Life habits, hox genes, and affinities of a 311 million-year-old holometabolan larva

Citation: Haug, J. T., Labandeira, C. C., Santiago-Blay, J. A., Haug, C., & Brown, S. (2015). Life habits, hox genes, and affinities of a 311 million-year-old holometabolan larva. Bmc Evolutionary Biology, 15, 10. doi:10.1186/s12862-015-0428-8Background: Holometabolous insects are the most diverse, speciose and ubiquitous group of multicellular organisms in terrestrial and freshwater ecosystems. The enormous evolutionary and ecological success of Holometabola has been attributed to their unique postembryonic life phases in which nonreproductive and wingless larvae differ significantly in morphology and life habits from their reproductive and mostly winged adults, separated by a resting stage, the pupa. Little is known of the evolutionary developmental mechanisms that produced the holometabolous larval condition and their Paleozoic origin based on fossils and phylogeny. Results: We provide a detailed anatomic description of a 311 million-year-old specimen, the oldest known holometabolous larva, from the Mazon Creek deposits of Illinois, U.S.A. The head is ovoidal, downwardly oriented, broadly attached to the anterior thorax, and bears possible simple eyes and antennae with insertions encircled by molting sutures; other sutures are present but often indistinct. Mouthparts are generalized, consisting of five recognizable segments: a clypeo-labral complex, mandibles, possible hypopharynx, a maxilla bearing indistinct palp-like appendages, and labium. Distinctive mandibles are robust, triangular, and dicondylic. The thorax is delineated into three, nonoverlapping regions of distinctive surface texture, each with legs of seven elements, the terminal-most bearing paired claws. The abdomen has ten segments deployed in register with overlapping tergites; the penultimate segment bears a paired, cercus-like structure. The anterior eight segments bear clawless leglets more diminutive than the thoracic legs in length and cross-sectional diameter, and inserted more ventrolaterally than ventrally on the abdominal sidewall. Conclusions: Srokalarva berthei occurred in an evolutionary developmental context likely responsible for the early macroevolutionary success of holometabolous insects. Srokalarva berthei bore head and prothoracic structures, leglet series on successive abdominal segments - in addition to comparable features on a second taxon eight million-years-younger - that indicates Hox-gene regulation of segmental and appendage patterning among earliest Holometabola. Srokalarva berthei body features suggest a caterpillar-like body plan and head structures indicating herbivory consistent with known, contemporaneous insect feeding damage on seed plants. Taxonomic resolution places Srokalarva berthei as an extinct lineage, apparently possessing features closer to neuropteroid than other holometabolous lineages

Studying the accretion geometry of EXO 2030+375 at luminosities close to the propeller regime

The Be X-ray binary EXO 2030+375 was in an extended low luminosity state during most of 2016. We observed this state with NuSTAR and Swift, supported by INTEGRAL observations as well as optical spectroscopy with the NOT. We present a comprehensive spectral and timing analysis of these data here to study the accretion geometry and investigate a possible onset of the propeller effect. The H-alpha data show that the circumstellar disk of the Be-star is still present. We measure equivalent widths similar to values found during more active phases in the past, indicating that the low-luminosity state is not simply triggered by a smaller Be disk. The NuSTAR data, taken at a 3-78 keV luminosity of ~6.8e35 erg/s (for a distance of 7.1 kpc), are well described by standard accreting pulsar models, such as an absorbed power-law with a high-energy cutoff. We find that pulsations are still clearly visible at these luminosities, indicating that accretion is continuing despite the very low mass transfer rate. In phase-resolved spectroscopy we find a peculiar variation of the photon index from ~1.5 to ~2.5 over only about 3% of the rotational period. This variation is similar to that observed with XMM-Newton at much higher luminosities. It may be connected to the accretion column passing through our line of sight. With Swift/XRT we observe luminosities as low as 1e34 erg/s during which the data quality did not allow us to search for pulsations, but the spectrum is much softer and well described by either a blackbody or soft power-law continuum. This softer spectrum might be due to the fact that accretion has been stopped by the propeller effect and we only observe the neutron star surface cooling.Comment: 11 pages, 6 figures, accepted for publication in A&A (v2 including language edits

Aggregation Patterns, Sampling Plan, and Economic Injury Levels for the New Citrus Pest Delottococcus aberiae (Hemiptera: Pseudococcidae)

[EN] Delottococcus aberiae De Lotto (Hemiptera: Pseudococcidae) is the latest exotic mealybug species introduced in citrus in the Mediterranean basin. It causes severe distortion and size reduction on developing fruits. Due to its first interaction with citrus, D. aberiae economic thresholds are still unknown for this crop and the current Integrated Pest Management programs have been disrupted. The objectives of this study were to determine the aggregation patterns of D. aberiae in citrus, develop an efficient sampling plan to assess its population density, and calculate its Economic and Economic Environmental Injury Levels (EIL and EEIL, respectively). Twelve and 19 orchards were sampled in 2014 and 2015, respectively. At each orchard, population densities were monitored fortnightly in leaves, twigs, and fruit, and fruit damage was determined at harvest. Our results showed a clumped aggregation of D. aberiae in all organs with no significant differences between generations on fruit. Fruit damage at harvest was strongly correlated with fruit occupation in spring. Based on these results and using chlorpyrifos as the insecticide of reference, the EIL and EEIL were calculated as 7.1 and 12.1% of occupied fruit in spring, respectively. With all this, we recommend sampling 275 fruits using a binomial sampling method or alternatively, 140 fruits with an enumerative method bimonthly between petal fall and July.We would like to thank the owners of the orchards for giving us permission to use their plantations, Aureli Marco and Jesus Marques for finding the orchards, and P. Bru (IVIA) and J. Catalan (IVIA) for their help in sampling. This research was supported by two predoctoral grant (FPU toV. M. and Val I+D to J.P.-R.) from the Spanish Ministry of Education, Culture, and Sport and Generalitat Valenciana, respectively, a national project provided by INIA (Project no. RTA2014-00067) and a European grant (FP7-IAPP324475 'Colbics')Pérez-Rodríguez, J.; Martínez-Blay, V.; Soto Sánchez, AI.; Selfa, J.; Monzó, C.; Urbaneja, A.; Tena, A. (2017). Aggregation Patterns, Sampling Plan, and Economic Injury Levels for the New Citrus Pest Delottococcus aberiae (Hemiptera: Pseudococcidae). Journal of Economic Entomology. 110(6):2699-2706. https://doi.org/10.1093/jee/tox258S269927061106Allsopp, P. G. (1991). Binomial sequential sampling of adult Saccharicoccus sacchari on sugarcane. Entomologia Experimentalis et Applicata, 60(3), 213-218. doi:10.1111/j.1570-7458.1991.tb01540.xBellard, C., Cassey, P., & Blackburn, T. M. (2016). Alien species as a driver of recent extinctions. Biology Letters, 12(2), 20150623. doi:10.1098/rsbl.2015.0623Beltrà, A., Garcia-Marí, F., & Soto, A. (2013). Seasonal Phenology, Spatial Distribution, and Sampling Plan for the Invasive Mealybug Phenacoccus peruvianus (Hemiptera: Pseudococcidae). 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L., & Garcia-Marí, F. (2006). Enumerative and Binomial Sampling Plans for Citrus Mealybug (Homoptera: Pseudococcidae) in Citrus Groves. Journal of Economic Entomology, 99(3), 993-1001. doi:10.1093/jee/99.3.993Meyerson, L. A., & Mooney, H. A. (2007). Invasive alien species in an era of globalization. Frontiers in Ecology and the Environment, 5(4), 199-208. doi:10.1890/1540-9295(2007)5[199:iasiae]2.0.co;2Mgocheki, N., & Addison, P. (2009). Incorporating sampling precision into an action threshold for monitoring ant (Hymenoptera: Formicidae) population levels in vineyards. Crop Protection, 28(3), 257-263. doi:10.1016/j.cropro.2008.10.010Miller, D. R., & Giliomee, J. H. (2011). Systematic Revision of the Mealybug GenusDelottococcusCox & Ben-Dov (Hemiptera: Pseudococcidae). African Entomology, 19(3), 614-640. doi:10.4001/003.019.0306Mudavanhu, P., Addison, P., & Pringle Ken, L. (2011). Monitoring and action threshold determination for the obscure mealybug Pseudococcus viburni (Signoret) (Hemiptera: Pseudococcidae) using pheromone-baited traps. Crop Protection, 30(7), 919-924. doi:10.1016/j.cropro.2011.02.034Navarro-Campos, C., Aguilar, A., & Garcia-Marí, F. (2011). Aggregation pattern, sampling plan, and intervention threshold for Pezothrips kellyanus in citrus groves. Entomologia Experimentalis et Applicata, 142(2), 130-139. doi:10.1111/j.1570-7458.2011.01204.xNestel, D., Cohen, H., Saphir, N., Klein, M., & Mendel, Z. (1995). Spatial Distribution of Scale Insects: Comparative Study Using Taylor’s Power Law. Environmental Entomology, 24(3), 506-512. doi:10.1093/ee/24.3.506PIMENTEL, D., LACH, L., ZUNIGA, R., & MORRISON, D. (2000). Environmental and Economic Costs of Nonindigenous Species in the United States. BioScience, 50(1), 53. doi:10.1641/0006-3568(2000)050[0053:eaecon]2.3.co;2Pimentel, D., Zuniga, R., & Morrison, D. (2005). 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J., Bardsley, S., Bennun, L., Clout, M., Côté, I. M., Depledge, M. H., … Fleishman, E. (2011). Horizon scan of global conservation issues for 2011. Trends in Ecology & Evolution, 26(1), 10-16. doi:10.1016/j.tree.2010.11.002TAYLOR, L. R. (1961). Aggregation, Variance and the Mean. Nature, 189(4766), 732-735. doi:10.1038/189732a0Tena, A., García-Bellón, J., & Urbaneja, A. (2016). Native and naturalized mealybug parasitoids fail to control the new citrus mealybug pest Delottococcus aberiae. Journal of Pest Science, 90(2), 659-667. doi:10.1007/s10340-016-0819-7Waterworth, R. A., Redak, R. A., & Millar, J. G. (2011). Pheromone-Baited Traps for Assessment of Seasonal Activity and Population Densities of Mealybug Species (Hemiptera: Pseudococcidae) in Nurseries Producing Ornamental Plants. Journal of Economic Entomology, 104(2), 555-565. doi:10.1603/ec1031

Probing stellar winds and accretion physics in high-mass X-ray binaries and ultra-luminous X-ray sources with LOFT

This is a White Paper in support of the mission concept of the Large Observatory for X-ray Timing (LOFT), proposed as a medium-sized ESA mission. We discuss the potential of LOFT for the study of high-mass X-ray binaries and ultra-luminous X-ray sources. For a summary, we refer to the paper.Comment: White Paper in Support of the Mission Concept of the Large Observatory for X-ray Timing. (v2 few typos corrected

Marker Assisted Foreground Selection for Identification of Striga Resistant Backcross Lines in Sorghum bicolor

Striga is a major constraint to sorghum production causing high yield loss due to increasing infestation. Locally-adapted cultivars with resistant genes/QTLs could be an effective control strategy for Striga. Marker-Assisted Foreground Selection was used to select backcross lines possessing Striga resistance QTLs from N13. Marker polymorphism was conducted for the donor parent N13 and 10 recurrent parents using 10 Simple Sequence Repeat (SSR) markers. Recurrent parents with SSR alleles, polymorphic to the donor parent allele were selected. F1 lines were developed by making a cross between the selected recurrent parent and the donor. The F1 were confirmed for heterozygosity using SSR markers. Selected heterozygote F1s were backcrossed to their recurrent parent to develop backcross populations (BC1F1 and BC2F1). BC1F1 and BC2F1 populations were genotyped using SSR markers flanking the Striga resistant QTLs in N13. Forty two DANYANA-N13 BC2F1 lines (with 4 QTLs in 3 lines, 3 QTLs in 10 lines and other 28 lines having 1 to 2 QTLs) were selected for the presence of N13 QTLs. Forty three SAMSORG39-N13 BC2F1 lines (with 3 QTLs in 2 lines while 41 lines had 1 to 2 QTLs) were also selected for the presence of N13 QTLs. Although, selected lines will be genotyped for the recovery of recurrent parent background and evaluated to identify elite genotypes for possible release as varieties, the successful introgression of Striga resistance QTLs using Marker Assisted Selection suggests that in developing superior sorghum varieties, breeders could make use of molecular marker technologies to speed up breeding programmes

Airports at Risk: The Impact of Information Sources on Security Decisions

Security decisions in high risk organizations such as airports involve obtaining ongoing and frequent information about potential threats. Utilizing questionnaire survey data from a sample of airport employees in European Airports across the continent, we analyzed how both formal and informal sources of security information affect employee's decisions to comply with the security rules and directives. This led us to trace information network flows to assess its impact on the degree employees making security decisions comply or deviate with the prescribed security rules. The results of the multivariate analysis showed that security information obtained through formal and informal networks differentially determine if employee will comply or not with the rules. Information sources emanating from the informal network tends to encourage employees to be more flexible in their security decisions while formal sources lead to be more rigid with complying with rules and protocols. These results suggest that alongside the formal administrative structure of airports, there exists a diverse and pervasiveness set of informal communications networks that are a potent factor in determining airport security levels