Characterization of tetranucleotide microsatellite loci and development and validation of multiplex reactions for the study of right whale species (genus Eubalaena)

A North Atlantic right whale (Eubalaena glacialis) genomic library was developed and screened with a (GATA)₈ probe to identify tetranucleotide microsatellite loci. Sixteen characterized loci were polymorphic in North Atlantic and/or South Atlantic (Eubalaena australis) right whales, 12 being polymorphic in E. glacialis, and 15 in E. australis. Fourteen of these were combined with 21 other previously identified loci for a suite of 35 loci which can be used to increase resolution of genetic analyses of these species. Multiplex reactions were developed for genotyping samples at these loci, providing a method that is rapid, reliable and cost‐effective.     

Novel strategies for assessing and managing the risks posed by invasive alien species to global crop production and biodiversity

International actions to combat the threat posed by invasive alien species (IAS) to crops and biodiversity have intensified in recent years. The formulation of 15 guiding principles on IAS by the Convention on Biological Diversity (CBD) stimulated the International Plant Protection Convention (IPPC) to review its role in protecting biodiversity. IPPC standards now demonstrate clearly that the risks posed by any organism that is directly or indirectly injurious to cultivated or uncultivated plants can be assessed and managed under the IPPC. Since the IPPC, unlike the CBD, constitutes an international legal instrument recognised by the World Trade Organization, greater protection from the introduction of IAS is now available. However, phytosanitary measures can only be enacted if they can be justified by risk analysis and we outline some novel strategies to improve the assessment and management of the risks posed by IAS, highlighting some of the key challenges which remain.     

Herbivory-induced signalling in plants: perception and action

Plants and herbivores have been interacting for millions of years. Over time, plants have evolved mechanisms to defend against herbivore attacks. Herbivore-challenged plants reconfigure their metabolism to produce compounds that are toxic, repellant or anti-digestive for the herbivores. Some compounds are volatile signals that attract the predators of herbivores. All these responses are tightly regulated by a signalling network triggered by the plant's perception machinery. Several compounds that specifically elicit herbivory-induced responses in plants have been isolated from herbivore oral secretions and oviposition fluids. Elicitor perception is rapidly followed by cell membrane depolarization, calcium influx and mitogen-activated protein kinase (MAPK) activation; plants also elevate the concentrations of reactive oxygen and nitrogen species, and modulate phytohormone levels accordingly. In addition to these reactions in the herbivore-attacked regions of a leaf, defence responses are also mounted in unattacked parts of the attacked leaf and as well in unattacked leaves. In this review, we summarize recent progress in understanding how plants recognize herbivory, the involvement of several important signalling pathways that mediate the responses to herbivore attack and the signals that transduce local into systemic responses.     

Barlow's Lark: a new species in the Karoo Lark Certhilauda albescens complex of southwest Africa

The Karoo Lark Certhilauda albescens complex, endemic to southwest Africa, is characterized by regional phenotypic variation. Recent consensus has been to recognize two species, Dune Lark Certhilauda erythrochlamys and Karoo Lark Certhilauda albescens, but intermediate forms around the mouth of the Orange River have resulted in some authors treating it as a single polytypic species complex. We reexamined the status of taxa in this group by sequencing a segment of the mitochondrial DNA cytochrome b gene. Most samples were from the area around the mouth of the Orange River, where there is considerable local phenotypic variation. Our results indicate that the complex comprises three species, Karoo Lark, Dune Lark and Barlow's Lark Certhilauda barlowi, separated by 1.9-5.5% sequence divergence. There were no sequence differences among described subspecies, but there was limited variation among Dune Lark individuals (sequence divergence values 0.2-0.4%). The Red Lark Certhilauda burra is closely related to the Karoo Lark complex; indeed, it may be that Karoo Lark is the ancestral form. There was morphological (biometrics and plumage) and behavioural (male display song structure) support for the recognition of Barlow's Lark as a separate species. Species ranges within the complex are allopatric or narrowly parapatric, and they occur in different habitats and climatic conditions. Discriminant function analysis correctly identified 99% of skins assigned to taxa based on range, but a few individuals collected in the contact zone between Karoo and Barlow's Larks exhibited intermediate phenotypes, and further investigations are warranted to search for evidence of hybridization. The newly recognized Barlow's Lark has a maximum range of 18,000 km². It appears to have disappeared from heavily grazed farms around Aus, southern Namibia, and occurs almost exclusively in diamond mining areas, where domestic livestock are excluded. Changes to land use practices which reduce vegetation cover could seriously impact this species.     

Analysis of growth during phototropic curvature of cress hypocotyls

Abstract. Growth rates throughout an organ curving phototropically under continuous, unilateral while light were monitored by lime-lapse photography of cress hypocotyls marked into 1 mm sections by two rows of ion-exchange beads. Curvature resulted from an integrated sequence of changes in growth rate on each side of the organ, but the actual patterns of change and, therefore rales of curvature, differed within even this one species, depending upon the immediate pretreatment of the seedlings. Transference of seedlings from darkness to unilateral irradiation gave immediate growth inhibition on both sides of the organ. Curvature resulted from differential recovery of growth rate, being seen first on the shaded side, most prominently in the apical regions; only 2h after initial exposure to light did growth recover on the lit (lower) side. On the other hand, transfer of seedlings from omnilateral to unilateral irradiation of the same intensity resulted in simultaneous growth inhibition on the irradiated side and stimulated growth on the shaded side: this growth stimulation of the shaded side was greater than occurred in totally darkened control plants.     

Characterization of polymorphic microsatellite markers for the Carnaby's cockatoo (Calyptorhynchus latirostris) and related black cockatoo species

Microsatellite loci were isolated from Carnaby's black cockatoo (Calyptorhynchus latirostris: Aves), a highly valued, endangered, and endemic species of bird from Western Australia. This study describes three dinucleotide and one tetranucleotide microsatellite loci for which the primers produced clear and polymorphic amplification patterns with between two and nine alleles and moderate levels of variability. Two additional dinucleotide markers which were monomorphic in the Carnaby's cockatoo were able to amplify and were polymorphic in two other species of black cockatoo, greatly increasing the utility of these markers.     

The Effects of Temperature and Daylength on the Rate of Development of Pigeonpea

Eleven cultivars of pigeonpea, representing five different maturitygroups, were grown under controlled conditions to determinehow the rate of development from sowing to flower bud initiation(FBI) and sowing to flowering was affected by temperature anddaylength, the two environmental variables thought to have mostinfluence on reproductive development. Both temperature and daylength had substantial effects overthe range 16–32 C and 10–14 h respectively. Comparisonswithin the 12 h daylength treatment showed no consistent patternwith mean temperature. A discrete-rate analysis was used todetermine the effect on development of each of the temperaturesmaking up the various treatment combinations of day and nighttemperature. The rate of development from sowing to FBI varied among cultivars.The responses to temperature were all strongly curvilinear withoptima between 20 and 24 C. The rate of development from sowingto flowering showed a similar pattern. The effect of daylengthon the rate of development was the greatest between sowing andFBI, with the greatest sensitivity between 12 and 14 h. For the range of conditions considered, temperature had at leastas great an influence as daylength on the rates of developmentfrom sowing to FBI and from sowing to flowering. Some of theresponses to time of planting that have previously been attributedto daylength effects may, in fact, have been due to temperature.The responses to temperature of reproductive and vegetativedevelopment are very different. Phenology, Cajanus cajan     

Observations on Mexican Rana pipiens

Mexican Rana pipiens now commonly sold in the United Statesdiffer morphologically and physiologically from their northerncounterparts. They resemble Arizona pipiens in appearance andbehavior, but their breeding cycle is distinctive. They aremost reproductively active in July and August. During late springand summer they can be ovulated readily and their pituitarygonadotropin levels are apparently high. Such is not the caseduring other times of the year. The role of Mexican frogs inteaching and research is discussed.     

Current status of the Drosophila melanogaster species-group (Diptera)

Abstract. The Drosphila melanogaster species-group, established by Sturtevant (1942) for fourteen species, is now known to contain 115 described species here divided into twelve named subgroups (including one newly proposed), as well as further undescribed species. Three of the species, melanogaster, simulans and ananassae , are cosmopolitan; two others, kikkawai and malerkotliana , are widespread in the southern hemisphere, the latter apparently a recent introduction to South America. The greatest numbers of species otherwise occur in the Oriental region with smaller numbers in the Ethiopian, eastern Palaearctic and Australian regions and in several islands of the South Pacific. D.rajasekari and D.raychaudhurii are synonymized with D.biamipes;also D.andamanensis Parshad & Singh is synonymized with D.andamanensis Gupta & Raychaudhuri.