Adhesive powder uptake and transfer by Mediterranean fruit flies, Ceratitis capitata (Dipt., Tephritidae)

Abstract:  Entostat^TM is an electrostatically charged wax powder that is used as a carrier particle in novel delivery systems for contaminating target insect pests with insecticides, biologicals or pheromones. Here, the adhesion of two forms of Entostat to the Mediterranean fruit fly (medfly) Ceratitis capitata (Wiedemann) was examined, and the adhesion of Entostat to live and dead medflies was compared. From controlled contaminations of medflies, it was shown that live medflies acquired larger quantities of Entostat than dead medflies, which could be due to the electrostatic charge shown to be carried by live insects. Air-milled Entostat (7.59  μ m mean diameter) adhered in larger quantities to medflies than pestle and mortar-ground Entostat (9.17  μ m mean diameter). Exposing medflies to different quantities of Entostat affected the initially adhering quantity but did not alter the proportion of powder retained over time. Medfly males contaminated with air-milled Entostat were shown to transfer small quantities to females during mating. This documentation of secondary powder transfer underscores the potential for using slow-acting killing agents on the basis of this delivery system.     

Assessing the potential impact of salmon fisheries management on the conservation status of harbour seals (Phoca vitulina) in north-east Scotland

Conservation efforts are often constrained by uncertainty over the factors driving declines in marine mammal populations. In Scotland, there is concern over the potential impact of unrecorded shooting of seals, particularly where this occurs near Special Areas of Conservation. Here, we show that the abundance of harbour seals Phoca vitulina in the Moray Firth, north-east Scotland, declined by 2–5% per annum between 1993 and 2004. Records from local salmon fisheries and aquaculture sites indicated that 66–327 harbour seals were shot each year between 1994 and 2002. Matrix models and estimates of potential biological removal indicate that this level of shooting is sufficient to explain observed declines. Nevertheless, uncertainty over the number and identity of seals shot means that other factors such as changes in food availability may be contributing. Recent conservation measures markedly reduced the recorded levels of shooting in 2003 and 2004. In 2005, a coordinated management plan was developed to protect salmon fisheries interests while minimizing impacts on local seal populations. Comprehensive monitoring of future population trends and improved regulation of culls are now required to provide more robust assessments of the impact of human persecution on harbour seal populations in the Moray Firth and in other parts of the UK.     

Efficient Strategies for Calculating Blockwise Likelihoods Under the Coalescent

The inference of demographic history from genome data is hindered by a lack of efficient computational approaches. In particular, it has proved difficult to exploit the information contained in the distribution of genealogies across the genome. We have previously shown that the generating function (GF) of genealogies can be used to analytically compute likelihoods of demographic models from configurations of mutations in short sequence blocks (Lohse et al. 2011). Although the GF has a simple, recursive form, the size of such likelihood calculations explodes quickly with the number of individuals and applications of this framework have so far been mainly limited to small samples (pairs and triplets) for which the GF can be written by hand. Here we investigate several strategies for exploiting the inherent symmetries of the coalescent. In particular, we show that the GF of genealogies can be decomposed into a set of equivalence classes that allows likelihood calculations from nontrivial samples. Using this strategy, we automated blockwise likelihood calculations for a general set of demographic scenarios in Mathematica. These histories may involve population size changes, continuous migration, discrete divergence, and admixture between multiple populations. To give a concrete example, we calculate the likelihood for a model of isolation with migration (IM), assuming two diploid samples without phase and outgroup information. We demonstrate the new inference scheme with an analysis of two individual butterfly genomes from the sister species Heliconius melpomene rosina and H. cydno.     

The influence of anthropogenic edge effects on primate populations and their habitat in a fragmented rainforest in Costa Rica

When a forest is fragmented, this increases the amount of forest edge relative to the interior. Edge effects can lead to loss of animal and plant species and decreased plant biomass near forest edges. We examined the influence of an anthropogenic forest edge comprising cattle pasture, coconut plantations, and human settlement on the mantled howler (Alouatta palliata), white-faced capuchin (Cebus capucinus), Central American spider monkey (Ateles geoffroyi), and plant populations at La Suerte Biological Research Station (LSBRS), Costa Rica. We predicted that there would be lower monkey encounter rate, mean tree species richness, and diameter at breast height (DBH) in forest edge versus interior, and that monkeys would show species-specific responses to edge based on diet, body size, and canopy height preferences. Specifically, we predicted that howler monkeys would show positive or neutral edge effects due to their flexible folivorous diet, large body size, and preference for high canopy, capuchins would show positive edge effects due to their diverse diet, small body size, and preference for low to middle canopy, and spider monkeys would show negative edge effects due their reliance on ripe fruit, large body size, and preference for high upper canopy. We conducted population and vegetation surveys along edge and interior transects at LSBRS. Contrary to predictions, total monkey encounter rate did not vary between the forest edge and forest interior. Furthermore, all three species showed neutral edge effects with no significant differences in encounter rate between forest edge and interior. Interior transects had significantly higher mean tree species richness than edge transects, and interior trees had greater DBH than edge trees, although this difference was not significant. These results suggest that forest edges negatively impact plant populations at La Suerte but that the monkeys are able to withstand these differences in vegetation.     

Chromosomal localization of the gene for the human trifunctional enzyme, methylenetetrahydrofolate dehydrogenase-methenyltetrahydrofolate cyclohydrolase-formyltetrahydrofolate synthetase.

A trifunctional protein in man, 5,10-methylenetetrahydrofolate dehydrogenase-5,10-methenyltetrahydrofolate cyclohydrolase-10-formyltetrahydrofolate synthetase, catalyzes three consecutive steps in the interconversion of tetrahydrofolate derivatives; these derivatives supply one-carbon units for intermediary metabolism. Somatic cell hybridization and in situ hybridization were used to localize the functional gene coding for this protein--to human chromosome 14q24, near the c-fos and TGF-beta 3 loci. A second hybridizing sequence, possibly a pseudogene, was identified near the centromere of the X chromosome, at Xp11.