Diptera are among the most diverse and ecologically important insect orders in forest ecosystems and hold strong potential as bioindicators of ecosystem transformations under anthropogenic and environmental pressures. We examined the effects of oak decline, a process that alters canopy structure and resource availability, on canopy-dwelling Diptera across 30 oak stands in six French forests. Diptera were sampled using green multi-funnel traps placed in the lower canopy. Decline severity was derived from Sentinel-2 imagery at multiple spatial scales. In total, more than 27,000 specimens were collected, representing 60 families and approximately 500 taxa. Overall diversity increased with decline severity, particularly for saproxylic and floricolous guilds. This pattern may result from changes in microclimatic conditions in more open, declining stands that promote Diptera activity, as well as from increased availability of deadwood and floral resources. Families such as Dolichopodidae, Empididae, Hybotidae and Anthomyiidae responded positively to decline severity, whereas Mycetophilidae and other mushroom-associated taxa declined, possibly due to reduced fungal productivity and drier microhabitats. Stand characteristics, including height, density and oak basal area, generally had negative effects on richness and abundance, potentially through their influence on microclimate or resource distribution in denser stands. Co-occurrence analyses indicated that species associations were predominantly random, followed by positive associations, and this pattern did not vary with decline severity. These results suggest that Diptera may serve as sensitive indicators of stand condition and structural changes associated with climate-driven canopy decline.

Three new species for science of Chersodromia Walker are described from the Moroccan Mediterranean coastline (C. kessabaesp. nov., C. moroccensissp. nov. and C. estuariasp. nov.), with the first record of Chersodromia oraria Collin, 1966 in Morocco and new distributional data are provided for Chersodromia pseudohirta Chvála, 1970. This study is based on intensive field surveys conducted by the third author along the Mediterranean coastline of Morocco between 2022 and 2024, targeting especially a variety of coastal habitats. Illustrations of the new species are given, along with COI barcodes of all species recorded. A key to the Moroccan Mediterranean species of Chersodromia is also provided.

Six species belonging to the genera Platypalpus Macquart, Tachydromia Meigen and Drapetis Meigen are described as new for science from the Asian part of Turkey (Anatolia): P. sivasensis sp. nov., P. hirfanlicus sp. nov., P. latemoides sp. nov., P. durulmusensis sp. nov., T. sivasensis sp. nov. and D. incompletoides sp. nov. The species P. nigritarsis Fallén is recorded herein for the first time from Turkey. We report for the first time the occurrence of Platypalpus bohousi Barták & Kubík, P. kirtlingensis Grootaert, P. longiseta Zetterstedt and Crossopalpus setiger Loew in previously unreported biogeographical areas within the country with detailed data on their distribution. All new species are described and illustrated.

Six species of the genus Crossopalpus were collected during a recent survey in the Kerkini National Park in northern Greece. Three species are reported from Greece for the first time: Crossopalpus chvalai Kovalev, 1976, Crossopalpus flexuosus (Loew, 1840) and Crossopalpus humilis (Frey, 1913). A key is provided to the species occurring in Greece as well as those expected to occur in Greece. New illustrations of the male genitalia of all these species are given.

Twelve species of Platypalpus Macquart are described as new to science from different regions in Morocco: P. atlasensis sp. nov., P. brevicornoides sp. nov., P. ebejeri sp. nov., P. fatnae sp. nov., P. pauli sp. nov., P. imlilensis sp. nov., P. miroslavi sp. nov., P. moroccensis sp. nov., P. nigritellus sp. nov., P. rifensis sp. nov., P. shamshevi sp. nov. and P. taninensis sp. nov. Platypalpus albocapillatus Fallén, 1815 and P. boreoalpinus Frey, 1943 are recorded here for the first time from the whole of North Africa, with the first report of P. verbekei Grootaert & Chvála, 1992 from Morocco. Some species newly recorded from new biogeographical areas within the country are also reported here. Descriptions and illustrations of new species are provided, as well as distributions of all species recorded from Morocco.

Conservation of the endangered notch-eared bat (M. emarginatus) requires a specific action plan based on precise ecological requirements of this species. The analysis of the diet of three colonies in southern Belgium revealed: (1) spatial and seasonal variations of the diet; (2) the consumption of web-building spiders (Araneus diadematus, Araneus triguttatus, Cyclosa conica, Enoplognatha sp., Larinioides patagiatus, Neriene emphana); (3) the predominance of blood-feeding dipterans in the diet (Stomoxys calcitrans and Musca autumnalis). Since the populations of these two ectoparasitic flies are sensitive to the use of antiparasitic drugs, these drugs should be used with caution by farmers and veterinarians in the vicinity of maternity colonies.

The long-legged fly genus Hercostomus Loew, 1857 is reported for the first time from mangrove habitats in Thailand. Two new species, H. obtusus sp. nov. and H. squamatus sp. nov. are described based on external morphology and supported by NGS barcoding. Four described species, namely, H. brevicornis Zhang, Yang & Grootaert, 2008, H. brevidigitalis Zhang, Yang & Grootaert, 2008, H. lanceolatus Zhang, Yang & Grootaert, 2008, and H. plumatus Zhang, Yang & Grootaert, 2008, previously known only from Singapore mangroves, are recorded for the first time from Thailand mangroves. In addition, species distributions are mapped and taxonomic notes are provided.

The described Nearctic species of the genus Tachydromia Meigen, 1803 (Diptera: Hybotidae, Tachydromiinae) are revised. Seventeen described species are recognised. The following two new synonyms are proposed: Tachista lundstroemi Frey, 1913 (Eurasian species) = Tachydromia enecator Melander, 1902; Tachydromia hirtipes Melander, 1928 = Tachydromia schwarzii Coquillett, 1895. Five Eurasian species are recorded for the first time from North America (T. aemula (Loew), T. fuscinervis (Frey), T. incompleta (Becker), T. magadanica Shamshev, T. punctifera (Becker)) and two North American species for the first time from Eurasia (T. chelana Melander, T. monacha Melander). Nearly half of Tachydromia species recorded currently from North America have Holarctic distributions (53 %). However, many new species remain undescribed. Redescriptions, photos of the habitus and illustrations of male terminalia (when available), as well as known distributions and a key to species are included.

Twelve new species of Platypalpus Macquart from Europe and the Middle East are described, classified in three out of the eleven West-Palaearctic species groups. The albiseta group is represented by only one species: P. flavisetoides sp. nov. (Turkey). Two species belong to the longicornis group: P. curvifemur sp. nov. (Turkey) and P. vercorsensis sp. nov. (France). The pallidiventris-cursitans group is the most abundant group with nine species: P. exsectus sp. nov. (Bulgaria), P. huzur sp. nov. (Turkey, Greece), P. kayakoyensis sp. nov. (Turkey), P. kubiki sp. nov. (Spain), P. lorcaensis sp. nov. (Spain), P. sanrossorensis sp. nov. (Italy), P. serviae sp. nov. (Spain, Portugal), P. slovacus sp. nov. (Slovakia) and P. turgidoides sp. nov. (Spain).

Nine species of Crossopalpus Bigot, 1857 (Diptera: Hybotidae) have been found recently in Morocco. Four species new for science are described: Crossopalpus favipes Grootaert et Zouhair, sp. n., C. favitibia Grootaert et Zouhair, sp. n., C. nigritelloides Grootaert et Zouhair, sp. n. and C. undulans Grootaert et Zouhair, sp. n. New data and extended diagnoses on previously described species are provided for Crossopalpus aeneus (Walker, 1871), C. atlanticus (Rafone, 2015), C. dilutipes (Strobl, 1906), C. nigritellus (Zetterstedt, 1842) and C. setiger (Loew, 1859). New species-groups of Crossopalpus are proposed here for the frst time. All species are fgured based on specimens from Morocco to allow comparison with specimens from Europe. Crossopalpus pilipes (Loew, 1859) expected but not yet recorded from Morocco is illustrated based on a specimen from Romania. A key to the Moroccan species of Crossopalpus is also provided

Krakatauia recta (Wiedemann, 1830) was recorded in Singapore in mangrove and on vegetation in the supralitoral zone of a sandy beach on Coney Island Park (Pulau Serangoon), and is re-described here. It forms a species complex with Krakatauia philippinensis, new species, described here from Mt. Makiling (Luzon) in the Philippines.

The present study is part of a long-term survey of the insect fauna of mangroves in Singapore. Pulau Ubin is home to a large number of unique dolichopodid species never been recorded previously in Singapore. Notably, the recent three-month survey of nine back mangrove sites and a patch of coastal forest on the western side of Pulau Ubin (OBS) in 2019 showed that these undisturbed old mangroves are amongst the most species diverse mangroves in Singapore, based on the diversity of long-legged flies. NGS barcoding revealed the presence of many cryptic species in the genera Chrysotus and Protomedetera and proved to be a useful tool in matching females with males. Here, eight new species are described in two subfamilies-in Diaphorinae: Chrysotus dot, new species, a dominant species in back mangroves, Chrysotus ubinensis, new species, Trigonocera pilifer, new species, and Trigonocera ubinensis, new species, and in Medeterinae: Medetera stigma, new species, Protomedetera squamata, new species, Protomedetera ubinensis, new species, and Protomedetera uncinata, new species.

Ninety hybotid species are recognized in the Botanic Garden Jean Massart (Brussels), representing 52 % of the hybotids ever recorded in Belgium. Two species new to science are described: Platypalpus massarti sp. nov. and P. pictitarsoides sp. nov. Following species are reported for the first time in Belgium: Drapetis infitialis (Collin, 1961), Platypalpus negrobovi Grootaert, Kustov & Shamshev, 2012 and Trichina opaca Loew, 1864. In addition, comments are given on a selected number of species: Bicellaria intermedia Lundbeck, 1910, Platypalpus aurantiacus (Collin, 1926), Platypalpus longimanus (Corti, 1907), Platypalpus nanus (Oldenberg, 1924), Platypalpus rapidoides Chvála, 1975, Platypalpus subtilis (Collin, 1926), Stilpon subnubilus Chvála, 1988 and on the genus Hybos Meigen, 1803. The holotype of P. cryptospina (Frey, 1909) is revised. Only 30 species or 33% of the species present are in a ‘Safe/Low risk’ Red Data Book category meaning that the other 66% are in a more or less ‘Threatened’ category.

Trichina Meigen, 1830, Euthyneura Macquart, 1836 and Oedalea Meigen, 1820 are reported for the first time in North Africa from northern Morocco, with seven species including two ones new to science, based on material collected at nine sites located in the Moroccan sector of the Mediterranean Intercontinental Biosphere reserve (MIBR). These new records represent also the first evidence of the occurrence of Trichininae and Oedaleinae subfamilies throughout North Africa and bring the total of Moroccan hybotid fauna to 51 species. The new species are described and illustrated. A key to MoroccanTrichina species is provided.