Convolvulous Hawk. (1 Viewer)

harry eales · Oct 7, 2005

Hello Jamie,
Sorry to hear your ova didn't hatch, mind you with the relatively high mortality I've been having, seven wasn't a lot to start off with.

It's always the smallest of the larva that are dying off in the brood and they have, so far, all been in their first instar. A few have now moulted for the second time, and are really starting to 'tuck in' to their food. I fed all the larva at 7.0am today and in one breeding cage, containing just three 2nd instar larva, I placed six large Bindweed leaves at least 5" long. At midday I carried out a check on them, and found all six leaves and the stalks had been consumed. The little bu****s are eating more than me. lol.

Why the little one's are dying off, I have no idea, it seems to be a common thing in all the Hawkmoth species I have bred, It's certainly not due to overcrowding, or is it that they have been attacked by larger larva, and I am scrupulously careful to disinfect the cages on a daily basis.

Hopefully now some of these larva have passed through into their second instar the death rate may fall off.

Harry

harry eales · Oct 7, 2005

Convolvulous Hawkmoth larva, update.

A major disaster today, I checked on my larva this evening and found over thirty of them dead. All had taken on a wet, watery or greasy appearance, as had their droppings. A brown watery discharge surrounded each affected individual. In all, over thirty larva have died between midday and this evening, although there was no trace of this at midday.

I'm at a loss to explain why this has happened, I've never lost so many larva so quickly in half a century of breeding lepidoptera.

Tomorrow, I intend to isolate every larva into individual containers and hopefully prevent any further cross infection. The larva are not overcrowded and the foodplant leaves I give them are dry and inspected for possible predators, snail slime and/or droppings, leaf rot etc. Each breeding cage is sterilised daily in a Domestos solution before being thoroughly rinsed and dried, prior to the larva being re-introduced.

In the meantime, has anyone had this occur themselves, and if so, did you find a solution to this problem?

Harry

alcedo.atthis · Oct 7, 2005

"Convolvulous Hawkmoth larva, update.

A major disaster today, I checked on my larva this evening and found over thirty of them dead. All had taken on a wet, watery or greasy appearance, as had their droppings. A brown watery discharge surrounded each affected individual. In all, over thirty larva have died between midday and this evening, although there was no trace of this at midday."

(Snipped)
"In the meantime, has anyone had this occur themselves, and if so, did you find a solution to this problem?"

Harry, have you come across " P. rapae granulosis virus " before. It may be worth an internet search if not and alittle bit of reading. This may or may not be linked to your situation.
http://www.altavista.com/web/results?itag=ody&q=P.+rapae+granulosis+virus+&kgs=0&kls=0

(Edited)
Came across this also. :-

http://www.ext.colostate.edu/pubs/insect/05556.html

Reactions seem different, but wondered if the leafs you are using as food are contaminated with something similar.

Regards

Malky

mother nature · Oct 7, 2005

good evening i have 2 green elephant hawk moths in my garden

harry eales said:
Over the last few months I have read with not a little jealousy, of reports of migrant Hawkmoths turning up all over Britain this year. Trapping as often as possible, and looking for Hummingbird Hawkmoths by day has been a total failure as far as I am concerned, possibly because I live in a well wooded valley some twenty miles from the coast.

On Wednesday morning I received an Email from my county recorder saying that he had trapped a Convolvulous Hawkmoth at Tynemouth Priory on the Northumberland coast and if anyone wanted to see it before it was released to get in touch with him asap.

Having only bred one specimen of this species from a fully fed larva, I was rather anxious to try and breed this species from ova. My CR kindly agree to let me try, and I collected the adult female yesterday morning.

Once I got the specimen home, I introduced her to warmer conditions (she had been in a fridge for the best part of two days. I made up a sugar/water solution and soaked this up in a cotten wool pad, placing this some 2" in front of her I teased out her rolled up proboscis and put the tip onto the sugar pad.
She immediately started to suck up this food as the undulations of her proboscis indicated. When she had finished feeding she was transferred to an 8" x 5" x 3" plastic container in which I had placed two large Convolvulous leaves. The container was then placed on a windowsill where the local street lighting would give a 'dusk like' lighting overnight.

This morning upon examining the container I found she had laid between 100-150 ova. (I haven't made an exact count yet) These ova are very small indeed, being no more than half the size of ova laid by Elephant or Poplar Hawks. They are also well camouflaged being almost the same shade of colour as the leaves they were laid upon.

I will now have to wait a week or ten days to see if they are fertile ova, unfortunately many moths will lay ova even if they have not mated. I intend to release this female tonight if the weather conditions are suitable. She is still in very good condition with only a little scale loss.

I'll keep you posted if and when the larva hatch. I have attached three pictures, sorry about the quality of these, I had to use my 'el cheapo' digital camera, as the batteries on my other camera were somewhat flat.

Harry

harry eales · Oct 7, 2005

alcedo.atthis said:
"Convolvulous Hawkmoth larva, update.

A major disaster today, I checked on my larva this evening and found over thirty of them dead. All had taken on a wet, watery or greasy appearance, as had their droppings. A brown watery discharge surrounded each affected individual. In all, over thirty larva have died between midday and this evening, although there was no trace of this at midday."

(Snipped)
"In the meantime, has anyone had this occur themselves, and if so, did you find a solution to this problem?"

Harry, have you come across " P. rapae granulosis virus " before. It may be worth an internet search if not and alittle bit of reading. This may or may not be linked to your situation.
http://www.altavista.com/web/results?itag=ody&q=P.+rapae+granulosis+virus+&kgs=0&kls=0

(Edited)
Came across this also. :-

http://www.ext.colostate.edu/pubs/insect/05556.html

Reactions seem different, but wondered if the leafs you are using as food are contaminated with something similar.

Regards

Malky

Hello Malky,
A fascinating subject, thanks for the URL. I have recently gathered my foodplant from hedgerows on a very minor country road (one vehicle width wide, with passing places) where there is very little traffic and the fields aroundabout are used mainly used for grazing cattle, sheep or horses. There is no evidence that I have seen, that spraying of any chemical has taken place in the vicinity.

The only other time I have seen a similar disease was amongst some Oak Eggar larva gathered off heather moorlands, where no spraying of any sort takes place. The seemed fine when collected but some died off even before I got home. The symptoms are very similar if not identical. From what I have been able to find out, this is commonly called a 'Wilt Disease'and it is highly infectious even in the wild. Unfortunately I don't know anyone who is involved in work on virus's in Lepidoptera, to whom I could submit samples for investigation. It may be worthwhile taking samples from the next larva to die and have a look at it under the microscope. If bacteria are involved it may be possible to see them, but if it is a virus my microscope may not be powerfull enough to let me see them.

I have heard that some infections of larva can be cured by dipping the larva into a 5% solution of distilled water and TCP, but just how effective this is I don't know. It may be worth trying though.

Harry

mothman · Oct 8, 2005

mother nature said:

Hi Mother nature,
There is an answer to your post at the URLs for moth and butterfly enthusiasts thread.

Colin.

harry eales · Oct 8, 2005

Hello Mother Nature,
There is also a reply from me in the same thread as Colins.

Harry

mother nature · Oct 8, 2005

Good morning Colin,
and Thank you for your response. I have read the previous threads in reference to the elephant hawk and gathered some good information. Still trying to get use to finding the threads.

stephonia :hippy:

mother nature · Oct 8, 2005

hello Harry,

I received it. It was the first thing I read this morning. I am concerned about the catterpillar it is laying in the garden unprotected and the other one is hidden under a butterfly bush. The temperature here is very cool and I dont know what stage it is going through. It is curled up. I am use to monarch butterflies and this species has me blown away. I dont know what food it eats and we dont grow the willowherb and other plans that grow for the survival of the larva you have in your part of the country. I am convinced it is an Elephant Hawk Moth catterpillar. :hippy:

harry eales · Oct 8, 2005

mother nature said:
hello Harry,

I received it. It was the first thing I read this morning. I am concerned about the catterpillar it is laying in the garden unprotected and the other one is hidden under a butterfly bush. The temperature here is very cool and I dont know what stage it is going through. It is curled up. I am use to monarch butterflies and this species has me blown away. I dont know what food it eats and we dont grow the willowherb and other plans that grow for the survival of the larva you have in your part of the country. I am convinced it is an Elephant Hawk Moth catterpillar. :hippy:

Hello MN,
The sooner you can post a picture the faster we can ID it and let you know what foodplant it eats.

In the meantime I would suggest you retreive the two larva and put them in a box containing dry leaves. If the larva have an oily or greasy appearance then they will be fully fed and looking for a place to pupate. Bringing them inside to a garage will reduce the chances of something predating on them.

If you manage to get a photograph reduce it size as I suggested and save it on your computer To upload it write a reply message then scroll down until you see a box called manage attachments, click on that and using the browse button locate your picture and then click upload, wait until you are informed the picture has been uploaded, click close manage attachments and then click send. Your text and picture should then appear on your screen aftere a few seconds.

Harry

harry eales · Oct 9, 2005

Convolvulous Hawkmoth larva update.

Dammit, another 20 or so larva died today of the same 'Wilt Disease'.
I have now isolated every individual larva into seperate containers. My dining table, sideboard and bookcase are littered with 'pots' each containing one larva.

It has been a case of doing whatever was possible under the circumstances. Each larva is in a large drinks carton with a clear plastic cap, curtesy of my local 'McDonalds'. The manager (a lady) was very understanding,
(it must be my smarmy 'chat up' line) and let me have over a three hundred large 'drink' containers at a very, very reasonable price. Whilst not exactly ideal breeding cages, they will suffice for the time being.

Hopefully, not all the larva have caught this infection, time alone, will tell.

Harry

alcedo.atthis · Oct 9, 2005

"Convolvulous Hawkmoth larva update.

Dammit, another 20 or so larva died today of the same 'Wilt Disease'."

Harry, came across this. Sounds interesting considering your first observations regarding the deaths and your conclusions that it's down to "Wilt".

http://www.nysaes.cornell.edu/ent/biocontrol/pathogens/viruses.html

See comment in last paragraph about "ultraviolet radiation."

I am still digging for more info.

Regards

Malky

harry eales · Oct 9, 2005

alcedo.atthis said:
"Convolvulous Hawkmoth larva update.

Dammit, another 20 or so larva died today of the same 'Wilt Disease'."

Harry, came across this. Sounds interesting considering your first observations regarding the deaths and your conclusions that it's down to "Wilt".

http://www.nysaes.cornell.edu/ent/biocontrol/pathogens/viruses.html

See comment in last paragraph about "ultraviolet radiation."

I am still digging for more info.

Regards

Malky

Hello Malky,

Thanks for that URL, it's very interesting indeed. Over the years I have had this virus turn up on several occasions in my breeding cages, and until now I have always believed that it was because I had picked up an already infected larva. But in breeding these larva from ova, the infection had to be brought in from another source, namely on the foodplant.

As it now seems very likely that the Polyhedrosis virus was present on the leaves of the foodplant. I found it very interesting that UV radiation can, in effect kill it off.

Bearing this in mind I am:-
1. Getting my foodplant from another source.
2. Putting all collected foodplant into the sterilised base of my Robinson Moth trap and inverting the MV bulb so it shines into the trap for a few hours. Hopefully the UV light will have a deterious effect on any parthogen present on the leaves.

I am convinced that this virus wasn't present in the breeding cages used in rearing the newly hatched larva as all were freshly constructed for them. Any breeding cage I have used in the past where this virus has turned up has been burnt as that was the only way I knew of destroying this virus.

Hopefully isolating each larva and feeding them of UV treated leaves from another source will cut down on my losses.

Harry

alcedo.atthis · Oct 9, 2005

Snipped

"Bearing this in mind I am:-
1. Getting my foodplant from another source.
2. Putting all collected foodplant into the sterilised base of my Robinson Moth trap and inverting the MV bulb so it shines into the trap for a few hours. Hopefully the UV light will have a deterious effect on any parthogen present on the leaves.

I am convinced that this virus wasn't present in the breeding cages used in rearing the newly hatched larva as all were freshly constructed for them. Any breeding cage I have used in the past where this virus has turned up has been burnt as that was the only way I knew of destroying this virus.

Hopefully isolating each larva and feeding them of UV treated leaves from another source will cut down on my losses."

Harry, having read the article from Cornell, I suspect that you may loose all, but at least you may be better prepared for the future.
I wonder if it would be wise, even at this late stage, to give some of the larva a bit of UV exposure, and see if there are any differences in survival from the un-exposed ones.
I am looking into overexposure to UV at present.
If I come across any more info, I will post it, but for now, the best of luck with the remainder of the larva.

Best wishes

Malky

harry eales · Oct 9, 2005

alcedo.atthis said:
Snipped

"Bearing this in mind I am:-
1. Getting my foodplant from another source.
2. Putting all collected foodplant into the sterilised base of my Robinson Moth trap and inverting the MV bulb so it shines into the trap for a few hours. Hopefully the UV light will have a deterious effect on any parthogen present on the leaves.

I am convinced that this virus wasn't present in the breeding cages used in rearing the newly hatched larva as all were freshly constructed for them. Any breeding cage I have used in the past where this virus has turned up has been burnt as that was the only way I knew of destroying this virus.

Hopefully isolating each larva and feeding them of UV treated leaves from another source will cut down on my losses."

Harry, having read the article from Cornell, I suspect that you may loose all, but at least you may be better prepared for the future.
I wonder if it would be wise, even at this late stage, to give some of the larva a bit of UV exposure, and see if there are any differences in survival from the un-exposed ones.
I am looking into overexposure to UV at present.
If I come across any more info, I will post it, but for now, the best of luck with the remainder of the larva.

Best wishes

Malky

Hello Malky,

The thought I might loose all of the larva had already occurred to me, I'm keeping my fingers crossed that at least some survive. They were split into ten and later 15 separate groups from hatching so (hopefully) not all may be infected. Now they are totally isolated from each other I'm hoping there will be no further cross infection.

Have you any suggestions as to how long I should expose the leaves to 125W MV light?

I'm not sure exposing the larva to MV light would have much effect as the virus developes in the gut, and by the time it shows, by being discharged as a brown fluid from the larva, they only last an hour or so before dying.

Harry

Wandered Scot · Oct 10, 2005

Morning Harry,

Sorry to read of latest troubles. Maybe there is more than just Cold weather being a problem for the species surviving wild in Britain?

Best of luck, interesting how versatile McDonalds property can be, I use their straws to drain the excess rain from the rearing glasses!!

Maybe we should keep away from mentioning Henry Brewis in future, it is getting near the bone now.

Cheers

Jim

harry eales · Oct 10, 2005

Wandered Scot said:
Morning Harry,

Sorry to read of latest troubles. Maybe there is more than just Cold weather being a problem for the species surviving wild in Britain?

Best of luck, interesting how versatile McDonalds property can be, I use their straws to drain the excess rain from the rearing glasses!!

Maybe we should keep away from mentioning Henry Brewis in future, it is getting near the bone now.

Cheers

Jim

Hello Jim,

I'm afraid loss of livestock is something that all breeders have to put up with from time to time. Viral or Bacterial infections are probably the breeders worst nightmare. Losses to avian and insect predators can be guarded against but invisible predators are virtually impossible to detect until it is too late.

Only eight larva died yesterday, again all were smaller larva, but then these are probably more likely to show the effects of the disease earlier than the more developed larva.

My only hope now, is that some larva may survive because they have'nt yet been infected, and as they are all now being reared in total isolation from each other in order to reduce the chances of cross infection.

This entails a hell of lot more work for me in looking after them, in that each individual breeding 'carton' has to be cleaned out daily and fresh food supplied, but then, if only a very few survive to adulthood, it will be well worth it, as far as I am concerned. I suppose it's a good job I'm retired and have the time to spare to do this amount of work.

Harry.

CornishExile · Oct 10, 2005

Good luck Harry. Sorry to hear of this latest setback; I well remember my anguish when I lost a whole batch of Large Copper larvae to a viral infection. The stuff of nightmares. I felt completely helpless at the time.

Don't envy you the task of mucking out now there's so many containers.

Jon

harry eales · Oct 10, 2005

CornishExile said:
Good luck Harry. Sorry to hear of this latest setback; I well remember my anguish when I lost a whole batch of Large Copper larvae to a viral infection. The stuff of nightmares. I felt completely helpless at the time.

Don't envy you the task of mucking out now there's so many containers.

Jon

Hello Jon,
Thanks for the sympathy. It isn't any fun at all to loose any livestock. As for the mucking out, it will be worth it to get at least some of them through to the adult stage.

I don't mind the work, it fills in the day and stops me hanging around street corners and getting into trouble.

Harry

mother nature · Oct 10, 2005

O Harry,
I lost them. I was so afraid to take them from their surroundings among the lamb's ear plant that I have growing in the garden. I went to check on them and both are gone. I have been searching the garden but since the caterpillars are so beautifully green it makes it difficult. At this point I am so sad in missing a great opportunity to study them.

Thank you so much for your help...Excellent :hippy:

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