Plumage maintenance affects ultraviolet colour and female preference in the budgerigar

Elaborate or colourful feathers are important traits in female-mate choice in birds but little attention has been given to the potential costs of maintaining these traits in good condition via preening behaviour. While preening is known to be an important component of plumage maintenance, it has received little attention with respect to colouration. We investigated whether preening can influence plumage reflectance and whether females show a preference for plumage cleanliness in captive-bred, wild-type budgerigars, Melopsittacus undulatus. To do this, we compared the spectral colour of birds that were allowed to preen their plumage and individuals that were prevented from preening. The plumage of birds that were prevented from preening showed a significant lower reflectance in the UV range (300-400 nm). Subsequently, we measured females’ preferences for preened and unpreened males using a two-choice test. In a second experiment we allowed females to choose between an unpreened male and a male smeared with UV-absorbing chemicals (UV-blocked male). The proportion of time that females stayed near preened males was statistically higher than for unpreened males, but females spent similar amounts of time with unpreened males and UV-blocked males. These results are consistent with the idea that female budgerigars are able to discriminate between preened and unpreened males, and that UV colours, mediated by preening, can convey information about a bird's current condition.     

The role of pressure difference reception in the directional hearing of budgerigars (Melopsittacus undulatus)

In many birds, the middle ears are connected through an air-filled interaural pathway. Sound transmission through this pathway may improve directional hearing. However, attempts to demonstrate such a mechanism have produced conflicting results. One reason is that some species of birds develop a lower static air pressure in the middle ears when anaesthetized, which reduces eardrum vibrations. In anaesthetized budgerigars with vented interaural air spaces and presumed normal eardrum vibrations, we find that sound propagating through the interaural pathway considerably improves cues to the directional hearing. The directional cues in the received sound combined with amplitude gain and time delay of sound propagating through the interaural pathway quantitatively account for the observed dependence of eardrum vibration on direction of sound incidence. Interaural sound propagation is responsible for most of the frontal gradient of eardrum vibration (i.e. when a sound source is moved from a small contralateral angle to the same ipsilateral angle). Our study confirms that at low frequencies the interaural sound propagation may cause vibrations of the eardrum to differ much in time, thus providing a possible cue for directional hearing. The acoustically effective size of the head of our birds (diameter 28 mm) is much larger than expected from the dimensions of the skull, so apparently the feathers on the head have a considerable acoustical effect.Dedicated to Professor Franz Huber on the occasion of his 80th birthday.     

Yawning: A possible confounding variable in EMG biofeedback studies

An elderly hemiplegic patient participating in an EMG biofeedback training program was observed to produce a synergistic flexion movement of the plegic (determined by functional evaluations) upper limb while yawning. In the course of the training sessions the electrical activity of the anterior deltoid (the target muscle) was recorded during yawning. These peak EMG values were greatly facilitated in comparison with the session mean peak values obtained during an attempted maximum voluntary isometric contraction (shoulder flexion) of the same limb (e.g., Trial 1: 85.00 vs. 4.33 µV). The possibility of yawning as a confounding variable in EMG biofeedback studies is presented and discussed.This research was supported in part by Health and Welfare Canada (NHRDP).     

Cytotoxic activity of acetogenins and styryl lactones isolated from Goniothalamus undulatus Ridl. root extracts against a lung cancer cell line (COR-L23)

An investigation of the chemical constituents in a dichloromethnae extract of Goniothalamus undulatus root led to the isolation of three known styryl lactones (5-acetoxyisogoniothalamin oxide, O-acetylaltholactone and altholactone), and four known annonaceous acetogenins (annonacin, cis-annonacin, goniothalamicin and cis-goniothalamicin). These compounds were subjected to a sulphorhodamine B (SRB) cytotoxicity assay against human large cell lung carcinoma (COR-L23), and normal human fetal fibroblast (MRC-5), cell lines. The isolated acetogenins showed higher cytotoxic activity against COR-L23 compared to the styryl lactones, with IC₅₀ values in the range of 0.5-1.7 μM and 7.4-15.4 μM, respectively. A similar pattern of cytotoxicity was also observed against the other cell line (MRC-5); acetogenins IC₅₀ values were in the range of 11.8-31.4 μM, and those for styryl lactones were in the range of 48.7-102.8 μM. This is the first report of a bioassay-guided isolation of chemical constituents from G. undulatus and on cytotoxic studies of the isolated compounds using these particular lung cancer cell lines.     

Body temperature and thermoregulation ofAntheraea assama larvae

Activity patterns and body temperature (T _b ) and its maintenance were investigated in the 5th instar larvae ofAntheraea assama Westwood (Lepidoptera: Saturniidae). These larvae thermoregulate by finding and utilizing favourable microenvironments and by restricting their activities to suitable times of the day. Further convective cooling, facilitated by a raised posture also serves to ameliorate T_b. Regression analysis suggests that environmental temperature is the major determinant of T_b along with solar radiation (SR) and wind (W).     

Some like it hot: body and weapon size affect thermoregulation in horned beetles

Body size and shape affect thermoregulatory properties of organisms, and in turn are believed to have shaped macroevolutionary patterns of morphological diversity across many taxa. However, it is less clear whether thermoregulation plays a role in shaping intraspecific morphological diversity such as sexual dimorphisms or the conditional expression of exaggerated secondary sexual traits. Here, we investigate individual thermoregulatory properties in two species of horned beetles that share similar ecologies and body size ranges, but differ substantially in degree of sexual and male dimorphism. We find that intraspecific variation in body size had an unexpectedly large effect on thermal preference behavior and the ability to passively regulate body temperature. Furthermore, we find that the presence or absence of exaggerated secondary sexual traits dramatically altered thermal preference behavior, consistent with a thermoregulatory cost of horn possession. Lastly, we show that the increase in surface area associated with the expression of enlarged horns is, by itself, insufficient to account for the radically altered thermoregulatory behavior observed in horn-bearing males, and discuss possible alternative, physiological explanations. These findings are among the first to link intra-and interspecific variation in body- and weapon size to thermal preferences within and between insect species.     

Chemotaxonomy of Portuguese Ulex: quinolizidine alkaloids as taxonomical markers

Six species of Portuguese Ulex L. in a total of nineteen populations were studied by GC-EIMS as to their content in quinolizidine alkaloids. Sparteine, beta-isosparteine, jussiaeiine A, N-methylcytisine, cytisine, 5,6-dehydrolupanine, rhombifoline, lupanine, jussiaeiine B, N-formylcytisine, N-acetylcytisine, anagyrine, jussiaeiine C, jussiaeiine D, pohakuline, baptifoline, and epibaptifoline were detected. Analysis of the chromatograms showed that the chemical profile of all species was mainly composed of N-methylcytisine, cytisine, anagyrine, and jussiaeiines A, B, C and D. Therefore a quantification study of these alkaloids in all the populations studied was done by GC. These data were then submitted to cluster analysis and principal component analysis, which allowed the definition of five chemotypes and the recognition of hybrids. N-methylcytisine, cytisine, and jussiaeiines A, C and D are recognized as markers of this genus in Portugal.     

Fatty acids as trophic tracers in an experimental estuarine food chain: Tracer transfer

The transfer of fatty acid (FA) biomarkers was assessed by an experimental food chain comprising three trophic levels: leaves of the mangrove Avicennia marina, the grapsid crab Parasesarma erythodactyla, and the blue swimmer crab Portunus pelagicus. FA compositions for each trophic level were investigated through a feeding/starving regime designed to reveal the transfer of FAs along the food chain. Comparison of the FA profiles of the mangrove leaves, the tissues and faecal material of P. erythodactyla suggests that the crab, contrary to previous studies, lacks the necessary enzymes to incorporate some FAs in its diet. Long chain FAs were egested while polyunsaturated acids seemed to be efficiently assimilated. The polyunsaturated FAs 18:2ω6 and 18:3ω3 were identified as useful biomarkers of the mangrove leaves for tracing their transfer to the higher trophic levels. The contribution of these markers to the FA profiles of the crabs was investigated and it was found that both 18:2ω6 and 18:3ω3 could be successfully traced across the first trophic transfer. However, only 18:3ω3 demonstrated a clear second transfer into the tissues of P. pelagicus. Multivariate analysis of the FA profiles of the study organisms was found to be a potentially useful tool for demonstrating differences in diet within a species and also what FAs, and therefore dietary items, are responsible for those differences. MDS analysis of the FA profiles of faecal material from P. erythodactyla showed that this species provides an important ecological link in estuarine systems by providing a substrate for the colonisation of bacteria.     

Relationships of plant pathogenic enterobacteria based on partial atpD, carA, and recA as individual and concatenated nucleotide and peptide sequences

Relationships of the genera in the Enterobacteriaceae containing plant pathogenic species: Brenneria, Dickeya, Enterobacter, Erwinia, Pantoea, Pectobacterium, and Samsonia, were investigated by comparison of their nucleotide and peptide sequences of atpD, carA, recA, and the concatenated sequences. Erwinia spp. and Pantoea spp., with Pectobacterium cypripedii, formed a group distinct from other pathogenic taxa. Pectobacterium, Brenneria, Dickeya, and Samsonia formed a contiguous clade. Samsonia was usually concurrent with Pectobacterium. Most Brenneria were also close to Pectobacterium, suggesting that these three taxa might be better represented as a single genus. Brenneria quercina was not closely associated with other members of this genus and may represent a separate genus. The sequences representing Dickeya were distinct, further supporting the generic status of the taxon. Plant pathogenic Enterobacter spp. display such sequence variability that few definite conclusions as to their specific placement could be made. These data highlight the difficulty of drawing reliable and robust taxonomic conclusions based on comparative analysis of sequence data without some independent criterion to calibrate a scale for diversity.     

Studies on Guizotia abyssinica L. oil: Biodiesel synthesis and process optimization

Guizotia abyssinica seeds, a common bird feedstock, have been explored for the potential of biodiesel synthesis. The oil was extracted from the seeds by solvent extraction and composition of G. abyssinica oil was examined. The reaction parameters for biodiesel synthesis have been optimized. Temperature, oil: methanol ratio, catalyst type and catalyst concentration were found to have significant role on ester conversion. According to this study, the maximum yield of ester (98.7%) can be obtained with optimized sodium methoxide catalyst dosage (0.6%) at an operational temperature of 65 °C. Methyl ester of G. abyssinica oil was also studied for its oxidation stability and low temperature properties. Further, the synthesized product was blended in diesel at 5–20% ratios and evaluated for physico-chemical properties.     

First record of Clonostachys rosea (Ascomycota: Hypocreales) as an entomopathogenic fungus of Oncometopia tucumana and Sonesimia grossa (Hemiptera: Cicadellidae) in Argentina

Clonostachys rosea (Link: Fries) Schroers, Samuels, Seifert, and Gams (Ascomycota: Hypocreales) has been reported as a mycoparasite of fungi and nematodes and as saprobe in soils, but this fungus has not been reported previously to be entomopathogenic. Many species of cicadellid leafhoppers cause economic damage to crops as vectors of plant pathogens. In the present work, we report the first record of C. rosea as an entomopathogenic fungus of two leafhoppers pest, Oncometopia tucumana and Sonesimia grossa (Hemiptera: Cicadellidae), in Argentina and evaluate the pathogenicity of C. rosea against them.     

Metarhizium anisopliae host-pathogen interaction: differential immunoproteomics reveals proteins involved in the infection process of arthropods

Metarhizium anisopliae is an entomopathogenic fungus well characterized for the biocontrol of a wide range of plagues. Its pathogenicity depends on the secretion of hydrolytic enzymes that degrade the host cuticle. To identify proteins involved in the infection process and in host specify, immunoproteomic analysis was performed using antiserum produced against crude extract of M. anisopliae cultured in the presence of Rhipicephalus (Boophilus) microplus and Dysdercus peruvianus cuticles. Spots detected using antisera produced against M. anisopliae cultured in cuticles and spore surface proteins, but not with antiserum against M. anisopliae cultured in glucose, were identified so as to give insights about the infection process. An MS/MS allowed the identification of proteases, like elastase, trypsin, chymotrypsin, carboxypeptidase and subtilisin (Pr1A, Pr1I and PR1J), chitinases, DNase I and proline-rich protein. Chymotrypsin and Pr1I were inferred as host specific, being recognized in D. peruvianus infection only. This research represents an important contribution to the understanding the adaptation mechanisms of M. anisopliae to different hosts.     

Free-living amoebae as opportunistic and non-opportunistic pathogens of humans and animals

Knowledge that free-living amoebae are capable of causing human disease dates back some 50 years, prior to which time they were regarded as harmless soil organisms or, at most, commensals of mammals. First Naegleria fowleri, then Acanthamoeba spp. and Balamuthia mandrillaris, and finally Sappinia diploidea have been recognised as etiologic agents of encephalitis; Acanthamoeba spp. are also responsible for amoebic keratitis. Some of the infections are opportunistic, occurring mainly in immunocompromised hosts (Acanthamoeba and Balamuthia encephalitides), while others are non-opportunistic (Acanthamoeba keratitis, Naegleria meningoencephalitis, and cases of Balamuthia encephalitis occurring in immunocompetent humans). The amoebae have a cosmopolitan distribution in soil and water, providing multiple opportunities for contacts with humans and animals, as evidenced by antibody titers in surveyed human populations. Although, the numbers of infections caused by these amoebae are low in comparison to other protozoal parasitoses (trypanosomiasis, toxoplasmosis, malaria, etc.), the difficulty in diagnosing them, the challenge of finding optimal antimicrobial treatments and the morbidity and relatively high mortality associated with, in particular, the encephalitides have been a cause for concern for clinical and laboratory personnel and parasitologists. This review presents information about the individual amoebae: their morphologies and life-cycles, laboratory cultivation, ecology, epidemiology, nature of the infections and appropriate antimicrobial therapies, the immune response, and molecular diagnostic procedures that have been developed for identification of the amoebae in the environment and in clinical specimens.