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:
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:
Rearing notes for our first instar ceanothus (Hyalophora euryalus) larvae. These are of northern California origin
Rearing Notes 4/6/17-4/18/17:
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.
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.
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.
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:
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.
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
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:
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.
This timeline is a series of daily posts recording our observations on and experiences with various insects in Albany California and surrounding areas, from 2012-2017. Since we did not publish this site until 2016, posts before that were constructed retroactively. Starting in August 2017, we moved to Ithaca, New York; posts from there on can be viewed at Timeline 2017-present: Ithaca, New York.
August 2017 (49)
July 2017 (121)
June 2017 (79)
May 2017 (77)
April 2017 (91)
March 2017 (35)
February 2017 (12)
January 2017 (10)
December 2016 (12)
November 2016 (26)
October 2016 (49)
September 2016 (84)
August 2016 (94)
July 2016 (99)
June 2016 (53)
May 2016 (21)
April 2016 (4)
January 2016 (1)
August 2015 (3)
July 2015 (3)
June 2015 (2)
June 2014 (3)
May 2014 (1)
April 2014 (3)
March 2014 (3)
December 2013 (2)
November 2013 (2)
October 2013 (5)
September 2013 (11)
August 2013 (15)
July 2013 (9)
June 2013 (5)
May 2013 (4)
April 2013 (3)
March 2013 (2)
February 2013 (3)
January 2013 (2)
December 2012 (2)
November 2012 (1)
October 2012 (2)
September 2012 (2)
August 2012 (5)
July 2012 (1)
June 2012 (1)
Full Species List
(Alphabetical by scientific name)
- Not every species we encounter is necessarily presented on this site, rather a selection of those that were of particular interest to us and that we felt were worth documenting.
- We can't guarantee that all species have been identified accurately, particularly taxa we are not as familiar with.
Battus philenor hirsuta
Coenonympha tullia california
Langia zenzeroides formosana
Orthosia hibisci quenquefasciata
Papilio machaon oregonius
Papilio polyxenes asterius
Samia cynthia advena
Papilio glaucus × Papilio rutulus
Papilio polyxenes asterius × Papilio zelicaon
Araneae (Class: Arachnida)