this book.
Some of the photos within the covers remind me why Triturus are my favaourite species of newt.

and also the picture of the albino crested newt...