We missed a great opportunity at Black Rock this year: hunting for crayfish worms aka branchiobdellidans. These tiny critters (<12 mm) are worms of the phylum Annelida, the same group that includes leeches, earthworms, and polychaetes.
Branchiobdellidans spend their whole lives on the exoskeleton of crayfish like the ones inhabiting the streams of Black Rock Forest. Some species may be parasitic, others muralists, sometimes it depends on their population density, and in most cases, we just don’t what impact - if any - branchiobdellidans have on their crayfish hosts.
With so little known about its ecology, it should comes as no surprise that their evolutionary relationships relative to other annelids, especially the true leeches (Hirudinida) and freshwater parasitic worms (Acanthobdellida) is equally murky. This murkiness is at the center of Michael Tessler, Magda and Olivia’s SRMP research.
Long story short: if you use shared characteristics in sperm morphology to recreate evolutionary relationships, you would find Hirudinida and Acanthobdellida
to be more closely related. But if you use the CO1 and 18S genes,Hirudinida and branchiobdellidans are more closely related.
Michael and his SRMP students are adding additional species and genes to form a more robust dataset to, hopefully, resolve the relationships. While Michael & Co work on that, I’ll practice saying “branchiobdellidans” 5x fast.
Team Sounds of Science brings you “Inspiral”: Listening for gravitational waves
So here’s the gist: As a pair of black holes orbit one another (the “Inspiral” part), some of the energy is lost as gravitational waves. (Gravitational waves - ripples in spacetime; akin to concentric rings a raindrop makes in a puddle, but trippier). As they approach one another, their orbital speed increases (think of a figure skater spinning faster as his/her arms are brought inward). The frequency of the gravitational waves increase. Finally - when the two black holes collide - BOOM. A spike in the frequency of gravitational waves - an elevation in pitch - that can be detected by instruments like LIGO (Laser Interferometer Gravitational-Wave Observatory). LIGO can catch these ultra low frequency gravitational waves, but our ears cannot. But it’s not enough to build a detector to expand upon humans’ senses. Scientists want to “hear” the gravitational waves for themselves.
As I said, these frequencies are very low. In fact the more massive the black holes, the slower the orbit, the lower the frequency of gravitational waves, and the harder to detect. Dr. Bartos and his team are attempting to making the necessary alterations to gravitational wave data to make it more audible to the human ear, as well as determining what size of orbiting black holes generate frequencies within this range.
I’m looking forward to Inspiral’s first big hit. For now, I encourage you to play Black Hole Hunter to see if you can hear the moment two black holes collide. I couldn’t get past level 3.
Everything is bigger in Texas: skull morphology in bull snakes across a desert-grassland gradient
To test this hypothesis, Yeasha and Skakel have already photographed over 100 snakes across the Chihuahuan desert and Texas grasslands and will soon be using geometric morphometrics to describe the shape of their snakes’ heads. Later comes mapping and correlating skull morphology with soil type data. But for now, it’s measuring and photographing a lot of big, dead snakes that still look very much alive when emerging from the formalin/ethanol bath.
Speciation: Islands vs Continents
If there is a topic that really excites a Museum evolutionary biologist, it's speciation:
What drives speciation?
What affects rates of speciation?
Why are some groups of organisms more diverse than others?
These are not easy questions at all..
Their hypothesis is higher dispersal abilities on continents will inhibit rates of speciation while higher dispersal abilities on islands will stimulate rates of speciation. Why? Because continents present the opportunity for more continuous, suitable habitat (as opposed to thousands of miles of ocean). Great ability for movement keeps genes a flowing which prevents distant populations from diverging, a step along the path of speciation. Due to the continuity of continental habitats greater ability for movement is not necessary for range expansion, and therefore speciation, whereas on islands it is.
The first step in this process is finding candidate birds (and islands) to test this hypothesis. To avoid an apples to oranges comparison, the team is scouring the literature for candidate bird clades that are well represented on BOTH islands and the mainland. So far, doves, flycatchers, and finches have made the list. Looking forward to an update once you start building those phylogenies and calculating speciation rates!
The blue-crowned Manakin revisited
Most scientific research is not wrapped up in a single study. Rather they go on for years. New data is added. Hypotheses are disproven or updated. SRMP research is often no different.
Last year I wrote about a study of the Blue-crowned Manakin (Lepidothrix coronata) conducted by Mazie and Ethan alongside mentor Jessica Shearer McKay . The team was investigating whether this widely distributed Amazonian bird was hiding more morphological and genetic diversity than previously described. Males of these species show the most phenotypic diversity with their crowns being all shades of blue and some subspecies have black bodies, others lime green.
Mazie and Ethan had seventeen individuals from Brazil, Costa Rica, Brazil, and Bolivia. Jessica’s new students, Nafilah and Desiree are adding several more specimens and widening the sampling to include Panama, Ecuador, Venezuela and Peru. A more complete geographic sampling will hopefully help resolve taxonomic uncertainties of this beautiful little bird: There are currently several sub-species. Are there more? And do these subspecies delineation correspond to major river basins? Are large rivers barriers to dispersal and therefore explain genetic and morphological difference observed across it’s range? Jessica thinks more birds clarify things - but not before making the story even more complicated! We shall see.
Dr. Zirakparvar has set a high bar for us mentors. He introduced his students to their project with a gift of garnet. I suppose my SRMP students are welcome to take home as much coyote scat as they want if they so wish.
I have always loved garnet for it’s beautiful dark red hue (although I now know that it comes in many colors all dependent on associated impurities) and for the fact that I could actually afford the gemstone on meager high school, college, then graduate student salary. After speaking with Lucie, Isaac, and Patrick, I appreciate it even more. Garnet is the sand in sand paper. It’s a very hard stone with no cleavage which makes it great for sand blasting or for giving a fine polish. It’s formed in many geologic settings and can be used to understand geological processes since its different varieties reflect the temperature and the pressure under which the surrounding rock was formed. And - more germane to my lab visit - some garnets are enriched in Heavy Rare Earth Elements (HREE).
HREE have so many uses in our modern life from powering your phones to medical imaging. Currently, China is the primary source of most HREEs and the process by which we extract HREEs is nasty. After milling (cracking ore and grinding rock into fine particles), HREEs must be extracted and purified using lots of different chemicals. Many HREE sources are often associated with uranium making for some really toxic, radioactive wastes. Feeling guilty yet as you read this off your cell phone?
Alternative sources are being considered like coal fly ash or some clay deposits, but garnet may have some advantages. Alex and his team are evaluating the possibility that
some garnets may provide a source of HREE that is a bit “cleaner” (e.g. no radioactive wastes). And garnet is EVERYWHERE including upstate NY meaning there may be opportunities for local industry.
Dr. Z and his SRMP team have been in communication with a variety of researches at other institutions interested in defining alternative sources of the HREE and have received a positive response. Now they have embarked on an exhaustive literature search to evaluate the potential of garnet as an industrial source of HREE. What are the HREE concentrations observed in garnets? Where are garnet deposits? What % of rock has garnet? And what % of garnet is associated with HREEs? What type of HREEs? Are there associated radioactive elements? How much does it cost to extract garnet from different mines?
Depending on the results of their research, I may start investing in garnet mines.
If you are a Chelonian (aka turtle), most likely it’s the temperature. For the majority of turtle species, the sex of the embryo developing inside its amniotic egg is determined by the incubation temperature.This is obviously not how sex determination works for us humans (nor for other mammals, birds, mammals, or amphibians) where sex is determined by genetics (e.g. in humans, XY = males, XX = females). Although I’m pretty sure if human parents could travel to the tropics or the poles to influence the sex of their baby, they probably would.
Back to temperature sex determination or TSD. Critical temperatures during incubation dictate whether a clutch of eggs are all females (warmer), all males (cooler), or mixed (intermediate temperatures). These critical temps are not fixed across turtle species or even within a single turtle species. Take our Black Rock friend, Rocky, the snapping turtle. There is geographic variation in critical temperatures such that what temperatures makes a female turtle in NYS will be different than in Florida.
Researchers have known about the existence of TSD for decades. TSD is thought to be the ancestral state in vertebrates, and then genetic sex determination, GSD, evolved in some species. That doesn’t mean they know how it evolved or when. Is TSD adaptive in turtles or is it just ubiquitous due to phylogenetic inertia (aka, it works and there’s no “easy way” for GSD to evolve). Even the genetic mechanisms driving intra & inter specific differences in critical temperature remained elusive. But there are some clues.
A recent study on the snapping turtle identified CIRBP as a candidate gene in part responsible for determining the critical temperatures that results in boy vs girl turtles.The idea is that variation in the CIRBP gene dictate how an embryo responds to temperature. Dr. Brendan Reid and his team, Rosemary and Michael are investigating how genetic variation in CIRBP corresponds to variation in critical temps across and within species. So far, this gene’s importance to TSD has only been demonstrated in the snapping turtle; however, CIRBP is known to be involved in temperature regulation in humans.
Brendan and his team’s research is timely. As climate changes brings warmer temperatures, the sex-ratio of turtles becomes skewed impacting population growth. This already being seen in a population of Florida sea turtles where temperatures were too warm for too many years resulting in mostly female baby turtles. You don’t have to be a demographer to know that’s not good.