Search for: All records

Abstract The ant genus Nylanderia Emery has a cosmopolitan distribution and includes 150 extant described species and subspecies, with potentially hundreds more undescribed. Global taxonomic revision has long been stalled by strong intra- and interspecific morphological variation, limited numbers of diagnostic characters, and dependence on infrequently collected male specimens for species description and identification. Taxonomy is further complicated by Nylanderia being one of the most frequently intercepted ant genera at ports of entry worldwide, and at least 15 globetrotting species have widespread and expanding ranges, making species-level diagnoses difficult. Three species complexes (‘bourbonica complex’, ‘fulva complex’, and ‘guatemalensis complex’) include globetrotting species. To elucidate the phylogenetic positions of these three complexes and delimit species boundaries within each, we used target enrichment of ultraconserved elements (UCEs) from 165 specimens representing 98 Nylanderia morphospecies worldwide. We also phased the UCEs, effectively doubling sample size and increasing population-level sampling. After recovering strong support for the monophyly of each complex, we extracted COI barcodes and SNPs from the UCE data and tested within-complex morphospecies hypotheses using three molecular delimitation methods (SODA, bPTP, and STACEY). This comparison revealed that most methods tended to over-split taxa, but results from STACEY were most consistent with our morphospecies hypotheses. Using these results, we recommend species boundaries that are conservative and most congruent across all methods. This work emphasizes the importance of integrative taxonomy for invasive species management, as globetrotting occurs independently across at least nine different lineages across Nylanderia. 

We present a concept for a high-precision optical atomic clock (OAC) operating on an Earth-orbiting space station. This pathfinder science mission will compare the space-based OAC with one or more ultra-stable terrestrial OACs to search for space-time-dependent signatures of dark scalar fields that manifest as anomalies in the relative frequencies of station-based and ground-based clocks. This opens the possibility of probing models of new physics that are inaccessible to purely ground-based OAC experiments where a dark scalar field may potentially be strongly screened near Earth’s surface. This unique enhancement of sensitivity to potential dark matter candidates harnesses the potential of space-based OACs.

 

Pinnixion sexdecennia n. gen., n. sp. is described from three pinnotherid hosts: Austinixa gorei (Manning & Felder, 1989), Pinnixa chaetopterana Stimpson, 1860, and Zaops ostreus (Say, 1817). Females of the new species are distinguished from all other entoniscids by possessing two transverse lobes on oostegite 1 and fused oostegites 2–5; males have a pair of lateral expansions on each of the first two pleomeres. The epicaridium larvae of the new species also have a unique elongated, cylindrical terminal process on the pereopod 6 dactylus. Pinnixion sexdecennian. gen., n. sp. exhibited highest prevalence (> 40%) in North Carolina and Florida. Examination of live specimens of P. chaetopterana infested with mature female isopods showed that larvae are liberated via a pore produced in the wall of the host’s branchial chamber. Mature females of P. sexdecennian. gen., n. sp. occupied nearly all available space within the host crab’s hemocoel. Female P. chaetopterana had higher prevalence than males, and intensities of infestations were also greater in females. Evidence from all locations showed that mature parasites do not inhibit breeding or molting in the host. Our report is one of the few studies on the ecology and biology of entoniscids, a cryptic but ecologically important group of parasitic isopods. We also resolve long-standing nomenclatural issues involving Entione Kossmann, 1881 and Entioninae Codreanu, Codreanu & Pike, 1960, the subfamily to which the new genus and species belongs, by synonymizing Grapsion Giard & Bonnier, 1886 with Entione.

 

Nylanderia(Emery) is one of the world's most diverse ant genera, with 123 described species worldwide and hundreds more undescribed. Fifteen globetrotting or invasive species have widespread distributions and are often encountered outside their native ranges. A molecular approach to understanding the evolutionary history and to revision ofNylanderiataxonomy is needed because historical efforts based on morphology have proven insufficient to define major lineages and delimit species boundaries, especially where adventive species are concerned. To address these problems, we generated the first genus‐wide genomic dataset ofNylanderiausing ultraconserved elements (UCEs) to resolve the phylogeny of major lineages, determine the age and origin of the genus, and describe global biogeographical patterns. Sampling from seven biogeographical regions revealed a Southeast Asian origin ofNylanderiain the mid‐Eocene and four distinct biogeographical clades in the Nearctic, the Neotropics, the Afrotropics/Malagasy region, and Australasia. The Nearctic and Neotropical clades are distantly related, indicating two separate dispersal events to the Americas between the late Oligocene and early Miocene. We also addressed the problem of misidentification that has characterized species‐level taxonomy inNylanderiaas a result of limited morphological variation in the worker caste by evaluating the integrity of species boundaries in six of the most widespreadNylanderiaspecies. We sampled across ranges of species in theN. bourbonicacomplex (N. bourbonica(Forel) + N. vaga(Forel)), theN. fulvacomplex (N. fulva(Mayr) + N. pubens(Forel)), and theN. guatemalensiscomplex (N. guatemalensis(Forel) + N. steinheili(Forel)) to clarify their phylogenetic placement. Deep splits within these complexes suggest that some species names – specificallyN. bourbonicaandN. guatemalensis– each are applied to multiple cryptic species. In exhaustively samplingNylanderiadiversity in the West Indies, a ‘hot spot’ for invasive taxa, we found five adventive species among 22 in the region; many remain morphologically indistinguishable from one another, despite being distantly related. We stress that overcoming the taxonomic impediment through the use of molecular phylogeny and revisionary study is essential for conservation and invasive species management.

 

Abstract We summarise the discussions at a virtual Community Workshop on Cold Atoms in Space concerning the status of cold atom technologies, the prospective scientific and societal opportunities offered by their deployment in space, and the developments needed before cold atoms could be operated in space. The cold atom technologies discussed include atomic clocks, quantum gravimeters and accelerometers, and atom interferometers. Prospective applications include metrology, geodesy and measurement of terrestrial mass change due to, e.g., climate change, and fundamental science experiments such as tests of the equivalence principle, searches for dark matter, measurements of gravitational waves and tests of quantum mechanics. We review the current status of cold atom technologies and outline the requirements for their space qualification, including the development paths and the corresponding technical milestones, and identifying possible pathfinder missions to pave the way for missions to exploit the full potential of cold atoms in space. Finally, we present a first draft of a possible road-map for achieving these goals, that we propose for discussion by the interested cold atom, Earth Observation, fundamental physics and other prospective scientific user communities, together with the European Space Agency (ESA) and national space and research funding agencies.