Scientists at Work: Why Do Mosquitoes Bite You?

This summer, we’re taking another look at one of the peskiest and deadliest insects on the planet: the mosquito. Millions of people are infected each year by diseases transmitted through mosquito bites, such as dengue fever, yellow fever, and malaria. In this episode, which originally aired in 2019, mosquito expert Carolyn “Lindy” McBride, a 2015 Pew biomedical scholar, shares the science behind why you may be more susceptible than other people to their bites.

As artificial intelligence grows in popularity, new data centers must accommodate the systems’ enormous need for energy. At the same time, household energy usage is rising throughout the United States. These increasing demands for electricity are stressing our nation’s aging electric grid. In this episode of “After the Fact,” we travel to Houston—the epicenter of the U.S. power industry—to talk with experts, journalists, and electricity providers about why investments in modernizing the grid are necessary for preventing higher energy bills for consumers, or worse, blackouts that leave communities in the dark. We also explore how innovative solutions such as tapping into battery storage and “microgrids” could connect nearly 2,600 gigawatts of alternative energy capacity to the grid, which would double the nation’s available power supply.

Because of their massive size, blue whales are known as the ocean’s “gentle giants.”  They are vital to the ocean ecosystem, but their numbers are declining. In this episode, 2016 Pew marine fellow Dr. Asha de Vos unpacks the significance of blue whales to our ocean’s health and how effects from human activity, such as increased shipping and the whale-watching industry, influence the blue whale’s population and migratory pattern. Since this episode first aired in 2019, de Vos has continued conservation efforts through her organization, Oceanswell, and has advanced research on the effects of plastic pollution in Sri Lanka.

Have you tried to figure out whether the fish you eat is sustainably sourced? At least 1 in 5 fish caught in the global ocean is a product of illegal, unreported, and unregulated fishing—one of the main threats to the health of the ocean. In this episode, part of our “From Lab to Life” series, we hear from Grantly Galland, who supports The Pew Charitable Trusts’ work on fisheries around the world. Grant tells us about his previous career as a fish biologist and researcher and how he traded in his wetsuit for a business suit to support policies leading to more sustainable fish stocks and to protect the marine environment from overfishing. 

Each year, The Pew Charitable Trusts releases the “State of the City” report, which offers a data-rich snapshot of Pew’s hometown, Philadelphia. In this episode, Katie Martin, who leads Pew’s Philadelphia research and policy initiative, breaks down the highlights from the 2025 edition. She discusses the city’s successes, such as the decrease in poverty—at 20.3%, it’s the lowest it’s been in more than two decades—and its ongoing challenges, including the decline in homeownership, and how this troubling trend impacts Philadelphia’s ranking as a city of homeowners.

According to Pew Research Center, 55% of U.S. parents report being extremely or very concerned about the mental health of teens today. And several factors are driving that concern: increased influence of technology and social media, lingering effects of the pandemic, and social pressures like extracurricular activities and academic performance. Substance use is also linked with mental health and is occurring at younger ages with a rise in youth overdoses.  Mental health wellness and prevention programs from previous generations, some of which are still used today, have been ineffective or even counterproductive. So, what strategies actually work? In this episode of “After the Fact,” psychologists Obari Adéye Cartman and Sharon Hoover, as well as Pew’s Jessica Roark, discuss how to improve youth mental health programs and address substance use.   If you or someone you know needs help with substance use, visit www.findtreatment.gov.

Story:  Wildfires have once again made headlines, highlighting the growing intensity and frequency of natural disasters across the United States. And these disasters leave more than destruction in their wake; they have lasting effects on communities, including expensive recovery bills. In fact, 2024 was the fourth-costliest year on record with 27 natural disasters that resulted in at least $1 billion in damage each. In this episode of “After the Fact,” we speak to Pew’s Colin Foard and Caitlyn Wan Smith about how states can prepare better financially for natural disasters rather than reacting to emergencies. And Kimiko Barrett, a research and policy analysist with Headwaters Economics, discusses why wildfires pose a particularly difficult challenge to state budgets and local communities. 

Stat: 1/3: Placental-related disorders, such as miscarriage and pre-eclampsia, affect around a third of human pregnancies. Story: The placenta is a temporary yet vital organ that can have long-term effects on the lives of babies and mothers. But it’s often discarded and remains an understudied part of pregnancy.  In this episode of our “From Lab to Life” series, Geetu Tuteja describes how her lab at Iowa State University is working to better understand the placenta’s functions and why placental disorders start. She also discusses how her background in genomics and computational biology informs the way she conducts her research. 

Stat: 40%: Up to 40% of the food supply in the United States is wasted each year, according to the U.S. Department of Agriculture. Story: When you see the perfect displays of produce in grocery stores, do you ever wonder whether it’s all sold before it spoils? It isn’t, and stores often pay to send unpurchased produce to landfills. In this episode of “After the Fact,” Evan Ehlers, founder of Sharing Excess, shares how his organization is working to solve what he calls “the world’s dumbest problem.” As a college student in Philadelphia, Ehlers saw how this problem of food waste could be prevented and hunger could be addressed in the United States, where millions of people. lack access to three healthy meals per day. In just a few years, Sharing Excess—which receives support from the Pew Fund for Health and Human Services in Philadelphia—has evolved from a group of college volunteers to a growing organization that redistributes millions of pounds of food across the country to people in need. Pew’s Kristin Romens discusses the factors that contribute to food insecurity for individuals and families—and how funding organizations that support economic mobility projects can improve community outcomes.