Today we found two gray hairstreak (Strymon melinus) eggs on mallow (Malva) at Albany Hill (Albany, California).

Along with the common checkerspot skippers (Pyrgus communis), west coast lady's (Vanessa annabella), the gray hairstreaks (Strymon melinus) get easy to find on mallows (Malva) late in the summer and into the fall. We found two of their eggs today on mallow at Albany Hill. They are hard to differentiate from the checkerspot eggs at first glance, but they are flatter and greenish. They also tend to be laid in slightly more obscure places such as on the buds like one of the eggs we found. The other was on the underside of a leaf -- also typical.

We found mating umber skippers (Poanes melane), common checkerspot skippers (Pyrgus communis) and gray hairstreaks (Strymon melinus) at Albany Hill (Albany, California). 

Once it hits summertime, we get all kinds of these common little prairie butterflies. Umber skippers (Poanes melane) are the most common skipper and gray hairstreaks (Strymon melinus) are the most common hairstreaks and we have been seeing many of them at Albany Hill these days. In fact, we witnessed two umber skippers in copula, the only ever natural butterfly pairing we have ever observed besides monarchs (Danaus plexippus). They must male must have been "done" by the time we got there because they separately promptly after taking the photograph.

​We also spotted some common checkerspot skippers (Pyrgus communis) two days ago, which, despite its name isn't actually that common here. Like the gray hairstreaks, it is a mallow (Malva) feeder which is where we discovered them. They were quite likely females looking to oviposit, but from a brief glance we couldn't find any eggs. Later in the season (August to September), however, they should be very easy to find. Alas, we would be in Ithaca by then. 

Rearing notes 10/10/16-10/13/16:

- Brian

- Brian

​Rearing notes 9/24/16-10/1/16:

- Brian

After finding over a hundred West Coast Lady (Vanessa annabella) eggs and a handful of Gray Hairstreak (Strymon melinus) eggs on wild mallow (Malva) this year we have gathered some knowledge on the ovipositing preferences of the adult female.

Egg and to some extent caterpillar hunting on low, weedy (herbaceous) plants is all about getting to know the ovipositing preferences of the adult. Even species that lay eggs on the same type of plant may have different preferences for where they lay. 

Over the past month, we have been collecting tons of West Coast Lady (Vanessa annabella) eggs as the fall influx of adult butterflies starts to really heat up as they pass through on their annual attitudinal migration. After locating over a hundred eggs on well over a dozen wild mallow (Malva) plants at five or so unique locations from Berkeley through El Cerrito, we have certainly gotten a better idea of the ovipositing preferences of V. annabella that we would like to share.

First off, V. annabella strongly adheres to the isolated plant technique. The chance of finding eggs in a patch of  mallow plants of over two square feet is low. In addition, wild mallow plants have different growth forms: some are very low (flat) on the ground growing out in a circular fashion where the leaves are very dense while others are much more branchy and tall; the latter is much more preferred. However, unlike the Anise Swallowtail (Papilio zelicaon), the number of eggs laid to the size of the plant is somewhat linear; relatively larger plants consistently get more eggs than relatively smaller ones. Rarely will a tiny plant be clobbered in a significant amount more eggs than it can reasonably handle and rarely will a larger plant that does have eggs only have a single one or two. 

Concerning the new growth technique, or the seasonal health of the host plant, V. annabella seems to have little preference. Eggs can be found on mallow plants of any life cycle stage (regardless sprouting/regenerating or flowering with mature seeds). Eggs are laid on any leaf, fresh or not. Each time we review our harvest, we see no pattern in the size of the leaves (larger leaves tend to be either mature or those from fresher, healthier plants in the shade and smaller leaves tend to be either new leaves or those from plants growing in full sun). The only thing that we have noticed that should be taken note of is that they tend to avoid plants that appear to be trampled on or very damaged. Because mallow is a weed that usually grows on the edges of dry grasses (like on the side of a lawn, near the sidewalk or the road, or at the end of a driveway), depending on the location of the plant, it may receive routine pounding by human feet or vehicular bashing. The weedy plants are designed to withstand quite a bit and will not easily die, but the leaves and stems will suffer damage that seems to render the plant unattractive. At the same time, plants growing in awkward locations are usually those that are more difficult to spot by the butterfly and/or less suitable for the butterfly to be to oviposit. (Not to mention, even if eggs were laid on these types of plants, they would probably be crushed or lost after being trampled on anyway!). 

V. annabella does not seem to have a very significant preference for sunny or open locations. The sun certainly might help to increase activity, but is not a requirement. One of our best plants was growing under the BART tracks where it is shaded 24/7. 

The location preferences of the Gray Hairstreak (Strymon melinus), a Malvaceae feeding species that we have been finding quite a number of eggs from this past week alongside V. annabella,  differ in some ways. Eggs are commonly found on or near buds or on stems as well as leaves (usually newer ones). They are almost always laid close to the periphery of the substrate rather there near the center. In that sense, they are more difficult to find than V. annabella eggs. Today we actually witnessed a S. melinus adult ovipositing on wild mallow. Her behavior might help to explain this: she landed on a shoot tip (part with buds and flowers) and walked up and down the stem several times while laying without flying. S. melinus eggs are virtually always laid singly.

On a side note, we also witnessed a S. melinus adult ovipositing on ornamental hibiscus, another introduced host in the mallow family.

S. melinus overall seems to be less picky than V. annabella about the specific plant.

But unlike V. annabella who may lay up to 20-30 eggs at once, a larger plant rarely means more eggs. The adult female tends to only lay a few eggs per plant at a time.  

The newborn and young caterpillar of V. annabella can be easily located using the egg locating strategies since they do not move far from their birth place. The newborn does not finish eating its egg shell after hatching and goes straight away to making its silken nest where it sits such that it inadvertently incorporates the egg shell (shown below)! S. melinus, on the other hand, is tougher. We have seen mallow plants smothered in hatched S. melinus eggs (the newborns also do not eat their egg shells) but not a caterpillar in sight. When we have found low instar caterpillars, they are usually on the undersides of the plant, on stems or immature seed pods (sometimes inside and eating it!).  ​

- Brian

The first installment of rearing notes for the Gray Hairstreak (Strymon melinus) eggs and caterpillars that we found on wild mallow (Malva) from 9/8-9/15. 

Rearing notes 9/8/16-9/15/16:

9/8:​

- Brian

Today we were quite disappointed to find that our newly molted Gray Hairstreak (Strymon melinus) chrysalises was being eaten by a fifth instar conspecific!

The family Lycaenidae is quite famous for the relationship its caterpillars have with ants. Most species produce honeydew to attract and appease ants who may inadvertantly act to protect the larvae by warding of insect predators and parasitoids. Honeydew is comprised of a combination of sugars (glucose, fructose, and sucrose) and amino acids in set ratios that may only attract a specific species of ant. The larvae is protected from the ants themselves (who may normally bite at or attack caterpillars) through the evolution of a unique body form: a tiny head and legs that can be retracted underneath the short and stout body, the slug-like gliding movement while in retracted, extremely thick exoskeleton (sometimes chitinized!), and in some cases appeasing pheromones or sounds. 

In quite a few species, larvae are carnivorous (an highly cannibalistic) such as those that use honeydew to get ants to carry them into their nests. Once inside the nest, larvae start attacking ant grubs. It is not difficult, then, to see why lycaenid caterpillars are notoriously cannibalistic in the lab, when housed together. 

The lycaenid Strymon melinus, the Gray Hairstreak, is part of a group that is not so aggressive; they are certainly not carnivorous by choice. The ant-larvae relationship, as far as we know, is not quite so extreme. The two fourth instars that we collected on mallow (Malva) ate foliage like normal caterpillars and did not behave aggressively towards each other. The newborns, living in the same petri dish, have not eaten each other yet (at least we think!). 

The scary part of the story unfolded today when we discovered a fourth instar rolled up around and feeding on a chrysalis that pupated today, both of which were confined in a small petri dish with a very dry leaf of mallow that was probably unappetizing. The opportunistic caterpillar clearly took advantage of the soft, teneral chrysalis and bit a huge hole at the thorax which was spewing an ungodly amount of blood when we arrived on the scene. Seeing this, we quickly made the decision to remove the other fourth instar inside the dish which had turned brown yesterday (is going to pupate) out to a dish of its own. 

- Brian

We have been finding what appear to be two kinds of eggs on wild mallow (Malva). At least one species involved is the Gray hairstreak (Strymon melinus); the other species could be the Common Checkered skipper (Pyrgus communis).

On 9/8, we found a fourth instar (mature) Gray hairstreak (Strymon melinus) caterpillar on wild mallow (Malva) in El Cerrito, CA. When we examined the particular plant more closely, we quickly realized that there were a series of eggs laid among it just by a glance. Most of them were already hatched with an obvious hole in the top where the caterpillar had exited, but we still managed to collect three fresh ones. We have found plenty of West Coast Lady (Vanessa annabella) caterpillars and eggs on mallow, their most preferred host plant in our region, which are easily recognizable, green, typical true nymphalid (Nymphalinae) shaped eggs and these were clearly not that. 

What we initially assumed was that all of these new eggs were those of the Gray hairstreak since we had found the caterpillar. Gray hairstreaks are extremely common in our area (as well as elsewhere!) and we often see them around so it wasn't a big surprise that they are breeding here. However, upon taking a few photos of the eggs (yes, the quality of the photos isn't too great because our cheap camera has its limitations) two of the three (mystery egg 2) did not appear to resemble hairstreak (lycaenid) eggs exactly though they looked extremely similar. After quite a long time of investigating, we came to the conclusion that there were actually two different kinds of eggs.

On 9/9, we collected three more fresh eggs, laid at a different location in Berkeley, CA, over a mile away from the ones that we found on 9/8. We have never monitored this site for butterflies. After taking a picture of these eggs, we again concluded that there were two different kinds of eggs (probably that same as the two kinds we found before, respectively). Unfortunately, we lost one of the eggs we found on 9/8 so we were down five eggs. 

Mystery egg 1 is relatively flat, with a small greenish indent in the center; in our opinion, it looks like a fairly typical hairstreak (lycaenid) egg. They do not seem to be very firmly attached to the substrate. Mystery egg 2 is more spherical and has very obvious ridges, evident even in our poorly taken photos. They are more whitish or yellow in color. The eggs are about the same size as far as we can tell.

Today (9/10), one of the eggs that we found had hatched into what appears to be a Gray hairstreak. It is difficult to say for certain what kind of egg it came out of because there is a hole in it now and the details are vague but we think it was probably mystery egg 1, especially since mystery egg 1 looked more like a hairstreak egg. Coincidentally, while picking mallow leaves, we found another newborn Gray hairstreak without even knowing. We could not locate the hatched egg shell that this one came from. We also found five more eggs. 

Because one of the two kinds of eggs has been confirmed to be that of the Gray hairstreak, the trouble now is figuring out the what else we have. Assuming that the newborn hatched out of mystery egg 1, our best guess for mystery egg 2 would be that of a skipper (Hesperiidae). Skipper eggs are typically spherical with the vertical ridges. 

What really increased our suspicions today was that while we were looking for the eggs, we discovered Common Checkered skippers (Pyrgus communis) around the mallow. In fact, we even had the opportunity to catch one and it turned out to be a female. Of all the skippers commonly found in our region, Common Checkered skippers are the only one that we know of that feed on mallows as larvae. We shall see for sure once they hatch.

- Brian