Fruit fly sperm are gigantic—about 40 times larger than human sperm, according to scientific research published in June 2026.

Fruit fly experiments helped identify genes responsible for major body development

The insects' fast life cycle and affordability have allowed geneticists to quickly identify which genes are responsible for limbs, eyes, and other body structures by inducing mutations. The same genes may be responsible for different parts of a species' body, such as limb-building genes being responsible for wing pigmentation in butterflies.

Fruit fly experiments show personality emerges, in part, from genetic factors

A 2025 study revealed that fruit flies exhibit unique behavioral preferences, akin to personalities, which could be artificially selected for when breeding to modify behavioral variability. This variability can be adaptive in unpredictable environments.

View an illustrative journey of sperm cells navigating toward fertilization

In this series of comic-style panels, a "fellowship" of sperm cells travels through fictionalized versions of reproductive anatomy on their way to an egg cell. Each panel includes informative commentary on each step of the adventure, with research insights provided by a reproductive biologist, a biomedical scientist, and an andrologist.

Sleep deprivation leads to buildup of danger molecules in the gut

Fruit flies genetically engineered to be awake for as long as they live tend to live half as long as their well-rested brethren. Analysis shows these modified flies suffer from a buildup of DNA-destroying reactive oxygen species in their guts. When enabled to sleep, the flies live as long as their counterparts.

The number and quality of sperm in men's semen is down, giving rise to various movements to avoid 'spermpocalypse'

A typical fertile, healthy young man produces over 100 million spermatozoa, or sperm cells, in his testicles every day. Scientists agree sperm figures are generally moving in the wrong direction, but also emphasize there's still a lot to learn about sperm.

In 2017, researchers won a Nobel Prize for their work controlling fruit fly circadian rhythms

This detailed circadian rhythm infographic breaks down a day in the biological life of a fly, providing a peek at some of the groundbreaking work that elicited a Nobel Prize in Physiology or Medicine.

Only about 0.0001% of sperm, on average, successfully reach the uterine cavity

We've evolved to make pregnancy a complex and difficult process. From the initial development of the blastocyst, to the energy and nutrients needed to grow a new human, our bodies are both fighting and supporting fetal development.

Billions of flies are being dropped from the sky

The US is dropping billions of sterile flies to stop a deadly parasite. Screwworm maggots eat animals alive, so scientists are collapsing the population by ensuring females can’t reproduce.

Scientists first observed a sperm and an egg uniting in 1876

Throughout human history, scholars and researchers have speculated on the origin of human reproduction. It wasn't until the late-19th century that the physical process of egg fertilization via sperm cells was observed (in sea urchins), forming the basis for modern fertility research.

Various pollutants may be contributing to a male infertility crisis

Male infertility, due to declining sperm counts or quality, accounts for about half of the cases of infertility among couples. Recent research has found that global sperm counts fell, on average, by 1.2% per year between 1973 and 2018—from 104 million to 49 million per milliliter. From 2000, this rate of decline accelerated to more than 2.6% per year. (Some users may encounter a paywall.)

Model organisms like yeast, mice, and flies help scientists decode the human body

Some species are used to quickly study the effects of human diseases and treatments because they are short-lived and have similar systems to those found in humans. Bacteria, like E. coli, have been used as human proxies given their rapid growth and ease of genetic manipulability.

Metamorphosis evolved over millions of years as species that hatched as smaller versions of adults started exhibiting genetic mutations that differentiated juvenile and adult bodies.

See a timeline of landmark discoveries in the field of genetics to gain a better understanding of more than a century of advances.

A new AI-assisted reproductive technique is finding 'hidden' sperm cells for those with very low sperm counts

Known as the Star system—for Sperm Track and Recovery—it uses artificial intelligence to help identify and locate "hidden" sperm in men with a rare infertility condition called azoospermia. The condition affects about 1% of men, and these individuals have sperm counts low enough that the individual spermatozoa in their ejaculate may be undetectable. In late 2025, the first baby was born after the child's parents used this assistive technique to locate sperm.

Tracking butterfly migration via the pollen they collect

Trillions of insects migrate around the world each year, but many are too small to track with physical trackers, leaving their migratory routes a mystery. In recent years, scientists have utilized pollen grains collected from butterflies to analyze which plants that pollen originated from—providing substantial data to infer the insect's specific route. Research has shed light on many insects' migrations since, including the Painted Lady butterfly. Read more and see a map here.

Scientific advances are unlocking a wide range of alternatives to IVF

From refined artificial insemination and microsurgical sperm extraction to experimental uterine transplants, scientific innovation is rapidly advancing potential fertilization technologies. But they come along with costly trials, some ethical dilemmas, regulatory issues, and more.

Fireflies light up to provide mating signals and warnings to predators

Variations in the illumination patterns and flight paths while emitting light have been observed across firefly species. Some species instead rely on pheromones if they are primarily active during the day or have lost the ability to illuminate.

Malaria mosquitoes in a lab were wiped out using CRISPR

Scientists at Imperial College London disabled a gene in female Anopheles gambiae mosquitoes to make them infertile and propagated the infertility mutation at unnaturally high rates using a gene drive. The entire population collapsed within a dozen generations, showing promise for subsequent with mosquitoes in mimicked tropical environments.

Why scientists are making robot insects

Insects have much to teach us about flying, jumping, moving quickly, and more. So, roboticists are studying how insects do the ridiculous things they do, like walk on water or jump fifty times their body height, to inform their design and engineering of a new slate of robots: tiny ones. Learn the future of this type of robot with this fascinating video with insights into both insects and robots.

South American lungfish has the largest animal genome, with 91 billion base pairs

This genome is 30 times larger than a human's due to significant amounts of "junk DNA" and jumping genes, or transposons. Transposons can jump or copy over to other parts of a genome and may aid adaptation.

Dragonfly migration season is believed to run from August to November

Researchers know much less about dragonfly migrations than they do about bird or whale migrations. However, North America may have up to 18 migratory dragonfly species. A recent study revealed that the species undertakes complex long-distance migrations every year that span generations and seem to be influenced by temperature, making them particularly vulnerable to climate change.

Sex determination isn't all XX and XY

We're generally taught that chromosomes determine an animal's sex, but it is way more nuanced than that. Watch this 12-minute video to find out how.

Over 1,500 insect species pollinate plants in the UK

These insects—including bumblebees, moths, butterflies, and beetles—play a crucial role in the reproduction of flowering plants, also known as angiosperms. They do so by transferring pollen from the male reproductive organ—the anther—to the female one—the stigma—which enables the plant to produce fruit.

Pollinators help develop seeds by transferring pollen between flowering plants

As bees approach a bright, colorful flower for nectar, they bump into its stamen—the flower's male reproductive organ—and pollen gets stuck to the pollinator's body. This pollen can then be deposited on another flower's sticky pistil—the flower's female reproductive organ—which brings the pollen down to the ovule for fertilization.

Cells cannot grow forever due to escalating inefficiency in transporting chemicals

As cells get larger, their volume grows much faster than the surface area through which nutrients and waste products pass, creating a bottleneck that eventually causes cells to die. This forces nearly all organisms visible to the naked eye to comprise enormous numbers of smaller cells, such as the approximately 30 trillion found in the average adult human.

How women grow tiny humans inside of them

Pregnancy is a complex biological journey, lasting about 40 weeks. When a sperm fertilizes an egg, that event triggers intricate cellular and hormonal processes, driven by hardwired cellular instructions, which lead to cell division, differentiation, and development—ultimately culminating in the birth of a baby.

Particle accelerators have been used to reveal detailed ant anatomy

Using a synchrotron facility at the Karlsruhe Institute of Technology in Germany, a pair of X-ray beams swept across about 2,200 ant specimens to create over 200 terabytes of projection images from multiple angles. The images were compiled into micrometer-resolution 3D reconstructions of 792 species, which are freely accessible on the Antscan platform.

Explore 3D models of some of the most dangerous viruses, allowing us to understand these and other pathogens in new ways.

The fish can climb walls

Scientists in Brazil captured rare footage of bumblebee catfish climbing waterfalls. How they do it is clear, but why remains a mystery.

View the fluorescently stained internal structures of a tardigrade

The photograph won the Olympus Global Life Science Light Microscopy Americas regional award in 2019. Using chemicals from biofluorescent organisms, the image illuminates internal structures with multiple hues in an otherwise mostly colorless organism.

Swarms of mechanical bees may one day support natural pollination

Engineers are racing to create tiny robot bees that can be programmed to mimic natural bee behavior, helping in specific scenarios such as indoor farming and space agriculture. Battery life challenges may be solved by having these robots accompanied by a nearby "mother" drone power supply.

In vitro gametogenesis: using induced stem cells to fertilize eggs

Using stem cells from skin and mouth cells could save hopeful parents time and money and spare egg donors from significant amounts of discomfort throughout the process. There are potential consequences, not just for infertility treatment, but for the ability to create customized cells of any type.

IVF procedures fertilize eggs outside the body in a laboratory dish

In vitro fertilization is a complex and expensive set of procedures that potential parents dealing with infertility or genetic disorders may turn to when other methods are unavailable. IVF births account for 2% to 3% of all live births in the US annually.

What a tiny marine worm can tell us about our brains

Meet the amphioxus, a small eel-like animal that has a lot to teach us about brain evolution. The genetic roots of our brains can be seen in these unusual creatures. This three-minute educational video focuses on the evolutionary history of the human brain through these odd little critters with a 500-million-year-old history.

Meet siphonophores, breathtaking jellyfish-like organisms

Siphonophores are colonial jelly-like creatures made up of specialized segments that work together as one. They're fairly unknown despite being a significant sea predator. Sink into their strange beauty with this video.

Bioluminescence provides organisms with a method of hunting, defense, or mating

Unlike glow sticks, bioluminescent reactions use renewable resources like oxygen and ATP. This ability allows fireflies to mate and deter predators, anglerfish to confuse and attract prey, and deep-sea shrimp to defend themselves by vomiting glowing slush.

The world's weirdest flowers

We mostly marvel at the beauty of flowers, but some kinds of flowers are incredibly weird. This video highlights 15 of the world's strangest flowers, from the massive Titan Arum to the rare Lady Slipper Orchid.

One dad, one hundred babies

A look at the companies offering surrogacy to the ultrarich—including Chinese men taking their reproductive cues from Elon Musk.

Why are there as many males as females?

Pretty much every species breaks down with an equal sex-ratio, with roughly the same number of males as females. But on the surface, it appears that most species wouldn't need many males to keep the population growing, with their energy-efficient, abundant sex cell production. So why is it equal? Scientists argue an equal ratio is the most evolutionarily stable. Learn about this quirk of biology here.

Follow an IVF procedure from lab to transplant

What happens once eggs are harvested from an ovary? How does an embryo form within a petri dish? This detailed video offers a glimpse of the transformations eggs experience as women age, and how sperm are injected into eggs in some forms of IVF treatment.

Watch insects and animal pollinators in slow motion

Louie Schwartzberg's "Moving Art" series showcases slow-motion footage of oceans, forests, deserts, flowers, and more. In this excerpt, organisms such as bats, monarch butterflies, bees, and hummingbirds are shown interacting with one another and with flowering plants.

Watch how scientists learn about hurricanes by flying into them

A specialized fleet of Air Force planes is built to fly into hurricanes and gather critical data from inside the storm. Beyond radar and microwave sensors, the planes are equipped with dropsondes—small instruments dropped into storms to measure pressure, temperature, and wind.

Explore a 3D model of the influenza virus

This interactive 3D model reveals the influenza virus’s structure—its outer coat and spike proteins—and compares it with other well-known viruses, offering a clear view of how flu differs from pathogens like HIV or coronaviruses.

Watch a salamander grow from fertilization to hatching

New microscopy techniques have allowed scientists to image the development of animal embryos with unprecedented detail. This six-minute time-lapse reveals the development of a salamander from initial fertilization to hatching from an egg.

Synchrotron radiation has revealed the fur color of creatures millions of years old

When electrons are accelerated in the loop, they produce intense X-rays that can reveal properties of a sample struck by them, just as X-rays can be used to show bone structure in humans. Studying the reflected light from fossils can uncover the presence of known pigmentation compounds.

Like fingerprints, brain anatomy is unique too

Researchers have discovered that a combination of experiences and genetic factors shape the anatomy of the human brain. They found even quick experiences affect the brain’s genetic makeup, which—over time—means every person develops a completely unique brain anatomy. While brain imaging could be used to identify individuals, it remains much more expensive than fingerprinting for now. Read to found out more about this study from the University of Zurich.

Cells modify their internal spacing to improve biochemical reaction efficiencies

Studies involving microscopy and genetic engineering tools in yeast and human cells show ribosomes act as crowding agents—much like packing peanuts—and their concentrations are actively tuned to alter the rate of cellular functions. However, these concentrations and cell crowding levels vary across different tissues and cell types.

Without dinosaurs, plants could produce fleshy fruits with bigger seeds

Previously disturbed by massive herbivores, denser and darker forests shifted plant evolution, reaching the greatest diversity of seed sizes, fruit sizes, and fruit types about 50 million years ago.

There are at least 6 fascinating examples of mind-controlling parasites

Parasitic organisms—including flatworms and barnacles, not just fungi—can modify animal behavior. They can give rise to dancing fish, pulsating snails, suicidal rats, and more. Though some of these pathogens can sicken humans, there is no strong evidence that any can control human behavior.

Has anyone had sex in space?

Reproduction is a basic human function, and while we've spent decades in space, no research has been done into the process. With many discussing the possibility of human-occupied bases on the moon, Mars, and more, understanding how sex works outside...