Repellent effects of pongam oil on settlement and oviposition of the common greenhouse whitefly Trialeurodes vaporariorum on chrysanthemum

The repellent activities, including host deterrence and anti-oviposion, of pongam oil against the adults of the common greenhouse whitefly Trialeurodes vaporariorum Westwood in greenhouses were tested. Chrysanthemum plants treated with different concentrations （0.5%-2.0%） of water-suspended pongam oil showed relatively long-lasting host deterrent and anti-oviposition effects on the adults of greenhouse whitefly. Although the repellent effect declined in time and concentration, strong effects on the reduction of oviposition were found, which lasts, dependent on concentration at least 12 days after application.     

Survival and development of five species of cyclopoid copepods in relation to food supply: experiments with algal food in a flow-through system

1. Cyclops spp. generally develop and grow during favourable food conditions in spring and undergo a diapause in summer, while Acanthocyclops robustus, Mesocyclops leuckarti and Thermocyclops crassus develop and grow in summer when they face poorer food conditions and more competition from Cladocera. Since nauplii are the bottleneck in copepod development, we tested the hypothesis that Cyclops abyssorum and C. vicinus nauplii have higher food requirements for survival and development than the nauplii of A. robustus, M. leuckarti and T. crassus. We also tested survivorship and development from hatching to adulthood. 2. Survivorship and development of the copepods was studied in a flow‐through system using five concentrations of the phytoflagellate Chlamydomonas reinhardtii in the range from 1 × 10⁴ to 4.5 × 10⁵ cells mL^?1 (approximately 0.5–22.5 mg C L^?1). 3. Nauplii of both species of Cyclops died at intermediate to low (C. abyssorum) and low (C. vicinus) food concentrations, while nauplii of A. robustus, M. leuckarti and T. crassus survived at all concentrations. 4. The negative effects of low food concentration were also reflected in development. In C. abyssorum and C. vicinus, development duration increased at low food concentration while development was much less affected in A. robustus and T. crassus. Mesocyclops leuckarti was intermediate between Cyclops spp. and A. robustus/T. crassus, with an increase in development duration at the lowest food concentration. 5. Our results support the hypothesis that summer diapause in Cyclops spp. has developed as a strategy to avoid a food bottleneck for nauplii.     

Impact of altering the water table height of an acidic fen on N2O and NO fluxes and soil concentrations

The impact of experimentally intensified summer drought and precipitation on N₂O and NO turnover and fluxes was investigated in a minerotrophic fen over a 2‐year period. On three treatment plots, drought was induced for 6 and 10 weeks by means of roofs and drainage and decreased water table levels by 0.1–0.3 m compared with three nonmanipulated control plots. When averaged over the three treatment plots, both N₂O and NO emission showed only little response to the drought. On the single plot scale, however, a clear impact of the treatment on N₂O and NO fluxes could be identified. On the plot with the weakest water table reduction hardly any response could be observed, while on the plot with the greatest drainage effect, N₂O and NO fluxes increased by 530% and 270%, respectively. Rewetting reduced NO emissions to background levels (0.05–0.15 μmol m^?2 h^?1), but heavily enhanced N₂O emission (18–36 μmol m^?2 h^?1) for several days in the plots with largest water table reduction. These peaks contributed up to 40% to the cumulative N₂O fluxes and were caused by rapid N₂O production according to isotope abundance data. According to N₂O concentrations and isotope abundance analysis N₂O was mostly produced at depths between 0.3 and 0.5 m. During water table reduction net N₂O production in 0.1 m depth steadily increased in the most effectively dried plot from 2 up to 44 pmol cm^?3 day^?1. Rewetting immediately increased net N₂O production in the topsoil of the drought plots, showing rates of 18–174 pmol cm^?3 day^?1. This study demonstrates that drought and rewetting can temporarily increase N₂O emission to levels that have to date only been reported from nutrient rich and degraded fens that have been drained for agricultural purposes.     

Pseudolunularia gen.n. (Cheilostomata), a IunuIitiform bryozoan from the Indo-West Pacific

A new genus of anascan lunulitiform bryozoan, Pseudolunularia . is introduced for two new species, P. enigma and P. unguis . It is inferred that live colonies both possess basal rhizoids and are supported and stabilized by elongate avicularian mandibles. The autozooids, brooding zooids and avicularia of both species bear a striking resemblance to a parallel pair of species belonging to the genus Lunularia, L. repandus and L. cupulus .     

Patterns of life history among cyclopoid copepods of central Europe

• 1 Life history characters (body size of adults, egg diameter, egg sac length and breadth) of nineteen species of central European cyclopoid copepods were measured and sexual size dimorphism (adult female length x adult male length^?1), relative egg size (egg weight X body weight^?1), weight of adult females and of eggs, egg sac shape (egg sac length x egg sac breadth^?1), and reproductive effort (clutch weight produced per female weight per day) were calculated to detect trends in life history strategies.
• 2 Typical planktonic species exhibited the lowest reproductive effort. Among planktonic species, the value for egg sac shape increased with clutch size.
• 3 Large species and small species exhibited different trends in life history characters. Large species had larger clutches, larger eggs, and a greater sex size dimorphism than small species. However, small species had a greater relative egg size.
• 4 Large species live in cold water and reproduce during the spring bloom of phytoplankton where the production of large clutches with relatively small eggs is advantageous. Reserves are unnecessary for juveniles because food is abundant. Small species generally are most abundant during the warm season, when conditions are less predictable, and relatively large eggs, possibly provided with reserves, are advantageous.

     

A quantification of shoot shedding in pedunculate oak (Quercus robur L.)

Almost 37 000 fragments (twigs, peduncles, inflorescences) were shed from a single mature oak tree over one year. Shedding showed strong seasonality with abrupt peaks in June and October, yet only weak correlations to weather parameters. The majority of shed twigs were short shoots, consisting of one or few extension units, which were not older than two years. In many twigs, shedding was preceded by the outgrowth of the terminal bud into either a male inflorescence or a defective extension unit. The large majority of shed twigs belong to a category of summer annual and biannual deciduous short shoots of an exploitative nature, only a minority are explorative long shoots. Implications for the architecture of the tree crown are that twigs of higher branching order are mostly affected by shedding, as they consist of short modules which exhibit a high proportion of flower buds.     

The Phlesirtes complex (Orthoptera,Tettigoniidae, Conocephalinae,Conocephalini) reviewed: integrating morphological,molecular, chromosomal and bioacoustic data

The tettigoniid genus Phlesirtes Bolivar and its allies are reviewed. Morphological, ecological and molecular data prompt the erection of the new genus Chortoscirtes gen.n. with type species Xiphidion meruense Sjöstedt. The genera Phlesirtes, Chortoscirtes, Karniella and Naskreckiella are characterized by morphological characters supported by molecular, acoustic, ecological and chromosomal data. Four species, Chortoscirtes pseudomeruensis sp.n. , C. masaicus sp.n. , C. puguensis sp.n. and C. serengeti sp.n. , are described from localities in northern and coastal Tanzania and one Karniella, K. crassicerca sp.n. , is described from Uganda. The following comb n. are proposed: Phlesirtes kibonotensis (Sjöstedt) and Phlesirtes kilimandjaricus (Sjöstedt). Subtribal status is proposed for the four investigated African genera. A key to the Chortoscirtes species is provided.     

Reconstructing the Anomalodesmata (Mollusca: Bivalvia): morphology and molecules

The extant anomalodesmatan bivalves have always proved rather enigmatic and difficult to interpret, both in terms of their relationships to other bivalve taxa and the interrelationships of the constituent families. These difficulties stem from their diverse and often highly specialized life habits which have resulted in a wide array of disparate morphologies, and also from the fact that many are extremely rare. Classifications based on morphological characters have been dogged by fears that convergent and parallel evolution has masked phylogenetic signals. Molecular surveys of members of 12 of the 15 constituent families, using the 18S rRNA gene, have revealed that anomalodesmatans are robustly monophyletic and lie within the basal heterodonts. The Anomalodesmata should no longer be regarded as a subclass, but as a part of the Heterodonta. Here we present an enhanced analysis of 32 anomalodesmatan species (representatives of 12 families). Our results, subjected to Maximum Parsimony, Maximum Likelihood and Bayesian analyses, challenge our understanding of the internal relationships within the Anomalodesmata. In particular they indicate the need for a re-distribution of the families traditionally placed in the Thracioidea and Pandoroidea into a 'thraciid' lineage (Thraciidae + Cleidothaeridae + Myochamidae) and a 'lyonsiid' lineage (polyphyletic Lyonsiidae + Clavagellidae + Laternulidae + Pandoridae). The endolithic Clavagella and endobenthic Brechites and Penicillus form a robust clade. The hypothesis that the carnivorous septibranchs are monophyletic can, thus far, be neither supported nor rejected. Mapping critical morphological characters onto our molecular results provides evidence of multiple loss of some characters (e.g. prismato-nacreous shell microstructure and shell spicules) and also multiple gain of others (e.g. chondrophores).  © 2006 The Linnean Society of London, Zoological Journal of the Linnean Society , 2006, 148 , 395–420.