Declining numbers of insects, coupled with climate change, can have devastating effects for people in more ways than one. But clever use of technologies like AI could keep them buzzing.
And because many insects serve as food for other species—bats, birds and freshwater fish—they’re an integral part of the ecosystem’s food chain. “If you like to eat good food, you should thank an insect,” says Scott Hoffman Black, an ecologist and executive director of the Xerces Society for Invertebrate Conservation in Portland, Oregon. “And if you like birds in your trees and fish in your streams, you should be concerned with insect conservation.”
Deforestation, urbanization, and agricultural spread have eaten away at large swaths of insect habitat. The increasingly poorly controlled use of insecticides, which harms unintended species, and the proliferation of invasive insect species that disrupt native ecosystems compound the problem.
“There is not a single reason why insects are in decline,” says Jessica L. Ware, associate curator in the Division of Invertebrate Zoology at the American Museum of Natural History in New York, and president of the Entomological Society of America. “There are over one million described insect species, occupying different niches and responding to environmental stressors in different ways.”
Jessica Ware, an entomologist at the American Museum of Natural History, is using DNA methods to monitor insects.
Credit:D.Finnin/AMNH
In addition to habitat loss fueling the decline in insect populations, the other “major drivers” Ware identified are invasive species, climate change, pollution, and fluctuating levels of nitrogen, which play a major role in the lifecycle of plants, some of which serve as insect habitants and others as their food. “The causes of world insect population declines are, unfortunately, very easy to link to human activities,” Lehmann says.
Climate change will undoubtedly make the problem worse. “As temperatures start to rise, it can essentially make it too hot for some insects to survive,” says Emily McDermott, an assistant professor in the Department of Entomology and Plant Pathology at the University of Arkansas. “Conversely in other areas, it could potentially also allow other insects to expand their ranges.”
Without Pollinators Humans Will Starve
We may not think much of our planet’s getting warmer by only one degree Celsius, but it can spell catastrophe for many insects, plants, and animals, because it’s often accompanied by less rainfall. “Changes in precipitation patterns will have cascading consequences across the tree of life,” says David Wagner, a professor of ecology and evolutionary biology at the University of Connecticut. Insects, in particular, are “very vulnerable” because “they’re small and susceptible to drying.”
For instance, droughts have put the monarch butterfly at risk of being unable to find nectar to “recharge its engine” as it migrates from Canada and New England to Mexico for winter, where it enters a hibernation state until it journeys back in the spring. “The monarch is an iconic and a much-loved insect,” whose migration “is imperiled by climate change,” Wagner says.
Warming and drying trends in the Western United States are perhaps having an even more severe impact on insects than in the eastern region. As a result, “we are seeing fewer individual butterflies per year,” says Matt Forister, a professor of insect ecology at the University of Nevada, Reno.
There are hundreds of butterfly species in the United States and thousands in the world. They are pollinators and can serve as good indicators of other species’ health. “Although butterflies are only one group among many important pollinators, in general we assume that what’s bad for butterflies is probably bad for other insects,” says Forister, whose research focuses on butterflies. Climate change and habitat destruction are wreaking havoc on butterflies as well as plants, leading to a further indirect effect on caterpillars and butterflies.
Different insect species have different levels of sensitivity to environmental changes. For example, one-half of the bumblebee species in the United States are showing declines, whereas the other half are not, says Christina Grozinger, a professor of entomology at the Pennsylvania State University. Some species of bumble bees are even increasing in their range, seemingly resilient to environmental changes. But other pollinators are dwindling to the point that farmers have to buy from the rearing facilities, which is the case for the California almond industry. “This is a massive cost to the farmer, which could be provided for free, in case the local habitats supported these pollinators,” Lehmann says.
For bees and other insects, climate change can harm the plants they depend on for survival or have a negative impact on the insects directly. Overly rainy and hot conditions may limit flowering in plants or reduce the ability of a pollinator to forage and feed, which then decreases their reproductive success, resulting in dwindling populations, Grozinger explains.
“Nutritional deprivation can also make pollinators more sensitive to viruses and parasites and therefore cause disease spread,” she says. “There are many ways that climate change can reduce our pollinator populations and make it more difficult to grow the many fruit, vegetable and nut crops that depend on pollinators.”
Disease-Causing Insects Can Bring More Outbreaks
While some much-needed insects are declining, certain disease-causing species may be spreading and proliferating, which is another reason for human concern. Many mosquito types spread malaria, Zika virus, West Nile virus, and a brain infection called equine encephalitis, along with other diseases as well as heartworms in dogs, says Michael Sabourin, president of the Vermont Entomological Society. An animal health specialist for the state, Sabourin conducts vector surveys that identify ticks and mosquitoes.
Scientists refer to disease-carrying insects as vector species and, while there’s a limited number of them, many of these infections can be deadly. Fleas were a well-known vector for the bubonic plague, while kissing bugs are a vector for Chagas disease, a potentially life-threatening parasitic illness in humans, dogs, and other mammals, Sabourin says.
As the planet heats up, some of the creepy crawlers are able to survive milder winters or move up north. Warmer temperatures and a shorter snow season have spawned an increasing abundance of ticks in Maine, including the blacklegged tick (Ixodes scapularis), known to transmit Lyme disease, says Sean Birkel, an assistant professor in the Climate Change Institute and Cooperative Extension at the University of Maine.
Coupled with more frequent and heavier precipitation, rising temperatures bring a longer warm season that can also lead to a longer period of mosquito activity. “While other factors may be at play, climate change affects important underlying conditions that can, in turn, facilitate the spread of vector-borne disease,” Birkel says.
For example, if mosquitoes are finding fewer of their preferred food sources, they may bite humans more. Both male and female mosquitoes feed on sugar as part of their normal behavior, but if they aren’t eating their fill, they may become more bloodthirsty. One recent paper found that sugar-deprived Anopheles gambiae females go for larger blood meals to stay in good health and lay eggs. “More blood meals equals more chances to pick up and transmit a pathogen,” McDermott says, He adds that climate change could reduce the number of available plants to feed on. And while most mosquitoes are “generalist sugar-feeders” meaning that they will likely find alternatives, losing their favorite plants can make them hungrier for blood.
Similar to the effect of losing plants, mosquitoes may get turned onto people if they lose their favorite animal species. For example, some studies found that Culex pipiens mosquitoes that transmit the West Nile virus feed primarily on birds in summer. But that changes in the fall, at least in some places. Because there are fewer birds around, C. pipiens switch to mammals, including humans. And if some disease-carrying insect species proliferate or increase their ranges, that increases chances for human infection, says McDermott. “A larger concern is that climate change could increase vector population sizes, making it more likely that people or animals would be bitten by an infected insect.”
Science Can Help Bring Back the Buzz
To help friendly insects thrive and keep the foes in check, scientists need better ways of trapping, counting, and monitoring insects. It’s not an easy job, but artificial intelligence and molecular methods can help. Ware’s lab uses various environmental DNA methods to monitor freshwater habitats. Molecular technologies hold much promise. The so-called DNA barcodes, in which species are identified using a short string of their genes, can now be used to identify birds, bees, moths and other creatures, and should be used on a larger scale, says Wagner, the University of Connecticut professor. “One day, something akin to Star Trek’s tricorder will soon be on sale down at the local science store.”
Scientists are also deploying artificial intelligence, or AI, to identify insects in agricultural systems and north latitudes where there are fewer bugs, Wagner says. For instance, some automated traps already use the wingbeat frequencies of mosquitoes to distinguish the harmless ones from the disease-carriers. But new technology and software are needed to further expand detection based on vision, sound, and odors.
“Because of their ubiquity, enormity of numbers, and seemingly boundless diversity, we desperately need to develop molecular and AI technologies that will allow us to automate sampling and identification,” says Wagner. “That would accelerate our ability to track insect populations, alert us to the presence of new disease vectors, exotic pest introductions, and unexpected declines.”
Swiss researchers have found a type of brain cell that appears to be a hybrid of the two other main types — and it could lead to new treatments for brain disorders.
A new brain cell: Researchers at the Wyss Center for Bio and Neuroengineering and the University of Lausanne believe they’ve definitively proven that some astrocytes do actively participate in neurotransmission, making them a sort of hybrid of neurons and glial cells.
According to the researchers, this third type of brain cell, which they call a “glutamatergic astrocyte,” could offer a way to treat Alzheimer’s, Parkinson’s, and other disorders of the nervous system.
“Its discovery opens up immense research prospects,” said study co-director Andrea Volterra.
The study: Neurotransmission starts with a neuron releasing a chemical called a neurotransmitter, so the first thing the researchers did in their study was look at whether astrocytes can release the main neurotransmitter used by neurons: glutamate.
By analyzing astrocytes taken from the brains of mice, they discovered that certain astrocytes in the brain’s hippocampus did include the “molecular machinery” needed to excrete glutamate. They found evidence of the same machinery when they looked at datasets of human glial cells.
Finally, to demonstrate that these hybrid cells are actually playing a role in brain signaling, the researchers suppressed their ability to secrete glutamate in the brains of mice. This caused the rodents to experience memory problems.
“Our next studies will explore the potential protective role of this type of cell against memory impairment in Alzheimer’s disease, as well as its role in other regions and pathologies than those explored here,” said Andrea Volterra, University of Lausanne.
But why? The researchers aren’t sure why the brain needs glutamatergic astrocytes when it already has neurons, but Volterra suspects the hybrid brain cells may help with the distribution of signals — a single astrocyte can be in contact with thousands of synapses.
“Often, we have neuronal information that needs to spread to larger ensembles, and neurons are not very good for the coordination of this,” researcher Ludovic Telley told New Scientist.
Looking ahead: More research is needed to see how the new brain cell functions in people, but the discovery that it plays a role in memory in mice suggests it might be a worthwhile target for Alzheimer’s disease treatments.
The researchers also found evidence during their study that the cell might play a role in brain circuits linked to seizures and voluntary movements, meaning it’s also a new lead in the hunt for better epilepsy and Parkinson’s treatments.
“Our next studies will explore the potential protective role of this type of cell against memory impairment in Alzheimer’s disease, as well as its role in other regions and pathologies than those explored here,” said Volterra.
In a recent research trial, patients with Parkinson's disease reported that their symptoms had improved after stem cells were implanted into their brains. Martin Taylor, far right, was diagnosed at age 32.
For years, there's been little improvement in the standard treatment. Patients are typically given the drug levodopa, a chemical that's absorbed by the brain’s nerve cells, or neurons, and converted into dopamine. This drug addresses the symptoms but has no impact on the course of the disease as patients continue to lose dopamine producing neurons. Eventually, the treatment stops working effectively.
BlueRock Therapeutics, a cell therapy company based in Massachusetts, is taking a different approach by focusing on the use of stem cells, which can divide into and generate new specialized cells. The company makes the dopamine-producing cells that patients have lost and inserts these cells into patients' brains. “We have a disease with a high unmet need,” says Ahmed Enayetallah, the senior vice president and head of development at BlueRock. “We know [which] cells…are lost to the disease, and we can make them. So it really came together to use stem cells in Parkinson's.”
In a phase 1 research trial announced late last month, patients reported that their symptoms had improved after a year of treatment. Brain scans also showed an increased number of neurons generating dopamine in patients’ brains.
Increases in dopamine signals
The recent phase 1 trial focused on deploying BlueRock’s cell therapy, called bemdaneprocel, to treat 12 patients suffering from Parkinson’s. The team developed the new nerve cells and implanted them into specific locations on each side of the patient's brain through two small holes in the skull made by a neurosurgeon. “We implant cells into the places in the brain where we think they have the potential to reform the neural networks that are lost to Parkinson's disease,” Enayetallah says. The goal is to restore motor function to patients over the long-term.
Five patients were given a relatively low dose of cells while seven got higher doses. Specialized brain scans showed evidence that the transplanted cells had survived, increasing the overall number of dopamine producing cells. The team compared the baseline number of these cells before surgery to the levels one year later. “The scans tell us there is evidence of increased dopamine signals in the part of the brain affected by Parkinson's,” Enayetallah says. “Normally you’d expect the signal to go down in untreated Parkinson’s patients.”
"I think it has a real chance to reverse motor symptoms, essentially replacing a missing part," says Tilo Kunath, a professor of regenerative neurobiology at the University of Edinburgh.
The team also asked patients to use a specific type of home diary to log the times when symptoms were well controlled and when they prevented normal activity. After a year of treatment, patients taking the higher dose reported symptoms were under control for an average of 2.16 hours per day above their baselines. At the smaller dose, these improvements were significantly lower, 0.72 hours per day. The higher-dose patients reported a corresponding decrease in the amount of time when symptoms were uncontrolled, by an average of 1.91 hours, compared to 0.75 hours for the lower dose. The trial was safe, and patients tolerated the year of immunosuppression needed to make sure their bodies could handle the foreign cells.
Claire Bale, the associate director of research at Parkinson's U.K., sees the promise of BlueRock's approach, while noting the need for more research on a possible placebo effect. The trial participants knew they were getting the active treatment, and placebo effects are known to be a potential factor in Parkinson’s research. Even so, “The results indicate that this therapy produces improvements in symptoms for Parkinson's, which is very encouraging,” Bale says.
Tilo Kunath, a professor of regenerative neurobiology at the University of Edinburgh, also finds the results intriguing. “I think it's excellent,” he says. “I think it has a real chance to reverse motor symptoms, essentially replacing a missing part.” However, it could take time for this therapy to become widely available, Kunath says, and patients in the late stages of the disease may not benefit as much. “Data from cell transplantation with fetal tissue in the 1980s and 90s show that cells did not survive well and release dopamine in these [late-stage] patients.”
Searching for the right approach
There's a long history of using cell therapy as a treatment for Parkinson's. About four decades ago, scientists at the University of Lund in Sweden developed a method in which they transferred parts of fetal brain tissue to patients with Parkinson's so that their nerve cells would produce dopamine. Many benefited, and some were able to stop their medication. However, the use of fetal tissue was highly controversial at that time, and the tissues were difficult to obtain. Later trials in the U.S. showed that people benefited only if a significant amount of the tissue was used, and several patients experienced side effects. Eventually, the work lost momentum.
“Like many in the community, I'm aware of the long history of cell therapy,” says Taylor, the patient living with Parkinson's. “They've long had that cure over the horizon.”
In 2000, Lorenz Studer led a team at the Memorial Sloan Kettering Centre, in New York, to find the chemical signals needed to get stem cells to differentiate into cells that release dopamine. Back then, the team managed to make cells that produced some dopamine, but they led to only limited improvements in animals. About a decade later, in 2011, Studer and his team found the specific signals needed to guide embryonic cells to become the right kind of dopamine producing cells. Their experiments in mice, rats and monkeys showed that their implanted cells had a significant impact, restoring lost movement.
Studer then co-founded BlueRock Therapeutics in 2016. Forming the most effective stem cells has been one of the biggest challenges, says Enayetallah, the BlueRock VP. “It's taken a lot of effort and investment to manufacture and make the cells at the right scale under the right conditions.” The team is now using cells that were first isolated in 1998 at the University of Wisconsin, a major advantage because they’re available in a virtually unlimited supply.
Other efforts underway
In the past several years, University of Lund researchers have begun to collaborate with the University of Cambridge on a project to use embryonic stem cells, similar to BlueRock’s approach. They began clinical trials this year.
A company in Japan called Sumitomo is using a different strategy; instead of stem cells from embryos, they’re reprogramming adults' blood or skin cells into induced pluripotent stem cells - meaning they can turn into any cell type - and then directing them into dopamine producing neurons. Although Sumitomo started clinical trials earlier than BlueRock, they haven’t yet revealed any results.
“It's a rapidly evolving field,” says Emma Lane, a pharmacologist at the University of Cardiff who researches clinical interventions for Parkinson’s. “But BlueRock’s trial is the first full phase 1 trial to report such positive findings with stem cell based therapies.” The company’s upcoming phase 2 research will be critical to show how effectively the therapy can improve disease symptoms, she added.
The cure over the horizon
BlueRock will continue to look at data from patients in the phase 1 trial to monitor the treatment’s effects over a two-year period. Meanwhile, the team is planning the phase 2 trial with more participants, including a placebo group.
For patients with Parkinson’s like Martin Taylor, the therapy offers some hope, though Taylor recognizes that more research is needed.
BlueRock Therapeutics
“Like many in the community, I'm aware of the long history of cell therapy,” he says. “They've long had that cure over the horizon.” His expectations are somewhat guarded, he says, but, “it's certainly positive to see…movement in the field again.”
"If we can demonstrate what we’re seeing today in a more robust study, that would be great,” Enayetallah says. “At the end of the day, we want to address that unmet need in a field that's been waiting for a long time.”