Rearing notes for our Mournful Duskywing (Erynnis tristis) caterpillars and pupae. They were originally found as eggs laid on the fresh shoots of Coast Live Oak (Quercus agrifolia) and reared indoors on an unidentified species of oak; the first pupated on 9/21/16.
Rearing Notes 9/22/16-10/??/16:
Our first Mournful Duskywing caterpillar (Erynnis tristis) has pupated.
Two days ago, our first Mournful Duskywing caterpillar built a loose silken cocoon in the oak leaves and became a stubby prepupa. Yesterday, it became even stubbier and its head capsule became dull and gray. Today, it turned into a shiny turquoise pupa. The pupa is directly inside the leaf shelter with its cremaster stuck to the end and its head poking out at the opening. The pupa is very glossy like monarch pupae, but the dorsal side of the abdomen is slightly hairy. The shape of the pupa is quite slender, with a heavily tapered abdomen, but the head, especially the eyes, are very large. It was a bright green when teneral but dulled into a pale turquoise, with the abdomen slightly yellowish in hue and parts of the thoracic outlines black. There are also two black spots on the dorsal side of the thorax. When disturbed or turned so that the ventral side facing up, it wriggles around and turns so that its dorsal side it facing up.
As for the other caterpillars, one of the fifth instars has become a prepupa and the other one looks quite close as well. Soon we'll have three pupae and four once the supernumerary sixth instar pupates as well. We're not sure whether these will diapause or not, though they probably should since its already fall. We'll just have to wait and see after a few weeks.
Rearing notes for our fifth instar Mournful Duskywing (Erynnis tristis) caterpillars. They were originally found as eggs laid on the fresh shoots of Coast Live Oak (Quercus agrifolia) and reared indoors on leaves picked from the same tree as well as an unidentified species of oak.
Rearing Notes 9/3/16-9/21/16:
Rearing notes for our fourth instar Mournful Duskywing (Erynnis tristis) caterpillars. They were originally found as eggs laid on the fresh shoots of Coast Live Oak (Quercus agrifolia) and reared indoors on leaves picked from the same tree as well as an unidentified species of oak.
Rearing Notes 8/21/16-9/??/16:
Rearing notes for our third instar Mournful Duskywing (Erynnis tristis) caterpillars. They were originally found as eggs laid on the fresh shoots of Coast Live Oak (Quercus agrifolia) and reared indoors on leaves picked from the same tree as well as an unidentified species of oak.
Rearing Notes 8/14/16-8/20/16:
Rearing notes for our second instar Mournful Duskywing (Erynnis tristis) caterpillars. They were originally found as eggs laid on the fresh shoots of Coast Live Oak (Quercus agrifolia) and reared indoors on leaves from the same tree as well as an unidentified species of oak.
Rearing Notes 8/10/16-8/13/16:
Rearing notes for our first instar Mournful Duskywing (Erynnis tristis) caterpillars. They were originally found as eggs laid on the fresh shoots of Coast Live Oak (Quercus agrifolia) and reared indoors on an unidentified species of oak.
Rearing Notes 8/4/16-8/9/16:
One of the seven yellow eggs we found on the fresh shoots on Coast Live Oak (Quercus agrifolia) that we believe are a species of Duskywing skippers (Erynnis) has hatched.
On 7/30, we went out to Albany Hill and found seven yellow eggs laid on the fresh shoots of Coast Live Oak (Quercus agrifolia) that we suspected were a species of Duskywing skippers (Erynnis), either the Propertius Duskywing (E. propertius) or the Mournful Duskywing (E. tristis). The day after we found the eggs, there was clearly development on all the eggs, except for a blaskish one that looked dead. The yellow had deepened to a yellow-orange, as seen below.
Today, four days after we found the eggs, one of them hatched. The pictures below are rather unfocused since the caterpillar is so small, but you can see that it is a grayish-orange color with a large orange head capsule, and it indeed looks like a Duskywing species.
Since obtaining fresh shoots of Q. agrifolia is several minutes walk away, we instead offered it a fresh shoot of an unidentified Oak variety right across our house.
We found a couple of nice looking eggs on Coast Live Oak (Quercus agrifolia) today at Albany Hill, but are having a hard time identifying them! So far we suspect a duskywing species (Erynnis), but there are several in our region that specialize on oaks.
Albany Hill is, without a question, Albany California's greatest landmark for wildlife. After all, the rest of the city is suburban; and yet, we have only investigated the place a few times since it is far from where we live. The few times that we have been there, we were collecting Western Tiger Swallowtails (Papilio rutulus). On those trips, we encountered several other lepidopteran species (well, butterflies since we have always gone in the day) such as the Common Buckeye (Junonia coenia), Monarch (Danaus plexippus), Mourning Cloak (Nymphalis antiopa), Red Admiral (Vanessa atalanta) and other Vanessas, Cabbage White (Pieris rapae), Umber Skipper (Poanes melane), Fiery Skipper (Hylephila phyleus), among quite a few other smaller butterflies (mostly nymphalids and lycaenids).
Today, we decided to venture back to Albany Hill not with any of these particular species in mind; we would simply catch whatever we thought would be worth catching. Like many summer days in the East Bay, today was quite cool and cloudy, with the temperature in the mid 60's and humidity around 50% when we went out around 2 PM. This was not at all good weather to hunt for butterflies since most such diurnal insects are programmed to roost when day time weather is unfavorable like this, but there was a hint of sunlight earlier so we took our chances. When we arrived, we could not see a single flying insect in sight -- not one butterfly or even a damselfly which we saw dozens of on the other trips. It was a bad call.
Nonetheless, we stayed around just in case we should see something. We found a Monarch roosting in a tree that darted out when we came by because me must have startled it. We also caught a Fiery Skipper that we immediately released because we have no use of such a species. We actually spent the bulk of our stay investigating the vegetation for eggs or caterpillars. Since the part of Albany Hill we were at was bordering Cerrito Creek, it was an excellent riparian area dense with willow (Salix), a host of a ridiculous number of lepidopterans in our region including a few of those that we have encountered at the hill. Mixed in were also a lot of evergreen coast live oaks (Quercus agrifolia), a much less popular host due to its divergence from its deciduous relatives (the foliage of many evergreen species, such as coast live oak, have evolved to be heavily defended against damage). None of the species we have encountered utilize it.
As we were searching, we found a single very young oak tree growing on the creek bed. It was a small tree and was actually putting on a substantial amount of new growth for this time during the season probably because the creek provided the necessary water (none of the trees growing away from the creek had any new growth whatsoever). There were several new, dark pink shoot tips. But that was not what initially interested in this plant; when we had first stepped upon it, we noticed a few fungal growths that we originally mistook for eggs (alas!). These fungal growths were more or less spherical, had a slight mottled appearance, could be easily detached from the leaf, and closely resembled some kind of Saturniid ova. However, when we looked closer, we realized that they could not possibly be eggs because they came in all different sizes, presumably because the smaller ones grow into the larger ones. Moreover, breaking them open did not yield any distinct egg shell or yolk piece at all; it was the same material all the way through the entire structure and it felt slightly rubbery rather than containing fluid.
As we were investigating these fungal growths, however, we noticed a bright yellow dot, conspicuously located on one of the pink new growths which would become the highlight of this trip. This time, it really was an egg, presumably lepidopteran. It was about the size of aVanessa egg, very spherical, and ribbed (shown below). Upon closer examination, we collected four more eggs, laid exclusively on the tender leaves of the new shoot tips. When we were leaving Albany Hill, we noticed another, much larger oak tree on the other side of the creek that was also putting on new growth and discovered two other eggs. One was blackened on one side and may be dead while the other one is a dark orange and is likely in a later developmental stage than the other bright yellow ones.
As discussed above, the evergreen coast live oak is a terrible host plant for most insects and it was the last tree at Albany Hill that we expected to find any eggs on. To defend against herbivory, this particular variety has incredibly tough and dry leaves adorned with spikes and seems quite indigestible. No wonder whatever laid the eggs has a preference for the tender new growths!
Upon returning, we flipped through our Lepidoptera field guides and did some quick internet searches to identify the eggs. Statistically speaking, most Lepidoptera found in the wild are moths as they constitute the majority of the order, but in this case we suspect a butterfly because the eggs were laid singly and strictly on new outer growing shoots which just doesn't seem very moth like (moths tend to be much more careless about where they lay eggs). So, we first looked at true butterflies (Papilionoidea), and the only few species in our region that specialize on oak are the California Sister (Adelpha californica) and a few random hairstreaks (Lycaenidae). However, we have never seen any California Sisters on any of our trips to Albany Hill and their eggs barely resemble ours, and the hairstreaks are far too small to lay eggs the size of ours and their eggs don't resemble ours anyhow. So, next we moved on the skippers (Hesperioidea), and we quickly found two likely candidates in the Erynnis genus (Duskywings): the Propertius Duskywing (E. propertius) and the Mournful Duskywing (E. tristis). They are very similar species that both commonly utilize live oaks and lay their eggs on the newest shoots. A few quick internet searches showed us eggs that look very similar to ours, though it is difficult to say for sure because they're so small are hard to see. Anyways, for now our best bet is that the eggs are that one of these two Duskywing species, though if they really are we probably won't be able to tell which one it is until they are adults.
- Alan, Brian
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)