Eight new pleasing lacewing species reveal China’s hidden insect diversity

Deep in the mountain forests of southwestern China, entomologists have uncovered a surprising wealth of insect life hiding in plain sight. A new study published in the Deutsche Entomologische Zeitschrift describes eight previously unknown species of pleasing lacewings, delicate insects whose males bear extravagantly comb-like antennae. The discovery, based on specimens collected over the past five years, raises the number of known Chinese species of the genus Dilar to 49 and strengthens the case that this region is one of the world’s most important centres of diversity for the family Dilaridae.

Pleasing lacewings are small neuropteran insects, related to green lacewings and antlions, found across the Palaearctic and Oriental regions. The genus Dilar, established in 1838, is by far the most species-rich member of its family, with 95 described living species worldwide. Despite their largely similar external appearance, these insects conceal remarkable anatomical variety in their genital structures, which taxonomists rely on to tell species apart. China has long been recognised as a hotspot for the genus, with 41 species recorded before this latest study, more than any other country.

The new research, led by entomologists at the Entomological Museum of China Agricultural University in Beijing, describes eight new species: Dilar jiquanyui, D. lanlingensis, D. lulanae, D. puerensis, D. qiongduensis, D. tuyuezhengi, D. weiningensis and D. yangyingae. All were collected from Oriental China, and six of them come from the country’s southwest, reinforcing the status of this area as a key distribution centre for the genus. The species were named in honour of the collectors who found them and after historic place names connected to their type localities.

To characterise the new species, the team prepared and examined the genitalia of male and female specimens using potassium hydroxide maceration, clearing the abdominal apex at 120 degrees Celsius for six to eight minutes before transferring the structures to glycerine for study. Photographs were taken with a Nikon D800 digital camera and a Leica DM 2000 optical microscope, while detailed line drawings of the genitalia were produced by hand using a stereomicroscope. This combination of imaging and illustration allowed the researchers to document the fine morphological differences that separate closely related species.

The male genitalia of Dilar lacewings are extraordinarily complex, comprising several sclerotised components including gonocoxites 9, 10 and 11, the ectoproct, and the hypandrium internum. Each species exhibits a distinctive arrangement of lobes, projections and curvatures in these structures. For example, Dilar yangyingae, from Hubei Province, is notable for its extremely short male gonocoxite 9, which is only one-fifth the length of gonocoxite 10, and for a pair of slender elongate projections on the ectoproct that reach nearly half the length of the entire structure. Dilar qiongduensis, from Sichuan Province, is distinguished by a notably inflated gonocoxite 9 with a rectangular proximal half and W-shaped fused gonocoxites 11.

Beyond describing the new species, the researchers reclassified the Chinese Dilar fauna into six species-groups, adding a new grouping to accommodate species described since the last comprehensive revision in 2015. The Dilar hastatus species-group is the largest, now containing 16 Chinese species, followed by the Dilar guangxiensis group with 10. Three species-groups — D. yunnanus, D. lijiangensis and D. spectabilis — each contain four or fewer Chinese representatives, while the D. caesarulus group is represented by a single Chinese species more closely allied to Central Asian fauna. Eleven Chinese species, including several of the newly described ones, could not yet be confidently assigned to any defined group.

To understand how these lacewings are distributed across the country, the team compiled 186 coordinate records covering 49 Chinese species and analysed them against the seven traditional zoogeographic regions of China. The results show a striking imbalance: roughly 45 of the 49 species occur in Oriental China, while the three Palaearctic regions together harbour only a handful. The South-western China Region alone contains 17 species across five species-groups, with 12 of them endemic, making it the primary diversity centre. The Mid-China and South China regions each also hold 17 species, with South China showing the highest endemism at 82.4 percent.

One of the most intriguing findings concerns Dilar lanlingensis, collected from Mount Jintanmaoshan in Jiangsu Province. This is the first record of the genus in Jiangsu since 1932, when the French entomologist R. Navás described Dilar subdolus from a nearby locality. Because the type specimen of D. subdolus has been lost and its original description lacks diagnostic characters, the species was later designated a nomen dubium. The researchers note that the possibility that D. lanlingensis is conspecific with D. subdolus cannot be ruled out, given the geographic proximity of the type localities.

The study also draws attention to a subtle anatomical feature shared by several species: a weakly protruding posteromedial portion of the male ninth tergum, accompanied by a strongly sclerotised median area. This condition, now documented in D. lanlingensis, D. tuyuezhengi, D. maculosus and D. septentrionalis, resembles the well-developed dorsoprocessus found in the D. guangxiensis species-group and in Central Asian and European relatives. The researchers suggest that the sclerotised area may provide structural reinforcement for the dorsoprocessus, potentially facilitating copulatory mechanisms or species recognition, and that species bearing this weakly protruding structure may share a closer evolutionary relationship with the D. guangxiensis group than previously appreciated.

The biogeographic picture that emerges is one of a genus shaped by complex historical processes. Southwestern China stands out as a primary diversification centre with high endemism, while the Mid-China Region serves as a secondary centre, particularly for the D. hastatus species-group, which shows strong faunal affinities with adjacent regions including northeastern China, North China and Taiwan Island. Faunal exchange between the Mid-China and South-western regions appears limited, with only a few species occurring at regional boundaries. Meanwhile, the Dilar species of the Qinghai-Xizang Region, though classified within a Palaearctic subregion, exhibit strong Oriental affinities, suggesting an extension of Himalayan biogeographic elements. The researchers emphasise that the underlying mechanisms driving these patterns — lineage diversification, historical dispersal and ecological specialisation — remain to be elucidated through future empirical studies incorporating broader taxon sampling and molecular phylogenetics.

Subject of Research: Taxonomy and biogeography of the pleasing lacewing genus Dilar in China

Article Title: Similar but diverse: New species and distribution pattern of the pleasing lacewing genus Dilar Rambur, 1838 ( Neuroptera , Dilaridae ) from China

Article References: Li, D., & Liu, X. (2025). Similar but diverse: New species and distribution pattern of the pleasing lacewing genus Dilar Rambur, 1838 (Neuroptera, Dilaridae) from China. Deutsche Entomologische Zeitschrift, 72(2), 155-178. https://doi.org/10.3897/dez.72.160701

Image Credits: AI Generated

DOI: 10.3897/dez.72.160701

Keywords: Dilar, Dilaridae, Neuroptera, pleasing lacewings, new species, China, taxonomy, biogeography, southwestern China, entomology, species-groups, zoogeography