Discovering fossilized insects is difficult, but a new find suggests a unique place to look.
- A new study demonstrates that dinosaur dung may contain fossilized insects unknown to science.
- The newly discovered bug, Triamyxa coprolithica, is a new species that shares a family with many modern aquatic beetles.
- The dinosaur that ate the bug 230 million years ago, Silesaurus, was a two-meter-long omnivore.
Learning about ancient animals is difficult. Fossilization is a rare event, possible only under very limited conditions. Preservation inside amber resin, as depicted in the film Jurassic Park, is also rare, particularly for species from before 140 million years ago.
Now, in an amazing find, a group of paleontologists has discovered a previously unknown species of insect in the fossilized excrement of a Triassic era dinosaur. Their findings have been published in Current Biology.
Hidden treasures inside coprolites
view of near-complete specimens of Triamyxa coprolothic as found in the coprolitesQvarnstro ̈m et al, Current Biology)
Coprolites are fossilized dung, and they are often an excellent source of information on the life and diet of ancient animals. Like other kinds of fossils, they are rare.
The coprolites described in this study were found in Poland and contained nearly complete casts (including legs and antennae) of a previously unknown species, dubbed Triamyxa coprolithica by the researchers. A kind of beetle, the insect is a member of a new family, Triamyxidae. The small size and sclerotized bodies of the insects likely protected them from the digestive system of the dinosaur that ate them, allowing us to learn about it today.
The find has excited the paleontologists, who have gone so far as to suggest that coprolites could be the "new amber" when it comes to learning about Mesozoic insects. Study co-author Martin Fikáček of National Sun Yat-sen University in Taiwan explained the possibilities to Scimex:
"We didn't know how insects looked in the Triassic period and now we have the chance. Maybe, when many more coprolites are analyzed, we will find that some groups of reptiles produced coprolites that are not really useful, while others have coprolites full of nicely preserved insects that we can study. We simply need to start looking inside coprolites to get at least some idea."
They went on to say:
"In that aspect, our discovery is very promising. It basically tells people, 'Hey, check more coprolites using microCT; there is a good chance to find insects in it. And if you find it, it can be really nicely preserved.'"
Importantly, unlike amber deposits, fossilized dinosaur dung can be much older than 140 million years. This sample is estimated to be at least 230 million years old.
The dinosaur responsible for this find
The researchers have credited the find to Silesaurus opolensis, a species of dinosaur known to live in that part of Poland. It could grow to about two meters long and was likely an agile creature with an excellent field of vision and a keratinous beak. This find adds to previous studies that suggested that Silesaurus was an omnivore rather than an herbivore.
Researchers develop a fungus that kills mites that contribute to honey bee Colony Collapse Disorder.
- Honeybee colony collapse is due in part to Varroa mites that weaken honey bee immune systems.
- Chemicals that were once effective against the mites are no longer working as well.
- Researchers are stepping in with a newly cultured fungus that goes after the mites without bothering the bees.
Honey bees are vitally important to agriculture — by some estimates, they're responsible for pollinating more than 80 crops, adding up to about one third of the crops that we eat. The USDA says they add at least $15 billion of value annually to U.S. crops in the form of higher yields and increased harvest quality. Humanity has a vested interest in helping to maintain healthy honeybee populations.
One problem for honeybees is a phenomenon known as Colony Collapse Disorder (CCD), which was first identified in 2006. With CCD, all adult bees in a hive die, leaving behind a queen, some immature bees, and honey. According to entomologist Sammy Ramsey, bees remain under pressure from what he calls the three Ps: parasites, pesticides, and poor nutrition.
Varroa destructor mites are a big part of that first P. They feed on bees — sucking fat from their bodies — leaving them with weakened immune systems that make the bees more susceptible to disease. Now entomologists at Washington State University (WSU) have developed a new strain of a mold-like fungus, Metarhizium, that can eradicate the mites. It does so without miticides, chemicals against which the mites are becoming increasingly resistant. The team's study is published in Scientific Reports.
Metarhizium made for the hive environment
Metarhizium killing varroa timelapse youtu.be
According to author Steve Sheppard of WSU's Department of Entomology, "We've known that metarhizium could kill mites, but it was expensive and didn't last long because the fungi died in the hive heat." The team's innovation was breeding a strain that can thrive in a hive. "Our team used directed evolution to develop a strain that survives at the higher temperatures."
There should be no safety issues introducing Metarhizium into a colony as bees are highly resistant to its spores. When Metarhizium encounters a mite, it drills into it before proliferating and killing the mite from the inside, as shown above.
As they cultured their Metarhizium, the researchers screened over 27,000 mites to identify the most deadly variants. "It was two solid years of work, plus some preliminary effort," says lead author Jennifer Han. When they arrived at their final Metarhizium, "We did real-world testing to make sure it would work in the field, not just in a lab."
Not their first fungus
The new strain of Metarhizium is the second agent the researchers have developed to aid bee colonies. In 2018, they announced the development of a mycelium extract that reduced virus levels in bees.
Together with their earlier invention, fungus expert Paul Stamets says the team has put together "a real one-two punch, using two different fungi to help bees fight varroa. The extracts help bee immune systems reduce virus counts while the metarhizium is a potentially great mite biocontrol agent."
(Star Trek Discovery fans may note that the crew member who interacts with a universal mycelial network is named… "Paul Stamets.")
Two things have to happen now before WSU's Metarhizium can be released to agricultural hives. First, the team has to nail down the optimal steps by which beekeepers can introduce the fungus to their bee colonies. Second, the Environmental Protection Agency has to approve Metarhizium for use.
Could this spell the end for mosquitos?
Researchers have used CRISPR/Cas9 gene editing to target a specific gene tied to fertility in male mosquitoes.
The researchers were then able to discern how this mutation can suppress the fertility of female mosquitoes.
Mosquitoes are one of humanity's greatest nemeses, estimated to spread infections to nearly 700 million people per year and cause more than one million deaths.
As reported in the Proceedings of the National Academy of Sciences, the discovery represents a breakthrough in one technique for controlling populations of Aedes aegypti, a mosquito that transmits dengue, yellow fever, Zika, and other viruses.
Craig Montell, professor of molecular, cellular, and developmental biology at the University of California, Santa Barbara, and coauthors were working to improve a vector-control practice called the sterile insect technique (SIT). To manage populations, scientists raise a lot of sterile male insects. They then release these males in numbers that overwhelm their wild counterparts.
The idea is that females that mate with sterile males before finding a fertile one are themselves rendered infertile, thereby decreasing the size of the next generation. Repeating this technique several times has the potential to crash the population. What's more, because each generation is smaller than the last, releasing a similar number of sterile males has a stronger effect over time.
CRISPR IS A BETTER ALTERNATIVE TO CHEMICALS
SIT has proven effective in managing a number of agricultural pests, including the medfly (Mediterranean fruit fly), a major pest in California. It has also been attempted with A. aegypti mosquitoes, which originated in Africa, but have since become invasive across many parts of the world, due in no small part to climate change and global travel.
In the past, scientists used chemicals or radiation to sterilize male A. aegypti.
"There are enough genes that affect fertility that just a random approach of blasting a large number of genes will cause the males to be infertile," says Montell. However, the chemicals or radiation affected the animals' health to such an extent that they were less successful in mating with females, which undercuts the effectiveness of the sterile insect technique.
Montell figured there had to be a more targeted approach with less collateral damage. He and his colleagues, including co-first authors Jieyan Chen and Junjie Luo, set out to mutate a gene in mosquitoes that specifically caused male sterility without otherwise affecting the insects' health. The best candidate they found was b2-tubulin (B2t); mutation of the related B2t gene in fruit flies is known to cause male sterility.
Using CRISPR/Cas9, the researchers knocked out B2t in male A. aegypti. They found that the mutant males produced no sperm, but unlike in previous efforts, the sterile studs were otherwise completely healthy. There was some debate over whether sperm—albeit defective sperm from the sterile males—was needed to render female mosquitoes infertile, or whether transfer of seminal fluid was all it took.
In one experiment, the researchers introduced 15 mutant males into a group of 15 females for 24 hours. Then they swapped the B2t males for 15 wild-type males, and left them there. "Essentially, all of the females remained sterile," Montell says. This confirmed that B2t males could suppress female fertility without producing sperm.
"THERE IS A PANDEMIC EVERY YEAR FROM MOSQUITO-BORNE DISEASES."
Next the team set out to determine how timing played into the effect. They exposed the females to mutant males for different lengths of time. The scientists noticed little difference after 30 minutes, but female fertility quickly dropped after that. Montell notes that females copulated twice on average even during the first 10 minutes. This indicated to him that females have to mate with many sterile males before being rendered infertile themselves.
Combining the females with the B2t males for four hours cut female fertility to 20% of normal levels. After eight hours the numbers began leveling out around 10%.
MOSQUITO MATING BEHAVIORS
With the insights from the time trials, the team sought to approximate SIT under more natural conditions. They added different ratios of B2t and wild-type males at the same time to a population of 15 females for one week, and recorded female fertility. A ratio of about 5 or 6 sterile males to one wild-type male reduced female fertility by half. A ratio of 15 to 1 suppressed fertility to about 20%, where it leveled off.
Now, Aedes aegypti populations could easily bounce back from an 80% drop in fertility, Montell says. The success of SIT comes from subsequent, successive releases of sterile males, where each release will be more effective than the last as sterile males account for an ever-growing proportion of the population.
Montell plans to continue investigating mosquito mating behaviors and fertility. They are devising a way to maintain stocks of B2t males so they are only sterile in the wild and not in the lab. In addition, they are characterizing male mating behavior to uncover new ways to suppress mosquito populations.
"We've become very interested in studying many aspects of behavior in Aedes aegypti because these mosquitoes impact the health of so many people," says Montell, who has conducted a lot of research using fruit flies in the past. "There is a pandemic every year from mosquito-borne diseases."
"When CRISPR/Cas9 came out several years ago it just offered new opportunities to do things that you couldn't do before. So, the time seemed right to for us to start working on Aedes aegypti."
Life finds a way — in this case, by smelling like death.
- Many plants use some kind of mimicry to attract pollinators.
- After bees, flies are the second most important pollinator on the planet.
- Plants that emit smelly odors usually try to mimic dead vertebrates, but Aristolochia microstoma is the first known plant to smell like dead insects.
Somewhere between four and six percent of all flowering plants use some form of deception to lure in pollinators. For instance, they can appear to be a source of food or even a potential mate. The pollinators, being unable to detect the illusion, are drawn in and rewarded with little more than a dusting of pollen. Research into the deceptive nature of these plants and how they evolved is ongoing.
One of these studies, recently published in Frontiers in Ecology and Evolution, sheds light on the deception strategy used by the plant Aristolochia microstoma. Uniquely, this flower lures pollinating insects by emitting the stench of dead invertebrates.
Insects head toward the smell of other dead insects
Credit: T. Rupp, B. Oelschlägel, K. Rabitsch et al.
A. microstoma is a purple-brown flower found in Greece. It typically blooms close to the ground, as seen in the above image. This is unusual, as most Aristolochia species have bold and easily seen flowers well above the ground. Additionally, this flower tends to be horizontally oriented, as opposed to the more vertical structure of similar species' flowers. A. microstoma is known to smell like decay, often to the displeasure of humans walking near it.
Pollinators stumble into the flower and — not unlike Hotel California — find themselves unable to leave. Their movements pollinate the plant. Later, they are covered in pollen from the male part of the flower before being released. The cycle then repeats as the insects fall for the same tricks again.
Enter the coffin fly
To learn more about the flower's strange traits and how that relates to its pollination, the authors collected 1457 flowers from three sites in Greece, two on the Peloponnese and one west of Athens. Of the samples, 72 percent were in the first, female stage of blooming. (These flowers go through two stages, first female, then male.) These samples contained 248 arthropods, but only a collection of Megaselia scalaris — also known as coffin flies — were found carrying pollen, suggesting that it is a typical pollinator of the flower.
How fitting, given the smell.
Before this study, it was presumed that A. microstoma was pollinated by ground dwelling pollinators, such as ants. It isn't too surprising that flies would be a primary pollinator, though. After bees, flies are the second most important pollinator on the planet. Many plants have scents and appearances that seem to be trying to attract flies. Unsurprisingly, few of them are known for smelling pleasant.
Fool me once, fool me twice
Between the smell and the location, it is possible the flower simulates a food source or breeding area for the flies well enough to fool them repeatedly.
Additionally, the researchers used gas chromatography to analyze the chemicals and compounds that give the flowers their unique scent. Sixteen compounds were found, including sulfur- and nitrogen-containing molecules, both likely contributors to the powerful odor of the plant.
These compounds included the alkylpyrazine 2,5-dimethylpyrazine. This compound has a unique aroma — decaying beetles, mouse urine, and roasted nuts — so it is unlikely to be used as a perfume. It also can be found in cigarettes and is occasionally used as a food additive for flavor purposes.
Few plants produce this compound, leading the authors to conclude that the plant is producing it to attract specific pollinators. They also mention that the decaying remains of vertebrate animals don't produce this compound either, further strengthening the idea that the plant is trying to smell like decaying insects.
Study co-author Stefan Dötterl from the Botanical Gardens at the Paris-Lodron University of Salzburg explained, "Our results suggest that this is the first known case of a flower that tricks pollinators by smelling like dead and rotting insects rather than vertebrate carrion."
The authors note that the next area of study is to see how fond potential pollinators are of this particular odor. Studies hoping to answer that question are already underway. Let us hope the bugs like it, as it seems nobody else does.
Darwin was right again—sort of.
- Charles Darwin speculated that wingless insects thrived on windy islands because they weren't blown off the land.
- While the reasoning was slightly faulty, researchers have now proved Darwin's 165-year-old "wind hypothesis."
- This finding is yet another example of how environments shape the animals that inhabit them.
All animals adapt to their environment. Even humans, self-isolating animals that we are, are shaped by our surroundings. Every one of us is interdependent with the environment that we inhabit—it shapes us as much as we shape it.
While the Buddhist notion of interdependence dates back roughly 2,500 years, we didn't understand how profoundly the environment affects biology until Charles Darwin. Now one of his theories, long known as the "wind hypothesis," has been shown to be true. It only took 165 years to verify his observations.
To be fair, the wind isn't the only reason increasing numbers of insects no longer grow wings. But as a new study, published in Proceedings of the Royal Society B, shows, the wind is a major factor in this evolutionary decision.
Not that the world is about to be overrun with unwinged critters. Roughly 95 percent of the world's insect population can fly. After boating around coastal Morocco, Darwin noticed something odd on the island of Madeira: many local beetles (his personal passion) were wingless. He suggested flying beetles would have been blown off the island given the strong winds. He then speculated that apterous (un-winged) beetles were better suited for the environment.
The theory commenced with a bit of a bet between Darwin and his friend, geographical botanist Joseph Dalton Hooker, as explained by lead researcher, Rachel Leihy, a Ph.D. candidate at Monash University's School of Biological Sciences:
"He and the famous botanist Joseph Hooker had a substantial argument about why this happens. Darwin's position was deceptively simple. If you fly, you get blown out to sea. Those left on land to produce the next generation are those most reluctant to fly, and eventually evolution does the rest. Voilà."
Charles Darwin statue
Credit: Christian / Adobe Stock
Monash researchers looked at three decades of data on various insect species living in Antarctica and 28 Southern Ocean islands—including Svalbard, Jan Mayen, Ellef Ringnes, Bathurst, and St. Matthew—and discovered a trend: wind (as well as low air pressure and freezing temperatures) made flight nearly impossible to resident insects. They simply didn't have the energetic resources needed to take to the sky. Better to crawl around and scavenge.
Darwin wasn't completely right. He thought the evolutionary adaptations were due purely to wind throwing insects off the island. But nutrition matters too. Flight consumes a ton of energy. The windier it is, the harder insects have to work. Battling a gale requires an inordinate amount of calories. As the team writes,
"Strong winds can also inhibit normal insect flight activity, thereby increasing the energetic costs of flying or maintaining flight structures. This energy trade-off is more complex than Darwin's single-step displacement mechanism because it requires genetic linkage between traits associated with flight ability, flight propensity, and fecundity or survival."
Still, you have to hand it to the man. During a time when most humans assumed animals were all the result of metaphysical tinkering, Darwin gazed out into nature and connected the dots. His mind has inspired over a century-and-a-half of scientific progress as we continue to build on—and, as this study shows, prove—his theories.
Darwin knew that every animal is the product of its environment, and therefore must respect both its boons and its boundaries. Talk about a lesson we need today. Environments are known to become very hostile to foreign invaders when pushed too hard. Right now, we're courting disaster. Hopefully, we won't wait for evolution to ground our ambitions.
Stay in touch with Derek on Twitter and Facebook. His most recent book is "Hero's Dose: The Case For Psychedelics in Ritual and Therapy."