Male dragonflies are known to engage in mid-air "dogfights" to defend their breeding territory, using different maneuvers than those they employ when hunting prey. A new paper published in the Journal of the Royal Society Interface concluded that relatively simple rules drive that behavior, namely that male dragonflies are trying to maintain a tactical position. This mirrors the tactics of human fighter pilots. The research could lead to the development of smarter drones capable of navigating with simple, vision-based guidance rather than complex computation.

Classic pursuits involving prey or mating rituals are asymmetric: there is a chaser and an evader, with each role requiring different maneuvers. In the case of male-on-male interactions, however, it is more of a mutual pursuit, per the authors, who thought that studying flight trajectories of insects or raptors could yield useful insights into the guidance laws that underlie the behavior. They chose the Trithemis Aurora species of dragonfly for study because the males are "fiercely territorial," and there are usually multiple males around a given pond, intent on defending their chosen perches. The dragonflies are also crimson-colored, making them easier to track.

Much of the prior research on dragonfly interactions relied on visual observations or single-camera recordings. For this study, the authors set up a portable stereovideographic rig with two shutter-synchronized cameras to record dragonfly interactions in both color and monochrome, and then reconstructed 102 paired male-on-male flight trajectories to capture the 3D kinematics. They also reconstructed nine trajectories for dragonflies intercepting prey for comparative purposes. This enabled the authors to develop a model for the rules governing the flight behavior.

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A butterfly that survives for nearly a year, while its closest relatives live only two weeks, offers a potential model for studying how aging and lifespan can evolve in nature.

A University of Bristol-led study published in Nature Communications reports that some Heliconius butterflies have evolved both longer lifespans and slower physical decline, distinguishing them from most other butterfly species studied to date.

Heliconius butterflies inhabit the rainforests of Central and South America, where most adult butterflies live only a few weeks. In the study, Heliconius hewitsoni reached a maximum lifespan of 348 days, while a related species, Dione juno, only survived about 14 days under observed conditions. This represents a 25-fold difference in maximum lifespan between two closely related species.

Old Age Without the Decline

Heliconius butterflies not only live longer than their relatives, but also show slower physical decline with age. The team, in collaboration with the Smithsonian Tropical Research Institute in Panama, measured grip strength in aging butterflies to assess physical decline. Older Heliconius hecale performed as well as the younger individuals tested, showing no detectable age-related decline in grip strength.

The team combined butterfly house data, mark–recapture field studies, and controlled lab experiments. In these cases, Heliconius butterflies consistently showed longer lifespans, lower mortality rates, and slower rates of aging than closely related species that do not feed on pollen.

The Pollen Connection

One hypothesis for their extended lifespan focuses on their unusual adult diet. While most butterflies feed only on nectar, Heliconius also consumes pollen, which was thought to provide the nutritional basis for its extended lifespan.

To test this idea, researchers compared pollen-feeding Heliconius hecale with its non-pollen-feeding relative, Dryas iulia. H. hecale maintained body mass and muscle performance longer than D. iulia. Even without pollen in its diet, H. hecale still outlived its relative by a wide margin. This suggests that diet alone does not explain Heliconius’s extended lifespan.

Dr. Jessica Foley, the study’s lead author from the University of Bristol’s School of Biological Sciences, explained that insects already show a huge range of lifespans. Some, like mayflies, live only a few days, while ant and termite queens can survive for decades. “This represents a roughly 5,000-fold difference within the class, compared with around a 100-fold difference in lifespan observed in mammals.”

Heliconius butterflies are notable because they have evolved both longer lifespans and slower rates of aging, allowing them to outlive close relatives from which they diverged only recently in evolutionary history.

A New Model for an Old Problem

Most aging research uses a limited set of laboratory organisms, such as mice, worms, and fruit flies, to study biological aging mechanisms. The heliconius butterfly provides a unique opportunity to study a long-lived species closely related to short-lived species, allowing for direct comparison in a natural context. Foley noted that comparing these two groups “can help reveal how lifespan is extended, making them a highly promising new model for research into the biology of aging and longevity.”

If pollen feeding and longevity evolved together but are not entirely dependent on each other, the next step is to identify the genetic and physiological changes responsible for both traits. Understanding these mechanisms in Heliconius butterflies could provide insight into how aging evolves across species.

Austin Burgess is a writer and researcher with a background in sales, marketing, and data analytics. He holds an MBA, a Bachelor of Science in Business Administration, and a data analytics certification. His work focuses on breaking scientific developments, with an emphasis on emerging biology, cognitive neuroscience, and archaeological discoveries.