Crop-pollinating Diptera have diverse diets and habitat needs in both larval and adult stages.

Insects are important pollinators of global food crops and wild plants. The adult and larval diet and habitat needs are well known for many bee taxa, but poorly understood for other pollinating taxa. Non-bee pollinators often feed on different substrates in their larval and adult life stages, and this diet and habitat diversity has important implications for their conservation and management. We reviewed the global literature on crop pollinating Diptera (the true flies) to identify both larval and adult fly diet and habitat needs. We then assembled the published larval and adult diets and habitat needs of beneficial fly pollinators found globally into a freely accessible database. Of the 405 fly species known to visit global food crops, we found relevant published evidence regarding larval and adult diet and habitat information for 254 species, which inhabited all eight global biogeographic regions. We found the larvae of these species lived in 35 different natural habitats and belong to 10 different feeding guilds. Additionally, differences between adult Diptera sexes also impacted diet needs; females from 14 species across five families fed on protein sources other than pollen to start the reproductive process of oogenesis (egg development) while males of the same species fed exclusively on pollen and nectar. While all adult species fed at least partially on floral nectar and/or pollen, only five species were recorded feeding on pollen and no fly larvae fed on nectar. Of the 242 species of larvae with established diet information, 33% were predators (n = 79) and 30% were detritivores (n = 73). Detritivores were the most generalist taxa and utilized 17 different habitats and 12 different feeding substrates. Of all fly taxa, only 2% belonged to the same feeding guild in both active life stages. Our results show that many floral management schemes may be insufficient to support pollinating Diptera. Pollinator conservation strategies in agroecosystems should consider other non-floral resources, such as wet organic materials and dung, as habitats for beneficial fly larvae.

Notes on the genus Micromorphus Mik (Diptera: Dolichopodidae) and the uncertain identity of its type species, M. albipes (Zetterstedt).

Micromorphus albipes (Zetterstedt), the type species of the genus Micromorphus Mik (Diptera: Dolichopodidae), was based on a female collected in Sweden. Diagnostic males have not been directly associated with the species, even though at least three distinct congeners based on male genitalia occur in northern Europe. Despite being inadequately described, the name has been applied to species in the New World, New Zealand and Nepal. Micromorphus albipes is demonstrated not to occur in the New World, and Micromorphus caudatus (Aldrich), new status, is redescribed and regarded as the valid name for these incorrect identifications. The records of Micromorphus albipes from New Zealand and Nepal are also unsubstantiated. As well, the enigmatic Central American Micromorphus micidus Parent is redescribed and figured. The genus Micromorphus as a whole is discussed.

Twenty years of Dipterology through the pages of Zootaxa.

We present a summary and analysis of the Diptera-related information published in Zootaxa from 2001 to 2020, with a focus on taxonomic papers. Altogether, 2,527 papers on Diptera were published, including 2,032 taxonomic papers and 1,931 papers containing new nomenclatural acts, equivalent to 22% of all publications with new nomenclatural acts for Diptera. The new nomenclatural acts include 7,431 new species, 277 new genera, 2,003 new synonymies, and 1,617 new combinations. A breakdown by family of new taxa and new replacement names proposed in the journal during the last two decades is provided, together with a comparison of Zootaxa's output to that of all other taxonomic publications on Diptera. Our results show that the journal has contributed to 20% of all biodiversity discovery in this megadiverse insect order over the last 20 years, and to about 31% in the last decade.

Indigenous plants promote insect biodiversity in urban greenspaces.

The contribution of urban greenspaces to support biodiversity and provide benefits for people is increasingly recognized. However, ongoing management practices favor vegetation oversimplification, often limiting greenspaces to lawns and tree canopy rather than multi-layered vegetation that includes under- and midstorey, and the use of nonnative species. These practices hinder the potential of greenspaces to sustain indigenous biodiversity, particularly for taxa like insects that rely on plants for food and habitat. Yet, little is known about which plant species may maximize positive outcomes for taxonomically and functionally diverse insect communities in greenspaces. Additionally, while cities are expected to experience high rates of introductions, quantitative assessments of the relative occupancy of indigenous vs. introduced insect species in greenspace are rare, hindering understanding of how management may promote indigenous biodiversity while limiting the establishment of introduced insects. Using a hierarchically replicated study design across 15 public parks, we recorded occurrence data from 552 insect species on 133 plant species, differing in planting design element (lawn, midstorey, and tree canopy), midstorey growth form (forbs, lilioids, graminoids, and shrubs) and origin (nonnative, native, and indigenous), to assess (1) the relative contributions of indigenous and introduced insect species and (2) which plant species sustained the highest number of indigenous insects. We found that the insect community was overwhelmingly composed of indigenous rather than introduced species. Our findings further highlight the core role of multi-layered vegetation in sustaining high insect biodiversity in urban areas, with indigenous midstorey and canopy representing key elements to maintain rich and functionally diverse indigenous insect communities. Intriguingly, graminoids supported the highest indigenous insect richness across all studied growth forms by plant origin groups. Our work highlights the opportunity presented by indigenous understory and midstorey plants, particularly indigenous graminoids, in our study area to promote indigenous insect biodiversity in urban greenspaces. Our study provides a blueprint and stimulus for architects, engineers, developers, designers, and planners to incorporate into their practice plant species palettes that foster a larger presence of indigenous over regionally native or nonnative plant species, while incorporating a broader mixture of midstorey growth forms.

Amber from the Triassic to Paleogene of Australia and New Zealand as exceptional preservation of poorly known terrestrial ecosystems.

The Northern Hemisphere dominates our knowledge of Mesozoic and Cenozoic fossilized tree resin (amber) with few findings from the high southern paleolatitudes of Southern Pangea and Southern Gondwana. Here we report new Pangean and Gondwana amber occurrences dating from ~230 to 40 Ma from Australia (Late Triassic and Paleogene of Tasmania; Late Cretaceous Gippsland Basin in Victoria; Paleocene and late middle Eocene of Victoria) and New Zealand (Late Cretaceous Chatham Islands). The Paleogene, richly fossiliferous deposits contain significant and diverse inclusions of arthropods, plants and fungi. These austral discoveries open six new windows to different but crucial intervals of the Mesozoic and early Cenozoic, providing the earliest occurrence(s) of some taxa in the modern fauna and flora giving new insights into the ecology and evolution of polar and subpolar terrestrial ecosystems.

Composition and organization of highly speciose Empidoidea (Diptera) communities in tropical montane forests of northern Thailand.

This study is based on more than 25,000 specimens of the superfamily Empidoidea (Diptera) collected throughout a full year on a 2000 m elevational habitat succession gradient along a 21 km transect on Doi Inthanon, the highest mountain in Thailand. The samples were sorted to 58 genera and 458 morphospecies (Empididae, 73; Hybotidae, 203; Dolichopodidae, 179; Brachystomatidae, 3).                                                                                                                          The data were used to prepare the first thorough taxon-focussed description of how diversity of a major group of Diptera is structured in tropical forest biotopes. We found significant spatial (elevation / habitat) and temporal (seasonal) variations in richness (α-diversity) and abundance at family-level. α-Diversity of the four families was maximal in damp evergreen forests at higher elevation (1500-2500 m), but Dolichopodidae also had a major subsidiary peak in lowland dry evergreen forest at 500-1000 m. Genus-, tribe- and subfamily level α-diversity / elevation profiles were varied, indicating that overall family-level richness is a composite of many taxa that contribute low, high or mid-elevation specialisms. We provide a detailed analysis of these specialisms for each of the 58 genera. Adult phenology was correlated with the monsoon and had three characteristic phases: (i) pre-monsoon commencement during the latter part of the hot dry season, (ii) a 'flush' of maximal richness during the early-monsoon, and (iii) a secondary richness maximum associated with the late-monsoon. Maximum α-diversity occurred in phases (i) and (ii) but communities in phase (iii) had characteristically low evenness in which a few abundant species were dominant. Cluster analysis and ordination resolved three well-founded communities with different species-abundance distributions, high levels of species-level specialism and habitat-fidelity associated with moist hill evergreen forest (MHE) at >2000 m; mid elevation evergreen forests (EM) at 1000-2000 m and dry lowland forest (DL) at 1000 m. The three forest types with which these communities are associated are widespread and typical of northern Thailand and the diversity characteristics of each habitat are likely scalable to larger geographic areas. The transition from lowland DL through to upper montane MHE communities was generally characterised by increasing abundance, lower evenness (higher dominance), slower temporal turnover of community composition (relaxation of seasonality), longer periods of adult flight activity and rare species contributing less to species richness. Oriental biogeographic influences are strong at lower elevations but Palaearctic influences are increasingly important at higher elevations. The mixing of Oriental and Palaearctic elements in MHE forests is thought to explain the greater phylogenetic complexity at higher elevation (as measured by taxonomic distinctness).

Minjerribah (Diptera: Dolichopodidae), a new genus from coastal Queensland, Australia.

A monotypic new genus, Minjerribah (Diptera: Dolichopodidae), and an included new species, M. litoura, are described from North Stradbroke Island in southeastern Queensland. The genus is assigned to the subfamily Hydrophorinae based on the pair of distinct converging postvertical setae on the dorsal postcranium, out of line with the postocular setae. Other diagnostic characters in Minjerribah include the highly encapsulated and reduced male postabdomen, the antennal pedicel with a conus (visible both in lateral and median view) projecting into the postpedicel, strong setation on tibia I, and very few male secondary sexual characters. It has only been collected in August from low coastal habitat and is probably a winter flying species.

Scorpiurus aramoana (Diptera: Dolichopodidae), a new species from New Zealand.

The New Zealand endemic genus Scorpiurus Parent is known from marine littoral habitats. A new species, S. aramoana sp. nov., is described from coastal Otago of the South Island. Males have diagnostic flattened and modified tarsomeres on legs I and II. A key is provided to the New Zealand genera of Hydrophorinae and the three described species of Scorpiurus.

Comprehensive inventory of true flies (Diptera) at a tropical site.

Estimations of tropical insect diversity generally suffer from lack of known groups or faunas against which extrapolations can be made, and have seriously underestimated the diversity of some taxa. Here we report the intensive inventory of a four-hectare tropical cloud forest in Costa Rica for one year, which yielded 4332 species of Diptera, providing the first verifiable basis for diversity of a major group of insects at a single site in the tropics. In total 73 families were present, all of which were studied to the species level, providing potentially complete coverage of all families of the order likely to be present at the site. Even so, extrapolations based on our data indicate that with further sampling, the actual total for the site could be closer to 8000 species. Efforts to completely sample a site, although resource-intensive and time-consuming, are needed to better ground estimations of world biodiversity based on limited sampling.

Remarkable fly (Diptera) diversity in a patch of Costa Rican cloud forest: Why inventory is a vital science.

Study of all flies (Diptera) collected for one year from a four-hectare (150 x 266 meter) patch of cloud forest at 1,600 meters above sea level at Zurquí de Moravia, San José Province, Costa Rica (hereafter referred to as Zurquí), revealed an astounding 4,332 species. This amounts to more than half the number of named species of flies for all of Central America. Specimens were collected with two Malaise traps running continuously and with a wide array of supplementary collecting methods for three days of each month. All morphospecies from all 73 families recorded were fully curated by technicians before submission to an international team of 59 taxonomic experts for identification.        Overall, a Malaise trap on the forest edge captured 1,988 species or 51% of all collected dipteran taxa (other than of Phoridae, subsampled only from this and one other Malaise trap). A Malaise trap in the forest sampled 906 species. Of other sampling methods, the combination of four other Malaise traps and an intercept trap, aerial/hand collecting, 10 emergence traps, and four CDC light traps added the greatest number of species to our inventory. This complement of sampling methods was an effective combination for retrieving substantial numbers of species of Diptera. Comparison of select sampling methods (considering 3,487 species of non-phorid Diptera) provided further details regarding how many species were sampled by various methods.        Comparison of species numbers from each of two permanent Malaise traps from Zurquí with those of single Malaise traps at each of Tapantí and Las Alturas, 40 and 180 km distant from Zurquí respectively, suggested significant species turnover. Comparison of the greater number of species collected in all traps from Zurquí did not markedly change the degree of similarity between the three sites, although the actual number of species shared did increase.        Comparisons of the total number of named and unnamed species of Diptera from four hectares at Zurquí is equivalent to 51% of all flies named from Central America, greater than all the named fly fauna of Colombia, equivalent to 14% of named Neotropical species and equal to about 2.7% of all named Diptera worldwide. Clearly the number of species of Diptera in tropical regions has been severely underestimated and the actual number may surpass the number of species of Coleoptera.        Various published extrapolations from limited data to estimate total numbers of species of larger taxonomic categories (e.g., Hexapoda, Arthropoda, Eukaryota, etc.) are highly questionable, and certainly will remain uncertain until we have more exhaustive surveys of all and diverse taxa (like Diptera) from multiple tropical sites.        Morphological characterization of species in inventories provides identifications placed in the context of taxonomy, phylogeny, form, and ecology. DNA barcoding species is a valuable tool to estimate species numbers but used alone fails to provide a broader context for the species identified.

The Costa Rican Systenus Loew (Diptera: Dolichopodidae): rich local sympatry in an otherwise rare genus.

The Costa Rican Systenus Loew (Diptera: Dolichopodidae: Medeterinae) are described, illustrated and keyed, and comprise nine new species: Systenus divericatus sp. nov., S. eboritibia sp. nov., S. emusorum sp. nov., S. flavifemoratus sp. nov., S. maculipennis sp. nov., S. naranjensis sp. nov., S. parkeri sp. nov., S. tenorio sp. nov., and S. zurqui sp. nov. Eight species are known only from Malaise traps at a locale in Guanacaste Province, in contrast to a single species collected as part of the long running INBio survey of the Costa Rican insect fauna. On a global scale, Systenus is uncommon in collections, possibly the result of its known larval tree hole habitat and adult arboreal associations, making the genus less likely to be captured by ground-level trapping. This makes the high level of sympatry at one site even more remarkable and suggesting that more cryptic species-rich arboreal faunas await discovery.

Entrapment bias of arthropods in Miocene amber revealed by trapping experiments in a tropical forest in Chiapas, Mexico.

All entomological traps have a capturing bias, and amber, viewed as a trap, is no exception. Thus the fauna trapped in amber does not represent the total existing fauna of the former amber forest, rather the fauna living in and around the resin producing tree. In this paper we compare arthropods from a forest very similar to the reconstruction of the Miocene Mexican amber forest, and determine the bias of different trapping methods, including amber. We also show, using cluster analyses, measurements of the trapped arthropods, and guild distribution, that the amber trap is a complex entomological trap not comparable with a single artificial trap. At the order level, the most similar trap to amber is the sticky trap. However, in the case of Diptera, at the family level, the Malaise trap is also very similar to amber. Amber captured a higher diversity of arthropods than each of the artificial traps, based on our study of Mexican amber from the Middle Miocene, a time of climate optimum, where temperature and humidity were probably higher than in modern Central America. We conclude that the size bias is qualitatively independent of the kind of trap for non-extreme values. We suggest that frequent specimens in amber were not necessarily the most frequent arthropods in the former amber forest. Selected taxa with higher numbers of specimens appear in amber because of their ecology and behavior, usually closely related with a tree-inhabiting life. Finally, changes of diversity from the Middle Miocene to Recent time in Central and South America can be analyzed by comparing the rich amber faunas from Mexico and the Dominican Republic with the fauna trapped using sticky and Malaise traps in Central America.