| 1. |
- Reinke, Beth A, et al.
(författare)
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Diverse aging rates in ectothermic tetrapods provide insights for the evolution of aging and longevity
- 2022
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Ingår i: Science. - : American Association for the Advancement of Science. - 0036-8075 .- 1095-9203. ; 376:6600, s. 1459-1466
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Tidskriftsartikel (refereegranskat)abstract
- Comparative studies of mortality in the wild are necessary to understand the evolution of aging; yet, ectothermic tetrapods are underrepresented in this comparative landscape, despite their suitability for testing evolutionary hypotheses. We present a study of aging rates and longevity across wild tetrapod ectotherms, using data from 107 populations (77 species) of nonavian reptiles and amphibians. We test hypotheses of how thermoregulatory mode, environmental temperature, protective phenotypes, and pace of life history contribute to demographic aging. Controlling for phylogeny and body size, ectotherms display a higher diversity of aging rates compared with endotherms and include phylogenetically widespread evidence of negligible aging. Protective phenotypes and life-history strategies further explain macroevolutionary patterns of aging. Analyzing ectothermic tetrapods in a comparative context enhances our understanding of the evolution of aging.
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| 2. |
- Bergsten, Johan, 1988, et al.
(författare)
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AlGaN/GaN high electron mobility transistors with intentionally doped GaN buffer using propane as carbon precursor
- 2016
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Ingår i: Japanese Journal of Applied Physics. - : IOP Publishing. - 1347-4065 .- 0021-4922. ; 55:5
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Tidskriftsartikel (refereegranskat)abstract
- AlGaN/GaN high electron mobility transistors (HEMTs) fabricated on a heterostructure grown by metalorganic chemical vapor deposition using an alternative method of carbon (C) doping the buffer are characterized. C-doping is achieved by using propane as precursor, as compared to tuning the growth process parameters to control C-incorporation from the gallium precursor. This approach allows for optimization of the GaN growth conditions without compromising material quality to achieve semi-insulating properties. The HEMTs are evaluated in terms of isolation and dispersion. Good isolation with OFF-state currents of 2 x 10(-6)A/mu m, breakdown fields of 70V/mu m, and low drain induced barrier lowering of 0.13mV/V are found. Dispersive effects are examined using pulsed current-voltage measurements. Current collapse and knee walkout effects limit the maximum output power to 1.3W/mm. With further optimization of the C-doping profile and GaN material quality this method should offer a versatile approach to decrease dispersive effects in GaN HEMTs. (C) 2016 The Japan Society of Applied Physics
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| 3. |
- Hansson, Christer, et al.
(författare)
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Integrative taxonomy of New World Euplectrus Westwood (Hymenoptera, Eulophidae), with focus on 55 new species from Area de Conservacion Guanacaste, northwestern Costa Rica
- 2015
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Ingår i: ZooKeys. - : Pensoft Publishers. - 1313-2970 .- 1313-2989. ; :485, s. 1-236
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Tidskriftsartikel (refereegranskat)abstract
- 90 species of Euplectrus are treated: 55 newly described, all from Area de Conservación Guanacaste (ACG),and 35 previously described species, of which 20 occur in ACG. Three of the previously described species(E. brasiliensis Ashmead, E. hircinus (Say), E. ronnai (Brèthes)) have unknown status, owing to missing or severely damaged type material. The new species, all authored by C. Hansson, are: Euplectrus alejandrovalerioi,E. alexsmithi, E. alvarowillei, E. andybennetti, E. andydeansi, E. annettewalkerae, E. billbrowni, E. bobwhartoni, E. carlosarmientoi, E. carlrettenmeyeri, E.charlesmicheneri, E. charlesporteri, E. chrisdarlingi, E. chrisgrinteri, E. corriemoreauae, E. daveroubiki, E. davesmithi, E. davidwahli, E. dianariasae, E. donquickei,E. eowilsoni, E. garygibsoni, E. gavinbroadi, E. gerarddelvarei, E. henrytownesi, E. howelldalyi, E. hugokonsi, E. iangauldi, E. jacklonginoi, E. jesusugaldei, E. jimwhitfieldi, E. jjrodriguezae, E. johnheratyi, E. johnlasallei, E. johnnoyesi, E. josefernandezi, E. lubomirmasneri, E. markshawi, E. mikegatesi, E. mikeschauffi, E. mikesharkeyi, E. ninazitaniae, E. pammitchellae, E. paulhansoni, E. paulheberti, E. paulhurdi, E.philwardi, E. robbinthorpi, E. ronaldzunigai, E. roysnellingi, E. scottshawi, E. sondrawardae, E. sydneycameronae, E. victoriapookae, E. wonyoungchoi. The species are described or redescribed, and thoroughly and uniformly illustrated, and included in two identification keys, one for females and one for males. Lectotypes are designated for eight species: Euplectrus catocalae Howard (♂), E. junctus Gahan (♀), E. leucotrophis Howard (♂), E. marginatus Ashmead (♀), E. pachyscaphus Girault (♀), E. platyhypenae Howard (♂), E. semimarginatus Girault (♀), Heteroscapus ronnai Brèthes (♂). One synonym is established: Euplectrus walteri Schauff is a junior synonym of E. testaceipes (Cameron). Brief image notes and host records are provided on the natural history of the wasps as well as the details of their morphology. Hosts are known for 74 Euplectrus species.
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| 4. |
- Hansson, Christer, et al.
(författare)
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New distributional, biological and taxonomic information on the genus Eulophinusia Girault (Hymenoptera : Eulophidae)
- 2021
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Ingår i: Zootaxa. - : Magnolia Press. - 1175-5326 .- 1175-5334. ; 5047:3, s. 370-376
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Tidskriftsartikel (refereegranskat)abstract
- The genus Eulophinusia Girault (Hymenoptera: Eulophidae), previously known from Australia and India, is newly recorded from the Americas (Canada, Costa Rica, Dominican Republic). The morphological diagnosis of the genus is enhanced through the discovery of an unnoticed and unique feature - an intricate jigsaw-like microsculptural pattern on the mesoscutellum. The new species described here, Eulophinusia andreamezae Hansson, is a hyperparasitoid. The majority of the Costa Rican specimens of this species were reared from pupae of Hypomicrogaster largus Valerio (Braconidae: Microgastrinae) that had parasitized a caterpillar of Anadasmus Janzen11 (Lepidoptera: Depressariidae) feeding on Ocotea insularis (Lauraceae).
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| 5. |
- Hosseinzadeh, Griffin, et al.
(författare)
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The Early Light Curve of SN 2023bee : Constraining Type Ia Supernova Progenitors the Apian Way
- 2023
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Ingår i: Astrophysical Journal Letters. - 2041-8205 .- 2041-8213. ; 953:1
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Tidskriftsartikel (refereegranskat)abstract
- We present very early photometric and spectroscopic observations of the Type Ia supernova (SN Ia) 2023bee, starting about 8 hr after the explosion, which reveal a strong excess in the optical and nearest UV (U and UVW1) bands during the first several days of explosion. This data set allows us to probe the nature of the binary companion of the exploding white dwarf and the conditions leading to its ignition. We find a good match to the Kasen model in which a main-sequence companion star stings the ejecta with a shock as they buzz past. Models of double detonations, shells of radioactive nickel near the surface, interaction with circumstellar material, and pulsational delayed detonations do not provide good matches to our light curves. We also observe signatures of unburned material, in the form of carbon absorption, in our earliest spectra. Our radio nondetections place a limit on the mass-loss rate from the putative companion that rules out a red giant but allows a main-sequence star. We discuss our results in the context of other similar SNe Ia in the literature.
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| 6. |
- Houshuai, Wang, et al.
(författare)
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Molecular phylogeny of Lymantriinae (Lepidoptera, Noctuoidea, Erebidae) inferred from eight gene regions
- 2015
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Ingår i: Cladistics. - : Wiley. - 0748-3007 .- 1096-0031. ; 31:6, s. 579-592
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Tidskriftsartikel (refereegranskat)abstract
- To understand the evolutionary history of Lymantriinae and test the present higher-level classification, we performed the first broad-scale molecular phylogenetic analysis of the subfamily, based on 154 exemplars representing all recognized tribes and drawn from all major biogeographical regions. We used two mitochondrial genes (cytochrome c oxidase subunit I and 16S ribosomal RNA) and six nuclear genes (elongation factor-1α, carbamoylphosphate synthase domain protein, ribosomal protein S5, cytosolic malate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase and wingless). Data matrices (in total 5424 bp) were analysed by parsimony and model-based evolutionary methods (maximum likelihood and Bayesian inference). Based on the results of the analyses, we present a new phylogenetic classification for Lymantriinae composed of seven well-supported tribes, two of which are proposed here as new: Arctornithini, Leucomini, Lymantriini, Orgyiini, Nygmiini, Daplasini trib. nov. and Locharnini trib. nov. We discuss the internal structure of each of these tribes and address some of the more complex problems with the genus-level classification, particularly within Orgyiini and Nygmiini.
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| 7. |
- Núñez, Rayner, et al.
(författare)
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Species delimitation and evolutionary relationships among Phoebis New World sulphur butterflies (Lepidoptera, Pieridae, Coliadinae)
- 2020
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Ingår i: Systematic Entomology. - : Wiley. - 0307-6970 .- 1365-3113. ; 45:2, s. 481-492
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Tidskriftsartikel (refereegranskat)abstract
- The most accepted taxonomic treatment of the New World sulphurs of the genus Phoebis Hübner, [1819] recognizes 16 species including those in the current synonyms Aphrissa and Rhabdodryas. This total conflicts with the results of several recent pierid DNA barcode studies across the Neotropics. We used a five-locus dataset to carry out species delimitation analyses using the coalescence-based method implemented in bpp software. After testing the resulting species hypotheses using marginal likelihood estimates, we inferred their phylogenetic relationships and performed an ancestral range reconstruction with biogeobears. Our analyses recovered two different hypotheses, 26 and 24 species, that scored the highest marginal likelihood estimate. Differences between these two hypotheses, when reconciled with barcode clusters and morphology, indicated that 24 is the most likely number of species. Phoebis neocypris stat. rev., Phoebis rurina stat. rev., Phoebis virgo stat. rev., Phoebis marcellina stat. rev., Phoebis thalestris stat. rev., and Phoebis rorata stat. rev. are raised to the species rank. We dated the crown age of Phoebis to the mid-Miocene, with the islands of the Greater Antilles as the most probable ancestral range. Three main clades of Phoebis diverged early in the evolutionary history of the genus, but most extant species-level diversity arose after the Pliocene–Pleistocene boundary. Our analyses recovered alternate range expansions and contractions, and dispersal from the islands to the continent and back, in the three main clades. Both sympatric and allopatric speciation seem to have shaped the current species richness.
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| 8. |
- Shevtsova, Ekaterina, et al.
(författare)
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Stable structural color patterns displayed on transparent insect wings.
- 2011
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Ingår i: Proceedings of the National Academy of Sciences. - : Proceedings of the National Academy of Sciences. - 1091-6490 .- 0027-8424. ; 108:2, s. 668-673
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Color patterns play central roles in the behavior of insects, and are important traits for taxonomic studies. Here we report striking and stable structural color patterns—wing interference patterns (WIPs) —in the transparent wings of small Hymenoptera and Diptera, patterns that have been largely overlooked by biologists. These extremely thin wings reflect vivid color patterns caused by thin film interference. The visibility of these patterns is affected by the way the insects display their wings against various backgrounds with different light properties. The specific color sequence displayed lacks pure red and matches the color vision of most insects, strongly suggesting that the biological significance of WIPs lies in visual signaling. Taxon-specific color patterns are formed by uneven membrane thickness, pigmentation, venation, and hair placement. The optically refracted pattern is also stabilized by microstructures of the wing such as membrane corrugations and spherical cell structures that reinforce the pattern and make it essentially noniridescent over a large range of light incidences. WIPs can be applied to map the micromorphology of wings through direct observation and are useful in several fields of biology. We demonstrate their usefulness as identification patterns to solve cases of cryptic species complexes in tiny parasitic wasps, and indicate their potentials for research on the genetic control of wing development through direct links between the transregulatory wing landscape and interference patterns we observe in Drosophila model species. Some species display sexually dimorphic WIPs, suggesting sexual selection as one of the driving forces for their evolution.
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