Condition‐dependent immune defence in the Magpie: how important is ectoparasitism?

The immune system has high costs of maintenance and production and expression of immune function should be dependent on the condition of the individual. The fitness cost that parasites impose on hosts may then be reflected in the investment that hosts make in immunity. Little is known about sources and consequences of intra- and interspecific variation in the presence and size of organs of the immune system in relation to ectoparasitism. Variation in the presence and size of the bursa of Fabricius and spleen size was measured to assess potential relationships between immune defence, nutritional condition and ectoparasites in the Magpie Pica pica. We found three species of lice (Mallophaga), two species of louse flies (Hippoboscidae), and the larvae of a tick (Ixodidae) infecting magpies. Age explained a significant proportion of variation in prevalence and number of parasite species, first-year birds being more parasitized than adults. Spleen size increased with nutritional condition, and the level of ectoparasitism negatively affected nutritional condition. Only one species of lice (Philopterus picae) was involved; the negative effect of this species on nutritional condition was more pronounced in males than females. These results are consistent with the hypotheses of condition-dependent investment in the immune system and sexual differences in susceptibility to parasite effects. Ectoparasites may thus play a role in modulating the relationship between condition and immune defence. We also found evidence for an interaction between the bursa and the spleen. Magpies with bursa had larger spleens than those where it had atrophied. This interaction did not affect ectoparasitism or nutritional condition.     

Voluntary exposure of some western‐hemisphere snake and lizard species to ultraviolet‐B radiation in the field: how much ultraviolet‐B should a lizard or snake receive in captivity?

Studies of voluntary exposure to ultraviolet‐B (UVB) radiation from the sun in the field were conducted in the southern US and Jamaica for 15 species of lizards and snakes occupying various habitats. Species were sorted into four zones of UVB exposure ranging from a median UV index of 0.35 for zone 1 to 3.1 for zone 4. Guidelines for UVB exposure in captivity of these and species occupying similar light environments are presented. Data for most species were collected during mid‐day during the spring breeding season, which appeared to be the time of maximum exposure. For two species of Sceloporus studied more intensively there was significant variation of exposure among times of the day and among seasons. So, all‐day studies over the entire active season are necessary to fully understand the pattern of natural exposure for a particular diurnal species. Environmental and body temperature and thermoregulation as well as UVB/vitamin D photoregulation influences exposure to UVB. Regressions allowing the inter‐conversion of readings among some meters with different detector sensitivities are presented. Readings of natural sunlight predict the same photobiosynthetic potential for vitamin D as the same reading from artificial sources whose wavelength distribution within the UVB band of the source is comparable to that of sunlight. Research approaches to further increase our understanding of vitamin D and UVB use and requirements for squamate reptiles in captivity are outlined. Zoo Biol 29:317–334, 2010. © 2009 Wiley‐Liss, Inc.     

Bottom‐up control in the benthos of ocean‐exposed sandy beaches?

Bottom‐up control is a fundamental structuring force in food webs. Food webs of ocean‐exposed sandy beaches are predicted to be bottom‐up controlled systems, underpinned by imported organic matter rather than in situ primary production. This ecological model of resource‐based regulation of biological assemblages is juxtaposed against a prevailing paradigm built around a dominance of physical drivers in sandy beach ecosystems. Surprisingly, given the apparently ubiquitous energetic subsidies of beach food webs, the central premise of bottom‐up control has not been tested. Here we experimentally manipulated in situ nutrient levels on a sandy beach to test food web responses at the levels of primary producers (benthic microalgae) and their grazers (meiofauna). The meiofauna community as a whole appeared most strongly influenced by the local physical environment, particularly changes in sediment grain size – this supports the traditional ‘environmental control paradigm’. We also detected a significant, positive response of two consumer groups of the meiofauna (nematodes, ostracods) to nutrient enrichment that supports a model of biological, bottom‐up control. Although the predicted response of elevated producer biomass following nutrient enrichment was not detected, intense grazing pressure on new, stimulated production may have masked positive responses by the primary producers. Multichannel regulation of food webs is likely for many exposed sandy beaches, albeit an often lower importance of in situ bottom‐up forces compared with stronger environmental control.     

Baculovirus‐induced tree‐top disease: how extended is the role of egt as a gene for the extended phenotype?

Many parasites alter host behaviour to enhance their chance of transmission. Recently, the ecdysteroid UDP‐glucosyl transferase (egt) gene from the baculovirus Lymantria dispar multiple nucleopolyhedrovirus (LdMNPV) was identified to induce tree‐top disease in L. dispar larvae. Infected gypsy moth larvae died at elevated positions (hence the term tree‐top disease), which is thought to promote dissemination of the virus to lower foliage. It is, however, unknown whether egt has a conserved role among baculoviruses in inducing tree‐top disease. Here, we studied tree‐top disease induced by the baculovirus Autographa californica multiple nucleopolyhedrovirus (AcMNPV) in two different host insects, Trichoplusia ni and Spodoptera exigua, and we investigated the role of the viral egt gene therein. AcMNPV induced tree‐top disease in both T. ni and S. exigua larvae, although in S. exigua a moulting‐dependent effect was seen. Those S. exigua larvae undergoing a larval moult during the infection process died at elevated positions, while larvae that did not moult after infection died at low positions. For both T. ni and S. exigua, infection with a mutant AcMNPV lacking egt did not change the position where the larvae died. We conclude that egt has no highly conserved role in inducing tree‐top disease in lepidopteran larvae. The conclusion that egt is a ‘gene for an extended phenotype’ is therefore not generally applicable for all baculovirus–host interactions. We hypothesize that in some baculovirus–host systems (including LdMNPV in L. dispar), an effect of egt on tree‐top disease can be observed through indirect effects of egt on moulting‐related climbing behaviour.     

Is the food‐entrainable circadian oscillator in the digestive system?

Food-anticipatory activity (FAA) is the increase in locomotion and core body temperature that precedes a daily scheduled meal. It is driven by a circadian oscillator but is independent of the suprachiasmatic nuclei. Recent results that reveal meal-entrained clock gene expression in rat and mouse peripheral organs raise the intriguing possibility that the digestive system is the site of the feeding-entrained oscillator (FEO) that underlies FAA. We tested this possibility by comparing FAA and Per1 rhythmicity in the digestive system of the Per 1-luciferase transgenic rat. First, rats were entrained to daytime restricted feeding (RF, 10 days), then fed ad libitum (AL, 10 days), then food deprived (FD, 2 days). As expected FAA was evident during RF and disappeared during subsequent AL feeding, but returned at the correct phase during deprivation. The phase of Per1 in liver, stomach and colon shifted from a nocturnal to a diurnal peak during RF, but shifted back to nocturnal phase during the subsequent AL and remained nocturnal during food deprivation periods. Second, rats were entrained to two daily meals at zeitgeber time (ZT) 0400 and ZT 1600. FAA to both meals emerged after about 10 days of dual RF. However, all tissues studied (all five liver lobes, esophagus, antral stomach, body of stomach, colon) showed entrainment consistent with only the night-time meal. These two results are inconsistent with the hypothesis that FAA arises as an output of rhythms in the gastrointestinal (GI) system. The results also highlight an interesting diversity among peripheral oscillators in their ability to entrain to meals and the direction of the phase shift after RF ends.     

How common is the funnel‐like energy landscape in protein‐protein interactions?

The goal of this study is to verify the concept of the funnel-like intermolecular energy landscape in protein-protein interactions by use of a series of computational experiments. Our preliminary analysis revealed the existence of the funnel in many protein-protein interactions. However, because of the uncertainties in the modeling of these interactions and the ambiguity of the analysis procedures, the detection of the funnels requires detailed quantitative approaches to the energy landscape analysis. A number of such approaches are presented in this study. We show that the funnel detection problem is equivalent to a problem of distinguishing between distributions of low-energy intermolecular matches in the funnel and in the low-frequency landscape fluctuations. If the fluctuations are random, the decision about whether the minimum is the funnel is equivalent to determining whether this minimum is significantly different from a would-be random one. A database of 475 nonredundant cocrystallized protein-protein complexes was used to re-dock the proteins by use of smoothed potentials. To detect the funnel, we developed a set of sophisticated models of random matches. The funnel was considered detected if the binding area was more populated by the low-energy docking predictions than by the matches generated in the random models. The number of funnels detected by use of different random models varied significantly. However, the results confirmed that the funnel may be the general feature in protein-protein association.     

Do weaver ants affect arthropod diversity and the natural‐enemy‐to‐pest ratio in horticultural systems?

High biodiversity is an important component of sustainable agricultural systems, and previous studies have found that increases in the diversity of the natural enemies of pests are associated with decreases in pest populations. Weaver ants are well known for their highly territorial and aggressive behaviour and for their control efficiency of many insect pests in tropical crop trees. Because of this, the ants have been used as a key component in integrated pest management (IPM) programmes for tropical crop trees. In implementing the IPM programmes, we received a number of enquiries related to whether weaver ants have negative effects on arthropod diversity and other natural enemies in orchard systems due to their aggressive behaviour. To answer these questions, we regularly sampled canopy arthropods in cashew and mango orchards in the Northern Territory of Australia in 1996, 2002 and 2003. We sampled, using a vacuum sampler, orchards with and without weaver ants. Cashew and mango plots with abundant weaver ants had similar or higher canopy arthropod and natural enemy diversity and similar ratios of natural enemies to insect pests, compared with plot where the weaver ant was absent. The study also showed that the application of insecticides reduced arthropod diversity and the ratio of natural enemies to insect pests in a mango orchard. However, insecticide spray did not affect natural enemy diversity and abundance, which may be related to a high immigration rate of natural enemies in small plots surrounded by areas that were not sprayed.     

Is the mTOR‐signalling cascade disrupted in Schizophrenia?

The mammalian target of rapamycin (mTOR) signalling cascade is involved in the intracellular regulation of protein synthesis, specifically for proteins involved in controlling neuronal morphology and facilitating synaptic plasticity. Research has revealed that the activity of the mTOR cascade is influenced by several extracellular and environmental factors that have been implicated in schizophrenia. Therefore, there is reason to believe that one of the downstream consequences of dysfunction or hypofunction of these factors in schizophrenia is disrupted mTOR signalling and hence impaired protein synthesis. This results in abnormal neurodevelopment and deficient synaptic plasticity, outcomes which could underlie some of the positive, negative and cognitive symptoms of schizophrenia. This review will discuss the functional roles of the mTOR cascade and present evidence in support of a novel mTOR‐based hypothesis of the neuropathology of schizophrenia.

     

Smith‐Lemli‐Opitz syndrome in trisomy 13: How does the mix work?

BACKGROUND: Trisomy 13 and Smith-Lemli-Opitz syndrome (SLOS) are both well-recognized multiple congenital anomaly/mental retardation syndromes. CASE: In this report we describe a male newborn with trisomy 13 who also has features of SLOS, such as 2/3 toe syndactyly and a shawl-like scrotum. Biochemical analysis was consistent with SLOS, and limited molecular analysis revealed 1 mutation in the DHCR7 gene. CONCLUSIONS: The challenges in establishing the diagnosis of SLOS in this patient are presented and the unique coexistence of the 2 major malformation syndromes is discussed. Given the overlapping phenotype of the 2 syndromes, our report should encourage further research on cholesterol biosynthesis in patients with trisomy 13.     

Mating in the pseudogamic apomictic Anemopaegma acutifolium DC: another case of pseudo‐self‐compatibility in Bignoniaceae?

Self‐compatibility in apomictic pseudogamic species is considered fundamental to assure reproduction by seeds in extreme situations, making apomictic species more advantageous than sexual ones in these scenarios. Anemopaegma acutifolium is a polyploidy, apomictic sporophytic species with no endosperm development in ovules of unpollinated pistils, which indicates obligate pseudogamy. Thus, the aim of the present work is to study the breeding system and post‐pollination events to test if there is similar pseudogamous development irrespective of pollination treatment. We analysed fruit and seed set obtained in controlled experimental pollinations, as well as embryo number per seed, and the progress of ovule penetration, fertilisation and early endosperm development between self‐ and cross‐pollinated pistils. We found that the species is self‐fertile and that spontaneous selfing fruit set is also possible, although emasculated flowers never form fruits. Selfed pistils were as efficient as crossed ones for all parameters analysed, except for a delay in endosperm development observed in the former that may be an effect of the late‐acting self‐incompatibility. Therefore, the avoidance of selfed pistil abortion seems to be promoted by the presence of adventitious embryos and a normal endosperm. We conclude that A. acutifolium shows apomixis‐related pseudo‐self‐compatibility, as in other self‐fertile apomictic species of Bignoniaceae, which confer reproductive assurance and increases fruit‐set and persistence ability in fast‐changing tropical habitats.     

DNA microarrays in the clinic: how soon,how extensively?

Although DNA microarrays are now widely used in research settings, they have been slow to penetrate clinical practice in spite of their apparent advantages. This is due to the very different requirements for a clinical test in contrast to a research tool, and to a strict necessity for demonstrated clinical utility. There is a clear differentiation between two types of DNA array tests: "genomic" diagnostics, developed to ascertain the presence or absence of mutations, deletions or duplications, and for which clinical evidence is already established, and tests using expression profiling for prognosis or predictive purposes, in which case the clinical correlate must be proven. Most array diagnostics currently used belong, understandably, to the "genomic" variety. It is to be expected that future improvements in tailored technology, as well as a logical trend towards measuring an ever-increasing number of parameters, will ensure an important diagnostic role for DNA arrays in the coming decade.     

Extended π‐Bridge in Organic Dye‐Sensitized Solar Cells: the Longer,the Better?

The elongation of π‐conjugated bridges between the donor (D) and the acceptor (A) represents a feasible strategy towards enhancement of light‐harvesting in both breadth and depth of organic D‐π‐A dyes suitable for nanocrystalline TiO₂‐based dye‐sensitized solar cells (DSSCs). Here, a series of organic dyes with elongating conjugated bridges is synthesized and characterized. DSSC devices employing a cobalt (II/III) redox electrolyte are fabricated using these dyes as light‐harvesting sensitizers. Compared to a dye with the 3,4‐ethylenedioxythiophene (EDOT) linker ( G188 ), the three counterparts with further extended π‐bridges present gradually red‐shifted electronic absorption spectra and a persistent decrease in oxidation potential. The photocurrent action spectra show that the extension of π‐conjugated bridges decreases the open‐circuit photovoltage. The best performance is shown in G268 with a short‐circuit photocurrent density (J_sc) of 16.27 mA cm², an open‐circuit photovoltage (V_oc) of 0.83 V, and a fill factor (FF) of 0.67, corresponding to an overall conversion efficiency of 9.24%. Unexpectedly, G270, which has with the longest π‐bridge , showed the lowest J_sc, V_oc, and efficiency.     

Are tyrosine residues involved in the photoconversion of the water‐soluble chlorophyll‐binding protein of Chenopodium album?

Non‐photosynthetic and hydrophilic chlorophyll (Chl) proteins, called water‐soluble Chl‐binding proteins (WSCPs), are distributed in various species of Chenopodiaceae, Amaranthaceae, Polygonaceae and Brassicaceae. Based on their photoconvertibility, WSCPs are categorised into two classes: Class I (photoconvertible) and Class II (non‐photoconvertible). Chenopodium album WSCP (CaWSCP; Class I) is able to convert the chlorin skeleton of Chl a into a bacteriochlorin‐like skeleton under light in the presence of molecular oxygen. Potassium iodide (KI) is a strong inhibitor of the photoconversion. Because KI attacks tyrosine residues in proteins, tyrosine residues in CaWSCP are considered to be important amino acid residues for the photoconversion. Recently, we identified the gene encoding CaWSCP and found that the mature region of CaWSCP contained four tyrosine residues: Tyr13, Tyr14, Tyr87 and Tyr134. To gain insight into the effect of the tyrosine residues on the photoconversion, we constructed 15 mutant proteins (Y13A, Y14A, Y87A, Y134A, Y13‐14A, Y13‐87A, Y13‐134A, Y14‐87A, Y14‐134A, Y87‐134A, Y13‐14‐87A, Y13‐14‐134A, Y13‐87‐134A, Y14‐87‐134A and Y13‐14‐87‐134A) using site‐directed mutagenesis. Amazingly, all the mutant proteins retained not only chlorophyll‐binding activity, but also photoconvertibility. Furthermore, we found that KI strongly inhibited the photoconversion of Y13‐14‐87‐134A. These findings indicated that the four tyrosine residues are not essential for the photoconversion.     

Poisoning for production: how effective is fox baiting in south‐eastern Australia?

• 1 The European red fox Vulpes vulpes represents a continuing threat to both livestock and native vertebrates in Australia, and is commonly managed by setting ground‐level baits impregnated with 1080 (sodium fluoroacetate) poison. However, the long‐term effectiveness of such control campaigns is likely to be limited due to the ability of foxes to disperse over considerable distances and to swiftly recolonize areas from where they had been removed.
• 2 To investigate the effectiveness of fox baiting in a production landscape, we assessed the potential for foxes to reinvade baited farm property areas within the jurisdiction of the Molong Rural Lands Protection Board (RLPB), an area of 815 000 ha on the central tablelands of New South Wales, Australia. The spatial distribution and timing of fox baiting campaigns between 1998 and 2002 was estimated from RLPB records and mapped using Geographical Information System software. The effectiveness of the control campaign was assessed on the basis of the likely immigration of foxes from non‐baited farms using immigration distances calculated from published relationships between dispersal distance and home range size.
• 3 Few landholders undertook baiting campaigns in any given year, and the area baited was always so small that no baited property would have been sufficiently far from an unbaited property to have been immune from immigrating individuals. It is likely, therefore, that immigration onto farms negated any long‐term effects of baiting operations. This study highlights some of the key deficiencies in current baiting practices in south‐eastern Australia and suggests that pest management programmes should be monitored using such methods to ensure they achieve their goals.

     

Could land‐based early photosynthesizing ecosystems have bioengineered the planet in mid‐Palaeozoic times?

The Ordovician and Silurian periods were times of major geological activity as regards palaeogeography, volcanism and climate change, the last of these evidenced by a series of cooling episodes and glaciations that climaxed in the Hirnantian (Late Ordovician). The presence of cryptospores in the Darriwilian (Middle Ordovician) marked the advent of higher plants on land. A critical survey of direct (mega‐ and microfossils) and some indirect evidence in succeeding rocks indicates the presence of algae, Bacteria, Cyanobacteria, Fungi, probable lichens, cryptophytes and basal tracheophytes. Similar associations of photosynthesizers and decomposers occur today in cryptogamic covers (CCs), for example biological crusts, except that bryophytes replace cryptophytes (basal embryophytes) and tracheophytes are absent. Thus, extant CCs, which make significant contributions today to global carbon and nitrogen fixation and prevention of erosion, provide an excellent analogue for the impacts of early land vegetation on both lithosphere and atmosphere. As a prerequisite to assessing impacts in Ordovician–Silurian times, with particular consideration of parameters used by climate modellers, the effects of a number of abiotic factors on the growth and survival of extant cryptogamic ground covers and their environmental impacts are reviewed. Factors include photosynthetically active radiation, ultraviolet radiation, temperature, water, oxygen, carbon dioxide, nitrogen, phosphorus, iron, surface roughness and albedo. A survey of the nature and extent of weathering facilitated by such vegetation concludes that it was limited based on depth of weathering when compared with that from rooted tracheophytes today, with minor effects on carbon dioxide drawdown. As global net productivity from Ordovician–Silurian CCs was very probably lower than today, and while the small fraction of intractable material in their organic carbon would have resulted in a more rapid turnover of terrestrial biomass, we conclude that there was decreased possibility of long‐term organic carbon burial. Hence, there would have been very limited increase in atmospheric oxygen and decrease in carbon dioxide resulting from carbon burial.     

Pair‐living in the Absence of Obligate Biparental Care in a Lizard: Trading‐off Sex and Food?

A pair‐living social organisation can typically be explained by obligate biparental care. We investigated pair‐living in the absence of biparental care in the Australian sleepy lizard, Tiliqua rugosa, which forms exceptionally strong pair bonds. We fitted 10 lizards, five male–female pairs, with Global Positioning System (GPS) recorders and continuously monitored social associations and separations between active pair partners, based on location records taken every 10 min over 3 mo. Males temporarily separated and reunited the pair more frequently than females, but females also contributed to the maintenance of the pair bond. These behavioural data were consistent with the hypothesis that females successfully coerce males into associations with one female. Lower frequencies of social association between pair partners once mating had finished support this interpretation. Males that are coerced into pair associations appear to experience higher costs of pair‐living than females, because males initiated temporary separations of the pair more frequently than females. Males showed higher movement activity and remained active later each day. This sex bias in activity may be an important mechanism to mitigate the higher costs of pair‐living for males. Costs for males might include within‐pair competition for food as females appear more competitive. Our study provides detailed empirical data on a lizard pair bond and provides important insights into pair‐living in the absence of biparental care.     

Dynamics in Central European near‐natural Abies‐Fagus forests: Does the mosaic‐cycle approach provide an appropriate model?

Question: The mosaic‐cycle concept of forest dynamics dominates in Central Europe. According to this concept intermediate‐scale disturbances only accelerate the forest break‐up under existing cycles of forest development. Is such an approach correct, or should new developmental cycles be elaborated for intermediate‐scale disturbances? Location: Near‐natural Abies alba ‐ Fagus sylvatica forests in the ?wiétokrzyski National Park in Central Poland. In these forests intermediate‐scale disturbances occurred between 1970 and 1990. Methods: Data were collected twice in areas surrounding 212 permanent sample points (in 1994 and 2004). Two increment cores were taken from 259 sample Abies trees. The effect of intermediate‐scale disturbances on radial increment of Abies was assessed. Probabilities of stand transition during a 10‐year period between individual stages and phases of development of the mixed forest were calculated. The development stages and phases were arranged into hypothetical succession series of successive changes. Results: In 1994 70 stands and in 2004, 47 stands representing stages and phases containing the older generation formed by trees > 100–150 years were found. Also, in 1994 142 and in 2004, 165 stands representing stages and phases containing the younger generations only, formed by trees < 100‐150 years, were recorded. Stages and phases containing only younger generations do not occur in the existing forest development cycle which does not consider the influence of intermediate‐scale disturbances separately. Two developmental cycles, which take into account the presence of the older generation and the younger generations only (under conditions of the occurrence of intermediate‐scale disturbances), are proposed. Conclusion: The mosaic‐cycle concept of forest dynamics can be used to analyse the dynamics of Central European near‐natural mixed‐species forests, but new developmental cycles should be elaborated for intermediate‐scale disturbances.     

What is the risk‐benefit ratio of long‐term antipsychotic treatment in people with schizophrenia?

The long‐term benefit‐to‐risk ratio of sustained antipsychotic treatment for schizophrenia has recently been questioned. In this paper, we critically examine the literature on the long‐term efficacy and effectiveness of this treatment. We also review the evidence on the undesired effects, the impact on physical morbidity and mortality, as well as the neurobiological correlates of chronic exposure to antipsychotics. Finally, we summarize factors that affect the risk‐benefit ratio. There is consistent evidence supporting the efficacy of antipsychotics in the short term and mid term following stabilization of acute psychotic symptoms. There is insufficient evidence supporting the notion that this effect changes in the long term. Most, but not all, of the long‐term cohort studies find a decrease in efficacy during chronic treatment with antipsychotics. However, these results are inconclusive, given the extensive risk of bias, including increasing non‐adherence. On the other hand, long‐term studies based on national registries, which have lower risk of bias, find an advantage in terms of effectiveness during sustained antipsychotic treatment. Sustained antipsychotic treatment has been also consistently associated with lower mortality in people with schizophrenia compared to no antipsychotic treatment. Nevertheless, chronic antipsychotic use is associated with metabolic disturbance and tardive dyskinesia. The latter is the clearest undesired clinical consequence of brain functioning as a potential result of chronic antipsychotic exposure, likely from dopaminergic hypersensitivity, without otherwise clear evidence of other irreversible neurobiological changes. Adjunctive psychosocial interventions seem critical for achieving recovery. However, overall, the current literature does not support the safe reduction of antipsychotic dosages by 50% or more in stabilized individuals receiving adjunctive psychosocial interventions. In conclusion, the critical appraisal of the literature indicates that, although chronic antipsychotic use can be associated with undesirable neurologic and metabolic side effects, the evidence supporting its long‐term efficacy and effectiveness, including impact on life expectancy, outweighs the evidence against this practice, overall indicating a favorable benefit‐to‐risk ratio. However, the finding that a minority of individuals diagnosed initially with schizophrenia appear to be relapse free for long periods, despite absence of sustained antipsychotic treatment, calls for further research on patient‐level predictors of positive outcomes in people with an initial psychotic presentation.     

Testing the effect of transient Plio‐Pleistocene barriers in monsoonal Australo‐Papua: did mangrove habitats maintain genetic connectivity in the Black Butcherbird?

Changes in climate and sea level are hypothesized to have promoted the diversification of biota in monsoonal Australia and New Guinea by causing repeated range disjunctions and restricting gene flow between isolated populations. Using a multilocus (one mtDNA locus, five nuclear introns) phylogeographic approach, we test whether populations of the mangrove and rainforest restricted Black Butcherbird (Cracticus quoyi) have diverged across several geographic barriers defined a priori for this region. Phylogeographic structure and estimates of divergence times revealed Plio-Pleistocene divergences and long-term restricted gene flow of populations on either side of four major geographic barriers between and within Australia and New Guinea. Overall, our data are consistent with the hypothesis that mesic-adapted species did not disperse across the open dry woodlands and grasslands that dominated the transient palaeo-landbridges during the Plio-Pleistocene despite the presence of mangrove forests that might have acted as dispersal corridors for mesic-adapted species. Our study offers one of the first multilocus perspectives on the impact of changes in climate and sea level on the population history of widespread species with disjunct ranges in Australia and New Guinea.