Some questions:

[Eris]

I have looked through my books and can't actually find these things mentioned so am asking here:

How much variation is there in the number of eggs laid by different butterflies?
Are the rarer one less productive in the number of eggs? eg what is the difference in egg numbers from things such as the wood white compared to the meadow brown or are the number of eggs laid similar?

Has anyone monitored butterflies, especially the rarer ones to see if the number of eggs they lay has remained consistent over the years of is there a downwards or upward trend?

Do they lay in batches of a few days at a time and then take a break? or do they lay continuously every day until they have finished?

How many times do they mate? Just once that fertilizes the eggs until the end of laying ? or do they mate more than once to keep the eggs fertilized? Or do they batch lay and have to have each batch fertilized?

Please excuse all the questions but I am a poultry keeper - so eggs are something I am always interested in!

[Pete Eeles]

Hi Eris - some responses to the best of my knowledge:

"How much variation is there in the number of eggs laid by different butterflies?"
If you mean different species - there is a huge difference. Some may lay as few as 30 or 40, others up to 300. In terms of individual butterflies, I believe the number is fairly consistent, although weaker, less-developed individuals will lay fewer eggs, I suspect.

"Are the rarer one less productive in the number of eggs?"
No - there is no correlation.

"Has anyone monitored butterflies, especially the rarer ones to see if the number of eggs they lay has remained consistent over the years of is there a downwards or upward trend? "
I don't know - but I expect that if that had been observed then it would be "big news". So I can only assume that the number of eggs has remained more-or-less constant for each species.

"Do they lay in batches of a few days at a time and then take a break? or do they lay continuously every day until they have finished?"
It depends on the species.

"How many times do they mate?"
Normally once only. However, some species will mate more than once although I believe that this is completely unnecessary for fertilisation of the eggs.

Cheers,

- Pete

[Eris]

Thanks for that very interesting so the batch layers must store the sperm. - I presume the butterflies that hibernate mate before winter?

I was wondering if we accept that around 90% of eggs get either taken by predators or fail to hatch for some other reason, the butterflies that laid the less eggs would show up in more limited numbers hence the paucity of some breeds. And also if sprayed herbicides even at low levels were affecting the reproductive qualities and resulting in either less eggs laid or less viability of eggs.

[Pete Eeles]

I presume the butterflies that hibernate mate before winter?

I don't know of any that do.

... the butterflies that laid the less eggs would show up in more limited numbers hence the paucity of some breeds.

I'm not sure if that's a good assumption. There are many factors at play and only one is the number of eggs laid. What I would agree with, just based on the maths, is that a greater proportion of the eggs must survive in those species that lay fewer eggs, in order to maintain a viable population.

Cheers,

- Pete

[eccles]

A good indicator that butterflies that overwinter as adults do not mate until Spring is to watch their behaviour, particularly the males. In Summer these butterflies take nectar at a much higher rate than in Spring. The impetus in Summer is to maintain sufficient energy reserves to get through the winter, whereas in Spring all they have to do is reproduce. Brimstone males only briefly stop to nectar in the Spring, spending much of their time searching for females. Peacocks in Spring are much more territorial than in Summer, spending long periods of time basking and guarding their patch.