Analysis of Branching in Spring-sown White Lupins (Lupinus albusL.): The Significance of the Number of Axillary Buds

Plant density and sowing date were shown to affect branchingin spring-sown white lupin (Lupinus albusL.), but the responsevaried among environments. The patterns of primary and secondarybranching in the cv. Lublanc were studied as a function of boththe number of axillary buds and the plant growth rate. Fieldexperiments that used a wide range of sowing dates and plantdensities to alter plant architecture were conducted over 5years, and these were supplemented with data from additionalglasshouse and growth cabinet experiments. The number of axillary buds on the main stem or primary branches,which determined the potential number of branches, increasedlinearly with the number of nodes. In situations where all axillarybuds did not produce branches, it was found that the numberof primary and secondary branches produced was related to theplant growth rate at the beginning of branch elongation. Knowledgeof the number of axillary buds improved the analysis of theinteraction between cultural practices and environmental conditionson plant architecture. The variability of branching potentialamong genotypes was discussed. Lupinus albus; branches; axillary buds; growth; sowing date; plant density     

Specialisation of bacterial endosymbionts that protect aphids from parasitoids

1. Infection by the bacterial endosymbiont Hamiltonella defensa is capable of protecting the pea aphid from parasitism by Aphidius ervi and the black bean aphid from parasitism by Lysiphlebus fabarum. Here we investigate protection of a third aphid species, the cowpea aphid, Aphis craccivora, from four parasitoid species: Binodoxys communis, B. koreanus, Lysiphlebus orientalis, and Aphidius colemani. 2. We compared parasitism of A. craccivora lines that were either infected with, or cured of H. defensa separately for the four parasitoid species. Infection by H. defensa almost completely eliminated parasitism of A. craccivora by B. communis and B. koreanus, but had no effect on parasitism by L. orientalis and A. colemani. 3. This indicates at least genus‐level specificity of protective effects by H. defensa and we discuss implications of our findings on the known world‐wide distribution of this host/symbiont interaction.     

ADAPTATION TO SEVERE CONDITIONS OF PROPAGATION: LONG-DISTANCE DISTRESS CALLS; AND COURTSHIP CALLS OF A COLONIAL SEABIRD

ABSTRACT

The boatwhistle sound produced by male toadfish during the reproductive season attracts females to the nest site. Boatwhistles consist of a series of rapidly produced, amplitude modulated ‘pulses’ of sound that are generated by specific muscles of the gas bladder. Previous studies have shown that boatwhistle characteristics vary with temperature and geographic location. This study investigated the normal range of variation in boatwhistles produced by males in a northern population of O. tau. Multiple boatwhistles were recorded from individuals at different sites around Waquoit Bay, Massachusetts. Multiple boatwhistles were recorded at different sites to assess the range of variation in boatwhistle production from this population. Pulse repetition rates varied from a low of 125 pulses/sec at 16 °C to a high of 219 pulses/sec at 21 °C. Careful examination of recordings from different sites indicated that individuals vary in the durations of their boatwhistles as well as in the pulse repetition rates during the very consistently produced second segment of the call. In particular, pulse repetition rate (PRR) varied significantly (p < 0.001) among most individuals recorded at the same temperatures. Psychophysical testing as well as behavioral choice experiments are needed to assess the relative importance of PRR and spectral cues in species recognition and/or mate choice.     

Characterization of polymorphic microsatellite loci in the terrestrial isopod Porcellionides pruinosus

We developed a set of six polymorphic microsatellite loci for the woodlouse, Porcellionides pruinosus. We screened 43 individuals from three French populations and found that locus‐specific allelic diversity ranges from 3 to 17 alleles (mean = 9.8) and observed heterozygosity ranges from 0.51 to 0.89 (mean = 0.77). These are the first microsatellites loci reported from the woodlouse.     

Will European soil-monitoring networks be able to detect changes in topsoil organic carbon content?

Within the United Nations Framework Convention on Climate Change, articles 3.3 and 3.4 stipulate that some voluntary activities leading to an additional carbon (C) sequestration in soils could be accounted as C sinks in national greenhouse gas inventories. These additional C stocks should be verifiable. In this work, we assess the feasibility of verifying the effects of changes in land use or management practice on soil organic carbon (SOC), by comparing minimum detectable changes in SOC concentration for existing European networks suitable for soil monitoring. Among the tested scenarios, the minimum detectable changes differed considerably among the soil-monitoring networks (SMNs). Considerable effort would be necessary for some member states to reach acceptable levels of minimum detectable change for C sequestration accounting. For SOC, a time interval of about 10 years would enable the detection of some simulated large changes in most European countries. In almost all cases, the minimum detectable change in SOC stocks remains greater than annual greenhouse gases emissions. Therefore, it is unlikely that SMNs could be used for annual national C accounting. However, the importance of organic C in soil functions, and as an indicator of soil condition and trends, underlines the importance of establishing effective national SMNs.     

Characterization of polymorphic microsatellite loci in the terrestrial isopod Armadillidium vulgare

The common pill bug, Armadillidium vulgare, is known to harbour two distinct strains of the feminizing proteobacteria Wolbachia. In order to study the effect of the presence of Wolbachia on the evolution of A. vulgare populations, we developed and characterized a set of nine polymorphic microsatellite loci from two microsatellite‐enriched genomic libraries. We screened 48 individuals from three French populations and found high genetic variation. Locus‐specific allelic diversity ranged from four to 28 and observed heterozygosity from 0.40 to 1.00, which indicates that these markers can be used to conduct population genetic studies in A. vulgare.     

Screening of ESTs from Septoria musiva (teleomorph Mycosphaerella populorum) for detection of SSR and PCR–RFLP markers

The development of an expressed sequence tag (EST) collection for the poplar pathogen Septoria musiva presented an opportunity for the development of locus‐specific polymorphic markers. Five microsatellites simple sequence repeat (SSR) and six polymerase chain reaction (PCR)–restriction fragment length polymorphism (RFLP) markers were identified and tested on three S. musiva populations collected in the north‐central and northeastern regions of North America. The results obtained support previously published random amplified polymorphic DNA (RAPD) data.     

On the monophyly of Dactylorhiza Necker ex Nevski (Orchidaceae): is Coeloglossum viride (L.) Hartman a Dactylorhiza?

Previous phylogenetic analyses of Orchidaceae subtribe Orchidinae resulted in the proposal to classify Coeloglossum viride (L.) Hartman within the genus Dactylorhiza in order to maintain its monophyly. In this paper, we report some results that contradict previous studies regarding the monophyly of the traditional Dactylorhiza and its phylogenetic relationship with Coeloglossum. Our results, which combine sequences of the internal and external transcribed spacers of the nuclear ribosomal DNA, support the monophyly of Dactylorhiza , with Coeloglossum being a sister clade. The position of C. viride in the phylogenetic tree, and the considerable morphological differences with respect to Dactylorhiza , incline us to retain both lineages as distinct genera.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 152 , 261–269.     

Efficacy of tags impregnated with pheromone and acaricide for control of Amblyomma variegatum

The efficacy of tags impregnated with pheromone and acaricide for control of Amblyomma variegatum on cattle in Guadeloupe was determined for a 13-week trial. Comparisons were made between untreated cattle and cattle with tags containing either pheromones alone (o-nitrophenol, methyl salicylate, 2,6-dichlorophenol and phenylacetaldehyde), pheromones plus acaricide (cyfluthrin or deltamethrin), or acaricide alone. Tags were fastened to cattle both on collars on the neck and with adhesive to tail hairs, with over 98 and 90% of tags retained, respectively, during the trial. By the end of the trial, tick infestations increased on untreated cattle (311.7%) and cattle with pheromone tags (154.8%) but decreased on cattle with pheromone/cyfluthrin (–45.0%), cyfluthrin (–42.8%), pheromone/deltamethrin (–68.7%) and deltamethrin tags (–87.6%). Cattle with pheromone tags had greater proportions of ticks on the hind regions (81%) compared to untreated cattle (62.5%) and on the front regions (18.2%) compared to untreated cattle (8.2%) indicating that ticks aggregated in response to pheromones. Analysis of hair samples by gas chromatography indicated that, within 2 days of placement, cyfluthrin spread rapidly over the body from the tags. Both cyfluthrin and deltamethrin were present in detectable levels on all eight body regions examined throughout the trial. Analysis of the tags indicated that they all still contained pheromone components after 13 weeks under field conditions.