Neglected Tropical Diseases among Two Indigenous Subtribes in Peninsular Malaysia: Highlighting Differences and Co-Infection of Helminthiasis and Sarcocystosis

Soil-transmitted helminth (STH) infections have been documented among these minority groups since 1938. However the prevalence of STH is still high among these communities. Most studies tend to consider the Orang Asli (indigenous) as a homogenous group. In contrary, different subtribes have their own cultural practices. To understand this variation better, we studied the prevalence and associated factors of STH and other gut parasitic infections among two common subtribes (i.e. Temuan and Temiar). Results showed that the prevalence of the overall STH infections was higher in the Temuan subtribe (53.2% of 171) compared to the Temiar subtribe (52.7% of 98). Trichuris trichiura (46.2%) was the most prevalent parasite in the Temuan subtribe, followed by Ascaris spp. (25.7%) and hookworm (4.1%). In contrast, Ascaris spp. (39.8%) was more prevalent among the Temiar subtribe, preceded by T. trichiura (35.7%) and finally hookworm (8.3%). There were also co-infections of helminthiasis and intestinal protozoa among both Temuan and Temiar subtribes with rates being three times higher among the Temiar compared to Temuan. The most common co-infection was with Entamoeba histolytica/dispar/moshkovskii (n = 24; 24.5%, 16.0–33.0), followed by Giardia spp. (n = 3; 3.1%, −0.3–6.5). In Temuan, STH infection individuals were also infected with Entamoeba histolytica/dispar/moshkovskii (n = 11; 6.4%, 5.0–13.8), Cryptosporidium spp. (n = 3, 1.8%, −0.2–3.8) and Giardia spp. (n = 2, 1.2%, −0.4–2.8). In comparison, there was no Cryptosporidium spp. detected among the Temiar. However, it was interesting to note that there was an occurrence of co-infection of intestinal helminthiasis and sarcocystosis (intestinal) in a Temiar individual. The last report of sarcocystosis (muscular) among the Orang Asli was in 1978. The present study highlighted the importance of understanding the variation of infections amongst the different Orang Asli subtribes. It is vital to note these differences and use this knowledge to customise effective control measures for the various subtribes.     

Two distinct genomic regions, harbouring the period and fruitless genes, affect male courtship song in Drosophila montana

Acoustic signals often have a significant role in pair formation and in species recognition. Determining the genetic basis of signal divergence will help to understand signal evolution by sexual selection and its role in the speciation process. An earlier study investigated quantitative trait locus for male courtship song carrier frequency (FRE) in Drosophila montana using microsatellite markers. We refined this study by adding to the linkage map markers for 10 candidate genes known to affect song production in Drosophila melanogaster. We also extended the analyses to additional song characters (pulse train length (PTL), pulse number (PN), interpulse interval, pulse length (PL) and cycle number (CN)). Our results indicate that loci in two different regions of the genome control distinct features of the courtship song. Pulse train traits (PTL and PN) mapped to the X chromosome, showing significant linkage with the period gene. In contrast, characters related to song pulse properties (PL, CN and carrier FRE) mapped to the region of chromosome 2 near the candidate gene fruitless, identifying these genes as suitable loci for further investigations. In previous studies, the pulse train traits have been found to vary substantially between Drosophila species, and so are potential species recognition signals, while the pulse traits may be more important in intra-specific mate choice.     

Simultaneous treatment with an aromatase inhibitor and an anti-androgen decreases the likelihood of dawn song in free-living male great tits, Parus major

Gonadal steroids, most importantly testosterone (T), are considered to be a major factor in the expression of adult song behavior in temperate-zone songbirds. The action of T within specific brain regions involved in the regulation of song may occur either directly, or through its androgenic or estrogenic metabolites. In the present study, we tested steroid-dependence of great tit dawn song by blocking both known pathways of T action by simultaneous implantation of flutamide, an anti-androgen, and ATD, an aromatase inhibitor. By our knowledge, this is the first study investigating the effects of androgen inhibitors on dawn song in free-living birds. Male great tits were implanted during their mate's egg laying stage, being the time of maximal male song activity at dawn. Treatment with ATD and flutamide significantly increased plasma T levels, probably because feedback mechanisms on T secretion were inhibited. The treatment decreased the likelihood of showing dawn song, which is in line with the hypothesis that sex steroids are involved in the endocrine control of song behavior. In males that did show dawn song, we found no evidence for a treatment effect on song quality. Although the implants were present for the larger part of the breeding season, males were able to maintain control of a territory and mate and to complete their brood cycle as successful as control males.     

Neighbor-stranger discrimination by song in a suboscine bird, the alder flycatcher, Empidonax alnorum

Bird song and its functions have been studied extensively formore than 50 years, but almost entirely in oscine passerines.Few studies have investigated any aspect of song in suboscinepasserines. This is significant because song development andthe extent of individual variation in song differs greatly betweenthese groups. Learning and auditory feedback play major rolesin song development in all oscines studied, but apparently nopart in song ontogeny in suboscines. The ability of territorialoscine males to discriminate between songs of neighbors andstrangers has received considerable attention, but this phenomenonis virtually unstudied in suboscines. We tested whether a suboscinebird, the alder flycatcher (Empidonax alnorum), was able todiscriminate between songs of neighbors and strangers despitelimited individual variation in song. We performed playbackexperiments to measure responses of males to songs of neighborsand strangers broadcast from the territory boundary shared bythe subject and the neighbor. Subjects responded more aggressivelyto songs of strangers than to songs of neighbors. These resultsfurther our understanding of the evolution of song and its functionsin suboscines by demonstrating that, similar to their oscinerelatives, they can discriminate between the songs of neighborsand strangers.     

Food for song: expression of c-Fos and ZENK in the zebra finch song nuclei during food aversion learning

Background

Specialized neural pathways, the song system, are required for acquiring, producing, and perceiving learned avian vocalizations. Birds that do not learn to produce their vocalizations lack telencephalic song system components. It is not known whether the song system forebrain regions are exclusively evolved for song or whether they also process information not related to song that might reflect their ‘evolutionary history’.

Methodology/Principal Findings

To address this question we monitored the induction of two immediate-early genes (IEGs) c-Fos and ZENK in various regions of the song system in zebra finches (Taeniopygia guttata) in response to an aversive food learning paradigm; this involves the association of a food item with a noxious stimulus that affects the oropharyngeal-esophageal cavity and tongue, causing subsequent avoidance of that food item. The motor response results in beak and head movements but not vocalizations. IEGs have been extensively used to map neuro-molecular correlates of song motor production and auditory processing. As previously reported, neurons in two pallial vocal motor regions, HVC and RA, expressed IEGs after singing. Surprisingly, c-Fos was induced equivalently also after food aversion learning in the absence of singing. The density of c-Fos positive neurons was significantly higher than that of birds in control conditions. This was not the case in two other pallial song nuclei important for vocal plasticity, LMAN and Area X, although singing did induce IEGs in these structures, as reported previously.

Conclusions/Significance

Our results are consistent with the possibility that some of the song nuclei may participate in non-vocal learning and the populations of neurons involved in the two tasks show partial overlap. These findings underscore the previously advanced notion that the specialized forebrain pre-motor nuclei controlling song evolved from circuits involved in behaviors related to feeding.     

Randomization Analyses: Mimicry, Geographic Variation and Cultural Evolution of Song in Brood-Parasitic Straw-Tailed Whydahs, Vidua fischeri

Although bird song has been an important model for investigating questions of behavior development, cultural evolution and population differentiation, the quantitative methods of analysis have been problematic. Here we develop and apply quantitative randomization methods to test hypotheses about these processes in a natural population of birds. Songs of the African brood-parasitic straw-tailed whydahs ( Vidua fischeri ) and songs of their host species, the purple grenadier ( Granatina ianthinogaster ), were compared in audiospectrograms for similarity to test the following hypotheses: Whydahs mimic the songs of their host species, they have local song dialects, neighboring males match their song themes, local males match the songs of local hosts, remote populations have different songs according to their geographic distance, and songs undergo cultural evolution over time across generations. Randomization analyses were completed using (1) Mantel matrix statistics and (2) tree-based measures employing Sankoff optimization of Manhattan matrices and approximate randomizations. Our results provide evidence for song mimicry, local song dialects, matching song themes between neighboring males, song matching of local whydah mimics and grenadier song models, correspondence of song differences and geographic distance, and cultural continuity with change in song traditions within a local population. These randomization methods may be useful in other studies of animal communication, and they are sufficiently general for use both with distance matrices derived either from naturalistic impressions of song similarity as in our example or from acoustic measurements.     

Testing the flexibility of song type bout duration in the chaffinch, Fringilla coelebs

Many songbird species with small song type repertoires repeat each type a few times before switching to the next. Thus, their singing style may constrain their ability to switch. However, the proximate causation of song type switching is poorly understood. We exposed male chaffinches to (nonoverlapping) playbacks of single renditions of their own songs rather than a series of songs, thus stimulating them with a single external auditory event. The most prominent effect of the playback was an increase in the duration of the current song type bout. If the song type played back was different to that the subject was singing at the time, bout duration increased less than if it was of the same song type. The short-term changes induced by the playback suggest that the auditory input increases the motivational level for a particular song type. In the chaffinch this results in a delayed switch rather than in song type matching as a reaction to acoustic stimulation by conspecific song. Copyright 2000 The Association for the Study of Animal Behaviour.     

Addition of song-related neurons in swamp sparrows coincides with memorization, not production, of learned songs

During song learning in birds, neurons are added to some song nuclei and lost from others. Previous studies have been unable to distinguish whether these neural changes are uniquely associated with memorizing a song model (sensory acquisition) or vocal practice (sensorimotor learning). In this study we measured changes in neuron number within song nuclei of swamp sparrows, a species in which the two phases of song learning are nonoverlapping. Male swamp sparrows were collected as hatchlings and tape-tutored from approximately 22 to 62 days of age. Swamp sparrows memorize about 60% of their song material during this period, but do not begin practicing this learned material until approximately 275 days of age. Birds were sacrificed at 23, 41, 61, 71, 274, or 340 days of age. During sensory acquisition, neuron number increased drastically in both the caudal nucleus of the ventral hyperstriatum (HVc) and Area X. The period of sensorimotor learning was not associated with any further changes in neuron number within these regions. We were unable to detect any significant changes in neuron number within the magnocellular nucleus of the neostriatum or the robust nucleus of the archistriatum during either stage of song learning. These results raise the possibility that ongoing addition of HVc and Area X neurons may encourage, and thereby temporally restrict, song acquisition.     

Variation in Song Rate during the Breeding Cycle of the Chaffinch,Fringilla coelebs

The variation in song rate during the breeding season was studied in two individually marked chaffinch Fringilla coelebs populations. We gathered data to investigate especially the recently presented mate-guarding hypothesis. The active singing has been supposed to function as a form of mate guarding during the female's fertile period by announcing the high status of the male and preventing extra-pair copulations by neighbouring males. There was no clear dawn chorus in the chaffinch, i.e. a peak in the song rate before sunrise. Male chaffinches continued to sing after mating, but the song rate dropped significantly. In contrast to the mate-guarding hypothesis the song rate was lower during the fertile period of the female than during pre-mating and incubation. Thus, the males do not announce the fertility status of their mates or their own quality and status by active singing. The song does not function as a form of mate guarding in the chaffinch. One function of the song of the chaffinch is mate attraction: singing activity was highest before pair formation in early spring and decreased after mating but increased again if the male lost his mate later in the breeding season.     

Coding in the song of the wren: importance of rhythmicity, syntax and element structure

Communication between territorial songbirds usually involves a transfer of encoded information over long distances. We would expect coding and decoding strategies to be adaptive given the constraints imposed by the habitat. We used playback to examine some song parameters important for information transfer in the wren, Troglodytes troglodytes. Six stimuli were tested with various modifications to song rhythmicity, song composition, element structure, syntax and overall song spectra. Song features encoding information essential for eliciting a territorial response seemed to be embedded in the fine structure of song elements, that is, their variations in frequency and amplitude over time. To function, this strategy must be flexible enough to accommodate the deleterious effects of habitat-induced degradation. All stimuli composed of original song elements elicited responses regardless of their other alterations. Rhythmicity seemed not to be essential for eliciting territorial behaviour. However, alterations in song rhythmicity, syntax and spectra affected territorial responses, suggesting that these nonessential song parameters do contribute to the options for discrimination. Copyright 2000 The Association for the Study of Animal Behaviour.     

New distributional and bioacoustic data about Cicadivetta goumenissa from Peloponnese,Greece (Hemiptera,Cicadidae)

Cicadivetta goumenissa, a small singing cicada described recently by Gogala et al. (2012), has been previously found only around the village of Goumenissa in northern Peloponnese. We visited this area again in June 2012 and tried to determine the distribution range of this species. We found Cicadivetta goumenissa in some further localities, but all within a very small area of about 15 by 25 km. We also made more than one hour of new song recordings and extended our knowledge of the song repertoire of this species.     

Early condition, song learning, and the volume of song brain nuclei in the zebra finch (Taeniopygia guttata)

Songbirds are an important model system for the study of the neurological bases of song learning, but variation in song learning accuracy and adult song complexity remains poorly understood. Current models of sexual selection predict that signals such as song must be costly to develop or maintain to constitute honest indicators of male quality. It has been proposed that reductions of nestling condition during song development might limit the expression of song learning. Adult song could thus act as an indicator of early stress as only males that enjoy good condition during development could learn accurately and sing long songs or large repertoires. We tested this hypothesis in the zebra finch by modifying early condition through cross-fostering chicks to small, medium, and large broods. Song learning was very accurate and was found to reflect very closely tutor song characteristics and to depend on the number of males in the tutoring group. Although the brood size manipulation strongly affected several measures of nestling condition and adult biometry, we found no relationship between early condition and song learning scores or song characteristics. Similarly, brain mass and high vocal center (HVC), robust nucleus of the arcopallium (RA), and lateral magnocellular nucleus of the anterior nidopallium (LMAN) volumes did not covary with nestling condition and growth measurements. We found no significant relationship between song repertoire size and HVC and RA volumes, although there was a nonsignificant trend for HVC to increase with increasing proportion of learnt elements in a song. In conclusion, the results provide no evidence for song learning to be limited by nestling condition during the period of nutritional dependence from the parents in this species.     

Re-expression of songs deleted during vocal development in white-crowned sparrows, Zonotrichia leucophrys

White-crowned sparrows learn and produce multiple song types as juveniles, but most individuals stop singing all except one by the end of the first singing season. This single song type is generally maintained throughout adulthood. We demonstrate that, at the start of the second and subsequent singing seasons, this species can recall songs that had been deleted during the first singing season. The re-expression of song occurred in both the oriantha and the gambelii subspecies. Although all our males recrystallized the original song in the second year, our results indicate a mechanism for seasonal song change without new song memorization. The traditional dichotomy of closed-ended versus open-ended learning is inadequate for birds that learn early in life but can change their song output seasonally. We suggest that species can exhibit a closed sensitive period for song memorization and first production, with the ability to recall deleted songs later in life. This type of learning, selective attrition followed by subsequent re-expression, may be used by some species currently considered open-ended learners. Copyright 2000 The Association for the Study of Animal Behaviour.     

Hearing in the swamp sparrow,Melospiza georgiana,and the song sparrow,Melospiza melodia

Operant conditioning techniques and a psychophysical tracking procedure were used to measure thresholds for pure tones in two congeneric species of sparrows: swamp sparrows and song sparrows. Thresholds were measured both in quiet conditions and in the presence of white noise. The two species were similar in their gross pattern of auditory sensitivity with most sensitive thresholds in the frequency region of 1·0–8·0 kHz and poor hearing above and below this range. However, the best sensitivity occurred at 2 kHz for the song sparrows and at 4 kHz for the swamp sparrows. This pattern was also observed in song spectra of the two species. The songs of song sparrows had more power in lower frequencies than the songs of swamp sparrows. Masked auditory thresholds for both species were very similar, showing a generally increasing signal-to-noise ratio with increasing frequency. The similarity between swamp and song sparrows in these measures of basic auditory sensitivity suggests that the primary mechanisms underlying selective vocal learning in these sparrows probably reside at higher levels than the peripheral auditory sensitivities.     

Habituation,Recovery and the Similarity of Song Types within Repertoires in Red-winged Blackbirds (Agelaius phoeniceus) (Aves,Emberizidae)

Male red-winged blackbirds (Agelaius phoeniceus) respond to playback of conspecific song on their territories with the song spread, a graded aggressive display in which males extend their wings to expose their red epaulets while singing. We show that the intensity of song spread display declines with repeated presentation of one song type, and recovers when song types are switched. Recovery is greater for switches between song types that are acoustically dissimilar than for switches between song types that are acoustically similar. Recovery is no different for switches between two song types taken from the repertoires of different males than for switches between song types recorded from the same male. Analysis of acoustic features also indicates that song types recorded from different males are not more dissimilar than are song types from the same male. Our results do not support the idea that repertoires of red-winged blackbirds are composed of similar song types in order to facilitate individual recognition. Rather, repertoires may be constructed of dissimilar song types, so as to help maintain the response of listeners despite habituation.     

The multiple functions of male song within the humpback whale (Megaptera novaeangliae) mating system: review,evaluation, and synthesis

Humpback whales (Megaptera novaeangliae) are seasonal breeders, annually migrating from high‐latitude summer feeding grounds to low‐latitude winter breeding grounds. The social matrix on the winter grounds is a loose network of interacting individuals and groups and notably includes lone males that produce long bouts of complex song that collectively yield an asynchronous chorus. Occasionally, a male will sing while accompanying other whales. Despite a wealth of knowledge about the social matrix, the full characterization of the mating system remains unresolved, without any firm consensus, as does the function of song within that system. Here, I consider and critically analyse three proposed functions of song that have received the most attention in the literature: female attraction to individual singers, determining or facilitating male–male interactions, and attracting females to a male aggregation within the context of a lekking system. Female attraction suggests that humpback song is an advertisement and invitation to females, but field observations and song playback studies reveal that female visits to individual singers are virtually absent. Other observations suggest instead that females might convey their presence to singers (or to other males) through the percussive sounds of flipper or tail slapping or possibly through vocalizations. There is some evidence for male–male interactions, both dominance and affiliative: visits to singers are almost always other lone males not singing at that time. The joiner may be seeking a coalition with the singer to engage cooperatively in attempts to obtain females, or may be seeking to disrupt the song or to affirm his dominance. Some observations support one or the other intent. However, other observations, in part based on the brevity of most pairings, suggest that the joiner is prospecting, seeking to determine whether the singer is accompanying a female, and if not soon departs. In the lekking hypothesis, the aggregation of vocalizing males on a winter ground and the visits there by non‐maternal females apparently for mating meet the fundamental definition of a lekking system and its role though communal display in attracting females to the aggregation, although not to an individual singer. Communal singing is viewed as a form of by‐product mutualism in which individuals benefit one another as incidental consequences of their own selfish actions. Possibly, communal singing may also act to stimulate female receptivity. Thus, there are both limitations and merit in all three proposals. Full consideration of song as serving multiple functions is therefore necessary to understand its role in the mating system and the forces acting on the evolution of song. I suggest that song may be the prime vector recruiting colonists to new winter grounds pioneered by vagrant males as population pressures increase or as former winter grounds become unavailable or undesirable, with such instances documented relatively recently. Speculatively, song may have evolved historically as an aggregating call during the dynamic ocean conditions and resulting habitat uncertainties in the late Miocene–early Pliocene epochs when Megaptera began to proliferate. Early song may have been comprised of simpler precursor sounds that through natural selection and ritualization evolved into complex song.     

Social influences during song development in the song sparrow: a laboratory experiment simulating field conditions

Oscine songbirds are exposed to many more songs than they keep for their final song repertoire and little is known about how a bird selects the particular song(s) to sing as an adult. We simulated in the laboratory the key variables of the natural song learning environment and examined the song selection process in nine hand-reared male song sparrows, Melospiza melodia, a species in which males sing 5-11 song types. During their second and third months (their presumed sensitive period), subjects were rotated equally among four live adult male tutors that had been neighbours in the field. Tutors were housed in individual aviary 'territories' in four corners of the roof of a building; subjects could see only one tutor at a time, but they could hear the others at a short distance. Later in their first year (months 5-12), half the subjects were again rotated among all four tutors and the other half were randomly stationed next to just one tutor. Results from this experiment confirm and extend the findings from our two previous field studies of song learning in this species. Young males in this experiment (1) learned whole song types, (2) learned songs from multiple tutors, (3) preferentially learned songs that were shared among their tutors, (4) learned songs that other young males in their group also chose, and (5) learned more songs from the tutor they were stationed next to during the later stage (stationary subjects). These last two results support the late influence hypothesis that interactions after a bird's sensitive period affect song repertoire development. Copyright 2000 The Association for the Study of Animal Behaviour.     

Translation, Value, and Space: Theorizing an Ethnographic and Engaged Environmental Anthropology

In this article, I argue for placing the politics of translation and theories of value and spatial production at the center of environmental anthropology. For the past ten years, the Gimi-speaking peoples living in Maimafu village, Papua New Guinea, have taken part in an integrated conservation and development project attempting to foster a local system of valuing "nature" by tying biological diversity to economic markets through the creation of "eco-enterprises." However, the project fails to consider how Gimi produce, theorize, transmit, and express knowledge. Using ethnographic material concerned with hunting and song composition, I show that Gimi understand their forests to be part of a series of transactive dialectical relationships that work to produce identity and space. I also demonstrate that, as part of this project, Gimi social relations with their forests have been translated in ways that fit their beliefs into generic and easily understandable categories. This has been detrimental to the conservation project and it is politically problematic for an engaged environmental anthropology.     

Song Learning, Early Nutrition and Sexual Selection in Songbirds

SYNOPSIS. The developmental processes through which songbirdsacquire their species—typical songs have been well—studiedfrom a proximate perspective, but less attention has been givento the ultimate question of why birds learn to sing. We presenta new hypothesis for the adaptive significance of song learningin songbirds, suggesting that this specialized form of vocaldevelopment provides an indicator mechanism by which femalescan accurately assess the quality of potential mates. This hypothesisexpands on the established idea that song can provide an indicatorof male quality, but it explicitly links the variation in songexpression that females use to choose mates to the developmentalprocesses through which song is acquired. How well a male sings—reflectedin repertoire size or in other learned features of a male'ssinging behavior—provides an honest indicator of qualitybecause the timing of song learning and, more importantly, thetiming of the development of brain structures mediating learningcorresponds to a period in development during which young songbirdsare most likely to undergo nutritional stress. This correspondencemeans that song learning can provide a sensitive indicator ofearly developmental history in general, which in turn reflectsvarious aspects of the phenotypic and genotypic quality of apotential mate.     

Song overproduction, selective attrition and song dialects in the white-crowned sparrow

Male Puget Sound white-crowned sparrows, Zonotrichia leucophrys pugetensis, form large vocal dialects along the Pacific northwest coast of North America. Most adult males sing a single song dialect throughout their lives. To determine how dialects are maintained in this species, I studied two populations at the Columbia River mouth in a contact zone between two dialects. Singers of each of the two dialects clustered together in space, forming local song 'neighbourhoods'. Two hypotheses for the maintenance of dialects were tested. The late acquisition hypothesis predicts that yearling or adult male immigrants memorize their song from the territory neighbours they settle next to. The selective attrition hypothesis predicts that males memorize a variety of dialects early in life, overproduce song dialects upon arrival, and later selectively retain the one prelearned dialect that best matches what their neighbours sing. In 1997 and 1998, 35-40% of new territory occupants sang two dialects upon arrival in April, and then over the course of days to several weeks, discarded one dialect from their repertoire. Fourteen of 16 (88%) kept as their adult song the dialect that matched the dialect sung by the majority of their neighbours. No male added a new dialect to his repertoire after arrival, nor did males alter their retained dialect to more closely resemble their neighbours' songs. New arrivals that overproduced dialects upon arrival were significantly more likely to match their neighbours' dialect than males that did not overproduce upon arrival. In a playback experiment, males in the overproduction stage engaged in matched countersinging to the dialect played to them. These observations and the experiment support the selective attrition hypothesis: males visit and memorize a variety of dialects, probably in their hatching-year summer, overproduce dialects upon arrival the next spring, and then selectively retain the one dialect that matches the local song culture. Vocal plasticity late in life is not the result of a late sensitive phase for song memorization, but rather results from behavioural selection operating on a pre-existing repertoire of song dialects. Copyright 2000 The Association for the Study of Animal Behaviour.