Egg mass structure of the processionary caterpillar Ochrogaster lunifer (Lepidoptera: Notodontidae): is the outer egg layer sacrificed for attack by the egg parasitoid Anastatus fuligispina (Hymenoptera: Chalcidoidea: Eupelmidae)?

Each life stage of an insect faces the challenge of various mortality factors. Through experimental and observational studies, we use those mortality agents to our advantage to control outbreaks of pest insects. The processionary caterpillar Ochrogaster lunifer Herrich-Schaffer, 1855, is a widespread native moth in Australia that defoliates host trees and causes medical problems in humans and animals. Anastatus fuligispina (Girault 1939) is an egg parasitoid described from eggs of O. lunifer in eastern Australia nearly 80 years ago for which few life history traits are known. This is the first study to investigate the life history of A. fuligispina, factors associated with parasitism levels in O. lunifer egg masses and its impacts on egg mortality. We found that parasitism level was related to the total number of eggs in an O. lunifer egg mass, with higher parasitism occurring in masses with fewer eggs. The inaccessible physical structure of the O. lunifer egg mass by layering and encasing eggs with other eggs and the searching efficiency of the parasitoid are possible key factors. Other variables such as exposure time in the field, host tree species and number of undeveloped eggs in the egg mass did not affect the level of parasitism. Further investigations on the life history of A. fuligispina may open possibilities for its application in controlling O. lunifer populations

In situ study of oxidation states of platinum nanoparticles on a polymer electrolyte fuel cell electrode by near ambient pressure hard X-ray photoelectron spectroscopy

We performed in situ hard X-ray photoelectron spectroscopy (HAXPES) measurements of the electronic states of platinum nanoparticles on the cathode electrocatalyst of a polymer electrolyte fuel cell (PEFC) using a near ambient pressure (NAP) HAXPES instrument having an 8 keV excitation source. We successfully observed in situ NAP-HAXPES spectra of the Pt/C cathode catalysts of PEFCs under working conditions involving water, not only for the Pt 3d states with large photoionization cross-sections in the hard X-ray regime but also for the Pt 4f states and the valence band with small photoionization cross-sections. Thus, this setup allowed in situ observation of a variety of hard PEFC systems under operating conditions. The Pt 4f spectra of the Pt/C electrocatalysts in PEFCs clearly showed peaks originating from oxidized Pt(II) at 1.4 V, which unambiguously shows that Pt(IV) species do not exist on the Pt nanoparticles even at such large positive voltages. The water oxidation reaction might take place at that potential (the standard potential of 1.23 V versus a standard hydrogen electrode) but such a reaction should not lead to a buildup of detectable Pt(IV) species. The voltage-dependent NAP-HAXPES Pt 3d spectra revealed different behaviors with increasing voltage (0.6 → 1.0 V) compared with decreasing voltage (1.0 → 0.6 V), showing a clear hysteresis. Moreover, quantitative peak-fitting analysis showed that the fraction of non-metallic Pt species matched the ratio of the surface to total Pt atoms in the nanoparticles, which suggests that Pt oxidation only takes place at the surface of the Pt nanoparticles on the PEFC cathode, and the inner Pt atoms do not participate in the reaction. In the valence band spectra, the density of electronic states near the Fermi edge reduces with decreasing particle size, indicating an increase in the electrocatalytic activity. Additionally, a change in the valence band structure due to the oxidation of platinum atoms was also observed at large positive voltages. The developed apparatus is a valuable in situ tool for the investigation of the electronic states of PEFC electrocatalysts under working conditions

Spectropolarimetric Study on Circumstellar Structure of Microquasar LS I +61deg 303

We present optical linear spectropolarimetry of the microquasar LS I +61$^{\circ}$ 303. The continuum emission is mildly polarized (up to 1.3 %) and shows almost no temporal change. We find a distinct change of polarization across the H$\alpha$ emission line, indicating the existence of polarization component intrinsic to the microquasar. We estimate the interstellar polarization (ISP) component from polarization of the H$\alpha$ line and derive the intrinsic polarization component. The wavelength dependence of the intrinsic component is well explained by Thomson scattering in equatorial disk of the Be-type mass donor. The position angle (PA) of the intrinsic polarization $\sim 25^{\circ}$ represents the rotational axis of the Be disk. This PA is nearly perpendicular to the PA of the radio jet found during quiescent phases. Assuming an orthogonal disk-jet geometry around the compact star, the rotational axis of the accretion disk is almost perpendicular to that of the Be disk. Moreover, according to the orbital parameters of the microquasar, the compact star is likely to get across the Be disk around their periastron passage. We discuss the peculiar circumstellar structure of this microquasar inferred from our observation and possible connection with its high-energy activities.Comment: 17pages, 7figures; accepted for Publications of the Astronomical Society of Japa

Detection of Polarimetric Variations Associated with the Shortest Time-Scale Variability in S5 0716+ + 714

We present the result of near-infrared and optical observations of the BL Lac object S5 0716$+$714 carried out by the KANATA telescope. S5 0716$+$714 has both a long term high-amplitude variability and a short-term variability within a night. The shortest variability (microvariability) time-scale is important for understanding the geometry of jets and magnetic field, because it provides a possible minimum size of variation sources. Here, we report the detection of 15-min variability in S5 0716$+$714, which is one of the shortest time-scales in optical and near-infrared variations observed in blazars. The detected microvariation had an amplitude of $0.061{\pm}0.005$ mag in $V$ band and a blue color of $\Delta(V-J)=-0.025{\pm}0.011$. Furthermore, we successfully detected an unprecedented, short time-scale polarimetric variation which correlated with the brightness change. We revealed that the microvariation had a specific polarization component. The polarization degree of the variation component was higher than that of the total flux. These results suggest that the microvariability originated from a small and local region where the magnetic field is aligned.Comment: 5 pages, 4 figures; Publications of the Astronomical Society of Japan letter accepte

Dwarf Novae in the Shortest Orbital Period Regime: I. A New Short Period Dwarf Nova, OT J055717+683226

We report the observation of a new dwarf nova, OT J055717+683226, during its first-ever recorded superoutburst in December 2006. Our observation shows that this object is an SU UMa-type dwarf nova having a very short superhump period of 76.67+/- 0.03 min (0.05324+/-0.00002 d). The next superoutburst was observed in March 2008. The recurrence time of superoutbursts (supercycle) is, hence, estimated to be ~480 d. The supercycle is much shorter than those of WZ Sge-type dwarf novae having supercycles of >~ 10 yr, which are a major population of dwarf novae in the shortest orbital period regime (<~85 min). Using a hierarchical cluster analysis, we identified seven groups of dwarf novae in the shortest orbital period regime. We identified a small group of objects that have short supercycles, small outburst amplitudes, and large superhump period excesses, compared with those of WZ Sge stars. OT J055717+683226 probably belongs to this group.Comment: 14 pages, 11 figures, accepted for publication in PAS

Optical and Near-Infrared Photometry of Nova V2362 Cyg : Rebrightening Event and Dust Formation

We present optical and near-infrared (NIR) photometry of a classical nova, V2362 Cyg (= Nova Cygni 2006). V2362 Cyg experienced a peculiar rebrightening with a long duration from 100 to 240 d after the maximum of the nova. Our multicolor observation indicates an emergence of a pseudophotosphere with an effective temperature of 9000 K at the rebrightening maximum. After the rebrightening maximum, the object showed a slow fading homogeneously in all of the used bands for one week. This implies that the fading just after the rebrightening maximum ( less or equal 1 week ) was caused by a slowly shrinking pseudophotosphere. Then, the NIR flux drastically increased, while the optical flux steeply declined. The optical and NIR flux was consistent with blackbody radiation with a temperature of 1500 K during this NIR rising phase. These facts are likely to be explained by dust formation in the nova ejecta. Assuming an optically thin case, we estimate the dust mass of 10^(-8) -- 10^(-10) M_solar, which is less than those in typical dust-forming novae. These results support the senario that a second, long-lasting outflow, which caused the rebrightening, interacted with a fraction of the initial outflow and formed dust grains.Comment: 6 pages, 4 figures, 2010, PASJ, 62, 1103--1108, in pres

Look but do not touch: the occurrence of venomous species across Lepidoptera

peer reviewedLepidoptera can cause several health issues in humans and domestic animals due to their setae, which are defensive adaptations that protect them from predators. The diversity of venomous Lepidoptera has been explored in several reviews starting from the first comprehensive attempt in 1984 by Kawamoto and Kumada (KK) who compiled a list of 228 species based on previous reviews; however, KK did not cite the original publications for listed species. In this review we validated and updated the KK table. The updated list of venomous Lepidoptera includes 5 superfamilies, 14 families, 208 genera, and 576 species, representing a two-fold increase for genera and 2.9-fold for species with respect to KK. The total number of species in the genera including at least one venomous species, which we argue is likely closer to the true number of venomous species, is 7 times higher (3,620). GBIF (Global Biodiversity Information Facility) occurrences for venomous species are 1–4 orders of magnitude higher than those of confamilial non-venomous species. The presence of venomous structures is independent of the relatedness of the clades or geographic region; venom is produced by many species of Zygaenoidea, Lasiocampoidea and Bombycoidea but only by some specialized groups in Papilionoidea and Noctuoidea. There are likely to be multiple evolutionary origins of venom within Lepidoptera, but the exact number is difficult to estimate. The knowledge gap between medical and natural history fields needs to be addressed with novel approaches to study ecology and toxicology. This review offers health practitioners a tool to better understand the origin of the reactions observed and to improve the identification of the causal agents