Drivers of arthropod biodiversity in an urban ecosystem.

Our world is becoming increasingly urbanized with a growing human population concentrated around cities. The expansion of urban areas has important consequences for biodiversity, yet the abiotic drivers of biodiversity in urban ecosystems have not been well characterized for the most diverse group of animals on the planet, arthropods. Given their great diversity, comparatively small home ranges, and ability to disperse, arthropods make an excellent model for studying which factors can most accurately predict urban biodiversity. We assessed the effects of (i) topography (distance to natural areas and to ocean) (ii) abiotic factors (mean annual temperature and diurnal range), and (iii) anthropogenic drivers (land value and amount of impervious surface) on the occurrence of six arthropod groups represented in Malaise trap collections run by the BioSCAN project across the Greater Los Angeles Area. We found striking heterogeneity in responses to all factors both within and between taxonomic groups. Diurnal temperature range had a consistently negative effect on occupancy but this effect was only significant in Phoridae. Anthropogenic drivers had mixed though mostly insignificant effects, as some groups and species were most diverse in highly urbanized areas, while other groups showed suppressed diversity. Only Phoridae was significantly affected by land value, where most species were more likely to occur in areas with lower land value. Los Angeles can support high regional arthropod diversity, but spatial community composition is highly dependent on the taxonomic group.

The stridulatory organ in Opetiidae and Phoridae (Diptera) and phylogenetic implications for the evolution of higher flies.

Stridulatory sound-making organs evolved in a group of flies-the family Phoridae-by modifications of the microstructure of foreleg segments present in the shared ancestor of the clade (Phoridae + Opetiidae). The opetiids are the only group amongst the lower Cyclorrhapha in which plausible homologous structures could be found, though in a less derived condition. On the forefemur of Opetia there are numerous elongate, flattened microtrichia that in basal phorids are organized into a curved linear group (the scraper) which are scraped against a curved, ridged carina on the forecoxa (the file). The file was possibly derived from an extremely unusual set of three setae that have transverse sculpturing and sockets that limit lateral motion, and which are distributed across the opetiid forecoxa. In some phorid lineages, these setae seem to be fused into the forecoxa forming the linear ridged surface against which the scraper on the forefemur could be moved. The relationship between opetiids and phorids dates back to the Cretaceous, and this pattern of file and scraper can be clearly seen in some 100 mya Myanmar amber phorid fly fossils. These structures shared between opetiids and phorids suggest that these two families may be sister groups amongst the Platypezoidea. Different modifications of the forelegs of other higher flies may have similar roles.

Necrophagy by insects in Oculudentavis and other lizard body fossils preserved in Cretaceous amber.

When a vertebrate carcass begins its decay in terrestrial environments, a succession of different necrophagous arthropod species, mainly insects, are attracted. Trophic aspects of the Mesozoic environments are of great comparative interest, to understand similarities and differences with extant counterparts. Here, we comprehensively study several exceptional Cretaceous amber pieces, in order to determine the early necrophagy by insects (flies in our case) on lizard specimens, ca. 99 Ma old. To obtain well-supported palaeoecological data from our amber assemblages, special attention has been paid in the analysis of the taphonomy, succession (stratigraphy), and content of the different amber layers, originally resin flows. In this respect, we revisited the concept of syninclusion, establishing two categories to make the palaeoecological inferences more accurate: eusyninclusions and parasyninclusions. We observe that resin acted as a "necrophagous trap". The lack of dipteran larvae and the presence of phorid flies indicates decay was in an early stage when the process was recorded. Similar patterns to those in our Cretaceous cases have been observed in Miocene ambers and actualistic experiments using sticky traps, which also act as "necrophagous traps"; for example, we observed that flies were indicative of the early necrophagous stage, but also ants. In contrast, the absence of ants in our Late Cretaceous cases confirms the rareness of ants during the Cretaceous and suggests that early ants lacked this trophic strategy, possibly related to their sociability and recruitment foraging strategies, which developed later in the dimensions we know them today. This situation potentially made necrophagy by insects less efficient in the Mesozoic.

Some remarkably common, but undescribed, Megaselia Rondani (Diptera: Phoridae) from northwestern Costa Rica.

A collection of 16,521 barcoded phorid flies from rea de Conservacin Guanacaste (ACG) in northwestern Costa Rica contains 1,498 recognized BINs (Barcode Index Numbers) in the BOLD database. These BINs were identified to genus, based on photographs, and the collection was found to be composed largely (893/1,498=60%) of specimens of the enormous genus Megaselia Rondani. The nine most common ACG Megaselia, represented by 100 or more specimens each, are briefly described, and diagnosed largely based on DNA barcodes. This study is a prelude and pilot to naming the many less-common species in a similar format.

Two new genera of phorid flies, Macgrathphora and Aurisetiphora, from Costa Rica (Diptera: Phoridae), with recommendations for naming new genera in the family.

Two new genera and four new species of metopinine phorid fly are described from Costa Rica. Macgrathphora new genus is described with the following new species: M. caribbea, M. longifurca, and M. pacifica. In particular, M. caribbea is one of the most abundant phorids collected in a recent inventory project in Northwestern Costa Rica. Aurisetiphora new genus is described for a single species, A. maggiesnowae new species, from a site in the Central Valley, near San Jos. Guidelines for describing new genera within the Phoridae, especially the Metopininae, are given, and genus Synaptophora Brown is synonymized with Dohrniphora Dahl (new synonymy).

Vertical stratification of insect abundance and species richness in an Amazonian tropical forest.

Tropical forests are among the most biodiverse biomes on the planet. Nevertheless, quantifying the abundance and species richness within megadiverse groups is a significant challenge. We designed a study to address this challenge by documenting the variability of the insect fauna across a vertical canopy gradient in a Central Amazonian tropical forest. Insects were sampled over two weeks using 6-m Gressitt-style Malaise traps set at five heights (0 m-32 m-8 m intervals) on a metal tower in a tropical forest north of Manaus, Brazil. The traps contained 37,778 specimens of 18 orders of insects. Using simulation approaches and nonparametric analyses, we interpreted the abundance and richness of insects along this gradient. Diptera, Hymenoptera, and Coleoptera had their greatest abundance at the ground level, whereas Lepidoptera and Hemiptera were more abundant in the upper levels of the canopy. We identified species of 38 of the 56 families of Diptera, finding that 527 out of 856 species (61.6%) were not sampled at the ground level. Mycetophilidae, Tipulidae, and Phoridae were significantly more diverse and/or abundant at the ground level, while Tachinidae, Dolichopodidae, and Lauxaniidae were more diverse or abundant at upper levels. Our study suggests the need for a careful discussion of strategies of tropical forest conservation based on a much more complete understanding of the three-dimensional distribution of its insect diversity.

Minimalist revision and description of 403 new species in 11 subfamilies of Costa Rican braconid parasitoid wasps, including host records for 219 species.

Three new genera are described: Michener (Proteropinae), Bioalfa (Rogadinae), and Hermosomastax (Rogadinae). Keys are given for the New World genera of the following braconid subfamilies: Agathidinae, Braconinae, Cheloninae, Homolobinae, Hormiinae, Ichneutinae, Macrocentrinae, Orgilinae, Proteropinae, Rhysipolinae, and Rogadinae. In these subfamilies 416 species are described or redescribed. Most of the species have been reared and all but 13 are new to science. A consensus sequence of the COI barcodes possessed by each species is employed to diagnose the species, and this approach is justified in the introduction. Most descriptions consist of a lateral or dorsal image of the holotype, a diagnostic COI consensus barcode, the Barcode Index Number (BIN) code with a link to the Barcode of Life Database (BOLD), and the holotype specimen information required by the International Code of Zoological Nomenclature. The following species are treated and those lacking authorship are newly described here with authorship attributable to Sharkey except for the new species of Macrocentrinae which are by Sharkey & van Achterberg: AGATHIDINAE: Aerophiluspaulmarshi, Mesocoelusdavidsmithi, Neothlipsisbobkulai, Plesiocoelusvanachterbergi, Pneumagathiserythrogastra (Cameron, 1905), Therophilusbobwhartoni, T.donaldquickei, T.gracewoodae, T.maetoi, T.montywoodi, T.penteadodiasae, Zacremnopsbrianbrowni, Z.coatlicue Sharkey, 1990, Zacremnopscressoni (Cameron, 1887), Z.ekchuah Sharkey, 1990, Z.josefernandezi, Zelomorphasarahmeierottoae. BRACONINAE: Braconalejandromarini, B.alejandromasisi, B.alexamasisae, B.andresmarini, B.andrewwalshi, B.anniapicadoae, B.anniemoriceae, B.barryhammeli, B.bernardoespinozai, B.carlossanabriai, B.chanchini, B.christophervallei, B.erasmocoronadoi, B.eugeniephillipsae, B.federicomatarritai, B.frankjoycei, B.gerardovegai, B.germanvegai, B.isidrochaconi, B.jimlewisi, B.josejaramilloi, B.juanjoseoviedoi, B.juliodiazi, B.luzmariaromeroae, B.manuelzumbadoi, B.marialuisariasae, B.mariamartachavarriae, B.mariorivasi, B.melissaespinozae, B.nelsonzamorai, B.nicklaphami, B.ninamasisae, B.oliverwalshi, B.paulamarinae, B.rafamoralesi, B.robertofernandezi, B.rogerblancoi, B.ronaldzunigai, B.sigifredomarini, B.tihisiaboshartae, B.wilberthbrizuelai, Digonogastramontylloydi, D.montywoodi, D.motohasegawai, D.natwheelwrighti, D.nickgrishini. CHELONINAE: Adeliusadrianguadamuzi, A.gauldi Shimbori & Shaw, 2019, A.janzeni Shimbori & Shaw, 2019, Ascogastergloriasihezarae, A.grettelvegae, A.guillermopereirai, A.gustavoecheverrii, A.katyvandusenae, A.luisdiegogomezi, Chelonusalejandrozaldivari, C.gustavogutierrezi, C.gustavoinduni, C.harryramirezi, C.hartmanguidoi, C.hazelcambroneroae, C.iangauldi, C.isidrochaconi, C.janecheverriae, C.jeffmilleri, C.jennyphillipsae, C.jeremydewaardi, C.jessiehillae, C.jesusugaldei, C.jimlewisi, C.jimmilleri, C.jimwhitfieldi, C.johanvalerioi, C.johnburnsi, C.johnnoyesi, C.jorgebaltodanoi, C.jorgehernandezi, C.josealfredohernandezi, C.josefernandeztrianai, C.josehernandezcortesi, C.josemanuelperezi, C.josephinerodriguezae, C.juanmatai, C.junkoshimurae, C.kateperezae, C.luciariosae, C.luzmariaromeroae, C.manuelpereirai, C.manuelzumbadoi, C.marianopereirai, C.maribellealvarezae, C.markmetzi, C.markshawi, C.martajimenezae, C.mayrabonillae, C.meganmiltonae, C.melaniamunozae, C.michaelstroudi, C.michellevanderbankae, C.mingfangi, C.minorcarmonai, C.monikaspringerae, C.moniquegilbertae, C.motohasegawai, C.nataliaivanovae, C.nelsonzamorai, C.normwoodleyi, C.osvaldoespinozai, C.pamelacastilloae, C.paulgoldsteini, C.paulhansoni, C.paulheberti, C.petronariosae, C.ramyamanjunathae, C.randallgarciai, C.rebeccakittelae, C.robertoespinozai, C.robertofernandezi, C.rocioecheverriae, C.rodrigogamezi, C.ronaldzunigai, C.rosibelelizondoae, C.rostermoragai, C.ruthfrancoae, C.scottmilleri, C.scottshawi, C.sergioriosi, C.sigifredomarini, C.stevearonsoni, C.stevestroudi, C.sujeevanratnasinghami, C.sureshnaiki, C.torbjornekremi, C.yeimycedenoae, Leptodrepanaalexisae, L.erasmocoronadoi, L.felipechavarriai, L.freddyquesadai, L.gilbertfuentesi, L.manuelriosi, Phanerotomaalmasolisae, P.alvaroherrerai, P.anacordobae, P.anamariamongeae, P.andydeansi, P.angelagonzalezae, P.angelsolisi, P.barryhammeli, P.bernardoespinozai, P.calixtomoragai, P.carolinacanoae, P.christerhanssoni, P.christhompsoni, P.davesmithi, P.davidduthiei, P.dirksteinkei, P.donquickei, P.duniagarciae, P.duvalierbricenoi, P.eddysanchezi, P.eldarayae, P.eliethcantillanoae, P.jenopappi, Pseudophanerotomaalanflemingi, Ps.albanjimenezi, Ps.alejandromarini, Ps.alexsmithi, Ps.allisonbrownae, Ps.bobrobbinsi. HOMOLOBINAE: Exasticolusjennyphillipsae, E.randallgarciai, E.robertofernandezi, E.sigifredomarini, E.tomlewinsoni. HORMIINAE: Hormiusanamariamongeae, H.angelsolisi, H.anniapicadoae, H.arthurchapmani, H.barryhammeli, H.carmenretanae, H.carloswalkeri, H.cesarsuarezi, H.danbrooksi, H.eddysanchezi, H.erikframstadi, H.georgedavisi, H.grettelvegae, H.gustavoinduni, H.hartmanguidoi, H.hectoraritai, H.hesiquiobenitezi, H.irenecanasae, H.isidrochaconi, H.jaygallegosi, H.jimbeachi, H.jimlewisi, H.joelcracrafti, H.johanvalerioi, H.johnburleyi, H.joncoddingtoni, H.jorgecarvajali, H.juanmatai, H.manuelzumbadoi, H.mercedesfosterae, H.modonnellyae, H.nelsonzamorai, H.pamelacastilloae, H.raycypessi, H.ritacolwellae, H.robcolwelli, H.rogerblancosegurai, H.ronaldzunigai, H.russchapmani, H.virginiaferrisae, H.warrenbrighami, H.willsflowersi. ICHNEUTINAE: Oligoneuruskriskrishtalkai, O.jorgejimenezi, Paroligoneuruselainehoaglandae, P.julianhumphriesi, P.mikeiviei. MACROCENTRINAE: Austrozelejorgecampabadali, A.jorgesoberoni, Dolichozelegravitarsis (Muesebeck, 1938), D.josefernandeztrianai, D.josephinerodriguezae, Hymenochaoniakalevikulli, H.kateperezae, H.katherinebaillieae, H.katherineellisonae, H.katyvandusenae, H.kazumifukunagae, H.keithlangdoni, H.keithwillmotti, H.kenjinishidai, H.kimberleysheldonae, H.krisnorvigae, H.lilianamadrigalae, H.lizlangleyae, Macrocentrusfredsingeri, M.geoffbarnardi, M.gregburtoni, M.gretchendailyae, M.grettelvegae, M.gustavogutierrezi, M.hannahjamesae, M.harisridhari, M.hillaryrosnerae, M.hiroshikidonoi, M.iangauldi, M.jennyphillipsae, M.jesseausubeli, M.jessemaysharkae, M.jimwhitfieldi, M.johnbrowni, M.johnburnsi, M.jonathanfranzeni, M.jonathanrosenbergi, M.jorgebaltodanoi, M.lucianocapelli. ORGILINAE: Orgilusamyrossmanae, O.carrolyoonae, O.christhompsoni, O.christinemcmahonae, O.dianalipscombae, O.ebbenielsoni, O.elizabethpennisiae, O.evertlindquisti, O.genestoermeri, O.jamesriegeri, O.jeanmillerae, O.jeffmilleri, O.jerrypowelli, O.jimtiedjei, O.johnlundbergi, O.johnpipolyi, O.jorgellorentei, O.larryspearsi, O.marlinricei, O.mellissaespinozae, O.mikesmithi, O.normplatnicki, O.peterrauchi, O.richardprimacki, O.sandraberriosae, O.sarahmirandae, O.scottmilleri, O.scottmorii, Stantoniabillalleni, S.brookejarvisae, S.donwilsoni, S.erikabjorstromae, S.garywolfi, S.henrikekmani, S.luismirandai, S.miriamzunzae, S.quentinwheeleri, S.robinkazmierae, S.ruthtifferae. PROTEROPINAE: Hebichneutestricolor Sharkey & Wharton, 1994, Proteropsiangauldi, P.vickifunkae, Michenercharlesi. RHYSIPOLINAE: Pseudorhysipolisluisfonsecai, P. mailyngonzalezaeRhysipolisjulioquirosi. ROGADINAE: Aleiodesadrianaradulovae, A.adrianforsythi, A.agnespeelleae, A.alaneaglei, A.alanflemingi, A.alanhalevii, A.alejandromasisi, A.alessandracallejae, A.alexsmithi, A.alfonsopescadori, A.alisundermieri, A.almasolisae, A.alvarougaldei, A.alvaroumanai, A.angelsolisi, A.annhowdenae, A.bobandersoni, A.carolinagodoyae, A.charlieobrieni, A.davefurthi, A.donwhiteheadi, A.doylemckeyi, A.frankhovorei, A.henryhowdeni, A.inga Shimbori & Shaw, 2020, A.johnchemsaki, A.johnkingsolveri, A.gonodontovorus Shimbori & Shaw, 2020, A.manuelzumbadoi, A.mayrabonillae, A.michelledsouzae, A.mikeiviei, A.normwoodleyi, A.pammitchellae, A.pauljohnsoni, A.rosewarnerae, A.steveashei, A.terryerwini, A.willsflowersi, Bioalfapedroleoni, B.alvarougaldei, B.rodrigogamezi, Choreborogasandydeansi, C.eladiocastroi, C.felipechavarriai, C.frankjoycei, Clinocentrusandywarreni, Cl.angelsolisi, Cystomastaxalexhausmanni, Cy.angelagonzalezae, Cy.ayaigarashiae, Hermosomastaxclavifemorus Quicke sp. nov., Heterogamusdonstonei, Pseudoyeliconesbernsweeneyi, Stiropiusbencrairi, S.berndkerni, S.edgargutierrezi, S.edwilsoni, S.ehakernae, Triraphisbillfreelandi, T.billmclarneyi, T.billripplei, T.bobandersoni, T.bobrobbinsi, T.bradzlotnicki, T.brianbrowni, T.brianlaueri, T.briannestjacquesae, T.camilocamargoi, T.carlosherrerai, T.carolinepalmerae, T.charlesmorrisi, T.chigiybinellae, T.christerhanssoni, T.christhompsoni, T.conniebarlowae, T.craigsimonsi, T.defectus Valerio, 2015, T.danielhubi, T.davidduthiei, T.davidwahli, T.federicomatarritai, T.ferrisjabri, T.mariobozai, T.martindohrni, T.matssegnestami, T.mehrdadhajibabaei, T.ollieflinti, T.tildalauerae, Yeliconesdirksteinkei, Y.markmetzi, Y.monserrathvargasae, Y.tricolor Quicke, 1996. Y.woldai Quicke, 1996. The following new combinations are proposed: Neothlipsissmithi (Ashmead), new combination for Microdussmithi Ashmead, 1894; Neothlipsispygmaeus (Enderlein), new combination for Microduspygmaeus Enderlein, 1920; Neothlipsisunicinctus (Ashmead), new combination for Microdusunicinctus Ashmead, 1894; Therophilusanomalus (Bortoni and Penteado-Dias) new combination for Plesiocoelusanomalus Bortoni and Penteado-Dias, 2015; Aerophilusareolatus (Bortoni and Penteado-Dias) new combination for Plesiocoelusareolatus Bortoni and Penteado-Dias, 2015; Pneumagathiserythrogastra (Cameron) new combination for Agathiserythrogastra Cameron, 1905. Dolichozelecitreitarsis (Enderlein), new combination for Paniscozelecitreitarsis Enderlein, 1920. Dolichozelefuscivertex (Enderlein) new combination for Paniscozelefuscivertex Enderlein, 1920. Finally, Bassusbrooksi Sharkey, 1998 is synonymized with Agathiserythrogastra Cameron, 1905; Paniscozelegriseipes Enderlein, 1920 is synonymized with Dolichozelekoebelei Viereck, 1911; Paniscozelecarinifrons Enderlein, 1920 is synonymized with Dolichozelefuscivertex (Enderlein, 1920); and Paniscozelenigricauda Enderlein,1920 is synonymized with Dolichozelequaestor (Fabricius, 1804). (originally described as Ophionquaestor Fabricius, 1804).

A remarkable legion of guests: Diversity and host specificity of army ant symbionts.

Tropical rainforests are among the most diverse biomes on Earth. While species inventories are far from complete for any tropical rainforest, even less is known about the intricate species interactions that form the basis of these ecological communities. One fascinating but poorly studied example are the symbiotic associations between army ants and their rich assemblages of parasitic arthropod guests. Hundreds of these guests, or myrmecophiles, have been taxonomically described. However, because previous work has mainly been based on haphazard collections from disjunct populations, it remains challenging to define species boundaries. We therefore know little about the species richness, abundance and host specificity of most guests in any given population, which is crucial to understand co-evolutionary and ecological dynamics. Here, we report a quantitative community survey of myrmecophiles parasitizing the six sympatric Eciton army ant species in a Costa Rican rainforest. Combining DNA barcoding with morphological identification of over 2,000 specimens, we discovered 62 species, including 49 beetles, 11 flies, one millipede and one silverfish. At least 14 of these species were new to science. Ecological network analysis revealed a clear signal of host partitioning, and each Eciton species was host to both specialists and generalists. These varying degrees in host specificities translated into a moderate level of network specificity, highlighting the system's level of biotic pluralism in terms of biodiversity and interaction diversity. By providing vouchered DNA barcodes for army ant guest species, this study provides a baseline for future work on co-evolutionary and ecological dynamics in these species-rich host-symbiont networks across the Neotropical realm.

Revision of the Oriental Region genus Epicnemis Borgmeier (Diptera: Phoridae).

The Oriental Region phorid genus Epicnemis Borgmeier is revised, resulting in the recognition of 15 species, 10 of which are new to science: E. alus, chaweewanae, digitalis, disjunctus, dorsalis, latus, projectus, ratanae, setosus, and sinuosus. Only males are treated, as females are highly modified and cannot be associated with their males based on morphology alone.

Forty-one new species of Coniceromyia Borgmeier (Diptera: Phoridae), an identification key, and new distributional records for the species of the genus.

Forty-one new species of the mostly neotropical genus Coniceromyia Borgmeier are described. The descriptions follow the methodology of recent works on the genus taxonomy and illustrate habitus, foremetatarsus, wing, hind femur, and hypopygium for each species. Unique features of some species are also illustrated, including several male features possibly related to sexual selection such as processes on different tarsomeres of the foreleg. New records for the known species are presented, as well as an identification key for the species of the genus and maps with their updated distribution. Coniceromyia brandaoi Ament Amorim is synonymized with Coniceromyia plaumanni Borgmeier. Even though this work examined the Coniceromyia of the major collections of neotropical Phoridae, the high number of singletons and doubletons indicates that the real diversity of the genus may still be far from understood.

Megaselia steptoeae (Diptera: Phoridae): specialists on smashed snails.

BACKGROUND: Phorid flies are amongst the most biologically diverse and species-rich groups of insects. Ways of life range from parasitism, herbivory, fungivory, to scavenging. Although the lifestyles of most species are unknown, many are parasitoids, especially of social insects. Some species of ant-parasitoids are attracted to injured hosts for feeding purposes to develop eggs, as well as for oviposition, requiring each female to find two injured hosts. NEW INFORMATION: Females of the phorid fly Megaselia steptoeae Hartop et al. (Diptera: Phoridae) were found to be quickly attracted to crushed glass snails of the species Oxychilus draparnaudi (Beck) (Gastropoda: Oxychilidae). Most females were without mature eggs and apparently were attracted for feeding purposes only; other injured molluscs offered at the same time were not attractive. One female laid eggs in captivity and offspring were reared to the pupal stage. The lifestyle of this species is similar to that of parasitoids of injured ants, which also require separate hosts of the same species for feeding and oviposition. We conclude that injured hosts must be common in the environment to attract these host-specific scavengers.

Local- and landscape-scale variables shape insect diversity in an urban biodiversity hot spot.

Local community structure is shaped by processes acting at local and landscape scales. The relative importance of drivers operating across different spatial scales is difficult to test without observations across regional or latitudinal gradients. Cities exhibit strong but predictable environmental gradients overlaying a mosaic of highly variable but repeated habitat types within a constrained area. Thus, cities present a unique opportunity to explore how both local and landscape factors influence local biotic communities. We used insect communities to examine the interactions among local environmental variables (such as temperature and relative humidity), local habitat characteristics (such as plant community composition), and broad-scale patterns of urbanization (including biophysical, human-built, and socioeconomic variables) on local insect abundance, species richness, and species composition in Los Angeles, a hot, dry, near-desert city. After accounting for seasonal trends, insect species richness and abundance were highest in drier and hotter sites, but the magnitude of local environmental effects varied with the degree of urbanization. In contrast, insect species composition was best predicted by broad-scale urbanization trends, with the more native communities occurring in less urbanized sites and more cosmopolitan insects occurring in highly urbanized sites. However, insect species richness and abundance were >30% higher and insect composition was similar across sites that hosted either native or drought-tolerant plants, regardless of the degree of urbanization. These results demonstrate that urban insect biodiversity is a product of interacting mechanisms working at both local and landscape scales. However, local-scale changes to urban habitats, such as cultivating plants that are adapted to the natural environment nearest the city, can positively impact urban biodiversity regardless of location.

Temperature accounts for the biodiversity of a hyperdiverse group of insects in urban Los Angeles.

The urban heat island effect is a worldwide phenomenon that has been linked to species distributions and abundances in cities. However, effects of urban heat on biotic communities are nearly impossible to disentangle from effects of land cover in most cases because hotter urban sites also have less vegetation and more impervious surfaces than cooler sites within cities. We sampled phorid flies, one of the largest, most biologically diverse families of true flies (Insecta: Diptera: Phoridae), at 30 sites distributed within the central Los Angeles Basin, where we found that temperature and the density of urban land cover are decoupled. Abundance, richness, and community composition of phorids inside urban Los Angeles were most parsimoniously accounted for by mean air temperature in the week preceding sampling. Sites with intermediate mean temperatures had more phorid fly individuals and higher richness. Communities were more even at urban sites with lower minimum temperatures and sites located further away from natural areas, suggesting that communities separated from natural source populations may be more homogenized. Species composition was best explained by minimum temperature. Inasmuch as warmer areas within cities can predict future effects of climate change, phorid fly communities are likely to shift nonlinearly under future climates in more natural areas. Exhaustive surveys of biotic communities within cities, such as the one we describe here, can provide baselines for determining the effects of urban and global climate warming as they intensify.

Quantification of migrant hoverfly movements (Diptera: Syrphidae) on the West Coast of North America.

The seasonal migration of huge numbers of hoverflies is frequently reported in Europe from mountain passes or spurs of land. The movement of such large numbers of beneficial insects is thought to provide significant ecosystem services in terms of pollination and pest control. Observations from the East Coast of the USA during the 1920s indicate the presence of migratory life histories among some hoverfly species there, but 90 years have now passed since the last reported observation of hoverfly migration in the USA. Here, we analyse video footage taken during a huge northward migration of hoverflies on 20 April 2017 on the West Coast of California. The quantification of migrant numbers from this footage allows us to estimate the passage of over 100 000 hoverflies in half an hour over a 200 m section of headland in Montaña de Oro State Park (San Luis Obispo County). Field collections and analysis of citizen science data indicate different species from the previously reported Eristalis tenax migrations on the East Coast of the USA and provide evidence for migration among North American hoverflies. We wish to raise awareness of this phenomenon and suggest approaches to advance the study of hoverfly migration in North America and elsewhere.

A new white-spotted Megaselia Rondani (Diptera: Phoridae) from western North America.

BACKGROUND: The phorid fly genus Megaselia Rondani is a large, poorly-known taxon whose species are found worldwide. NEW INFORMATION: A new species of Megaselia Rondani, M. simunorum, is described from both urban and rural sites in southern California. With a large area of white colour on the posterior part of the abdominal dorsum, it closely resembles the much more common species M. sulphurizona, but M. simunorum has distinctly thicker ventral setae on the abdomen and a differently-shaped white spot.

Comparisons of Citizen Science Data-Gathering Approaches to Evaluate Urban Butterfly Diversity.

By 2030, ten percent of earth's landmass will be occupied by cities. Urban environments can be home to many plants and animals, but surveying and estimating biodiversity in these spaces is complicated by a heterogeneous built environment where access and landscaping are highly variable due to human activity. Citizen science approaches may be the best way to assess urban biodiversity, but little is known about their relative effectiveness and efficiency. Here, we compare three techniques for acquiring data on butterfly (Lepidoptera: Rhopalocera) species richness: trained volunteer Pollard walks, Malaise trapping with expert identification, and crowd-sourced iNaturalist observations. A total of 30 butterfly species were observed; 27 (90%) were recorded by Pollard walk observers, 18 (60%) were found in Malaise traps, and 22 (73%) were reported by iNaturalist observers. Pollard walks reported the highest butterfly species richness, followed by iNaturalist and then Malaise traps during the four-month time period. Pollard walks also had significantly higher species diversity than Malaise traps.

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.

Adapting the bioblitz to meet conservation needs.

When conservation strategies require new, field-based information, practitioners must find the best ways to rapidly deliver high-quality survey data. To address this challenge, several rapid-assessment approaches have been developed since the early 1990s. These typically involve large areas, take many months to complete, and are not appropriate when conservation-relevant survey data are urgently needed for a specific locale. In contrast, bioblitzes are designed for quick collection of site-specific survey data. Although bioblitzes are commonly used to achieve educational or public-engagement goals, conservation practitioners are increasingly using a modified bioblitz approach to generate conservation-relevant data while simultaneously enhancing research capacity and building working partnerships focused on conservation concerns. We term these modified events expert bioblitzes. Several expert bioblitzes have taken place on lands of conservation concern in Southern California and have involved collaborative efforts of government agencies, nonprofit organizations, botanic gardens, museums, and universities. The results of expert bioblitzes directly informed on-the-ground conservation and decision-making; increased capacity for rapid deployment of expert bioblitzes in the future; and fostered collaboration and communication among taxonomically and institutionally diverse experts. As research and conservation funding becomes increasingly scarce, expert bioblitzes can play an increasingly important role in biodiversity conservation.

A second contender for "world's smallest fly" (Diptera: Phoridae).

BACKGROUND: Flies of the family Phoridae (Insecta: Diptera) are amongst the most diverse insects in the world, with an incredible array of species, structures and life histories. Wiithin their structural diversity is the world's smallest fly, Euryplatea nanaknihali Brown, 2012. NEW INFORMATION: A second minute, limuloid female phorid parasitoid fly (Diptera: Phoridae) is described. Known from a single specimen from a site near Manaus, Brazil, Megapropodiphora arnoldigen. n., sp. n. is only 0.395 mm in body length, slightly smaller than the currently recognised smallest fly, Euryplatea nanaknihali from Thailand. The distinctive body shape of M. arnoldi, particularly the relatively enormous head, mesothorax and scutellum, the latter of which covers most of the abdomen, easily separates it from other described phorids. Most remarkably, the forelegs are extremely enlarged, whereas mid- and hind legs are reduced to small, possibly vestigial remnants. A possible male specimen, unfortunately destroyed during processing, is briefly described.