We have probably went to Albany Hill over a hundred times in just this year. Today was the last time. We took a bunch of photographs on the way, just to see how it will change by the next time we come back to Albany. A new segment has just been added to the Bay Trail this year with newly propagated willows (Salix) and alders (Alnus) along a man-made creek that mimics the rest of the trail perfectly. In a few year's time, we expect that it will grow in a lot. 

The following are pictures of the two blocks of the trail that have always been here. Most of the trees are really declining as the season passes, but it is still rich with life. 

At the end of the trail is Albany Hill. We did't see too much flying today, except for some skippers as detailed in here. We were not able to find any red admiral (Vanessa atalanta) larvae or eggs on the pellitory (Parietaria) even though the plants were getting clobbered in eggs all throughout the summer. 

After exploring the outside of the hill, we crossed the creek to get inside. The pipevine here was in pretty bad shape, but there were still a one or two pipevine swallowtail (Battus philenor hirsuta) larvae. A while ago we had come and found a least a dozen or two, so we suppose they either pupated or died. 

Inside the hill, the scenery was a far step from when we first came in the Spring. The ground was covered in yellow hay and the trees were mature and dry. To our surprise, we saw a single western tiger swallowtail (Papilio rutulus) at some point. We took this as an opportunity to take a few pictures of ourselves one last time before we leave (as you may have noticed, the pictures of us have changed on this website).

Rearing notes 8/9/17-8/16/17​:

Because we will be moving to Ithaca, New York tonight, we had no choice but to collect all the cecropia moth (Hyalophora cecropia) cocoons despite that not all larvae have spun.

We never thought a cecropia brood started all the way back in April would still not be finished now in mid August. We normally would have collected all the cocoons once all larvae had finished spinning, but since we will be moving tonight, we had to collect all the finished ones and resleeve up the remaining few larvae with as many leaves as possible. 

The cocoons this year are far smaller than the ones last year, despite having received nearly identical treatment (indoors on apple first three instars, and sleeved outside in the last two). The only difference was that some of the larvae this year were sleeved since birth. The larvae this year also grew much, much slower than last year's which all finished spinning at the beginning of August and began in June. We can't really understand why this year's rearing was so poor. We started off with hundreds this year and nearly all died off overtime, mostly the ones that were sleeved since birth. Last year we started with three dozen and got about the same amount through and they were respectable in size, with females at 8 g and males at 6 g. This year, the cocoons are a measly 3-6 g. We didn't imagine cecropias could even get down to 3 g without opting for a supernumerary sixth. Maybe inbreeding reduced their size?

​Authors
Alan Liang

Rearing notes for a common checkerspot (Pyrgus communis) fourth larva originally found as an egg on wild mallow (Malva sp.) in Albany, California

Rearing notes 8/13/17-8/16/17:

Rearing notes 8/12/17-8/16/17:

Our final non-diapausing ♀ ​polyxenes asterius × ♂ zelicaon hybrid pupa eclosed into a crippled male. Fortunately, the important wing and body patterns are visible enough to compare to parent species, P. polyxenes asterius and P. zelicaon.

The hybrid eclosed today, and weak and small as it is, it could not expand its wins fully just like the first one. However, this one managed to expand enough for us to clearly see the wing patterns, unlike the first who's wings were completely crumpled. Below are sided by side live comparisons between the hybrid and the parent species, P. polyxenes asterius and P. zelicaon; all individuals are males. Though intermediate between the parent species and many traits, the hybrid superficially resembles polyxenes more due to the black (rather than yellow) ground color. However, all the yellow regions on the hybrid are darker than in polyxenes more closely match the shade in zelicaon.

Now let's get into the details, starting with the wings.

​Dorsal Forewing

The dorsal forewing of the hybrid is primarily black like polyxenes, though it is not quite as dark and is slightly brownish. The band of yellow spots in the middle is more or less consistent in width, unlike in polyxenes which typically tapers going upwards or like in zelicaon which is thick on both ends and narrower in the center. Also, The marginal yellow spots are somewhat intermediate of the parents, being more rectangular than polyxenes' but rounder than zelicaon's. ​

​Dorsal Hindwing

The dorsal hindwings of the hybrid are similarly intermediate between the parent species as the forewings are. They are primarily black, but the band of yellow spots is larger than in polyxenes. Also, the marginal yellow spots are larger and more crescent shaped than in the polyxenes of our lineage, more like in zelicaon.

Ventral Forewing

The central hindwing is again more polyxenes like that zelicaon, simply due to the black ground color (though again, slightly brownish rather than pitch black). However, the other traits seem more intermediate, with the band of spots in the middle being orange-yellow, rather than orange in polyxenes or yellow in zelicaon. The marginal yellow spots are longer lengthwise and more rectangular, similar to zelicaon, and not rounded or tear drop like in polyxenes.

​Ventral Hindwing

The ventral hindwing of the hybrid is perhaps the most interesting of the wings. It is again black in ground color rather than yellow. However, intermediate of the parents, it contains much more blue past the band of orange spots than in polyxenes, and less than in zelicaon. Also, the band of orange spots is lighter and more yellow than in polyxenes, and is more simplistic, lacking the orange spot on the discal cell like in zelicaon.

​Now, onto the body

Head & Thorax

Like mentioned in the previous post with the first hybrid, the yellow stripes on the head and thorax of the hybrid are short and small like in polyxenes, unlike the long, connected stripes in zelicaon. However, like other yellow regions of the hybrid's body, the yellow is darker than in polyxenes, and more like the shade in zelicaon.

​Abdomen

The hybrid abdomen is very interestingly intermediate between the parents which we briefly described it in the previous post already. On the hybrid, the abdomen very clearly has two rows of rectangular yellow spots laterally. This is intermediate between polyxenes and zelicaon, because in polyxenes, the abdomen has three rows of rounded yellow spots - two lateral and one dorsal, and in zelicaon there are two solid yellow stripes rather than  rows of spots. The placement of the top row of yellow spots in the hybrid is also intermediate between the location of the dorsal and top lateral row in polyxenes, and right in the middle of where the larger solid yellow stripe in zelicaon is.

​Authors
Alan Liang

Rearing Notes 8/6/17-8/14/17:

​Authors
Alan Liang

Rearing Notes 8/10/17-8/15/17:

​Authors
Alan Liang

Rearing Notes 8/10/17-8/??/17:

​Authors
Alan Liang

And another brood finished. The last of the larvae finished spinning, so like always, we collected all of them in a tub and weighed them. There are 20 in total, and this time they are quite large compared to previous rearings. This is our fourth rearing of Samia ricini; summary stats are listed below for this brood, as well as two previous broods (the third brood of winter 2016 was never recorded, but was very small). Note that this brood was reared on Liquidambar while the other two were on Prunus, and the fall 2016 brood was of a different lineage.

Summary Statistics for Samia ricini Cocoon Mass:
                                  Mean     Std Dev     Median     Min     Max     N 
Fall 2016                 2.221       0.356          2.1               1.6         2.8        14
Spring 2017            1.773       0.337           1.7               1.2         2.5       33
Summer 2017        2.218       0.294          2.19            1.78       2.86     20

The majority of cocoons this time were 2 g or larger which is quite good, and masses were less variable than in previous broods. Of the three broods, both the fall 2016 and summer 2017 broods were significantly larger in mean mass than the spring 2017 brood (p=0.0002 and p<0.0001, respectively), and between those two larger broods, there was no significant difference in mean mass. 

​Shown above are this brood's cocoons compared to the fall and spring cocoons. The spring are visibly much smaller, and the silk was thinner and and more papery, rather than thick and fluffy. The fall cocoons look about the same size visually as this time's cocoons, but as they were of a different lineage, the shape of the cocoons were flatter and less round.

Most likely the spring rearing produced small cocoons because of much more severe overcrowding in the final instar compared to in the other two and the food quality was not as good. Or, maybe it was the host plant species that made the difference, as this time we used Liquidambar for the first time rather than Prunus. Perhaps Liquidambar was a better host than Prunus, and the reason why the fall brood was on par with the summer brood because that lineage was larger or utilized Prunus more efficiently.

​Authors
Alan Liang