Polymerase chain reaction primers for microsatellite loci in the semi‐aquatic grasshopper,Cornops aquaticum

The semi‐aquatic grasshopper Cornops aquaticum is native to South America, with a distribution as far south as the Argentinian pampas and as far north as the Gulf of Mexico. This study reports the characterization of nine microsatellite loci for this species. To our knowledge, no molecular studies have been conducted on C. aquaticum, therefore, little is known about this species’ genetic diversity and how this relates to host specificity. These primers will allow further studies to elucidate the population history of C. aquaticum across both its native and introduced ranges.     

Biogeography of the grasses (Poaceae): a phylogenetic approach to reveal evolutionary history in geographical space and geological time

The grasses (Poaceae) are the fifth most diverse family of angiosperms, including 800 genera and more than 10 000 species. Few phylogenetic studies have tried to investigate palaeo‐biogeographical and palaeo‐ecological scenarios that may have led to present‐day distribution and diversity of grasses at the family level. We produced a dated phylogenetic tree based on combined plastid DNA sequences and a comprehensive sample of Poaceae. Furthermore, we produced an additional tree using a supermatrix of morphological and molecular data that included all 800 grass genera so that ancestral biogeography and ecological habitats could be inferred. We used a likelihood‐based method, which allows the estimation of ancestral polymorphism in both biogeographical and ecological analyses for large data sets. The origin of Poaceae was retrieved as African and shade adapted. The crown node of the BEP + PACCMAD clade was dated at 57 Mya, in the early Eocene. Grasses dispersed to all continents by approximately 60 million years after their Gondwanan origin in the late Cretaceous. PACCMAD taxa adapted to open habitats as early as the late Eocene, a date consistent with recent phytolith fossil data for North America. C₄ photosynthesis first originated in Africa, at least for Chloridoideae in the Eocene at c. 30 Mya. The BEP clade members adapted to open habitats later than PACCMAD members; this was inferred to occur in Eurasia in the Oligocene. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 162 , 543–557.     

A New Species of Platymantis (Anura: Ranidae) from Quaternary Deposits On Viti Levu, Fiji

Fossil bones of the frog Platymantis are reported for the first time. Platymantis megabotoniviti sp. nov. is described from fossil bones of late Quaternary age from caves on Viti Levu, Fiji, south-west Pacific, where it was associated with fossils of the extant P. vitianus P. vitiensis . The new species is much larger than any extant congeners, and its robust form indicates that it was a ground-dwelling frog. It appears to have become extinct in the late Holocene after humans arrived on Fiji with commensal rodents.     

Osmotic Requirement for Shoot Formation in Tobacco Callus

Tobacco callus grown on medium containing 3% sucrose (w/v) shows optimum growth and produces the highest number of shoots; whereas cultures grown on medium with lower or higher sucrose levels show a reduced growth rate and capacity to form shoots. Cultures grown on a low sucrose containing medium produce a high number of shoots only if the medium is supplemented with mannitol to give the same water potential as that of the 3% sucrose medium. Mannitol cannot replace the sucrose requirement for growth. Increased levels of Bacto Agar, tricarboxylic acid cycle intermediates and amino acids added to the medium do not promote shoot formation or replace the carbohydrate requirement for that process. The success in partially replacing the sucrose requirement for shoot formation with mannitol supports the view that part of the tissue carbohydrate is acting in an osmoregulatory role. This finding is further interpreted in terms of the hypothesis of turgor-driven growth and cell expansion.     

Analysis, purification and quantification of extracellular DNA from aquatic environments

SUMMARY 1. The presence of extracellular DNA, but not RNA, at μg 1⁻¹ concentrations was demonstrated in seawater, river water and in a series of eutrophic lowland ponds.
2. Extracellular DNA in natural waters invariably comprised two major components: one of high molecular weight (>20 kb) derived from viruses, and another of low molecular weight (1–500 bp) and apparently free in solution. Similar species of DNA molecules were produced within 2 weeks in simple laboratory modules.
3. A purification procedure was developed which separated extracellular DNA from other components of dissolved organic matter, and which also separated viral from soluble DNA. Both types of DNA were purified sufficiently to constitute active templates for enzymes used in DNA manipulation.     

Saliva activated transmission (SAT) of Thogoto virus: relationship with vector potential of different haematophagous arthropods

Tick saliva (or salivary gland extract) potentiates the transmission of Thogoto (THO) virus to uninfected ticks feeding on a non-viraemic guinea-pig. This phenomenon has been named saliva activated transmission (SAT). To investigate the potential of different haematophagous arthropods to mediate SAT, guinea-pigs were infested with uninfected R.appendiculatus Neumann nymphs and inoculated with THO virus and salivary gland extract (SGE) derived from a range of ixodid (metastriate and prostriate) or argasid ticks, or mosquitoes; control guinea-pigs were inoculated with virus alone. Enhancement of THO virus transmission was observed only when SGE was derived from metastriate ticks. Comparison with the vector potential of these various arthropod species revealed that enhancement of THO virus transmission was specific for ticks which were competent vectors of the virus. The data indicate a correlation between vector competence and the ability of haematophagous arthropods to mediate SAT of THO virus.     

DIFFERENCES IN THE FORAGING OF JUVENILE AND ADULT BIRDS: THE IMPORTANCE OF DEVELOPMENTAL CONSTRAINTS

Juvenile birds differ from conspecific adults in their diet and methods of prey capture and prey handling. Juvenile-adult differences in foraging result from (1) immaturity of the beak, skeleto-muscular and neurological systems and (2) the time required to learn foraging skills. These conclusions are largely based on field observations. More experimental studies to assess the relative importance of the various constraints are needed.
Juvenile birds appear to be under strong selection to reach adult form and function as rapidly as possible. Remaining differences between juveniles and adults are largely attributable to constraints. In contrast to many other taxa there are few examples in which juvenile-adult differences in foraging have been accentuated by selection on the juvenile behaviours.