"What a thousand acres of Silphiums looked like when they tickled the bellies of the buffalo is a question never again to be answered, and perhaps not even asked." -Aldo Leopold
Photographed in April, this Agapostemon (either sericeus or splendens) bee is seen visiting blooms of Claytonia virginica (spring beauty). Agapostemon comes from two Greek words – agapetos, meaning beloved, and stemon, for stamen – these referring to their obvious fondness and attraction to flowers, particularly those in the Asteraceae. We can tell this bee is female because males of this genus have yellow and black striped abdomens.
It was a pleasure seeing my first wild Magnolia tripetala on our trip to Arkansas back in May 2021. To make things even better, this plant was found within a hundred feet or so from the Kentucky lady’s slippers we were there to photograph.
A little late for a Halloween post, my apologies, but I wanted to share what is probably the best-preserved example of a Gibellula-infected spider I have found to date. Gibellula is a genus of endoparasitic Cordyceps fungi that primarily infect spiders. Although the nicely preserved jumping spider (Salticidae) and the fruiting branches of the fungus is what grabs the eye, it wasn’t until I finished processing the photos that a question came to mind for me.
See the white fibers that surround the spider? I see two possible options for the origin of these. First, I should explain a little of what I have read about the life history of these parasitic fungi. Similar to the Cordyceps that infect insects, Gibellula-infected spiders become “zombies” and will typically position themselves on the undersides of leaves, as the one pictured here was found. Here the fungus finally kills its host and sends out spores that are now nicely positioned to fall upon potential new spider hosts. Back to that bed of white threads. I see one function and two possible origin ideas of these. I believe the function of these is to keep the spider anchored to the leaf so that it does not fall to the ground and greatly hinder the ability of the fungi to infect new hosts. For the potential origin, these could be mycelia of the infecting fungus, or, even better, these could be silk created by the spider, induced by the fungus to anchor itself as the last act before its death.
If you have other ideas as to the potential origin or function of this bead of threads, please let me know!
Both the common and genus names refer to the supposed resemblance of the flowers to the simian face. I don’t readily see it but they are fantastic blooms.
One of two Buprestidae family members I was fortunate to photograph this year. This guy was found at Bush Wildlife Conservation Area in St. Charles County, MO on 01/AUG/21.
All three of the Salvia azurea I planted in the front bed did very well this year and even played host to an equally gorgeous moth, Pyrausta inornatalis.
Agalinis fasciculata, known as the fasciculate false foxglove and beach false foxglove was one of the more fascinating and unexpected plants I became acquainted with this year. A member of the Orobanchaceae family, this species is an annual hemiparasitic plant that does well in poor and sandy soils. I photographed these plants at the Missouri Mines State Historic Site in St. Francois County.
The genus Agalinis comes from the Greek – agan, meaning ‘very’ and linon, refering to ‘flax’, apparently in reference to the similarity of the flowers to those of flax. The species and common names refer to the fasciculate, or bundled manner in which the leaves are attached to the stem – something I failed to take any photos of this year. In my defense, much of the stem and leaves of these plants in mid-September were beginning to senesce and were not very photogenic.
For the past few years I have noticed a good number of native bee nest holes along exposed sections of bare soil at one of my favorite hiking and nature observation sites – August G. Beckemeier Conservation Area in St. Louis Co., MO. This past spring I finally decided to make this a project and set about a quest to make some images of these gals provisioning their nests. As usual, I wound up learning along the way.
As is commonly known, many of our native bees are solitary and nest without close contact or cooperation in regards to conspecifics. At the opposite side of this spectrum of sociality in the Hymenoptera are most species of bumble bees and the honeybee. These bees are considered truly social, or, eusocial. The characteristics necessary to be considered a eusocial species are 1) cooperative care of offspring of others within the colony, 2) overlapping generations within a colony of adults, and 3) a division of labor into reproductive and non-reproductive groups. Many of our bee species lie somewhere between these two extremes. The bee of focus here, Agapostemon virescens, lies early in the area we call being presocial, aka parasocial.
Let’s clarify the differences between a presocial species such as A. virescens and the eusocial honeybee. The honeybee shows all three necessary characteristics of a eusocial species. The individual workers obviously care for brood that are not their own – they don’t even have offspring of their own, instead spending much of their lives caring for the offspring of their queen (sisters). They have multiple overlapping generations within the hive in a particular season, as well as across multiple seasons and as just mentioned, there is a division of labor into reproductive and non-reproductive castes. A. virescens on the other hand, is not nearly as cooperative. Individuals of this species share basically just a front door to their brood chambers and nothing more. After entering the communal nest, each female builds their own brood sub-chamber cells and each provisions their own by processing pollen into cakes and leaving them in their respective brood chambers. There is no brood care after the egg is deposited and the sub-chamber sealed. The offspring then emerges later in the summer.
So, what are the pre-conditions necessary for the eventual development of more complicated forms of sociality, i.e. eusociality? Or more directly, what advantages are there in adopting more of a social lifestyle if we assume the starting point was a solitary existence? Scientists consider two important pre-conditions need be met for the evolution of eusociality. First, the species offspring must be altricial, or require a great amount of parental care in order to reach maturity. Second, there need be low reproductive success rates of solitary pairs that attempt to reproduce. Here is what is believed to be the primary driver that pushed A. virescens into this presocial condition.
Kleptoparasitism is where one animal takes advantage of the hard work of another by taking their prey or collected foods. In this case, we are primarily concerned with the large group of bees known as cuckoo bees. Kleptoparasitism has evolved numerous times in the Hymenoptera and cuckoo bees lay their egg on or near the host’s provisions. The parasite will hatch first and eat the host’s pollen and will often kill and eat the host’s larvae as well. With such an obviously successful reproductive strategy, it should come as no surprise that there would be a strong selective advantage of finding ways to thwart these parasites. In the case of A. virescens, evidence suggests that by communal living as described here, the rate of kleptoparasitism is much lower when compared to related species that have the completely solitary reproductive strategy.
I guess the obvious next question is how in the world could eusociality evolve from this state? This is a fascinating story that involves terms like kin selection, altruism and haplodiploidy. It also involves a good deal of math and explanation from some of the greatest evolutionary thinkers since the time of Darwin (read anything by William D. Hamilton for example). It is also well out of the scope of this piece. But, I hope it is clear that before getting near the high rung of eusociality on this ladder, that a small first step like seen in this example would be necessary.
I hope I got most of this correct enough. It’s been a long time since I took Zuleyma Tang-Martinez’s Evolution of Animal Sociality class at University, which I thoroughly enjoyed. Please feel free to leave a comment to correct or clarify or ask a question.
Much of what I covered here and a lot more can be found in Malte Andersson’s The evolution of eusociality (Ann. Rev. Ecol. Syst. 1984. 15:165-89
The evolution of Eusociality
I finally lucked out and found a late instar Battus philenor. This guy was walking along a trail, presumably looking for a good spot to pupate. I persuaded it to walk on a stick for a brief period to pose for a couple of portraits and then left it where I found it.
Here is my last new orchid for the season. It is also probably the orchid I had to work the hardest to find in this entire project. Platanthera flava var. flava is classified as S2 (imperiled) in Missouri due to the very few remaining populations. This is an orchid that likes its feet wet and can be found in a variety of habitats containing moist to wet soils. After trying unsuccessfully in 2020, Pete and I went back to the same location this year – a wet prairie in southern Missouri in early June. This was very tough searching as the high temps, strong sun and saturated air created a potentially dangerous heat index. We tried our best, slowly slogging through the already quite thick prairie. Just when it looked like Pete was wanting to throw in the towel, we came across a patch of less-dense vegetation with water about ankle-high. Here we found young orchids that numbered in the hundreds. Unfortunately, most were on the early side and were not fully flowering but we did find a few that made us happy. We also found that many of the orchids in this group had grazed top leaves – most likely from white-tailed deer that usually find orchids to be very appetizing.
There is another variety of this orchid, P. flava var. herbiola that is also found in Missouri. Recently Pete and I tried to find this in most of the known locations but came up short. As of now my quest stands at 33 of 36 orchid forms that can be found in the state (36 is my accepted number and others may disagree). In addition to P. flava var. herbiola, I also need to find Coeloglossum viride (Long-bract Frog Orchid) – this species is known from a single location in the state but apparently does not flower and Epipactis helleborine, the broad-leaved helleborine – the exotic orchid that is becoming naturalized in this state but originates in Asia and Europe. Finding these three remaining orchids should be quite the task and I look forward to attempting these next year.
I have run into a couple other circumstances in our orchid flora where intermediate forms have caused problems in determining the identity of a plant or population. Where these two varieties overlap, as they seem to do in Missouri, there are intermediate forms between these two varieties as well. I will hope that when I do find a potential herbiola variety that this will not become a problem.
A Thousand Acres of Silphiums 