Tag: fly species

New giant wormlion fly species identified on the southern slopes of the Himalayas

This enigmatic new species of wormlion fly’s larvae construct clever pitfall traps to capture prey.

An enigmatic new species of wormlion fly, whose larvae construct clever pitfall traps to capture prey, has been revealed in a study led by researchers at Dali University in China.

The fly, described in a recent paper in the open-access journal ZooKeys, was identified after a 2025 expedition successfully collected adult specimens in Yadong County, southern Xizang. Unidentified larvae belonging to the same group had first been collected in the region forty-eight years earlier in 1978, but because the adult stage remained unknown, scientists had been unable to confirm its true identity until now.

Analysing the physical traits of the newly discovered insect, the research team noted that it is particularly large for its group, with adult bodies measuring up to 19.5 millimetres in length and wings reaching nearly 16 millimetres long. The fully grown larvae are even larger, reaching lengths between 20 and 28 millimetres, and they possess a single semicircular proleg bearing a distinct row of five to seven spines.

It has been named Vermitigris tsangyanggyatso, with the species name dedicated to Tsangyang Gyatso, the sixth Dalai Lama, who was a celebrated seventeenth-century Tibetan poet-monk from Xizang known for his romantic verse and unconventional life.

Habitats and habitus of Vermitigris tsangyanggyatso sp. nov. Image credit: Li-Xia Shan and Ji-Shen Wang.

The discovery increases the number of species recorded in China within the genus Vermitigris from one to two, expands the total number of species in the genus from four to five, and brings the total number of known living wormlion fly species in the world to sixty-seven.

The insect belongs to the brachyceran family Vermileonidae, a unique group of flies commonly known as wormlions. These flies are notable because their larvae employ a pitfall-feeding strategy that is evolutionarily convergent with pitfall-building antlions, making them the only known family of flies whose larvae capture prey by constructing funnel-shaped pits in loose sand or soil.

The team’s motivation to study this unique family stems from an unexpected discovery a decade ago:

“Well, it was probably an accidental discovery that first motivated us. In 2015, while searching for pit-building antlions on Cangshan Mountain in Dali, China, we discovered an unfamiliar larva that we found particularly interesting. However, because the adults have an extremely short lifespan, we failed for many years to determine its identity.

It was not until 2024 that we finally obtained adults through artificial rearing in the laboratory. It turned out to be a new species, which we named Vermiophis cangshanensis. This first discovery therefore took nine years. Since then, we have paid close attention to wormlions wherever we encounter them.”

Unlike some related lineages that diversified during the Late Mesozoic by developing elongated mouthparts to feed on nectar, this new species features a significantly shortened rostrum, suggesting that the adults do not feed at all during their final stage of life. Although adult flies were primarily found resting quietly on leaf surfaces near their larval breeding grounds on sunny days, one specimen was discovered further away around agricultural fields, indicating that the species possesses strong flight and dispersal capabilities.

The environment where the immature stages thrive consists of rain-protected microhabitats, which provide the stable microenvironments necessary for the wormlions to build their pitfall traps. The research team found the larvae living in three distinct types of sheltered habitats, including fine-grained soil under giant rocks, wood debris beneath a pavilion, and fine-grained river sands accumulated beside a river, with field observations indicating a strong preference for the river sands.

When asked about the specific physical features enabling the larvae to build effective traps across such diverse textures, the team noted:

“We honestly do not know yet. Perhaps future behavioural experiments will help answer this question.”

While wet forested regions have traditionally been shown to act as barriers to the dispersal of wormlion flies, this discovery highlights how the genus Vermitigris manages to thrive in such environments by exploiting these rain-protected microhabitats. The presence of this species on the southern slopes of the Himalayas suggests that the region serves as both a transitional zone and a biodiversity corridor, facilitating the penetration of Oriental elements into Eurasia.

Distribution of Vermitigris spp. Question mark (?) indicates an unconfirmed record from India (Oldroyd 1947).

The team elaborated on what this Himalayan discovery implies for the group’s evolutionary history:

“The previously known species were first discovered in tropical Southeast Asia, and these insects were therefore thought to be restricted to tropical regions. The discovery of this species suggests that they may also be capable of adapting to subtropical climates.

We hope that more unknown species will eventually be discovered in mainland Southeast Asia, such as Thailand, as well as in southwestern China, including Yunnan, Guizhou, and Sichuan Provinces.”

Vermitigris tsangyanggyatso is physically distinct from its closest relatives due to its uniform yellowish-brown to reddish-brown abdomen, which lacks the light and dark rings or longitudinal stripes seen on other species within the genus. Scientists believe that many neighbouring regions along the southern slopes of the Himalayas remain unsampled, meaning that further fieldwork could well yield additional members of this poorly documented group of flies.

Morphological characters of Vermitigris tsangyanggyatso sp. nov.

Reflecting on the deeper personal connection to this work from a science communication standpoint, co-author Ji-Shen Wang shared:

“I would say that although my primary research interest is the insect order Mecoptera (scorpionflies), I have gradually expanded my interests into Diptera (flies) as well.

As a naturalist, I find the diversity of life on Earth endlessly fascinating, and this curiosity about nature continually motivates me to explore and wonder. I would like to quote Herman Melville from Moby-Dick: ‘As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas, and land on barbarous coasts.’”

Original study:

Shan L-X, Wang J-S (2026) After forty-eight years: An enigmatic new wormlion fly from Xizang, China (Diptera, Vermileonidae). ZooKeys 1276: 249-262. https://doi.org/10.3897/zookeys.1276.184675

For more articles on zoology, visit the ZooKeys website and follow the journal on BlueSky and Facebook.

A New Species of Fly Found on the Lesser Brown Horseshoe Bat

A bizarre new species of parasitic fly sheds its wings and legs to live permanently embedded in a bat’s ear.

Imagine a fly that decides flying is overrated. Instead, it finds a bat, sheds its wings, drops its legs, and burrows into the host’s skin for the rest of its days. This is the reality of the genus Ascodipteron, a group of highly specialised bat flies that challenge our basic definition of what an insect looks like.

In a recent study published in the open-access journal ZooKeys, researchers led by Haoran Sun of Beijing Forestry University have identified a new member of this strange family in the Yunnan Province of China. It brings some fascinating, if slightly macabre, biological quirks to the table.

The newly discovered species has been named Ascodipteron euryale and was found on the lesser brown horseshoe bat, known scientifically as Rhinolophus stheno. This discovery is particularly significant because it represents the first time a fly from this genus has been documented on this specific species of bat. These flies often show an incredibly narrow host range and a strict preference for where they live on the bat’s body. In the case of Ascodipteron euryale, they prefer the base of the bat’s ear, the tragus, or the ear pinna.

Ascodipteron euryale sp. nov. and its host Rhinolophus stheno. (Image credit: Haoran Sun et al.).

The life of a female Ascodipteron fly is especially interesting. After a very brief period of seeking out a host, the female undergoes a radical transformation into what scientists call a neosome. It essentially becomes an endoparasite, embedded so deeply in the bat’s tissue that often only its posterior end is visible, protruding slightly so it can breathe and release larvae. This particular species was discovered in Xianren Cave, located in the Simao District of Pu’er City, at an elevation of 2428 meters above sea level.

Ascodipteron euryale sp. nov., ex. R. stheno – the top two images display the whole neosome. (Image credit: Haoran Sun et al.).

What makes Ascodipteron euryale stand out from its 17 known cousins? The most defining physical trait is the shape of its mesosternum, a part of its underside, which features gently rounded lobes on the back corners. Further, unlike many related flies that are covered in soft skin and easily removed, these neosomes were found encased in a fibrous cyst or shell – this is a reaction from the host bat’s own immune system, creating a protective barrier that makes the parasite very difficult to extract.

Ascodipteron euryale sp. nov., ex. R. stheno, head and thorax. (Image credit: Haoran Sun et al.).

The naming of the species is a clever nod to Greek mythology. The host bat, Rhinolophus stheno, shares a name with Stheno, one of the three Gorgon sisters who could turn onlookers to stone. The researchers decided to name the new fly euryale after Euryale, another of the Gorgon sisters. In the myths, these two sisters were immortal, and the authors note that this name choice reflects their hope that the deep-rooted biological association between this specific bat and its resident fly continues long into the future.

This research adds a sixth species of Ascodipteron to the records in China, emphasising the impressive biodiversity hidden within the country’s cave systems. It also raises new questions for future study, particularly regarding why some of these flies trigger the formation of fibrous shells while others do not. For now, Ascodipteron euryale remains a testament to the strange and highly specific ways life finds a niche (even if that niche is the inside of a bat’s ear)!

Original source:

Sun H, Ding L, Zhang D, Pape T (2026) Ascodipteron (Diptera, Nycteribiidae, streblid grade) from China: a new species from the lesser brown horseshoe bat, Rhinolophus stheno. ZooKeys 1273: 277-286. https://doi.org/10.3897/zookeys.1273.183551

Tiny fly from Los Angeles has a taste for crushed invasive snails

Living individual of Draparnaud’s glass snail
Photo by Kat Halsey

As part of their project BioSCAN – devoted to the exploration of the unknown insect diversity in and around the city of Los Angeles – the scientists at the Natural History Museum of Los Angeles County (USA) have already discovered numerous insects that are new to science, but they are still only guessing about the lifestyles of these species.

“Imagine trying to find a given 2 mm long fly in the environment and tracking its behavior: it is the smallest imaginable needle in the largest haystack. So when researchers discover new life histories, it is something worth celebrating,”

explains Dr. Brian Brown, lead author of a recent paper, published in the scholarly open-access Biodiversity Data Journal.

However, Brown and Maria Wong, former BioSCAN technician, while doing field work at the L.A. County Arboretum, were quick to reveal a curious peculiarity about one particular species discovered as part of the project a few years ago. They successfully lured female phorid flies by means of crushing tiny, invasive snails and using them as bait. In comparison, the majority of phorid flies, whose lifestyles have been observed, are parasitoids of social insects like ants.

Within mere seconds after the team crushed tiny invasive snails (Oxychilus draparnaudi), females representing the fly species Megaselia steptoeae arrived at the scene and busied themselves feeding. Brown and Wong then collected some and brought them home alive along with some dead snails. One of the flies even laid eggs. After hatching, the larvae were observed feeding upon the rotting snails and soon they developed to the pupal stage. However, none was reared to adulthood.

Female phorid fly feeding on a crushed Draparnaud’s glass snail
Photo by Kat Halsey

Interestingly, the host species – used by the fly to both feed on and lay eggs inside – commonly known as Draparnaud’s glass snail, is a European species that has been introduced into many parts of the world. Meanwhile, the studied fly is native to L.A. So far, it is unknown when and how the mollusc appeared on the menu of the insect.

To make things even more curious, species of other snail genera failed to attract the flies, which hints at a peculiar interaction worth of further study, point out the scientists behind the study, Brown and Jann Vendetti, curator of the NHM Malacology collection. They also hope to lure in other species of flies by crushing other species of snails.

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In recent years, the BioSCAN project led to other curious discoveries from L.A., also published in Biodiversity Data Journal. In 2016, a whole batch of twelve previously unknown scuttle fly species was described from the heart of the city. A year later, another mysterious phorid fly was caught ovipositing in mushroom caps after Bed & Breakfast owners called in entomologists to report on what they had been observing in their yard.

Original source:

Brown BV, Vendetti JE (2020) Megaselia steptoeae (Diptera: Phoridae): specialists on smashed snails. Biodiversity Data Journal 8: e50943. https://doi.org/10.3897/BDJ.8.e50943

New ‘big-armed fly’ species named after former California governor Arnold Schwarzenegger

New species can be named for all types of attributes, but Natural History Museum of Los Angeles County entomologist Brian Brown knew exactly what name to give a bizarre new fly species he discovered in the Brazilian Amazon.

“As soon as I saw those bulging legs, I knew I had to name this one after Arnold,” says Brown. “Not only is he a major cultural icon and an important person in the political realm, his autobiography gave me some hope that I could improve my body as a skinny teenager.” For these reasons, Brown says, the former governor deserves to have the new fly named in his honor.

His research article is published in the open access Biodiversity Data Journal.

The fly is impressive in other ways, Brown explains. “It is known only from one female specimen that we almost overlooked because it is so incredibly small.”

In fact, it is the world’s smallest known fly, according to Brown, who should know, since he had previously described what was formerly the world’s smallest fly, at 0.400 mm in body length. The new fly, named Megapropodiphora arnoldi, is just a fraction smaller, coming in at 0.395 mm.

MegapropodiphoraHowever, unlike the enlarged forelegs that prompted the naming, the mid- and hind legs appear to be highly reduced, and the wings reduced to tiny stubs.

Even though the fly has not been observed in the wild, Brown concludes that it is clearly a parasitoid, probably of ants or termites, based on its pointed, sharp ovipositor. He further speculates that these flies probably grab onto the hosts and “hold on for dear life” until they reach a nest or colony where they can parasitize their victims more effectively.

Brown has had considerable success finding new species of tiny flies, which he says are “the continuing frontier for insect discovery.”

Some of the more obvious, larger insects might have already been described, but by looking at smaller specimens, especially from remote, tropical sites, the entomologist finds that almost everything is new.

Even in his home city of Los Angeles, Brown and collaborators found that almost half of the phorid flies were previously unknown.

For example, it was last year that they finally figured why a secretive fly had been observed around mushrooms with no clear explanation for nearly 30 years. The revelation occurred when L.A. Bed & Breakfast owners Patsy Carter and Lisa Carter-Davis decided to alert entomologists about a phenomenon happening in their yard.

Back in 2016, Brian and his team described at once a total of twelve scuttle fly species new to science after ‘field’ trips in the backyards of houses around the city of angels.

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Original source:

Citation: Brown B (2018) A second contender for “world’s smallest fly” (Diptera: Phoridae). Biodiversity Data Journal 6: e22396. https://doi.org/10.3897/BDJ.6.e22396