Adjustment of vibratory signals to ambient temperature in a host-searching parasitoid

Abstract.  Certain ichneumonid parasitoids (Hymenoptera) use self-produced vibrations transmitted on plant substrate, so-called vibrational sounding, to locate their immobile concealed pupal hosts. An ambient temperature dependency with higher frequencies and intensities at higher temperatures is postulated because signals are of myogenic origin. Here, temperature influence on vibratory signals is analysed in the temperate parasitoid Pimpla turionellae under different thermal conditions using plant-stem models to elicit host-searching behaviour. Signals are measured with laser Doppler vibrometry and analysed for time parameters and frequency components applying fast-Fourier transformations. The results reveal an unexpected effect of ambient temperature on signals produced by the female wasps. Although average values of time parameters (pulse trains, pulse train periods, inter pulse duration) are unchanged by ambient temperature, the frequency parameters show an inverse thermal effect. Within the temperature range tested (8–26 °C), decreasing temperature leads to significantly higher frequency and intensity of the self-produced vibrations in the temperate species. This inverse thermal effect may be explained by a temperature-coupled signal production in the frequency domain to compensate negative low-temperature effects on the mechanoreceptors by increased muscle activity. The option of heterothermy to produce signals reliably during vibrational sounding under low temperature is also discussed.     

Water permeability of plant cuticular membranes: the effects of humidity and temperature on the permeability of non-isolated cuticles of onion bulb scales

Abstract. Water permeability of cuticular membranes (CM) from the inner bulb scales of Allium cepa has been investigated. CM have a thickness ranging from 0.6 to 1.3 μm. They are composed of a thin (120–200 nm) lamellated cuticle proper and a thicker (300–900 nm) cuticular layer. Permeability coefficients for diffusion of water across these thin membranes are very low (4 × lO⁻¹⁰ms⁻¹⁰). There was no difference in permeability of CM from successive scales of the same onion. Extraction of soluble cuticular lipids (SCL) with chloroform increased permeability by a factor of 1350 to 2050. Preliminary data indicate that only 1 μg cm⁻¹⁰ of SCL are removed by this treatment, hydrocarbons being the main (75%) consistuent. Permeability coefficients of cuticular transpiration were little affected by relative humidity, showing that transport is limited by a hydrophobic barrier that lacks dipoles. However, following extraction, permeability of the membranes depended strongly on humidity due to the presence of polar functional groups in the polymer matrix. Soluble cuticular lipids undergo a phase transition around 47°C. Temperatures higher than that irreversibly increased water permeability.     

The deciduous dentition and dental replacement in the Eocene bat Palaeochiropteryx tupaiodon from Messel: The primitive condition and beginning of specialization of milk teeth among Chiroptera

The deciduous dentition and tooth replacement pattern of Palaeochiropteryx tupaiodon from the early Middle Eocene of Messel, near Frankfurt, Germany, are described. Ontogenetic states include fetuses to subadults. The posterior portion of the deciduous dentition (dP3-4) still shows the primitive eutherian condition of molarization, while the anterior part (dI-dC) was already engaged in the evolution of the highly derived condition found in living bats for clinging to the mother's fur. A styliform and sharp anterior dentition is considered a prerequisite in earliest chiropteran evolution. The greatly modified milk teeth of all living bats developed in different clades by parallel evolution under high selective pressure. The tiny and, at initial stages, poorly calcified teeth are substantiated by a newly developed microradiographic technique which is described in detail.     

Dinoflagellate cyst biostratigraphy of the Opalinuston Formation (Middle Jurassic) in the Aalenian type area in southwest Germany and north Switzerland

Feist‐Burkhardt, S. & Pross, J. 2010: Dinoflagellate cyst biostratigraphy of the Opalinuston Formation (Middle Jurassic) in the Aalenian type area in southwest Germany and north Switzerland. Lethaia, Vol. 43, pp. 10–31. In order to provide a detailed dinoflagellate cyst stratigraphy of the Lower Aalenian Opalinuston Formation from the Aalenian type area, 68 samples from four boreholes and one outcrop section were analysed. The sample localities are Hausen an der Fils and Wittnau in southwest Germany, Weiach in north Switzerland and Mont Russelin in the Swiss Jura Mountains. Dinoflagellate cyst assemblages were recovered from the Late Toarcian Aalensis Zone to the Late Aalenian Murchisonae Zone. The samples yielded rich, well‐preserved and diverse assemblages with 51 dinoflagellate cyst taxa identified in total. The dinoflagellate cyst distribution data obtained from this study allow a high‐resolution biostratigraphical subdivision of the lowermost Middle Jurassic Opalinuston Formation into four palynostratigraphical units. First and last occurrences, acmes and consistent presence of the species Batiacasphaera sp. A, Evansia cf. granochagrinata, Kallosphaeridium praussii, Nannoceratopsis triangulata, Phallocysta? frommernensis and Wallodinium laganum were selected as the criteria for defining these units. The obtained high‐resolution palynostratigraphical scheme provides a basis for establishing and further refining early Middle Jurassic biostratigraphy in the Boreal and Tethyan realms. □Aalenian, biostratigraphy, dinoflagellate cysts, Germany, Jurassic, Switzerland, Toarcian.     

Analysis of the mitochondrial genome of Schistocerca gregaria gregaria (Orthoptera: Acrididae)

In the present study, we present the full sequence of the mitochondrial genome of the African desert locust Schistocerca gregaria gregaria. The size of 15625 bp reported matches very well with mitochondrial genomes of other Orthopteriodea. The mitochondrial genome comprises 13 protein‐coding genes, two ribosomal RNAs and 22 t‐RNAs with two t‐RNA (trnD and trnK) rearrangements that are typical for the taxon Caelifera. We compared the sequence with 12 mitochondrial genes of Schistocerca gregaria flaviventris and Schistocerca americana and used some of these data to construct phylogenetic trees, which confirm the close relationship between the two subspecies S. g. flaviventris and S. g. gregaria. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99 , 296–305.     

Effect of NSAIDs and Diuretics on Nephrogenesis in an Ex Vivo Embryogenic Kidney Model

The kidney is one of the key organs in clearing foreign compounds. The effects of drugs on the developing kidney are relatively unknown. We studied the direct effect of furosemide, hydrochlorothiazide, ibuprofen, and indomethacin on kidney development in an ex vivo embryonic kidney model. At embryonic day 13, metanephroi were dissected from mice and cultured in control media or media supplemented with various clinically relevant concentrations of drugs. The ureteric tree was visualized by whole‐mount staining and branching was evaluated by counting. Additionally, gene expression levels of Wt1, Sox9, Bmp7, Fgf8, and Gdnf were investigated. No distinct differences were noted on either ureteric tip development or gene expression analysis for each drug after 24 hr of exposure. Even though short‐term exposure to clinically relevant concentrations seems not to disturb renal development, future research is needed to study prolonged or repeated exposures.     

Immunofluorescence studies of neurofilaments in the rat and human peripheral and central nervous system

Localization of antisera to neurofilament antigens derived from rat peripheral nerve was carried out in tissues of rat and human peripheral and central nervous systems by indirect immunofluorescence. Unfixed and chloroform-methanol-fixed frozen sections of tissues were incubated in purified IgG of the experimental rabbit antisera and subsequently exposed to goat anti-rabbit IgG conjugated with fluorescein isothiocyanate. Control studies were conducted on identical tissue preparations incubated in the same concentrations of nonspecific rabbit IgG or in experimental rabbit IgG absorbed with extracts of rat peripheral nerve containing neurofilament antigen. Extensive immunofluorescence was observed in rat and human peripheral and central nervous systems. The distribution and configuration of immunofluorescence corresponded to neurofilament-rich structural components of these tissues. Prominent immunofluorescence was also noted in neuronal cell bodies of spinal sensory ganglia, especially in perikarya of the large neuronal type. Immunofluorescence of the central nervous system was located predominantly in myelinated axons of the white matter in cerebrum, cerebellum, brain stem, and spinal cord. Less intense immunofluorescence was also seen in neuronal perikarya and in short thin linear processes of grey matter.     

The Upper Tremadocian (Ordovician) graptolite Bryograptus: taxonomy, biostratigraphy and biogeography

Abstract:  The taxonomy, biostratigraphical and palaeogeographical distribution of the Lower Ordovician graptolite genus Bryograptus is evaluated. Bryograptus is recognized as a distinct triradiate anisograptid with a multiramous, pendent rhabdosome. The species of the genus Bryograptus can be interpreted as shallow water faunal elements with a strongly limited biogeographical distribution to the Atlantic Faunal Realm. Bryograptus is restricted to a narrow interval in the Upper Tremadocian, the Bryograptus Biozone of Scandinavia and South America (Argentina), making it a taxon with a high potential for precise biostratigraphical correlations. The proximal end development can be used to differentiate the genus Bryograptus from other pendent multiramous graptoloid genera with a homoplastic rhabdosome development. Characteristics of the proximal end development and structure easily differentiate these genera in relief specimens, but not in flattened material.