Category: Hyalophora_euryalus

Hyalophora euryalus L3 Rearing Notes (4/27/17-5/??/17)

5/7/2017

Rearing notes for our third instar ceanothus (Hyalophora euryalus) larvae. This stock is of northern California origin, obtained March, 2017.

Rearing Notes 4/27/17-5/??/17:

5/7:

The only remaining larva is still alive and feeds; its tubercles have darkened and become yellowish at the base; not sure if it is diseased or not since it has remained in this instar for quite a while now

5/2:

The younger third instar died, still clinging to the plant but with a flaccid, discolored body

5/1:

Sadly, the remaining second instar larvae on ceanothus and alder all died, most likely from the very hot weather this week (Hyalophora larvae tend to get diseased when reared in high temperatures)
Of the two remaining third instars, the younger one hasn't fed very much lately though the older one has fed some

4/30:

Third instar larvae still seem okay, feeding a decent amount; they are both definitely quite a bit larger than they were when first molted and the orange tubercles are turning red

4/29:

The two third instars are doing okay and seem to be feeding normally, though detecting disease is tricky as even sick caterpillars can continue feeding for weeks before dying
The second instar that was in apolysis mismolted and died; the other two on ceanothus seem to be making slow progress
One of the two remaining alder feeders died and dissolved into mush; the other will likely suffer a similar fate

4/28:

The third instar larva has eaten a decent amount and has grown a little plumper
Another larva on ceanothus molted into third instar and was transferred to a separate dish; another larva is apolysis
The alder larvae do not look so good anymore - another one died; only the largest two are remaining but have not been feeding well

4/27:

The oldest larva on ceanothus molted into third isntar, having spent eight days in second instar; we moved it to a seperate container from the rest of the larvae, as larvae of this difficult species should be thinned as they grow larger when rearing to avoid disease
The third instar is very different from the previous instar, being extremely brightly and attractively colored - the body is yellow-green laterally and turquoise dorsally, the dorsal scoli are red-orange and the lateral rows are pale blue with black ring at the base, and the legs and head are yellow
Morphologically, the larva's body shape has become more elongated with much larger, developed scoli tipped with black spikes and the thorax has a bulge
Unfortunately, one of the smaller larvae on alder died; it was immediately removed in fear that it may have been diseased

Authors
Alan Liang

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Hyalophora euryalus Rearing Notes (4/19/17-4/26/17)

4/26/2017

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Rearing notes for our second instar ceanothus (Hyalophora euryalus) larvae. These are of northern California origin and reared indoors on ceanothus (Ceanothus) and red alder (Alnus rubra)

Rearing Notes 4/19/17-4/26/17:

4/26:

The larva in apolysis till hasn't molted, but its current head capsule has become much more translucent and the red and blue coloration at the base of the scoli is now a deeper shade

4/25:

The largest larva on ceanothus entered apolysis; its cuticle is very tight and the scoli are very swollen, making its body look shiny and plump; it is now completely green now compared to the yellow that it once was in the beginning of the instar
Full grown second instar length is about 13 or 14 mm

4/24:

The larva continue to grow well and are likely close to third instar now - the base of the scoli are all acquiring color, red for the dorsal rows and blue for the lateral rows

4/23:

Larvae are becoming increasingly greener and plumper; the red at the scoli bases is even more evident
The larvae are loosely gregarious still, as they are often feeding on the same leave, but not always
The larvae on alder seemed to be doing better before, but the oldest larva on ceanothus is still the largest by far and looks very healthy

4/22:

The second instar larva are all growing and feeding extremely well; the larger ones are already very plump and green; the base of some of their scoli are already turning reddish, the scoli color in the third instar

4/21:

High temperatures (24 °C afternoon) caused the second instars to grow very rapidly, becoming much larger and greener than before, with swollen, firm thoraxes and more erect scoli; the larva on alder has fed an especially large amount - the tenderness and high water content of the host seems much easier to feed and digest than ceanothus
All larvae have molted into second instar except for two on alder and one on ceanothus

4/20:

the second instars have already begun to fill in their new cuticles again, becoming plumper after just a day; the dorsal side is becoming increasingly greener as well

4/19:

The oldest larva on ceanothus finally molted into second instar after spending 13 days in first instar, a very long time due to low temperatures
The second instar larva is very different from the first instar, being bright greenish yellow all around with reddish black scoli and rows of black spots between the rows of scoli; proportinately, the scoli are much larger and tipped with spikes, the thorax is larger, and the body shape is less flat

Authors
Alan Liang

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Hyalophora euryalus L1 Rearing Notes (4/6/17-4/18/17)

4/18/2017

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Rearing notes for our first instar ceanothus (Hyalophora euryalus) larvae. These are of northern California origin

Rearing Notes 4/6/17-4/18/17:

4/18:

Another two larva on ceanothus entered apolysis and so did one on alder; the larva on alder is clearly larger than the ones on ceanothus and have grown at a faster rate

4/17:

One of the larva on ceanothus entered apolysis (bottom left and middle); the integument is tight and shiny with a yellow undertone; full grown first instar larva length is 9 mm

4/16:

The entire cuticle now has a orangish yellow undertone to it
Larvae were very sluggish and did not feed very much due to the low temperatures today
We placed all the unhatched eggs into the incubator to try to make them hatch sooner assuming they are still alive

4/15:

The largest larvae look almost full grown now; the yellow at the base of the scoli is now orangish
Larvae can be seen aggregating on the leaf above; definitely at least semi-gregarious

4/14:

One of the larva on ceanothus died, perhaps dessication
All the larvae are again noticeably larger than before and are becoming increasingly yellowish

4/13:

The base of the older larvae's scoli are all turning bright yellow due to the second instar scoli forming underneath
Larvae are quite plump now and are probably close to full grown for this instar

4/12:

Larvae are finally beginning to make fast progress now, especially the alder feeders; all are noticeably larger than before and have produced a large amount of frass; the larger ones are beginning to acquire a yellowish undertone which would be the second instar cuticle

4/11:

The larvae on alder are feeding very well, possibly better than the ones on ceanothus; the leaves seem easier to bite as they are thinner an softer
The larvae on ceanothus feed primarily on the edges cut by scissors
Another larva hatched and was placed with the three alder feeders

4/10:

The three newly hatched larvae from yesterday accepted the red alder, making quite a few holes on the edges of the leaf
The larvae on ceanothus are doing quite well now; they have settled down and feed more now, especially on the newer growth

4/9:

None of the three larvae offered willow or plum fed so we moved them onto ceanothus with the others
Three more hatched; this time we gave them a choice of red alder (Alnus rubra) and a different species of willow (maybe Salix lasiolepis); so far it looks like there is a hole on the alder
The larvae seem to be slightly gregarious, though their aggregations could be coincidental

4/8:

Four more hatched today - one in the morning and afternoon, and two in the evening; the first one we put with the older two on ceanothus and the later three we put in a separate dish with a choice of plum and willow
The oldest larva definitely fed some more since yesterday but not sure about the one that hatched yesterday; it still looks the same size as before

4/7:

As thought, the larva settled on the ceanothus and abandoned the willow; it is now resting contently on it and has made a hole on the edge
The day-old larva is already slightly larger and sturdier in stance; the cuticle looks smoother and the thorax looks slightly larger
Another single egg hatched today - weird how they are so off sync (laid on different days?); it indeed looks smaller than the day-old larva which has grown; we offered it a choice of willow and cherry-plum (Prunus cerasifera) but by nighttime it still looked completely uninterested so we moved it onto ceanothus with the other larva

4/6:

See Hyalophora euryalus Egg Hatches

Authors
Alan Liang

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Hyalophora euryalus Egg Hatches

4/6/2017

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One of our ceanothus silkmoth (hyalophora euryalus) eggs has hatched from our batch of 42. These are of northern California origin

We weren't really expecting this, but our Hyalophora euryalus eggs began hatching this afternoon, but only one. Today was extremely cold for this time of year here, with much rain and wind. We thought the low temperature would push back the hatch date for these eggs until next week as most of our other species have been growing very slowly.

Prepared or not, we were still excited about the hatching as this is such an incredible species. The newborn larva is black with pinkish dorsal thoracic scoli and yellow dorsal abdominal scoli. This is the usual dorsal scoli color scheme of euryalus in the early three instars. These dorsal tubercles are all quite large in relation to the larva's body, especially because of their very long tufts of yellowish pink setae. The lateral sets of scoli are undeveloped and look like small black spots and the spiracles are white circles but very small and hard to see. The head capsule is shiny black. Looking at it up close, the larva actually resembles the mature larva of the species quite a bit due to the scoli, but it has a black body rather than a green one.

For food, we went and got some very large leafed cuttings of a ceanothus variety (probably C. griseus) and also a willow leaf to offer the newborn larva. We let it wander on both hosts but it seemed uninterested in feeding on either until dark came, which is typical behavior for most newborn Saturniid larvae.

When we checked late in the night, it had crawled onto the ceanothus and looked pretty content so it will probably settle on it. This is exactly what happened last summer when we offered our newborn euryalus both ceanothus and willow as food choices - the larvae all preferred the ceanothus. This seems a little odd as both seem like very commonly utilized hosts in the wild, so willow should definitely work. We'd probably have to take out the ceanothus and only offer the larva willow for it to settle down on it. Willow seems like a nicer quality and more convenient host for rearing these on, but ceanothus should probably do just fine, so we'll just let this larva be for now. We might try to get some larva on willow when more hatch though.

Authors
Alan Liang

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Hyalophora euryalus Eggs

3/28/2017

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We have received ceanothus silkmoth (Hyalophora euryalus) eggs of northern California origin.

Ah yes, Hyalophora euryalus - the pride of the Pacific coast when it comes to Saturniidae. This large red moth is one of the largest in North America and a close relative to the better known eastern cecropia moth (H. cecropia). We've always wanted to rear and breed this species since we were little. Last summer we managed to get a handful of eggs to try, but since this species is a very disease prone and challenging species to rear, they all died off in the third or fourth instar. Several factors likely caused us to be unsuccessful, the main culprits probably being the lack of airflow due to indoor closed container rearing, and the overly high humidity which we discussed in this post.

Well, this year we have received another batch Hyalophora euryalus eggs and we have high hopes for our second rearing attempt for a number of reasons. First off, we will be rearing the larvae much earlier in the season than last year, about the same time that wild populations would be breeding around here. Thus, weather conditions couldn't be more favorable. Also, these euryalus originated from a local source not too far from our home, and thus they are well adapted to living in our exact climate and area. These two factors alone should hopefully boost our chances at least a bit for this tricky species.

We have also learned from our mistakes in the past, which should definitely help us out this year. Although outdoor sleeve rearing would be ideal, we do not have any hosts on our property so we will probably be forced to rear indoors again this year unless we get a potted host. But, this time we will make sure to give them some good ventilation in their containers by giving this screen lids and possibly putting them by a window. We'll also make sure to keep the humidity down but make sure the food stays fresh. This should minimize the risk of disease. Finally, we might experiment with new hosts this year that the larvae may do better on. Last year we just used the standard ceanothus (Ceanothus) which is extremely common here in California, and is a common wild host for the moth. However, the cuttings wilt quite quickly and the leaves usually get covered in mildew or are in poor quality as the season drags on. Thus, we might try willow (Salix) this year which is also common around here, but unlike ceanothus, will store well when placed in water and always has very vigorous, high quality foliage all season. We might also consider Prunus as it is a good host in general for Hyalophora, but it doesn't seem to be as commonly used by euryalus in the wild as other hosts. If we could find some around here, we could also consider madrone (Arbutus) or manzanita (Arctostaphylos), but we probably won't be able to.

Anyway, here are the eggs below. They are quite large and oval like other Attacini eggs. The ground color is a tannish off-white mottled messily in brown, probably both as a pattern of the shell and from the adhesive secreted by the moth. Interestingly, they don't look quite the same as the ones from last year, which had a darker ground color, were a more purplish shade of brown, and had less messy, crisper mottling. It is likely due to the differences in the strains' geographical origins.

Authors
Alan Liang

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End of Euryalus & Future Plans

8/7/2016

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Alas, our final Ceanothus caterpillar passed away today, ending our Ceanothus brood this year that began on 6/10. Here we discuss some of the hardships with this species and future plans regarding the rearing of this species.

Today, with disappointment but little surprise, we found the last third instar Ceanothus caterpillar limp on the bottom of the rearing sleeve. It had been feeding yesterday, but it seems there was never any hope left for it from the start and death was to be expected sooner or later. It has been in the third instar ever since the onset of the disease which broke out in 6/28, so clearly there has been something drastically wrong with it as well as the other "growth-less" caterpillars, because it should have molted into fourth instar a month ago.

Rearing this species has been very rough over the months, struggling endlessly with the disease that broke out on 6/28 just as they were beginning to molt in third instar. We took painstaking measures in order to save them -- from isolating each caterpillar, to transferring them onto cuttings outside of closed containers, and finally moving them onto a live plant outdoors, but nothing had any affect. One by one, every caterpillar fell dead, most very clearly from disease, while others for no apparent reason. Finally, the last caterpillar dropped (below), marking the end of our Ceanothus brood which began on 6/10 and ended 8/7 (today).

Though we had a very rough time with this species this year, we are still considering trying this species again next year if offered again on the Insect Classifieds. If we do, then we will rear them at a lower humidity than we did this year, rearing the first and possibly second instars in petri dishes and transferring them onto the live Ceanothus plant for later instars which should minimize risk for disease. Alternatively, we could try a different host plant such as willow (Salix) which might give different (hopefully better) results. Anyways, we are still hopeful that we will someday rear this species successfully and are not discouraged with our failure this year since according to several hobbyists, the Hyalophoras are very disease prone, often dying out in the third or first instar, and are a hit and miss species to rear even for the experienced. Thus, in retrospect, it was not extremely surprising that we failed to raise them as this was our first time with this species.

- Alan

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H. euryalus Rearing Notes (7/8/16-8/7/16)

8/2/2016

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Rearing notes for our fourth instar Ceanothus caterpillars (Hyalophora euryalus) from 7/8/16-8/2/16. These were purchased as eggs from a Pennsylvania breeder and reared indoors on Ceanothus (Ceanothus) cuttings.

Rearing Notes 7/8/16-8/2/16:

8/2:

The smaller of the two remaining third instars died the seemingly same way as all the others that died outside; it became weak and dropped off the plant, but with no vomit or diarrhea
Count: L3: 1; dead: 23 (1 missing, 16 disease, 1 squashed, 5 unknown)

7/28:

Haven't posted hear for a while, but yes, the two third instar euryalus are still hanging on there and are still eating a little (but seriously though, they've been in third instar for a month now and aren't getting much larger)
Count: L3: 2; dead: 22 (1 missing, 16 disease, 1 squashed, 4 unknown)

7/16:

The remaining two third instars (surprising) still look fine and are eating normally
Count: L3: 2; dead: 22 (1 missing, 16 disease, 1 squashed, 4 unknown)

7/15:

The remaining fourth instar died today with no apparent reason just like all the rest that died after transfering to the live Ceanothus plant
There just doesn't seem to be any hope left with this species this year with just two individuals remaining, though we may try it again next year
Count: L4: 0; L3: 2; dead: 22 (1 missing, 16 disease, 1 squashed, 4 unknown)

7/14:

Moving the plant to a shadier location did not help -- the second instar died today, o it is likely not desiccation but it doesn't look quite like disease either since the caterpillar simply dropped off the plant and became limp with no vomit or diarrhea
Count: L4: 1; L3: 2; dead: 21 (1 missing, 16 disease, 1 squashed, 3 unknown)

7/13:

Count: L4: 1; L3: 2; L2: 0; dead: 21 (1 missing, 16 disease, 1 squashed, 3 unknown)

7/12:

We are completely baffled and crushed -- the older fourth instar died today along with another seemingly healthy third instar -- either the live plant outdoors hasn't helped with the disease problem, or is this unrelated?; so far we aren't quite sure because the two deaths don't look quite like a disease death since there was no diarrhea or vomit, albeit they lost their appetites; perhaps it was simply desiccation this time due to being outdoors, so we moved the plant to a shady location
Count: L4: 1; L3: 2; L2: 1; dead: 20 (1 missing, 16 disease, 1 squashed, 2 unknown)

7/11:

The third instar in apolysis ecdysed into fourth instar today (shown above), but teh otehr fourth instar just doesn't seem to be doing very well -- it still doesn't eat very much and keeps wandering around the side of the sleeve
Count: L4: 2; L3+: 0; L3: 3; L2: 1; dead: 18 (1 missing, 16 disease, 1 squashed); suspected sick: 2

7/10:

The fourth instar still looks healthy, but it doesn't seem to have eaten very much since yesterday which is quite unsettling -- hopefully is does not go like the many others that have
Count: L4: 1; L3+: 1; L3: 3; L2: 1; dead: 18 (1 missing, 16 disease, 1 squashed)

7/9:

Another third instar entered apolysis today, which is very good news; hopefully it and the other fourth instar will remain healthy
Count: L4: 1; L3+: 1; L3: 3; L2: 1; dead: 18 (1 missing, 16 disease, 1 squashed); suspected sick: 0

7/8:

We transferred all the remaining few healthy caterpillars onto the live ceanothus plant and sleeved them; hopefully the disease problem will end!
The fourth instar is till looking good so far (shown above)
Count: L4: 1; L3+: 1; L3: 3; L2: 1; dead: 18 (1 missing, 16 disease, 1 squashed); suspected sick: 0

- Alan

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First Ceanothus Caterpillar Ecdyses into Fourth Instar

7/7/2016

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Our oldest third instar Ceanothus caterpillar (Hyalophora euryalus) has ecdysed into fourth instar.

This afternoon at around 5:30 PM, the third instar Ceanothus caterpillar that entered apolysis on 7/5 began ecdysing into fourth instar and we took several time lapse photos as shown below with the time labeled.

Dorsal view:

Lateral view:

After ecdysing and tanning, a very apparent difference can be seen between the fourth and third instar. First, all the dorsal red tubercles have turned yellow and are more elongated but slimmer. They are also smoother, with only a few black spikes at the tip. The lateral blue tubercles are now paler and tipped with white. Also, there is now a black ring at the base of the six large yellow dorsal and middorsal tubercles on T2, T3, and A8 as well as on all the lateral blue tubercles. There is also now a white ring around the spircles. The body color is much more yellow green now rather than turquoise green. At around 9:00, the caterpillar began eating its exuviae, shown below.

On another note, it is interesting to compare how different the Ceanothus caterpillar's body shape and tubercles are from the Cecropia's caterpillars now. Below are pictures of the newly molted fourth instar Ceanothus caterpillar next to a newly molted fourth instar Cecropia caterpillar. The Ceanothus tubercles are much less pronounced and are rod-shaped, with a slight taper down the base. On the other hand, the Cecropia tubercles are much larger and more knob-shaped and are somewhat spherical at the top. The main difference in body shape is in the thorax between the two species. The Ceanothus thorax, when viewed laterally, is swollen and is bent at a defined angle at each of the large dorsal tubercles while the Cecropia thorax is a smooth curve. Also, the cross sections of the Ceanothus body in general are slightly angled at each tubercle (especially at the thorax), creating a very subtle octagonal prism body shape while the Cecropia is less so, having a more cylindrical body shape. Size-wise, the two species are still quite close, but the Ceanothus seems just slightly slimmer, though their head capsule are about the same size.

Also, since we are still struggling to deal with the disease, we decided the best option for us now is to purchase a live Ceanothus plant. Thus, we did so tonight and bought a decently sized Ceanothus griseus horizontalis plant. Once we make some small sleeves, we will put all the remaining healthy caterpillars on it and place the plant outside. Also, since we are unsure about pesticides, we placed the healthy second instar on it as a "lab rat" for now.

Today marks the end of third instar for the oldest caterpillar that lasted for approximately 8 days and 20 hours from 6/28-7/7. Second instar lasted for approximately 5 days and 8 hours from 6/23-6/28 and first instar for the oldest Ceanothus caterpillar lasted for approximately 5 days and 2 hours from 6/18-6/23.

Count: L4: 1; L3+: 0; L3: 8; L2: 1; dead: 14 (1 missing, 12 disease, 1 squashed); suspected sick: 1

- Alan

Comments

H. euryalus L3 Rearing Notes (6/29/16-7/6/16)

7/6/2016

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Rearing notes for our third instar Ceanothus caterpillars (Hyalophora euryalus) from 6/29/16-7/6/16. These were purchased as eggs from a Pennsylvania breeder and reared indoors on Ceanothus (Ceanothus) cuttings.

Rearing Notes 6/29/16-7/6/16:

7/6:

The caterpillar that entered apolysis yesterday still hasn't molted yet, but the head capsule is more displaced and translucent
Count: L3 +: 1; L3: 8; L2+: 0; L2: 1; dead: 14 (1 missing, 12 disease, 1 squashed); suspected sick: 1

7/5:

The largest caterpillar is now far ahead of the remaining caterpillars -- it entered apolysis today as shown above; the tubercles are swollen at the base and are yellow at the base for the dorsal red ones and whitish blue at the base for the blue lateral ones, the colors that they will be next instar
There are very few caterpillars left which is incredibly sad; at this point, we are literally just hoping the oldest caterpillar will make it to adulthood
Count: L3+: 1; L3: 7; L2+: 1; L2: 1; dead: 14 (1 missing, 12 disease, 1 squashed); suspected sick: 0

7/4:

Today has been a very disappointing and upsetting day; many more died today despite the removal of air tight containers -- they just became weak and dropped off the plant with either diarrhea or vomit; to make matters worse, one of the few presumably healthy caterpillars left the cutting (perhaps sick now) and went missing until we found it squashed
Mixed in some Ceanothus thyrsiflorus "Snow Flurry" variety from a residential house into the cuttings because the leaves are of better quality
Count: L3: 10; L2+: 1; L2: 1; dead: 12 (1 missing, 10 disease, 1 squashed); suspected sick: 3

7/3:

No more dead caterpillars, but more are starting to look sick which is bafling since they are now on cuttings with now container
The largest caterpillar (shown above) seems to be pulling much farther ahead of the others and is still very healthy looking (thankfully!)
Count: L3: 15; L2+: 1; L2: 1; dead: 7 (1 missing, 6 disease); suspected sick: 4

7/2:

After a day in the separated containers, the disease problem doesn't seem to be improving; today we went out to get a whole bunch of Ceanothus cuttings (thyrsiflorus this time, actually, because their branches are leafier), stuck each one in either a water tuber or bottle and placed one caterpillar on each cutting; by taking them out of the air tight containers, there is lower humidity and high ventilation which should hopefully stop the disease from spreading
Count: L3: 14; L2+: 1; L2: 2; dead: 7 (1 missing, 6 disease); suspected sick: 3

7/1:

The oldest third instar's tubercles are starting to look red, not orange, and is getting quite large
Because the disease problem seems to be getting worse, we painstaking bought several more sterile containers, got some plastic containers, and divided up all the remaining caterpillars according based on their perceived health: six confidently healthy caterpillars- one each in six plastic containers, two suspected sick caterpillars- one each in their old plastic tubs, eight caterpillars of unknown health- one each in six platic containers and two each in two plastic containers
Count: L3: 12; L2+: 4; L2: 2; dead: 6 (1 missing, 5 disease); suspected sick: 2

6/30:

Many more molted into third instars today; the two day old ones are starting to get much larger and the tubercles seem to be darker than before and the dorsal side is much bluer
Count: L3: 12; L2+: 2; L2: 6; dead: 4 (1 missing, 3 disease); suspected sick: 0

6/29:

The third instar caterpillars are still feeding healthily
So far, it only looks like one more sick individual
Count: L3: 5; L2+: 6; L2: 12; dead: 3 (1 missing, 2 disease); suspected sick: 1

- Alan

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Devastating Disease Outbreak in Ceanothus and Cecropia Caterpillars

6/28/2016

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Today when we checked on our Ceanothus (Hyalophora euryalus) and Cecropia (Hyalophora cecropia) caterpillars, we were absolutely devastated to discover that several caterpillars from both species appeared to be sick with a disease, the first major caterpillar disease outbreak we have had in years.

For the past few weeks up until now, both our Cecropia and Ceanothus caterpillars looked healthy and strong, with only three accidental deaths since hatching. The Cecropias are just now molting into fourth instar while the Ceanothus are now molting in third; so far, so good. However, today when we checked on them in the morning, we found two Ceanothus caterpillars dead and a very sick looking Cecropia caterpillar as there was no evidence of feeding from it (no hole in the leaf in its immediate vicinity) and its body looked limp and weak. In addition, several other Cecropia and maybe a few Ceanothus caterpillars didn't seem quite right either and seemed to have eaten less than usual.

We quickly removed all sick looking individuals from their containers and disinfected all six Ceanothus containers and the Cecropia container that contained the sick individual with bleach. We then gave all the healthy looking Ceanothus caterpillars new leaves and made sure to wear a new set of gloves for each container to minimize cross contamination. For the sick individuals, we put them each in a different plastic cup with a petri dish lid and gave them a fresh leaf, though it is unlikely they will eat it.

We are now very worried for both our Ceanothus and Cecropia caterpillars because we had small cultures of both to begin with (36 Cecropias and 24 Ceanothus), and we can not obtain more of either of them in the wild here in Albany. For years we have never had a serious disease problem with our caterpillars, except for the year of 2013 with the Anise Swallowtail caterpillars.

To admit, however, over the years we have primarily reared butterfly species and only dabbled with Saturniidae because there are very few species from this family hear in Albany (and Western North America in general; the vast majority reside in Eastern North America), and the few species that are apparently here are rare. Thus, this disease outbreak is likely a result of our inexperience with rearing Saturniidae species. Most guides for rearing Saturniidae recommend sleaving tree branches for outdoor rearing or closed (air-tight) containers for indoor rearing. As we do not have Ceanothus caterpillar host plants in our yard and were afraid that outdoor rearing would dehydrate the Cecropia caterpillars because the California summer climate is much drier than most of their natural range, we chose indoor rearing for both species. However, indoor rearing has a much higher risk of disease than outdoor rearing, especially with air-tight containers because there is no ventilation. The purpose of closed containers is to keep the humidity high so that the caterpillars won't desiccate, but this sacrifices ventilation and increases the chance for disease greatly (high humidity + no ventilation = perfect environment for pathogens). We are almost certain that these factors played at least some part in creating the disease outbreak, and air-tight containers was our biggest mistake. Nothing else could have played a very significant role in instigating disease because the food was always kept very fresh (water tubes and changed everyday), and the frass was changed everyday which should be adequate enough in maintaining good sanitation. We do not even know if the disease started in the Ceanothus caterpillars or the Cecropias, or if the two outbreaks are even related, but we suspect it began with the Ceanothus since two were already dead when we checked compared to one sick Cecropia. Also, Ceanothus caterpillars are native to California which has a much drier summer climate than the habitat of most other Saturniids, so an air-tight container with high humidity may have been a serious mistake (we did not know if this was the right thing to do because there's almost no information out there at all on rearing this specific species). Species that normally reside in drier environments generally would have the highest disease risk in a humid one because they are not accustomed to it.

In either case, we have learned our lesson now and will try to get all the healthy Cecropias onto live host plants as soon as we figure out how to create rearing sleaves from mesh screening. For the Ceanothus we might consider buying a live plant from a nursery or simply take them out of the closed containers and raise them on cuttings in the open room.

Update: Here of some pictures of the sick caterpillars that eventually died on 6/30. The left shows a third instar Cecropia caterpillar in apolysis that turned brown and flaccid, unable to carry through with its molt. The right photo is of a second instar Ceanothus caterpillar that lost its appetite and eventually shriveled up and died in a pool of orange-brown fluid. Several other caterpillars have died since as will.

- Alan

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