Wednesday, August 29, 2018

Secret Science Club Post-Lecture Recap: Vampire Hell Ants of the Cretaceous

Last night, I headed down to the beautiful Bell House, in the Gowanus section of Brooklyn, for this month's Secret Science Club lecture featuring paleontologist and entomologist Dr Phillip Barden of the New Jersey Institute of Technology and the American Museum of Natural History. Dr Barden specializes in the study of fossils of social insects such as termites and ants.

Dr Barden began his lecture with a short definition of paleontology. Paleontologists ask two main questions: What is the history of life on Earth? How does evolution work? Paleontologists study finite events, such as the extinction of the non-avian dinosaurs. Life on Earth is 3.7 billion years old, with humans occupying a miniscule span of time. Most life is extinct, almost everything that has ever lived is now dead. Dr Barden asked the audience to picture a fossil, immediately following this up with the admonition that not every fossil is dinosaur remains. Some of the most famous non-dinosaur fossils are trilobite and ammonite fossils. There are also environmental remains of organisms, such as footprints. His concentration is the study of fossil insects.

Eighty percent of animal species are insects, While dinosaurs, being charismatic megafauna, attract most of the public's attention, there are spectacular insect fossils, such as that of Meganeura, a dragonfly-esque creature with a wingspan attaining over two feet which hunted in the Carboniferous skies, which had a higher oxygen content than our modern atmosphere- insects breath through treachea, so the surface area of these tubes limit body size. Dr Barden also displayed a fossil of a Jurassic Era lacewing which resembled a butterfly.

The best-preserved insect fossils are encased in amber, fossilized tree resin (NOT SAP!). Resin is secreted when a tree is injured, forming 'scabs' in which organisms can be trapped. When subjected to heat and pressure through geological processes, it becomes polymerized- Dr Barden joked that amber is 'OG Plastic'. Amber, known to the ancient Greeks as 'elektros', produces electric sparks when rubbed. Insects trapped in amber are preserved in three dimensions. Dr Barden accompanied this portion of the lecture with gorgeous photographs of amber-trapped insects, such as two ants trapped in amber while fighting (evidence of a social structure).

Amber is distributed worldwide, with particularly nice Cretaceous amber being found in New Jersey. Dr Barden showed us photos of various amber sources, such as an amber deposit in a Gujarati lignite mine (the remains of a forest compacted and rendered into coal), excavated amber mines in the Dominican Republic, and Baltic amber which is typically found on beaches or 'fished' from the sea. Amber is often fashioned into jewelry, sometimes including fossilized animal remains.

Dr Barden then showed us the 'Mr DNA' clip (though not the Mr DNA you were thinking of) from Jurassic Park, noting that the stand-in for the giant prehistoric mosquito in the amber walkingstick ornament is actually a crane fly and chiding anyone who killed a harmless crane fly as a 'giant mosquito'):

Dr Barden noted that the book Jurassic Park was released in 1990, and that in 1992, it was reported that DNA was extracted from an Oligo-Miocene termite, but that this study posed a problem of reproducibility. DNA from bones has a half-life of 521 years and that new techniques for DNA extraction are constantly sought.

Dr Barden continued to display images of amber encased animal remains, such as a thumb-sized, feathered dinosaur tail found in Myanmar, a tick attached to a dinosaur feather, and an ant queen (the wings identify it as such) transporting a symbiotic mealybug in her mandibles- mealybugs excrete honeydew, which ants consume. Another fossil was that of a lacewing larva with spines for collecting camouflaging detritus. Dr Barden noted that there are about as many ant fossils as there are dinosaur fossils, but that only he and a French paleontologists are studying them- he joked that his job prospects are good. Among these fossil ants was one the size of a hummingbird.

Dr Barden stated that the oldest ants were not like was expected- early ants were thought to be wasplike, having similar body plans. The oldest ants discovered were more like basal Hymenoptera than wasps, with the similarities in body resulting from adaptive radiation.

Dr Barden conducted 3D imaging of ant fossils at the Advanced Photon Source at Argonne National Laboratory, fluorescing specimens while rotating them to provide the three-dimensional images. He joked that he was the guy putting bugs in the machine. As a comedic aside, he displayed a stupid tweet by a Kardashian: Do ants have dicks? He then displayed a photo of a drone ant fossilized in amber, then zoomed in, showing us a dick pic of a 20 million year old ant.

The topic of the lecture then shifted to the vampire hell ants of the post title. Haidomyrmex scimitarus was a Cretaceous Era ant found in an amber deposit in Myanmar. A detailed reconstruction using animations based off CT scans of this ant suggested that it used its mandibles to impale other insects, and grooves in the mouthparts hint that these ants consumed the hemolymph of the impaled. Dibs on "Hemolymph of the Impaled" for the name of my Doom Metal band. The queen ant was found outside of the nest, and lacked fat storage, indicating that the queen had to forage like a common worker. The generic name Haidomyrmex is a combination of 'Hades' and the Greek term for 'ant', so Dr Barden decided to make 'Hell Ant' the popular term for these insects- he asked the audience members to 'hashtag' #hellant. Another similar 'hell ant', Ceratomyrmex had a horn as well as the impaling jaws. Then, a scan of an ant dubbed Linguamyrmex vladi revealed that the horn was so dense as to suggest that the horn contained sequestered metal, leading to such lurid headlines as: 'Meet the vampire ant from hell with huge jaws and a metal horn.' Dr Braden then displayed a succession of increasingly lurid and 'clickbaity' headlines about this ant. The good doctor then displayed an articulated model of this ant's head, about the size of an American football.

The hell ants thrived for about twenty-million years, during the Cretaceous Era. It is not known what happened to this diverse clade of ants. The earliest ants were social, there is evidence of different specialized castes among early ants. About fifty million years ago, ants became more abundant, ants now currently compose 50-80% of insects in tropical tree communities. The hell ants don't seem to have been all that ecologically impactful. There are many Cretaceous ant fossils. There is a gap in the fossil record until the Eocene, a sort of 'black box' from which only modern ants emerge, while having diverse behaviors, extant ants have similar body forms. Divergent forms, such as the hell ants, disappeared. Dr Braden likened this emergence from a 'black box' to the K-T extinction event, from which one lineage of dinosaurs, the birds, emerged.

Dr Barden posed a question: Does extinction mean failure? He displayed a picture of the thylacine, a wolf-shaped marsupial that was killed off by humans (as an aside, I am obliged to plug SSC goddess Margaret Mittelbach's Carnivorous Nights: On the Trail of the Tasmanian Tiger, co-written with SSC alum Michael Crewdson- it's a great book by good friends, a funny, sad, and informative read). Dr Barden offered his three measures of evolutionary success: Diversity of species (beetles, with over 350,000 species, are very successful), Ecological Impact (South African harvester ant foraging territories can be seen in satellite images, such is their ability to reshape their environment), and Longevity (Neandertals were around for 430,000 years while modern Homo sapiens has been around for about 300,000 years). Certain taxons were extremely successful- about twenty thousand trilobite species are known, which indicates that there were probably many more. The impact of the dinosaurs on other evolutionary lineages is difficult to understate. The hell ants were around for about twenty-one million years, great apes a mere eight million. We only see about .01, much of the evolutionary legacy is hidden.

The lecture was followed by a Q&A session, as always. The first question regarded the phenotype of the hell ants- the 'archtecture' of the hell ant lineage has been lost, no traces last into modern ant lineages. The next question was, why did the hell ants go extinct? While this is unknown, it could be that their social structure was outcompeted by the social structure of modern ants which supplanted them. Perhaps the hell ants were 'painted into a corner' evolutionarily. Another question regarded evidence of the large structures which ants and termites build- fossil remains of these structures have been found, and Dr Barden likened this evidence to an 'extended phenotype' which provides clues to the behavior of the insects themselves. Regarding the gaps in the fossil record, new amber deposits have been found in Alaska and compression fossils have been found in Alberta- gradually, the 'black box' is being filled in. Regarding the half life of DNA, while DNA sequences degrade, partial genomes provide information valuable to researchers. Some Bastard in the audience asked about molecular evidence from insects trapped in amber- can inferences be made about pigmentation or the composition of venoms? Dr Barden noted that coloration is often preserved in amber, and stingers are often present in fossil insects, but no molecular structures for pigments or poisons have been found. Regarding prey items of hell ants, they have been found in association with a larva of an insect and a cockroach like insect. The musculature of an insect, useful in computer modelling, can be inferred from bulges in the interior of the exoskeleton, to which muscles, inside the skeleton, are attached. Regarding the caste system of social insects, insects from the same species have the same genome but different gene expression- while a worker has a lifespan of 1-3 years, a queen may live as long as twenty years- transcriptomes play a role in this sort of development. The earliest known modern style ant dates back to the Cretaceous, about ninety-two million years ago, and was found in New Jersey- the lineage probably split off from other ant lineages about 120 million years ago. Finally, asked about his application of the species concept, Dr Barden indicated that, due to the nature of his work, he applied the paleontological species concept, largely working off whether specimens look similar or different.

Once again, the Secret Science Club delivered a fantastic lecture. I make no bones about loving the life sciences the most, so this lecture was right up my alley, or allele... Dr Barden hit what I call the 'Secret Science Sweet Spot'- the lecture was specific, extremely informative about recent discoveries, accompanied by gorgeous images of fossils, and leavened with humor. I call it a grand slam. Kudos to Dr Barden, the staff of the Beautiful Bell House, and Margaret and Dorian for another great monthly event. It was also great to see both the NJIT 'swarm lab' crowd with Dr Garnier and the AMNH crowd, represented by Dr Hekkala and her husband, in attendance. High fives to everyone!

Poking around the t00bz, I found a fun video of Dr Barden giving a tour of the AMNH insect collections to a budding young entomologist:

I only have one quibble, and that's because bugs suck. The video, however, is great. Pour yourself a nice beverage, and watch two cool young dudes talk about SCIENCE!


The New York Crank said...

I love the image of two ants duking it out while an amber ooze slowly covers them and leaves them smothered to death and frozen in place for eternity.

Was the end worth it for those two? Or were they simply behaving like today's doctrinaire politicians, mindlessly beating each other over the head with word bombs while civilization is slowly killed and frozen in place for all time?

Just asking.

Yours crankily,
The New York Crank

Big Bad Bald Bastard said...

Remember that those ants don’t reproduce, their ‘destiny’ is wholly that of the colony as a whole. Their imperative is the survival of the queen and her progeny, their own individual survival is immaterial.

Kinda depressing...

The New York Crank said...

Well, BBBB, if ya gotta put it that way, then think instead of the Dr. Seuss poem about the north-going Zax and the south going Zax on the (was it the Prairie of Prax?) when they came to a place where they stood nose to nose, toe to toe, face to face. And neither would get out of the other's way because macho, so they stood there, enraged, each trying to stare down the other for 50 years, (I'm a north-going Zax and I always go north, so get out of my way and let me go forth!) until civilization rolled right over them. You could look it up.

Damn, am I feeling cranky tonight,
The New York Crank