Dynamic and temporal structure of the troglobitic beetle Speonomus hydrophilus (Coleoptera: Bathyscimae)

The population ecology of the beetle Speonomus hydrophilus , occurring both in caves (reduced fluctuations in many abiotic parameters) and under the deepest layer of soil in mountains (MSS, more exposed to climatic variations), was studied in four habitats in the French central Pyrenees We have assessed some of the characteristics of the environment where these populations occur c g physical data (altitude and exposure), geologic data (nature of the parent-rock) and abiotic parameters (temperature with its seasonal fluctuations) and we investigated the relative importance of environmental structure and ecological characteristics on the temporal organization of S hydrophilus and the troglobitic fauna which cohabits The climatic study shows the existence of an annual thermal cycle which is regular and well marked for the MSS habitats but slightly out of phase with the surface cycle These periodic variations however slight may be stressful for troglobitic species In the MSS populations, the phenology of the entire community is reflected in the pattern seen in Speonomus The analysis of faunal profiles shows that samples follow the same seasonal succession during the annual cycle A potential seasonal rhythm of emergence may reflect a seasonal rhythm of vitellogenesis which produces a rhythm of egg-laying     

Reaction mechanism of surfactant‐sensitized chemiluminescence of bis(2,4,6‐trichlorophyenyl) oxalate and hydrogen peroxide induced by gold nanoparticles

The chemiluminescence (CL) of bis(2,4,6‐trichlorophyenyl) oxalate with hydrogen peroxide in the present of cationic surfactant and gold nanoparticles was studied. The CL emission was obviously enhanced in the presence of surfactant at a suitable concentration, with a synergetic catalysis effect exhibited. Different sizes of gold nanoparticles (15 and 50 nm) showed different effects on CL intensity. Mechanisms of the CL reaction and sensitization effect are discussed. Copyright © 2008 John Wiley & Sons, Ltd.     

Pre‐copulation intervals,copulation frequencies,and initial progeny sex ratios in two biotypes of whitefly,Bemisia tabaci

The whitefly Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) is a species complex, and its systematic classification requires controlled crossing experiments among its genetic groups. Accurate information on pre‐copulation intervals, copulation frequencies, and initial frequency of egg fertilization of newly emerged adults is critical for designing procedures for collecting the virgin adults necessary for these experiments. In the literature, considerable variation is reported between B. tabaci populations, with respect to the length of the pre‐copulation interval and the initial frequency of egg fertilization. Here, we used a video‐recording method to observe continuously the copulation behaviour of the Mediterranean/Asia Minor/Africa (B biotype) and the Asia II (ZHJ1 biotype) groups of B. tabaci. We also recorded the initial frequency of egg fertilization, as determined by the sex of the progeny. When adults were caged in female–male pairs on leaves of cotton plants, the earliest copulation events occurred 2–6 h after emergence; at 12 h after emergence 56–84% of the females had copulated at least once, and nearly all (92–100%) had copulated at least once by 36 h after emergence. Both females and males copulated repeatedly. Approximately 80 and 20% of copulation events occurred during the photophase and scotophase, respectively. By 72 h post‐emergence, the females of the B and ZHJ1 biotypes had copulated on average 6.1 and 3.9 times, respectively. When adults were caged in groups on plants 1–13 h after emergence, 30–35% of the eggs deposited during this period were fertilized, and approximately 90% of females were fertilized by the end of the 13 h. Although timing of copulation differed in detail between the two genetic groups, the results demonstrate that B. tabaci adults can start to copulate as early as 2–6 h post‐emergence and the majority of females can become fertilized on the day that they emerge.     

Regulation of auxin transport in pea (Pisum sativum L.) by phenylacetic acid: effects on the components of transmembrane transport of indol-3yl-acetic acid

Phenylacetic acid (PAA), a naturally-occurring acidic plant growth substance, was readily taken up by pea (Pisum sativum L. cv. Alderman) stem segments from buffered external solutions by a pH-dependent, non-mediated diffusion. Net uptake from a 0.2 M solution at pH 4.5 proceeded at a constant rate for at least 60 min and, up to approx. 100 M, the rate of uptake was directly proportional to the external concentration of the compound. The net rate of uptake of PAA was not affected by the inclusion of indol-3yl-acetic acid (IAA) in the uptake medium (up to approx. 30 M) and, unlike the net uptake of IAA, was not stimulated by N-1-naphthylphthalamic acid (NPA) or 2,3,5-triiodobenzoic acid. At an external concentration of 0.2 M and pH 4.5, the net rate of uptake of PAA was about twice that of IAA. It was concluded that the uptake of PAA did not involve the participation of carriers and that PAA was not a transported substrate for the carriers involved in the uptake and polar transport of IAA. Nevertheless, the inclusion of 3–100 M unlabelled PAA in the external medium greatly stimulated the uptake by pea stem segments of [1-¹⁴C]IAA (external concentration 0.2 M). It was concluded that whilst PAA was not a transported substrate for the NPA-sensitive IAA efflux carrier, it interacted with this carrier to inhibit IAA efflux from cells. Over the concentration range 3–100 M, PAA progressively reduced the stimulatory effect of NPA on IAA uptake, indicating that PAA also inhibited carrier-mediated uptake of IAA. The consequences of these observations for the regulation of polar auxin transport are discussed.Abbreviations IAA indol-3yl-acetic acid - DMO 5,5-dimethyloxazolidine-2,4-dione - NPA N-1-naphthylphthalamic acid - PAA phenylacetic acid - TIBA 2,3,5-triiodobenzoic acid     

Stability of Lanatoside C content in thein vitro propagatedDigitalis lanata clones

In vitro culture was established from shoot tips ofDigitalis lanata cotyledonous plants. The propagated plant material was rooted, transplanted into soil and grown under field conditions. Lanatoside C content was determined in a total of 20 clones and statistically evaluated by means of variance analysis of unequal-sized samples.In vitro clonal propagation ofD. lanata was found not to affect lanatoside C content. Drug level was dependent on a plant genotype.