Female plumage spottiness and parasite resistance in the barn owl (Tyto alba)

The hypothesis that extravagant ornaments signal parasite resistance has received support in several species for ornamented males but more rarely for ornamented females. However, recent theories have proposed that females should often be under sexual selection, and therefore females may signal the heritable capacity to resist parasites. We investigated this hypothesis in the socially monogamous barn owl, Tyto alba, in which females exhibit on average more and larger black spots on the plumage than males, and in which males were suggested to choose a mate with respect to female plumage spottiness. We hypothesized that the proportion of the plumage surface covered by black spots signals parasite resistance. In line with this hypothesis, we found that the ectoparasitic fly, Carnus hemapterus, was less abundant on young raised by more heavily spotted females and those flies were less fecund. In an experiment, where entire clutches were cross-fostered between nests, we found that the fecundity of the flies collected on nestlings was negatively correlated with the genetic mother's plumage spottiness. These results suggest that the ability to resist parasites covaries with the extent of female plumage spottiness. Among females collected dead along roads, those with a lot of black spots had a small bursa of Fabricius. Given that parasites bigger the development of this immune organ, this observation further suggests that more spotted females are usually less parasitized. The same analyses performed on male plumage spottiness all provided non-significant results. To our knowledge, this study is the first one showing that a heritable secondary sexual characteristics displayed by females reflects parasite resistance.

Lack of evidence of the interaction of the Aß peptide with the Wnt signaling cascade in Drosophila models of Alzheimer's disease.

Background Alzheimer's disease (AD) is the leading form of dementia worldwide. The Aß-peptide is believed to be the major pathogenic compound of the disease. Since several years it is hypothesized that Aß impacts the Wnt signaling cascade and therefore activation of this signaling pathway is proposed to rescue the neurotoxic effect of Aß. Findings Expression of the human Aß42 in the Drosophila nervous system leads to a drastically shortened life span. We found that the action of Aß42 specifically in the glutamatergic motoneurons is responsible for the reduced survival. However, we find that the morphology of the glutamatergic larval neuromuscular junctions, which are widely used as the model for mammalian central nervous system synapses, is not affected by Aß42 expression. We furthermore demonstrate that genetic activation of the Wnt signal transduction pathway in the nervous system is not able to rescue the shortened life span or a rough eye phenotype in Drosophila. Conclusions Our data confirm that the life span is a useful readout of Aß42 induced neurotoxicity in Drosophila; the neuromuscular junction seems however not to be an appropriate model to study AD in flies. Additionally, our results challenge the hypothesis that Wnt signaling might be implicated in Aß42 toxicity and might serve as a drug target against AD.

Chemosensory ecology: deceiving Drosophila.

The Solomon's lily arum mimics the odours of yeast to attract drosophilid flies as unrewarded pollinators.

Generos Voriinos de Taquinidos chilenos (Diptera: Tachinidae, Voriini)

Nine genera and 16 species of Chilean Voriini Tachinid flies are reported in this paper, with a key to differentiate them, a list of recorded species, its geographic distibution within the country and known hosts. The examined examples belong and are deposited at the Collection of Insects of the Instituto de Entomología (UMCE), Santiago. Neochaetoplagia pastranai Blanchard, 1963, from Argentina, and Velardemyia ica Valencia, 1972, from Perú, are reported as present in Chile, while Nothovoria praestans n. gen. & sp., is described as a new monotypic genus.

Diseminación de enteroparasitos por Calliphoridae (Insecta, Diptera)

It is establish the dissemination enteroparasite by Calliphoridae in a district situated around by Federal Capital of Argentina. The species implicated in this dispersal are: Phaenicia sericata (meigen, 1826); Calliphora vicina Robineau-Desvoidy, 1830; Chrysomya chloropyga (Wiedemann, 1818) and Phaenicia eximia (Wiedemann, 1819). Fifty two flies was studies, thirty four (65%) to belong at the family Calliphoridae. Of this thirteen (38%) have eggs of taeniid and cysts of Entamoeba coli (Grassi, 1879) and Giardia lamblia Styles, 1915.

Sarcopromusca pruna (Diptera: Muscidae) as an egg transport host of Dermatobia hominis (Diptera: Cuterebridae) in the cacau region of Bahia, Brazil

Sarcopromusca pruna appears to be the predominant transport host for Dermatobia hominis eggs among cattle herds in central eastern Bahia, Brazil. In the study area, two seasonal peaks of S. Pruna abundance coincide with those of Dermatobia, from mid July through late September and from mid November until early January, two periods of moderate monthly rainfall between anual extremes. Among more than 26,000 flies examined during the study, 75 (all female S. pruna) bore Dermatobia eggs. Certain aspects of Dermatobia behavior and ovoposition habits in the field are also discussed.

Drosophila melanogaster dHCF Interacts with both PcG and TrxG Epigenetic Regulators.

Repression and activation of gene transcription involves multiprotein complexes that modify chromatin structure. The integration of these complexes at regulatory sites can be assisted by co-factors that link them to DNA-bound transcriptional regulators. In humans, one such co-factor is the herpes simplex virus host-cell factor 1 (HCF-1), which is implicated in both activation and repression of transcription. We show here that disruption of the gene encoding the Drosophila melanogaster homolog of HCF-1, dHCF, leads to a pleiotropic phenotype involving lethality, sterility, small size, apoptosis, and morphological defects. In Drosophila, repressed and activated transcriptional states of cell fate-determining genes are maintained throughout development by Polycomb Group (PcG) and Trithorax Group (TrxG) genes, respectively. dHCF mutant flies display morphological phenotypes typical of TrxG mutants and dHCF interacts genetically with both PcG and TrxG genes. Thus, dHCF inactivation enhances the mutant phenotypes of the Pc PcG as well as brm and mor TrxG genes, suggesting that dHCF possesses Enhancer of TrxG and PcG (ETP) properties. Additionally, dHCF interacts with the previously established ETP gene skd. These pleiotropic phenotypes are consistent with broad roles for dHCF in both activation and repression of transcription during fly development.

Preliminary laboratory and field trials of a heated pheromone trap for the sandfly lutzomyia logipalpis (Diptera: Psychodidae)

A heated pheromone trap for the sandfly Lutzomyia longipalpis was tested in the laboratory using filter paper or plastic vial dispensers. Male pheromone extracted from 8 male tergal glands and absorbed on to filter paper dispensers attracted 82/120 (68.3%) of virgin females released in cages. Similarly plastic vial dispensers baited with the extract of 24 males caught 73/120 (61%). In field trials carried out near januária, Minas Gerais, Brazil using the plastic dispensers baited with extracts of 50 male tergal glands only 70 female L. longipalpis were captured. Over 1000 male flies were, however, caught during 6 nights, with greater numbers in the unbaited control traps than in the pheromone baited test traps. It is concluded that at excessive concentrations male L. longipalpis pheromone may act as a repellent to conspecific males.

Susceptibility of laboratory-reared female Lutzomyia longipalpis (Lutz & Neiva, 1912) to infection by different species and strains of Leishmania Ross, 1903

A study was undertaken to compare the susceptibility of laboratory-reared female Lutzomyia longipalpis to infection by different species or strains of New World Leishmania. The sand flies proved to be highly susceptible to infection by a strain of Le. guyanensis, with flagellates developing in all (18/18) of the specimens examined. A lower infection rate of 37 per cents (10/27) was recorded in flies exposed to infection by a strain of Le. amazonensis. Flagellates developed in 13 per cents (6/46) of the sand flies that glood fed on dogs in the earlly stage of experimental infection with an old laboratory strain of Le. chagasi. In contrast, promastigotes did not develop in sand flies that blood fed on dogs with naturally acquired Le. chagasi. The naturally infected dogas were in an advanced stage of disease. Flagellates developed in 9// (3/32) of the sand flies that blood fed on lesions of hamsters infected with a strain of Le. braziliensis and in 9 per cents (3/34) of those that fed on hamsters with lesions due to a parasite fo the mexicana complex (strain MHOM/BR/73/BH121). Sand flies did not develop flagellate infections after blood feeding on hamsters bearing lesions induced by strain MHOM/BR/71/BR49. Factors influencing the susceptibility of Lu. longipalpis to infection by New World species of Leishmania are discussed.

A role for clock genes in sleep homeostasis.

The timing and quality of both sleep and wakefulness are thought to be regulated by the interaction of two processes. One of these two processes keeps track of the prior sleep-wake history and controls the homeostatic need for sleep while the other sets the time-of-day that sleep preferably occurs. The molecular pathways underlying the latter, circadian process have been studied in detail and their key role in physiological time-keeping has been well established. Analyses of sleep in mice and flies lacking core circadian clock gene proteins have demonstrated, however, that besides disrupting circadian rhythms, also sleep homeostatic processes were affected. Subsequent studies revealed that sleep loss alters both the mRNA levels and the specific DNA-binding of the key circadian transcriptional regulators to their target sequences in the mouse brain. The fact that sleep loss impinges on the very core of the molecular circadian circuitry might explain why both inadequate sleep and disrupted circadian rhythms can similarly lead to metabolic pathology. The evidence for a role for clock genes in sleep homeostasis will be reviewed here.

Calyptrate diptera (Muscidae and Anthomyidae) of the state of Rio de Janeiro: I. Synanthropy

The synanthropy of Muscidae and Anthomyidae was studied in three ecologically distinct areas of the metropolitan region of Rio de Janeiro. Using baits such row fish, decomposing bovine liver, fresh human faeces and mashed banana it was found that Synthesiomyia nudiseta, Atherigona orientalis, and Musca domestica are highly synanthropic in contrast with Neomuscina pictipenis, Phaonantho devia and Morellia maculipenis found exclusively in the forest.

Determinação das exigências térmicas de Stomoxys calcitrans (L.) (Diptera, Muscidae), em condições de laboratório

The biology immature stage of Stomoxys calcitrans (L.) was studied in the laboratory under four constant temperature. The study was carried out in biological incubators at 20, 25, 30 and 35-C; 65 ñ 10% relative humidity and 14 hours of photophase. The most favorable temperature for developing eggs, larval and pupal was 25-C, while 35-C proved to be harmful for a normal developing of S. calcitrans in larval stage. The incubation periods for egg were 69.90, 42.58, 26.10, 21.78 hours and 2.91, 1.77, 1.08, 0.90 days at 20, 25, 30, 35-C, respectively . The larval stage was 18.40, 11.63, 8.55 days and, the pupal stage, 8.60, 4.54, 3.60 days at 20, 25, 30-C, respectively. Threshold temperatures for males were a little higher than for females, however, this difference was lesser than 1-C. On the other hand, the quantity of energy (GD) for developing females was a little higher than for males. No difference was observed between the two methods used for calculating the above mentioned biological parameters of S. calcitrans.

A mixed finite element method for nonlinear diffusion equations

We propose a mixed finite element method for a class of nonlinear diffusion equations, which is based on their interpretation as gradient flows in optimal transportation metrics. We introduce an appropriate linearization of the optimal transport problem, which leads to a mixed symmetric formulation. This formulation preserves the maximum principle in case of the semi-discrete scheme as well as the fully discrete scheme for a certain class of problems. In addition solutions of the mixed formulation maintain exponential convergence in the relative entropy towards the steady state in case of a nonlinear Fokker-Planck equation with uniformly convex potential. We demonstrate the behavior of the proposed scheme with 2D simulations of the porous medium equations and blow-up questions in the Patlak-Keller-Segel model.

A one-dimensional Keller-Segel equation with a drift issued from the boundary

We investigate in this note the dynamics of a one-dimensional Keller-Segel type model on the half-line. On the contrary to the classical configuration, the chemical production term is located on the boundary. We prove, under suitable assumptions, the following dichotomy which is reminiscent of the two-dimensional Keller-Segel system. Solutions are global if the mass is below the critical mass, they blow-up in finite time above the critical mass, and they converge to some equilibrium at the critical mass. Entropy techniques are presented which aim at providing quantitative convergence results for the subcritical case. This note is completed with a brief introduction to a more realistic model (still one-dimensional).

Visceral leishmaniasis in Teresina, state of Piauí, Brazil: preliminary observations on the detection and transmissibility of canine and sandfly infections

A Leishmania donovani-complex specific DNA probe was usedto confirm the widespread dissemination of amastigotes in apparently normal skinof dogs with canine visceral leishmaniasis. When Lutzomyia longipalpis were fed on abnormal skin of five naturally infected dogs 57 of 163 (35 per cent) fliesbecame infected: four of 65 flies (6 per cent) became infected when fed on apparently normal skin. The bite of a single sandfly that had fed seven days previouslyon a naturally infected dog transmitted the infection to a young dog from a non-endemic area. Within 22 days a lesion had developed at the site of the infectivebite (inner ear): 98 days after infection organisms had not disseminated throughout the skin, bone marrow, spleen or liver and the animal was still serologically negative by indirect immunofluorescence and dot-enzyme-linked immunosorbent assay. When fed Lu. longipalpis were captured from a kennel with a sick dog known to be infected, 33 out of 49 (67 per cent) of flies contained promastigotes. In contrast only two infections were detected among more than 200 sandflies captured in houses. These observations confirm the ease of transmissibility of L.chagasi from dog to sandfly to dog in Teresina. It is likely that canine VL is the major source of human VL by the transmission route dog-sandfly-human. the Lmet2 DNA probe was a useful epidemiological tool for detecting L. chagasi in sandflies.