Brown hairstreaks

[Susie]

Okay, back to my favourite subject at the moment ....



Does anyone know what sort of loss of eggs is common over the winter? So far from the 40+ eggs I had at least 80% has gone, taken by birds I assume, and it is still only December!

Today I have cut down some of the blackthorn twigs and put them in a box to protect them until the spring.

[Pete Eeles]

Hi Susie,

The only detailed information I have is in the spreadsheet below - although this doesn't cover the pre-spring loss. But it certainly does give an indication of the high amount of loss that can occur.

Brown Hairstreak survival table.gif (17.37 KiB) Viewed 2393 times

Cheers,

- Pete

[Susie]

Wow, thanks Pete. That really is interesting.

I would love to know what percentage of eggs would have been lost had they tagged in September.

It is amazing that anything survives, especially as predation when caterpillars hasn't even been covered.

[JKT]

One Finnish professional wrote a few days ago: If one female lays 200 eggs, on average 198 of them have to die before producing offspring or we are going to have a problem.

[Pete Eeles]

One Finnish professional wrote a few days ago: If one female lays 200 eggs, on average 198 of them have to die before producing offspring or we are going to have a problem.

Absolutely right - that's certainly the maths. Otherwise the population would double ever other generation.

Not sure what the problem is though

Cheers,

- Pete

[Padfield]

One Finnish professional wrote a few days ago: If one female lays 200 eggs, on average 198 of them have to die before producing offspring or we are going to have a problem.

My Swiss 'Bible' puts the same maths (almost) the other way round: of every 200 eggs laid, one male and one female have to survive in order for the population to remain stable. Evolution is, of course, predicated upon massive mortality rates...

Guy

[JKT]

Not sure what the problem is though

Considering the current situation, none for the first five generations. After that we might notice.

My Swiss 'Bible' puts the same maths (almost) the other way round: of every 200 eggs laid, one male and one female have to survive in order for the population to remain stable.

The writer's glass seems to be half empty. Then again the speed the habitats are going does justify that attitude.

[chitin]

Looking on the bright side if 4 out of 196 eggs result in a Male and Female we are in business. It's that delicately balanced !!. I have 50 eggs from Brown Hairstreaks bred in captivity. They are sleeved on potted Blackthorn. will keep you posted as to numbers that become butterflies if and when when they develop. Even in sleeves things just "disappear" .

[Susie]

Any idea how many caterpillars you have from the 50 eggs, Chitin? I keep trying to count mine but it doesn't work!

[chitin]

Placed on sleeved potted Blackthorn in a greenhouse I now have about half (25) larvae from the original 50 eggs. My colleague also has the same 50% from his original 25 eggs. Where the others go I don't know, did not check eggs for hatching. They are reputed to be cannibals so have sleeved mine on each branch with 2 or 3 in each sleeve depending on amount of vegetation. Next problem is pairing and feeding as they don't come down to flowers and feed on aphid secretions on Oaks like Purple Emperors . Have just finished a 4ft high x 2ft x2 ft cage. Today started building a walk-in netted enclosure built on the foundations left from my long defunct 10 x 7 greenhouse. Then I can sit in it with butterflies flying around me. Heaven n The eggs were purchased from a dealer who breeds them in captivity and so have not been subject to the forces of nature. All sorts of creatures will make a meal of butterfly eggs.

[Susie]

Next problem is pairing and feeding as they don't come down to flowers and feed on aphid secretions on Oaks like Purple Emperors . Have just finished a 4ft high x 2ft x2 ft cage. Today started building a walk-in netted enclosure built on the foundations left from my long defunct 10 x 7 greenhouse. Then I can sit in it with butterflies flying around me. Heaven n

Sounds like heaven to me too I thought it was honeydew on ash they preferred but I guess honeydew is honeydew. I have seen them feeding on flowers though. One of our members suggested offering a sugar solution for them to feed on in place of honeydew so that may be worth a try if keeping them captive.

[Susie]

Denise and Jack.

[Denise]

That's brilliant.

[eccles]

Is Jack the grumpy looking one?

[Susie]

I'm not going to reply on that on the basis that I might incriminate myself.

Interesting to see that some of the brown hairstreak caterpillars are now being attended by ants in one of the netted pots.

[Susie]

I thought I would give them a quick look today and saw one on the earth of the pot just as it was about to disappear down a hole! It had changed colour.

A quick search of that pot produced four caterpillars in cracks in the soil (and there are at least two green still on the leaves) and one in the earth in the other pot. I know the other pot had far more hairstreaks than just this one and as this was the pot which has the ant nest I wonder if the ants took them down deeper. I only did a tentative search as I didn't want to harm any of them.

I am keeping five of the hairstreaks in a separate container where I can monitor them closely until they emerge.

[Susie]

Of 12 eggs in a cage I have at least eight full grown adult caterpillars. I reckon that's pretty good going.

Edit: checked both cages today and from approximately 20 eggs I have found 15 fully grown or pupating caterpillars and there are probably more I haven't found. Now I reckon that is damn good going and if they successfully turn into adults that should go some way to repopulating the area and making good the damage done when the hedges were trimmed around here and so many eggs were lost.

[Susie]

I'm dreaming of a scorching summer filled with brown hairstreaks.

If you ever need a brown hairstreak champion, kipper, let me know cos I'm obsessed by the things!

[Susie]

Two brown hairstreaks emerged this morning.

[Susie]

Now it's three!

They've arrived to the exact day I expected them to emerge - how's that for being punctual.