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Tuesday, 3 May 2016

What's new for 'birdRS' in PubMed: Week 1, May 2016

birdRS - Latest Research from Pubmed


1."Vicious, Aggressive Bird Stalks Cyclist": The Australian Magpie (Cracticus tibicen) in the News.
van Vuuren K, O'Keeffe S, Jones DN.
Animals (Basel). 2016 Apr 26;6(5). pii: E29.

Abstract


The Australian Magpie ( Cracticus tibicen ) is a common bird found in urban Australian environments where its nest defense behavior during spring brings it into conflict with humans. This article explores the role of print media in covering this conflict. Leximancer software was used to analyze newspaper reports about the Australian Magpie from a sample of 634 news stories, letters-to-the editor and opinion pieces, published in newspapers from around Australia between 1 January 2010 and 31 December 2014. The results confirm that stories about these birds are primarily published in the daily regional and weekly suburban press, and that the dominant story frame concerns the risk of "swooping" behavior to cyclists and pedestrians from birds protecting their nests during the spring breeding season. The most prominent sources used by journalists are local and state government representatives, as well as members of the public. The results show that the "swooping season" has become a normal part of the annual news cycle for these publications, with the implication that discourse surrounding the Australian Magpie predominantly concerns the risk these birds pose to humans, and ignores their decline in non-urban environments.
PMID: 27128947 [PubMed - as supplied by publisher]
2.The shapes of bird beaks are highly controlled by nondietary factors.
Bright JA, Marugán-Lobón J, Cobb SN, Rayfield EJ.
Proc Natl Acad Sci U S A. 2016 Apr 28. pii: 201602683. [Epub ahead of print]

Abstract

Bird beaks are textbook examples of ecological adaptation to diet, but their shapes are also controlled by genetic and developmental histories. To test the effects of these factors on the avian craniofacial skeleton, we conducted morphometric analyses on raptors, a polyphyletic group at the base of the landbird radiation. Despite common perception, we find that the beak is not an independently targeted module for selection. Instead, the beak and skull are highly integrated structures strongly regulated by size, with axes of shape change linked to the actions of recently identified regulatory genes. Together, size and integration account for almost 80% of the shape variation seen between different species to the exclusion of morphological dietary adaptation. Instead, birds of prey use size as a mechanism to modify their feeding ecology. The extent to which shape variation is confined to a few major axes may provide an advantage in that it facilitates rapid morphological evolution via changes in body size, but may also make raptors especially vulnerable when selection pressures act against these axes. The phylogenetic position of raptors suggests that this constraint is prevalent in all landbirds and that breaking the developmental correspondence between beak and braincase may be the key novelty in classic passerine adaptive radiations.
PMID: 27125856 [PubMed - as supplied by publisher]

3.Reference intervals for biochemical analytes of captive Black-Fronted Piping-Guan (Aburria jacutinga).
Vaz FF, Locatelli-Dittrich R, Lange RR, Beltrame OC, Przydzimirski AC, de O Koch M, de Q Castilhos B.
Vet Clin Pathol. 2016 Apr 28. doi: 10.1111/vcp.12356. [Epub ahead of print]

Abstract
BACKGROUND:
Black-Fronted Piping-Guan (Aburria jacutinga) is considered one of the most threatened bird species on the American continent. Ex situ conservation efforts have been developed in Brazil, and monitoring the health status of these populations is essential to ensure reproductive success in captivity. Reference intervals (RI) for biochemistry analytes from a larger population of Black-Fronted Piping-Guan are unavailable.
OBJECTIVES:
This study was aimed at establishing RI for biochemical analytes of captive Black-Fronted Piping-Guan for future improved health assessments in these animals.
METHODS:
Blood samples were collected from 32 adult Black-Fronted Piping-Guans for serum and plasma separation. Liver and kidney function markers, and concentration of protein and lipids were measured. Reference intervals were determined using an Excel program with Reference Value Adviser (version 2.0).
RESULTS:
The RI of the analytes were: AST 20.7-188.0 U/L; CK 713.7-4741.4 U/L; LDH 360.7-1173.7 U/L; γ Glutamyl Transferase 1.1-5.4 U/L; total plasma protein 3.5-6.2 g/dL; total serum protein 1.7-4.7 g/dL; uric acid 0.9-19.2 mg/dL; urea 7.0-25.3 mg/dL; cholesterol 71.8-232.2 mg/dL; triglycerides 25.6-183.4 mg/dL.
CONCLUSIONS:

The RI are similar to the ones published for other avian species. Only CK and uric acid values were in discordance with the usually reported avian ranges. This could be due to different methods of capture and physical restraint. Alternatively, some differences could be species-specific. In general, physical restraint should be limited to a minimum and without stress to prevent capture myopathy and death.
PMID: 27124293 [PubMed - as supplied by publisher]

4.Natural melatonin fluctuation and its minimally invasive simulation in the zebra finch.
Seltmann S, Trost L, Ter Maat A, Gahr M.
PeerJ. 2016 Apr 21;4:e1939. doi: 10.7717/peerj.1939. eCollection 2016.

Abstract


Melatonin is a key hormone in the regulation of circadian rhythms of vertebrates, including songbirds. Understanding diurnal melatonin fluctuations and being able to reverse or simulate natural melatonin levels are critical to investigating the influence of melatonin on various behaviors such as singing in birds. Here we give a detailed overview of natural fluctuations in plasma melatonin concentration throughout the night in the zebra finch. As shown in previous studies, we confirm that "lights off" initiates melatonin production at night in a natural situation. Notably, we find that melatonin levels return to daytime levels as early as two hours prior to the end of the dark-phase in some individuals and 30 min before "lights on" in all animals, suggesting that the presence of light in the morning is not essential for cessation of melatonin production in zebra finches. Thus, the duration of melatonin production seems not to be specified by the length of night and might therefore be less likely to directly couple circadian and annual rhythms. Additionally, we show that natural melatonin levels can be successfully simulated through a combination of light-treatment (daytime levels during subjective night) and the application of melatonin containing skin-cream (nighttime levels during subjective day). Moreover, natural levels and their fluctuation in the transition from day to night can be imitated, enabling the decoupling of the effects of melatonin, for example on neuronal activity, from sleep and circadian rhythmicity. Taken together, our high-resolution profile of natural melatonin levels and manipulation techniques open up new possibilities to answer various melatonin related questions in songbirds.
PMID: 27123378 [PubMed] Free Article

5.Consecutive cohort effects driven by density-dependence and climate influence early-life survival in a long-lived bird.
Payo-Payo A, Genovart M, Bertolero A, Pradel R, Oro D.
Proc Biol Sci. 2016 Apr 27;283(1829). pii: 20153042. doi: 10.1098/rspb.2015.3042.

Abstract


Conditions during early life, including maternal cohort effects, can influence the future fitness of individuals. This may be particularly true for long-distance migrating birds, because, apart from conditions experienced by cohorts during rearing, conditions during early life in regions far from breeding grounds may also influence their population dynamics. Very little is known about the fitness consequences of those conditions experienced by juveniles after independence, especially in wild populations and for long-lived birds. We used multi-event capture-recapture-recovery models and a unique 26-year dataset for the Audouin's gull (Larus audouinii) to assess for the first time whether survival was influenced by early conditions, both during the rearing period (i.e. a maternal cohort effect potentially affected by density dependence) and the first winter (i.e. a cohort effect driven by climate when birds disperse to wintering grounds). Our results show that juvenile survival was highly sensitive to early-life conditions and that survival decreased with stronger density dependence and harsh climate. The two consecutive cohort effects were of similar magnitude and they may represent a selection filter. Thus, early-life conditions had a strong impact on survival, and neglecting this complexity may hinder our understanding on how populations of long-lived animals fluctuate and respond to perturbations.
PMID: 27122556 [PubMed - in process]

6.Evidence for r- and K-selection in a wild bird population: a reciprocal link between ecology and evolution.
Sæther BE, Visser ME, Grøtan V, Engen S.
Proc Biol Sci. 2016 Apr 27;283(1829). pii: 20152411. doi: 10.1098/rspb.2015.2411.

Abstract


Understanding the variation in selection pressure on key life-history traits is crucial in our rapidly changing world. Density is rarely considered as a selective agent. To study its importance, we partition phenotypic selection in fluctuating environments into components representing the population growth rate at low densities and the strength of density dependence, using a new stochastic modelling framework. We analysed the number of eggs laid per season in a small song-bird, the great tit, and found balancing selection favouring large clutch sizes at small population densities and smaller clutches in years with large populations. A significant interaction between clutch size and population size in the regression for the Malthusian fitness reveals that those females producing large clutch sizes at small population sizes also are those that show the strongest reduction in fitness when population size is increased. This provides empirical support for ongoing r- and K-selection in this population, favouring phenotypes with large growth rates r at small population sizes and phenotypes with high competitive skills when populations are close to the carrying capacity K This selection causes long-term fluctuations around a stable mean clutch size caused by variation in population size, implying that r- and K-selection is an important mechanism influencing phenotypic evolution in fluctuating environments. This provides a general link between ecological dynamics and evolutionary processes, operating through a joint influence of density dependence and environmental stochasticity on fluctuations in population size.
PMID: 27122550 [PubMed - in process]

7.Pollinator shifts drive petal epidermal evolution on the Macaronesian Islands bird-flowered species.
Ojeda DI, Valido A, Fernández de Castro AG, Ortega-Olivencia A, Fuertes-Aguilar J, Carvalho JA, Santos-Guerra A.
Biol Lett. 2016 Apr;12(4). pii: 20160022. doi: 10.1098/rsbl.2016.0022.

Abstract


Pollinator shifts are considered to drive floral trait evolution, yet little is still known about the modifications of petal epidermal surface at a biogeographic region scale. Here we investigated how independent shifts from insects to passerine birds in the Macaronesian Islands consistently modified this floral trait (i.e. absence of papillate cells). Using current phylogenies and extensive evidence from field observations, we selected a total of 81 plant species and subspecies for petal microscopy and comparative analysis, including 19 of the 23 insular species pollinated by opportunistic passerine birds (Macaronesian bird-flowered element). Species relying on passerine birds as the most effective pollinators (bird-pollinated) independently evolved at least five times and in all instances associated with a loss of papillate cells, whereas species with a mixed pollination system (birds plus insects and/or other vertebrates) evolved at least five times in Macaronesia and papillate cells were lost in only 25% of these transitions. Our findings suggest that petal micromorphology is a labile trait during pollinator shifts and that papillate cells tend to be absent on those species where pollinators have limited mechanical interaction with flowers, including opportunistic passerine birds that forage by hovering or from the ground.
PMID: 27122008 [PubMed - in process]

8.Long-term effect of yolk carotenoid levels on testis size in a precocial bird.
Giraudeau M, Ziegler AK, Tschirren B.
Biol Lett. 2016 Apr;12(4). pii: 20160008. doi: 10.1098/rsbl.2016.0008.

Abstract


Conditions experienced during prenatal development can have long-lasting organizational effects on offspring. Maternal carotenoids deposited in the eggs of birds and other oviparous species play an important role during fast embryonic growth and chick development through their antioxidant properties. However, the long-term consequences of variation in maternal carotenoid transfer for the offspring have seldom been considered. Since plasma carotenoid levels at adulthood are known to influence testis size and yolk carotenoid levels influence the ability to extract carotenoids later in life, we hypothesized that maternally transmitted carotenoids might influence gonad size at adulthood. Here, we showed that male Japanese quail (Coturnix japonica) originating from a carotenoid-enriched egg had smaller testes than control individuals at adulthood. This result shows that yolk carotenoids have long-term organizational effects. In addition, given that carotenoid intake at sexual maturity increases sperm quality and that a decreased testis size is associated with a lower sperm production, we propose that carotenoid exposure during embryo development might influence a trade-off between ejaculate size and sperm quality.
PMID: 27122006 [PubMed - in process]

9.Immunohistochemical localization of cocaine- and amphetamine-regulated transcript peptide (CARTp) in the brain of the pigeon (Columba livia) and zebra finch (Taeniopygia guttata).
Gutierrez-Ibanez C, Iwaniuk AN, Jensen M, Graham DJ, Pogány Á, Mongomery BC, Stafford JL, Luksh H, Wylie DR.
J Comp Neurol. 2016 Apr 28. doi: 10.1002/cne.24028. [Epub ahead of print]

Abstract


Cocaine- and amphetamine-regulated transcript peptides (CARTp) are neuropeptides that acts as neurotransmitters in the brain of vertebrates. The expression of CARTp has been characterised in teleost, amphibians and several mammalian species, but comparative data in reptiles and birds is non-existant. In this study, we show the distribution of immunoreactivity against CART peptides (CARTp-ir) in the brains of the two bird species: the pigeon (Columba livia) and zebra finch (Taeniopygia guttata). We found CARTp-ir cells and terminals in the brains of both, but no major differences between the two species. As in mammals, teleost fish and amphibians, CARTp-ir terminals and cells were abundant in subpallial regions, particularly the striatum and nucleus accumbens. We also found CARTp-ir cells and terminals in the hypothalamus, and a large number of CARTp -ir terminals in the substantia nigra, ventral tegmental area, periaqueductal grey, parabrachial nucleus and the dorsal vagal complex. However, in contrast to other vertebrates, CARTp-ir was not found in the olfactory bulb. In addition there was almost no CARTp-ir in the pallium or the hippocampal formation, and little CARTp-ir in the cerebellum. The conserved expression of CARTp in the subpallium, hypothalamus and dorsal vagal complex of birds suggest some of the functions of CARTp, such as regulation of food intake and interactions with the social control network and mesolimbic reward system, are conserved among vertebrates. 
PMID: 27121571 [PubMed - as supplied by publisher]

10.Basing Turkey Lighting Programs on Broiler Research: A Good Idea? A Comparison of 18 Daylength Effects on Broiler and Turkey Welfare.
Schwean-Lardner K, Vermette C, Leis M, Classen HL.
Animals (Basel). 2016 Apr 25;6(5). pii: E27. doi: 10.3390/ani6050027.

Abstract


Daylength used as a management tool has powerful implications on the welfare of both broilers and turkeys. Near-constant light results in many detrimental impacts, including lack of behavioural rhythms and circadian melatonin rhythms. Both are suggestive that sleep fragmentation could result in birds reared on long photoperiods, which can lead to the same negative health and physiological responses as total sleep deprivation. An indirect comparison of the welfare implications of graded levels of daylength on broilers and turkeys clearly indicate that long daylengths depress welfare by increasing mortality, reducing mobility, increasing ocular pathologies and changing behaviour in both species. Furthermore, long daylengths change melatonin secretion patterns and eliminate behavioural and melatonin circadian rhythms, which were measured in broilers in these works. However, feather pecking in turkeys was reduced when birds were exposed to long daylengths. Exactly how much darkness should be included in a management program to maximize welfare will depend on the species, the age of marketing, and in turkeys, bird gender.
PMID: 27120624 [PubMed] Free Article

11.Female Infidelity Is Constrained by El Niño Conditions in a Long-lived Bird.
Kiere LM, Drummond H.
J Anim Ecol. 2016 Apr 27. doi: 10.1111/1365-2656.12537. [Epub ahead of print]

Abstract


Explaining the remarkable variation in socially monogamous females' extra-pair (EP) behaviour revealed by decades of molecular paternity testing remains an important challenge. One hypothesis proposes that restrictive environmental conditions (e.g. extreme weather, food scarcity) limit females' resources and increase EP behaviour costs, forcing females to reduce EP reproductive behaviours. For the first time, we tested this hypothesis by directly quantifying within-pair and EP behaviours rather than inferring behaviour from paternity. We evaluated whether warmer sea surface temperatures depress total pre-laying reproductive behaviours, and particularly EP behaviours, in socially paired female blue-footed boobies (Sula nebouxii). Warm waters in the Eastern Pacific are associated with El Niño Southern Oscillation and lead to decreased food availability and reproductive success in this and other marine predators. With warmer waters, females decreased their neighbourhood attendance, total copulation frequency, and laying probability, suggesting that they contend with restricted resources by prioritizing self-maintenance and committing less to reproduction, sometimes abandoning the attempt altogether. Females were also less likely to participate in EP courtship and copulations, but when they did, rates of these behaviours were unaffected by water temperature. Females' neighbourhood attendance, total copulation frequency, and EP courtship probability responded to temperature differences at the between-season scale, and neighbourhood attendance and EP copulation probability were affected by within-season fluctuations. Path analysis indicated that decreased EP participation was not attributable to reduced female time available for EP activities. Together, our results suggest that immediate time and energy constraints were not the main factors limiting females' infidelity. Our study shows that El Niño conditions depress female boobies' EP participation and total reproductive activity. In addition to increasing general self-maintenance and reproductive costs, warm waters may increase costs specific to EP behaviours including divorce, reduced male parental care or pathogen exposure. Our results suggest that female boobies strategically refrained from EP behaviours to avoid these or other longer term costs, rather than being compelled by immediate constraints. This study demonstrates that current environmental conditions affect females' mating decisions, contributing to variation in EP behaviours, even in a long-lived, iteroparous species that can buffer against temporary adversity.
PMID: 27119773 [PubMed - as supplied by publisher]

12.Emergence of Swarming Behavior: Foraging Agents Evolve Collective Motion Based on Signaling.
Witkowski O, Ikegami T.
PLoS One. 2016 Apr 27;11(4):e0152756. doi: 10.1371/journal.pone.0152756. eCollection 2016.

Abstract


Swarming behavior is common in biology, from cell colonies to insect swarms and bird flocks. However, the conditions leading to the emergence of such behavior are still subject to research. Since Reynolds' boids, many artificial models have reproduced swarming behavior, focusing on details ranging from obstacle avoidance to the introduction of fixed leaders. This paper presents a model of evolved artificial agents, able to develop swarming using only their ability to listen to each other's signals. The model simulates a population of agents looking for a vital resource they cannot directly detect, in a 3D environment. Instead of a centralized algorithm, each agent is controlled by an artificial neural network, whose weights are encoded in a genotype and adapted by an original asynchronous genetic algorithm. The results demonstrate that agents progressively evolve the ability to use the information exchanged between each other via signaling to establish temporary leader-follower relations. These relations allow agents to form swarming patterns, emerging as a transient behavior that improves the agents' ability to forage for the resource. Once they have acquired the ability to swarm, the individuals are able to outperform the non-swarmers at finding the resource. The population hence reaches a neutral evolutionary space which leads to a genetic drift of the genotypes. This reductionist approach to signal-based swarming not only contributes to shed light on the minimal conditions for the evolution of a swarming behavior, but also more generally it exemplifies the effect communication can have on optimal search patterns in collective groups of individuals.
PMID: 27119340 [PubMed - in process] Free Article

13.Behavioural, brain and cardiac responses to hypobaric hypoxia in broiler chickens.
Martin JE, Christensen K, Vizzier-Thaxton Y, Mitchell M, McKeegan DE.
Physiol Behav. 2016 Apr 23. pii: S0031-9384(16)30186-X. doi: 10.1016/j.physbeh.2016.04.038. [Epub ahead of print]

Abstract


A novel approach to pre-slaughter stunning of chickens has been developed in which birds are rendered unconscious by progressive hypobaric hypoxia. Termed Low Atmospheric Pressure Stunning (LAPS), this approach involves application of gradual decompression lasting 280s according to a prescribed curve. We examined responses to LAPS by recording behaviour, electroencephalogram (EEG) and electrocardiogram (ECG) in individual male chickens, and interpreted these with regard to the welfare impact of the process. We also examined the effect of two temperature adjusted pressure curves on these responses. Broiler chickens were exposed to LAPS in 30 triplets (16 and 14 triplets assigned to each pressure curve). In each triplet, one bird was instrumented for recording of EEG and ECG while the behaviour of all three birds was observed. Birds showed a consistent sequence of behaviours during LAPS (ataxia, loss of posture, clonic convulsions and motionless) which were observed in all birds. Leg paddling, tonic convulsions, slow wing flapping, mandibulation, head shaking, open bill breathing, deep inhalation, jumping and vocalisation were observed in a proportion of birds. Spectral analysis of EEG responses at 2s intervals throughout LAPS revealed progressive decreases in median frequency at the same time as corresponding progressive increases in total power, followed later by decreases in total power as all birds exhibited isoelectric EEG and died. There was a very pronounced increase in total power at 50-60s into the LAPS cycle, which corresponded to dominance of the signal by high amplitude slow waves, indicating loss of consciousness. Slow wave EEG was seen early in the LAPS process, before behavioural evidence of loss of consciousness such as ataxia and loss of posture, almost certainly due to the fact that it was completely dark in the LAPS chamber. ECG recordings showed a pronounced bradycardia (starting on average 49.6s into LAPS), often associated with arrhythmia, until around 60s into LAPS when heart rate levelled off. There was a good correlation between behavioural, EEG and cardiac measures in relation to loss of consciousness which collectively provide a loss of consciousness estimate of around 60s. There were some effects of temperature adjusted pressure curves on behavioural latencies and ECG responses, but in general responses were consistent and very similar to those reported in previous research on controlled atmosphere stunning with inert gases. The results suggest that the process is humane (slaughter without avoidable fear, anxiety, pain, suffering and distress). In particular, the maintenance of slow wave EEG patterns in the early part of LAPS (while birds are still conscious) is strongly suggestive that LAPS is non-aversive, since we would expect this to be interrupted by pain or discomfort.
PMID: 27117817 [PubMed - as supplied by publisher]

14.Morphological characteristics of Mesocestoides canislagopodis (Krabbe 1865) tetrathyridia found in rock ptarmigan (Lagopus muta) in Iceland.
Skirnisson K, Sigurðardóttir ÓG, Nielsen ÓK.
Parasitol Res. 2016 Apr 27. [Epub ahead of print]

Abstract


Necropsies of 1010 rock ptarmigans (Lagopus muta) sampled in autumn 2006-2015 in northeast Iceland revealed Mesocestoides canislagopodis tetrathyridia infections in six birds (0.6 %), two juvenile birds (3 month old), and four adult birds (15 months or older). Four birds had tetrathyridia in the body cavity, one bird in the liver, and one bird both in the body cavity and the liver. There were more tetrathyridia in the body cavity of the two juveniles (c. 50 in each) than in three adults (10-40), possibly indicating a host-age-related tetrathyridia mortality. Approximately, half of tetrathyridia in the body cavity were free or loosely attached to the serosa, the other half were encapsulated in a thin, loose connective tissue stroma, frequently attached to the lungs and the liver. Tetrathyridia in the liver parenchyma incited variably intense inflammation. Tetrathyridia from the juvenile hosts were whitish, heart-shaped, and flattened, with unsegmented bodies with a slightly pointed posterior end. In the adult hosts, tetrathyridia were sometimes almost rectangular-shaped, slightly wider compared to those in the juveniles, but more than twice as long as the younger-aged tetrathyridia. Tetrathyridia infections are most likely acquired during the brief insectivorous feeding phase of ptarmigan chicks, and the tetrathyridia persist throughout the lifespan of the birds.
PMID: 27117162 [PubMed - as supplied by publisher]

15.Ecoacoustics of a production-protected area mosaic for better conservation.
Grant PB, Samways MJ.
Conserv Biol. 2016 Apr 26. doi: 10.1111/cobi.12748. [Epub ahead of print]

Abstract


The variety of local animal sounds can characterize the landscape. Ecoacoustics uses this biotic environmental sound as a non-invasive, reliable proxy for investigating biodiversity patterns across ecological gradients. We used this method to assess the conservation value of various biotopes typical of an eco-friendly plantation forestry landscape with diverse ecological gradients, and containing both alien and indigenous vegetation. The reference area was an adjacent large World Heritage Site protected area (PA). All sites were in a global biodiversity hotspot. Ecoacoustics gave a new perspective on how taxa segregated into various biotopes. Nocturnal acoustic surveys identified a total of 65 singing species, including bird, frog, cricket and katydid species. Large, natural, protected grassland sites in the PA had the highest acoustic diversity. Areas largely covered in alien timber or alien grass were devoid of acoustic species. Sites grazed by native and domestic megaherbivores were fairly rich in acoustic species but none was unique to this habitat type, which was richer than intensively managed grassland sites. Natural vegetation patches inside the plantation mosaic supported high acoustic species richness, which increased with increased plant heterogeneity and patch size. Grassland patches <1 ha were greatly influenced by edge effects, and did not maintain the full complement of acoustic biodiversity. Isolated grassland patches within the plantation mosaic supported moderate but slightly impoverished acoustic diversity compared to the PA. Indigenous forest patches within the plantation mosaic contained a highly characteristic acoustic species assemblage, emphasizing their complementary contribution to local biodiversity. Overall, utilizing acoustic signals across landscapes is effective for determining spatial biodiversity patterns and is a useful tool for guiding conservation.
PMID: 27113387 [PubMed - as supplied by publisher]

16.Dental Disparity and Ecological Stability in Bird-like Dinosaurs prior to the End-Cretaceous Mass Extinction.
Larson DW, Brown CM, Evans DC.
Curr Biol. 2016 Apr 20. pii: S0960-9822(16)30249-4. doi: 10.1016/j.cub.2016.03.039. [Epub ahead of print]

Abstract


The causes, rate, and selectivity of the end-Cretaceous mass extinction continue to be highly debated [1-5]. Extinction patterns in small, feathered maniraptoran dinosaurs (including birds) are important for understanding extant biodiversity and present an enigma considering the survival of crown group birds (Neornithes) and the extinction of their close kin across the end-Cretaceous boundary [6]. Because of the patchy Cretaceous fossil record of small maniraptorans [7-12], this important transition has not been closely examined in this group. Here, we test the hypothesis that morphological disparity in bird-like dinosaurs was decreasing leading up to the end-Cretaceous mass extinction, as has been hypothesized in some dinosaurs [13, 14]. To test this, we examined tooth morphology, an ecological indicator in fossil reptiles [15-19], from over 3,100 maniraptoran teeth from four groups (Troodontidae, Dromaeosauridae, Richardoestesia, and cf. Aves) across the last 18 million years of the Cretaceous. We demonstrate that tooth disparity, a proxy for variation in feeding ecology, shows no significant decline leading up to the extinction event within any of the groups. Tooth morphospace occupation also remains static over this time interval except for increased size during the early Maastrichtian. Our data provide strong support that extinction within this group occurred suddenly after a prolonged period of ecological stability. To explain this sudden extinction of toothed maniraptorans and the survival of Neornithes, we propose that diet may have been an extinction filter and suggest that granivory associated with an edentulous beak was a key ecological trait in the survival of some lineages.
PMID: 27112293 [PubMed - as supplied by publisher]

17.A framework for evaluating and designing citizen science programs for natural resources monitoring.
Chase SK, Levine A.
Conserv Biol. 2016 Apr 25. doi: 10.1111/cobi.12697. [Epub ahead of print]

Abstract


We present a framework of resource characteristics critical to the design and assessment of citizen science programs that monitor natural resources. To develop the framework we reviewed 52 citizen science programs that monitored a wide range of resources and provided insights into what resource characteristics are most conducive to developing citizen science programs and how resource characteristics may constrain the use or growth of these programs. We focused on 4 types of resource characteristics: biophysical and geographical, management and monitoring, public awareness and knowledge, and social and cultural characteristics. We applied the framework to 2 programs, the Tucson (U.S.A.) Bird Count and the Maui (U.S.A.) Great Whale Count. We found that resource characteristics such as accessibility, diverse institutional involvement in resource management, and social or cultural importance of the resource affected program endurance and success. However, the relative influence of each characteristic was in turn affected by goals of the citizen science programs. Although the goals of public engagement and education sometimes complimented the goal of collecting reliable data, in many cases trade-offs must be made between these 2 goals. Program goals and priorities ultimately dictate the design of citizen science programs, but for a program to endure and successfully meet its goals, program managers must consider the diverse ways that the nature of the resource being monitored influences public participation in monitoring.
PMID: 27111860 [PubMed - as supplied by publisher]

18.Comparative histology of some craniofacial sutures and skull-base synchondroses in non-avian dinosaurs and their extant phylogenetic bracket.
Bailleul AM, Horner JR.
J Anat. 2016 Apr 25. doi: 10.1111/joa.12471. [Epub ahead of print]

Abstract


Sutures and synchondroses, the fibrous and cartilaginous articulations found in the skulls of vertebrates, have been studied for many biological applications at the morphological scale. However, little is known about these articulations at the microscopic scale in non-mammalian vertebrates, including extant archosaurs (birds and crocodilians). The major goals of this paper were to: (i) document the microstructure of some sutures and synchondroses through ontogeny in archosaurs; (ii) compare these microstructures with previously published sutural histology (i.e. that of mammals); and (iii) document how these articulations with different morphological degrees of closure (open or obliterated) appear histologically. This was performed with histological analyses of skulls of emus, American alligators, a fossil crocodilian and ornithischian dinosaurs (hadrosaurids, pachycephalosaurids and ceratopsids). Emus and mammals possess a sutural periosteum until sutural fusion, but it disappears rapidly during ontogeny in American alligators. This study identified seven types of sutural mineralized tissues in extant and extinct archosaurs and grouped them into four categories: periosteal tissues; acellular tissues; fibrous tissues; and intratendinous tissues. Due to the presence of a periosteum in their sutures, emus and mammals possess periosteal tissues at their sutural borders. The mineralized sutural tissues of crocodilians and ornithischian dinosaurs are more variable and can also develop via a form of necrosis for acellular tissues and metaplasia for fibrous and intratendinous tissues. It was hypothesized that non-avian dinosaurs, like the American alligator, lacked a sutural periosteum and that their primary mode of ossification involved the direct mineralization of craniofacial sutures (instead of intramembranous ossification found in mammals and birds). However, we keep in mind that a bird-like sutural microstructure might have arisen within non-avian saurichians. While synchondroseal histology is relatively similar in archosaurs and mammals, the microstructural differences between the sutures of these two clades are undeniable. Moreover, the current results suggest that the degree of sutural closure can only accurately be known via microstructural analyses. This study sheds light on the microstructure and growth of archosaurian sutures and synchondroses, and reveals a unique, undocumented histological diversity in non-avian dinosaur skulls.
PMID: 27111332 [PubMed - as supplied by publisher]

19.The multidimensional causal factors of 'wet litter' in chicken-meat production.
Dunlop MW, Moss AF, Groves PJ, Wilkinson SJ, Stuetz RM, Selle PH.
Sci Total Environ. 2016 Apr 22;562:766-776. doi: 10.1016/j.scitotenv.2016.03.147. [Epub ahead of print] Review.

Abstract


The problem of 'wet litter', which occurs primarily in grow-out sheds for meat chickens (broilers), has been recognised for nearly a century. Nevertheless, it is an increasingly important problem in contemporary chicken-meat production as wet litter and associated conditions, especially footpad dermatitis, have developed into tangible welfare issues. This is only compounded by the market demand for chicken paws and compromised bird performance. This review considers the multidimensional causal factors of wet litter. While many causal factors can be listed it is evident that the critical ones could be described as micro-environmental factors and chief amongst them is proper management of drinking systems and adequate shed ventilation. Thus, this review focuses on these environmental factors and pays less attention to issues stemming from health and nutrition. Clearly, there are times when related avian health issues of coccidiosis and necrotic enteritis cannot be overlooked and the development of efficacious vaccines for the latter disease would be advantageous. Presently, the inclusion of phytate-degrading enzymes in meat chicken diets is routine and, therefore, the implication that exogenous phytases may contribute to wet litter is given consideration. Opinion is somewhat divided as how best to counter the problem of wet litter as some see education and extension as being more beneficial than furthering research efforts. However, it may prove instructive to assess the practice of whole grain feeding in relation to litter quality and the incidence of footpad dermatitis. Additional research could investigate the relationships between dietary concentrations of key minerals and the application of exogenous enzymes with litter quality.
PMID: 27110988 [PubMed - as supplied by publisher] Free Article
















































































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