As the sole obligate symbiotic birds in Africa,oxpeckers offer a unique model for studying symbiotic relationships.Due to the multitrophic level they occupy and the context dependent foraging behavior they exhibit,the...As the sole obligate symbiotic birds in Africa,oxpeckers offer a unique model for studying symbiotic relationships.Due to the multitrophic level they occupy and the context dependent foraging behavior they exhibit,the type of symbiotic relationship can be variable.In addition to providing a cleaning service to the host by removing ticks,oxpeckers frequently feed on blood,mucus,and saliva,inflicting potential damage on the host.Here,we used DNA metabarcoding on faecal samples to analyze the taxonomic composition of the trophic interactions of the Yellow-billed Oxpecker(Buphagus africanus)and Red-billed Oxpecker(B.erythrorhynchus)in northeastern Namibia.In contrast to conventional methods,DNA metabarcoding allows for a detailed identification of dietary resources encompassing both mammal hosts and consumed arthropods within the same samples.With this information,we examined differences in the diet composition between oxpecker species and localities,as well as the co-occurrence between host and arthropod species.Our findings revealed that oxpeckers predominantly source their diet from mammals,ticks,and flies;however,ticks and flies rarely co-occur in the diet of an individual.We observed variability among individuals in their feeding ecology,which is strongly correlated with locality and,to a lesser extent,with the mammal host.We noted a high degree of mobility between hosts within relatively short periods,with 32%of the samples showing traces of at least two mammal hosts.This study illustrates the dynamic foraging behavior of these specialized symbiotic birds,shedding light on their potential role in pest control services and disease transmission.展开更多
Marine heatwaves(MHWs)caused by anthropogenic climate change are becoming a key driver of change at the ecosystem level.Thermal conditions experienced by marine organisms across their distribution,particularly towards...Marine heatwaves(MHWs)caused by anthropogenic climate change are becoming a key driver of change at the ecosystem level.Thermal conditions experienced by marine organisms across their distribution,particularly towards the equator,are likely to approach their physiological limits,resulting in extensive mortality and subsequent changes at the population level.Populations at the margins of their species’distribution are thought to be more sensitive to climate-induced environmental pressures than central populations,but our understanding of variability in fitness-related physiological traits in trailing versus leading-edge populations is limited.In a laboratory simulation study,we tested whether two leading(Iceland)and two trailing(Spain)peripheral populations of the intertidal macroalga Corallina officinalis display different levels of maximum potential quantum efficiency(Fv/Fm)resilience to current and future winter MHWs scenarios.Our study revealed that ongoing and future local winter MHWs will not negatively affect leading-edge populations of C.officinalis,which exhibited stable photosynthetic efficiency throughout the study.Trailing edge populations showed a positive though non-significant trend in photosynthetic efficiency throughout winter MHWs exposure.Poleward and equatorward populations did not produce significantly different results,with winter MHWs having no negative affect on Fv/Fm of either population.Additionally,we found no long-term regional or population-level influence of a winter MHWs on this species’photosynthetic efficiency.Thus,we found no statistically significant difference in thermal stress responses between leading and trailing populations.Nonetheless,C.officinalis showed a trend towards higher stress responses in southern than northern populations.Because responses rest on a variety of local population traits,they are difficult to predict based solely on thermal pressures.展开更多
The rates at which birds use energy may have profound effects on fitness, thereby influencing physiology, behavior, ecology and evolution. Comparisons of standardized metabolic rates (e.g., lower and upper limits of ...The rates at which birds use energy may have profound effects on fitness, thereby influencing physiology, behavior, ecology and evolution. Comparisons of standardized metabolic rates (e.g., lower and upper limits of metabolic power output) present a method for elucidating the effects of ecological and evolutionary factors on the interface between physiology and life history in birds. In this paper we review variation in avian metabolic rates [basal metabolic rate (BMR; minimum normothermic metabolic rate), summit metabolic rate (Msum; maximal thermoregulatory metabolic rate), and maximal metabolic rate (MMR; maximal exercise metabolic rate)], the factors associated with this variation, the evidence for functional links between these metabolic traits, and the ecological and evolutionary significance of avian metabolic diversity. Both lower and upper limits to metabolic power production are phenotypically flexible traits, and vary in association with numerous ecological and evolutionary factors. For both inter- and intraspecific comparisons, lower and upper limits to metabolic power production are generally upregulated in response to energetically demanding conditions and downregulated when energetic demands are relaxed, or under conditions of energetic scarcity. Positive correlations have been documented between BMR, Msum and MMR in some, but not all studies on birds, providing partial support for the idea of a functional link between lower and upper limits to metabolic power production, but more intraspecific studies are needed to determine the robustness of this conclusion. Correlations between BMR and field metabolic rate (or daily energy expenditure) in birds are variable, suggesting that the linkage between these traits is subject to behavioral adjustment, and studies of the relationship between field and maximal metabolic rates are lacking. Our understanding of avian metabolic diversity would benefit from future studies of: (1) the functional and mechanistic links between lower and upper limits of metabolic power output; (2) the environmental and ecological cues driving phenotypically flexible metabolic responses, and how responses to such cues might impact population responses to climate change; (3) the shapes of metabolic reaction norms and their association with environmental variability; and (4) the relationship of metabolic variation to fitness, including studies of repeatability and heritability of minimum and maximum metabolic power output [Current Zoology 56 (6): 741-758, 2010].展开更多
The present study was to investigate the copepodid species infecting rosy goatfish Parupeneus rubescens,one of the most economically important fishes in the Arabian Gulf.A copepodid species identified from the examine...The present study was to investigate the copepodid species infecting rosy goatfish Parupeneus rubescens,one of the most economically important fishes in the Arabian Gulf.A copepodid species identified from the examined fish specimens belongs to the Taeniacanthidae family and is labeled as Taeniacanthus yamagutii Shiino,1957,mainly depending on its morphological,morphometric,and ultrastructural characteristics,in particular the presence of maxilliped claw with a conspicuous digitiform process at the base,the terminal process of the second maxilla stout,and a setiform element at the tip of each exopod spine of legs 2-4.In order to ensure the accurate identification and exact taxonomic characterization of this species,the 28S rRNA gene sequence was analyzed.The result revealed that the present copepodid species belong to the Taenicanthidae family and has a close relationship with Taeniacanthus yamagutii(gb|KR048852.1)in the same taxon.The present study demonstrated that the rosy goatfish is a host for Taeniacanthus species,which will be helpful to prevent this parasitic infection.展开更多
Mimosa diplotricha is an invasive perennial, scrambling, thorny, leguminous shrub of neotropical origin widely acknowledged as a major economic, agricultural and ecological burden in its introduced ranges. Although th...Mimosa diplotricha is an invasive perennial, scrambling, thorny, leguminous shrub of neotropical origin widely acknowledged as a major economic, agricultural and ecological burden in its introduced ranges. Although the plant is thought to have been present in Nigeria for well over two decades, its mode and time of introduction is uncertain. In spite of the continuing spread of, and the menace caused by M. diplotricha in Nigeria, no attempt has been made to map the distribution of the plant countrywide. Therefore, we conducted a countrywide survey between 2007 and 2009, sponsored by the Weed Science Society of Nigeria (WSSN) to determine the spread and status of Mimosa diplotricha in Nigeria. A further objective of this paper was to review literatures on Mimosa diplotricha in Nigeria and elsewhere to enable comparison. In this paper, we report on the spread, distribution and problems of Mimosa diplotricha in Nigeria based on the field monitoring surveys conducted. The distribution of this invasive plant in Nigeria has been mapped and is presented together with its ecology and problems being caused. Since the early 1990s, the weed has started to spread and invade many parts of the country causing significant damage to many natural and semi natural ecosystems. The different control options used by farmers to control Mimosa diplotricha in Nigeria are discussed. Based on the successful control of this invasive plant using the biocontrol agent, Heteropsylla spinulosa in countries such as Australia and Papua New Guinea (PNG), we discussed the biological control prospects for the management of Mimosa diplotricha in Nigeria. Such control attempts stands to benefit from international collaborations between Nigerian institutions and a host of others in Australia, PNG and/or Brazil. Finally three major causes for the massive and continuing spread of this weed in Nigeria are presented with recommendations for the Nigerian government and institutions to: 1) formulate policies and legislations regarding the control and management of invasive alien plant species which is currently nonexistent;2) enlighten the general public on the dangers of invasive alien plant species such as Mimosa diplotricha;and 3) initiate actions such as early detection and rapid response (EDRR) and biological control in order to prevent further spread of, and invasion by invasive plant species including Mimosa diplotricha.展开更多
Knowledge of carnivore diets is essential to understand how carnivore populations respond demographically to variations in prey abundance. Analysis of stable isotopes is a useful complement to traditional methods of a...Knowledge of carnivore diets is essential to understand how carnivore populations respond demographically to variations in prey abundance. Analysis of stable isotopes is a useful complement to traditional methods of analyzing carnivore diets. We used data on δ^13C and δ^15N in wolverine tissues to investigate patterns of seasonal and annual diet variation in a wolverine Gulo gulo population in the western Brooks Range, Alaska, USA. The stable isotope ratios in wolverine tissues generally reflected that of terrestrial carnivores, corroborating previous diet studies on wolverines. We also found variation in δ^13C and δ^15N both between muscle samples collected over several years and between tissues with different assimilation rates, even after correcting for isotopic fractionation. This suggests both annual and seasonal diet variation. Our results indicate that data on δ^13C and δ^15N holds promise for qualitative assessments of wolverine diet changes over time. Such temporal variation may be important indicators of ecological responses to environmental perturbations, and we suggest that more refined studies of stable isotopes may be an important tool when studying temporal change in diets of wolverines and similar carnivores [ Current Zoology 55 (3): 188- 192, 2009].展开更多
Exposure to mercury can cause immune, sensory, neurological, motor and behavioral dysfunctions similar to traits associated with autism spectrum disorders (ASDs), and these similarities extend to neuroanatomy, neuro...Exposure to mercury can cause immune, sensory, neurological, motor and behavioral dysfunctions similar to traits associated with autism spectrum disorders (ASDs), and these similarities extend to neuroanatomy, neurotransmitters and biochemistry. It also affects antioxidant system in the cell, resulting in loss of membrane integrity and finally cellular necrosis (Abdel Moneim, 2015).展开更多
Objective In this study, the ameliorative effects of gold nanoparticles (gold NP) on the renal tissue damage in Schistosoma mansoni (S. mansoni)-infected mice was investigated. Methods High-resolution transmission...Objective In this study, the ameliorative effects of gold nanoparticles (gold NP) on the renal tissue damage in Schistosoma mansoni (S. mansoni)-infected mice was investigated. Methods High-resolution transmission electron microscopy was used for the characterization of NP. The gold NP at concentrations of 250, 500, and 1000 μg/kg body weight were inoculated into 5. mansoni-infected mice. Results The parasite caused alterations in the histological architecture. Furthermore, it induced a significant reduction in the renal glutathione levels; however, the levels of nitric oxide and malondialdehyde were significantly elevated. The parasite also managed to downregulate KIM-I, NGAL, MCP-1, and TGF-8 mRNA expression in infected animals. Notably, gold NP treatment in mice reduced the extent of histological impairment and renal oxidative damage. Gold NP were able to regulate gene expression impaired by 5. Mansoni infection. Conclusion The curative effect of gold NP against renal toxicity in 5. mansoni-infected mice is associated with their role as free radical scavengers.展开更多
This study aimed to make an inventory of fruit fly species in Burundi, by use of parapheromones. The trapping by parapheromones is a method used to capture fruit fly species. Four types of parapheromones were used, na...This study aimed to make an inventory of fruit fly species in Burundi, by use of parapheromones. The trapping by parapheromones is a method used to capture fruit fly species. Four types of parapheromones were used, namely, methyl eugenol, cuelure, terpinyl acetate and trimedlure. In total, 70,115 individuals were captured, of which, 68,728 individuals (or 98.02%) were fruit flies, while 1,387 individuals (1.98%) were non-fruit flies. The majority of Tephritidae has been captured by methyl eugenol with 62,538 individuals (90.97%), followed by cuelure with 3,621 individuals (5.27%). Terpinyl acetate and trimedlure have captured 1,900 and 669 individuals, respectively. The effectiveness of parapheromones has varied from one locality to another. In fact, methyl eugenol showed efficiency in the city of Bujumbura, Rumonge, Kigwena and Cibitoke located at an altitude between 780 m and 887 m; cuelure in Bubanza and Kayanza at an altitude between 1,101 m and 2,219 m; trimedlure and terpinyl acetate at Mwaro at an altitude of 1,640 m. From the point of view of abundance of species caught, Bactrocera dorsalis dominates with 62,349 individuals (90.72%), and it is in the Bujumbura city that this species has been captured in abundance.展开更多
Lead (Pb) is one of the most common environmental toxicants, exposure to which can cause significant neurotoxicity and an associated decline in brain function. This study investigated the possible neuroprotective ro...Lead (Pb) is one of the most common environmental toxicants, exposure to which can cause significant neurotoxicity and an associated decline in brain function. This study investigated the possible neuroprotective role oflndigofera oblongifolia leaf methanolic extract (IOLME) against lead-induced neurotoxicity. Rats were intraperitoneally injected with lead acetate, with or without IOLME (intragastric administration for 5 days), and the neuroprotective effect of IOLME was assessed by measuring the lead concentration, redox status (lipid peroxidation, nitric oxide and glutathione), enzymatic antioxidant activities (superoxide dismutase, catalase, glutathione peroxidase and reductase), PCR assays of apoptosis markers (Bax and Bcl-2) and histopathology of the brain. The increases in the lipid peroxidation, nitric oxide, and apoptosis, the decreases in the glutathione level and the activity of antioxidant enzymes, and the altered histology of the brain induced by lead acetate were mitigated in the brain of rats pre-treated with IOLME. These findings indicate that IOLME has beneficial effects and it mitigates lead acetate-induced neurotoxicity via its antiox-idant and anti-apoptotic activities.展开更多
This study assessed the influence of a freshwater pulse on selected physico-chemical and biological variables in a permanently open freshwater deprived southern African estuary. In the absence of the freshwater pulse ...This study assessed the influence of a freshwater pulse on selected physico-chemical and biological variables in a permanently open freshwater deprived southern African estuary. In the absence of the freshwater pulse a reverse gradient in salinity was evident with hypersaline (salinity > 40) conditions prevailing in the upper reaches of the estuary. Total chlorophyll-a (chl-a) concentration during this period ranged from 0.25 to 0.60 μg·l-1. The mean total zooplankton abundance and biomass in the absence of freshwater during the daytime was 666 ind·m-3 (SD ± 196) and 12.4 mg·dwt·m-3 (SD ± 3.3), respectively. During the night time the mean total zooplankton abundance was 3121 ind·m-3 (SD ± 1203) and the biomass 21.8 mg·dwt·m-3 (SD ± 196). The total zooplankton abundance during the dry season was numerically dominated by the copepod nauplii and the calanoid copepod, Pseudodiaptomus hessei, which contributed up to 76% of the total zooplankton counts. The freshwater pulse was associated with the establishment of a horizontal gradient in salinity along the length of the estuary and a significant increase in the total chl-a concentration (range from 0.74 to 11.75 μg·l-1) and zooplankton biomass (range from 23.7 to 76.6 mg·dwt·m-3) (p ally, there was a marked increase in the total zooplankton abundances and biomass within the estuary. A distinct shift in the zooplankton community composition was evident with the copepod, Acartia longipatella numerically dominating the zooplankton counts.展开更多
The polymerase chain reaction combined with direct sequencing was employed to deduce the variety of the grey-rumped pheasant populations in China. Totally 1079 basepair sequences of mitochondrial DNA (mtDNA) control...The polymerase chain reaction combined with direct sequencing was employed to deduce the variety of the grey-rumped pheasant populations in China. Totally 1079 basepair sequences of mitochondrial DNA (mtDNA) control-region gene were analyzed from 121 grey-rumpod pheasants obtained from 13 Chinese lo- calities, 76 variable sites resulted in 91 haplotypes. These populations possessed a high level of genetic diversity, indicating that during their evolution effective population size and polymorphism were not reduced by climatic fluctuations in the Pleistocene ice ages. Phylogenetie analysis indicates that all populations were clustered into two groups, western and eastern. The degree of population differentiation presumably results from a low gene flow ( N, = 0. 33, F,, = 0. 60, P 〈 0. 001 ) between the two groups, and the divergence occurred in the years (2.1 ×10^5 - 2.2 × 105 ). The genetic structure of grey-rumped pheasants in China ap- pears to be the result of the uplift of Qinghai-Tibet Plateau, the existence of Qinling Mountains and Liupan Mountains and cyclical climatic oscillations during the late Pleistocene.展开更多
Morphometric studies of 3D micro CT-scanned images can provide insights into the evolution of the brain and sensory structures but such data are still scarce for the most diverse mammalian order of rodents.From review...Morphometric studies of 3D micro CT-scanned images can provide insights into the evolution of the brain and sensory structures but such data are still scarce for the most diverse mammalian order of rodents.From reviewed and new data,we tested for convergence to extreme aridity and high elevation in the sensory and brain morphology of rodents,from morphometric data from micro-CT X-ray scans of 174 crania of 16 species of three distantly re-lated African murid(soft-furred mice,Praomyini,laminate-toothed rats,Otomyini,and gerbils,Gerbillinae)clades and one North American cricetid(deer mice and white-footed mice,Peromyscus)clade.Recent studies demon-strated convergent evolution acting on the oval window area of the cochlea(enlarged in extremely arid-adapted species of Otomyini and Gerbillinae)and on endocranial volume(reduced in high elevation taxa of Otomyini and Peromyscus).However,contrary to our predictions,we did notfind evidence of convergence in brain struc-ture to aridity,or in the olfactory/respiratory system(turbinate bones)to high elevation.Brain structure differed,particularly in the petrosal lobules of the cerebellum and the olfactory bulbs,between Otomyini and Gerbillinae,with extreme arid-adapted species in each clade being highly divergent(not convergent)from other species in the same clade.We observed greater“packing”of the maxillary turbinate bones,which have important respiratory functions,in Peromyscus mice from high and low elevations compared to the high-elevation African Praomyini,but more complex patterns within Peromyscus,probably related to trade-offs in respiratory physiology and heat exchange in the nasal epithelium associated with high-elevation adaptation.展开更多
Chrysomya megacephala (Fabricius,1794) occurs on every continent and is closely associated with carrion and decaying material in human environments.Its abilities to find dead bodies and carry pathogens give it a promi...Chrysomya megacephala (Fabricius,1794) occurs on every continent and is closely associated with carrion and decaying material in human environments.Its abilities to find dead bodies and carry pathogens give it a prominence in human affairs that may involve prosecution or litigation,and therefore forensic entomologists.The identification,geographical distribution and biology of the species are reviewed to provide a background for approaches that four branches of forensic entomology (urban,stored-product,medico-criminal and environmental) might take to investigations involving this fly.展开更多
Terrestrial and aquatic ecosystems are increasingly threatened by pesticide pollution resulting from extensive use of pes-ticides,and due to the lack of regulatory measures in the developing world,there is a need for ...Terrestrial and aquatic ecosystems are increasingly threatened by pesticide pollution resulting from extensive use of pes-ticides,and due to the lack of regulatory measures in the developing world,there is a need for affordable means to lessen environmental effects.This study aimed to investigate the impact of biochar amendment on the toxicity of imidacloprid to life-cycle parameters and biomarker responses of the earthworm Eisenia fetida.E.fetida was exposed to 10%biochar-amended and non-amended OECD artificial soils spiked with 0,0.75,1.5,2.25 and 3 mg imidacloprid/kg for 28 days.An LC50 of 2.7 mg/kg was only computed in the non-amended soil but not in the biochar-amended soil due to insignificant mortality.The EC50 calculated in the non-amended soil(0.92 mg/kg)for reproduction(fertility)was lower than the one computed in the biochar amended(0.98 mg/kg),indicating a decrease in toxicity in the biochar-amended substrate.Significant weight loss was observed at the two highest imidacloprid treatments in the non-amended soil and only at the highest treatment in the biochar-amended substrate,further highlighting the beneficial effects of biochar.Catalase activity decreased significantly at the two highest concentrations of non-amended soil.Yet,in the amended soil,the activity remained high,especially in the highest concentration,where it was significantly higher than the controls.This indicated more severe oxidative stress in the absence of biochar.In all non-amended treatments,there was a significant acetylcholinesterase inhibition,while lower inhibition percentages were observed in the biochar-amended soil.In most endpoints,the addition of biochar alleviated the toxic effects of imidacloprid,which shows that biochar has the potential to be useful in soil remediation.However,there is still a need for field studies to identify the most effective application rate of biochar for land application.展开更多
Accurate age estimates of immature necrophagous insects associated with a human or animal body can provide evidence of how long the body has been dead.These estimates are based on species-specific details of the inse...Accurate age estimates of immature necrophagous insects associated with a human or animal body can provide evidence of how long the body has been dead.These estimates are based on species-specific details of the insects’aging processes,and therefore require accurate species identification and developmental stage estimation.Many professionals who produce or use identified organisms as forensic evidence have little training in taxonomy or metrology,and appreciate the availability of formalized principles and standards for biological identification.Taxonomic identifications are usually most readily and economically made using categorical and qualitative morphological characters,but it may be necessary to use less convenient and potentially more ambiguous characters that are continuous and quantitative if two candidate species are closely related,or if identifying developmental stages within a species.Characters should be selected by criteria such as taxonomic specificity and metrological repeatability and relative error.We propose such a hierarchical framework,critique various measurements of immature insects,and suggest some standard approaches to determine the reliability of organismal identifications and measurements in estimating postmortem intervals.Relevant criteria for good characters include high repeatability(including low scope for ambiguity or parallax effects),pronounced discreteness,and small relative error in measurements.These same principles apply to individuation of unique objects in general.展开更多
基金partially supported by the Namibia Students Financial Assistance Fund(NSFAF)Kreditanstalt für Wiederaufbau(KfW)-University of Namibia(UNAM,BMZ Ref.2015.67.015)+2 种基金funded by the project TROPIBIO NORTE-01-0145-FEDER-000046supported by Norte Portugal Regional Operational Programme(NORTE2020)developed in the framework of the“Twin Lab CIBIO/UNAM”(UNESCO Chair Life on Land)。
文摘As the sole obligate symbiotic birds in Africa,oxpeckers offer a unique model for studying symbiotic relationships.Due to the multitrophic level they occupy and the context dependent foraging behavior they exhibit,the type of symbiotic relationship can be variable.In addition to providing a cleaning service to the host by removing ticks,oxpeckers frequently feed on blood,mucus,and saliva,inflicting potential damage on the host.Here,we used DNA metabarcoding on faecal samples to analyze the taxonomic composition of the trophic interactions of the Yellow-billed Oxpecker(Buphagus africanus)and Red-billed Oxpecker(B.erythrorhynchus)in northeastern Namibia.In contrast to conventional methods,DNA metabarcoding allows for a detailed identification of dietary resources encompassing both mammal hosts and consumed arthropods within the same samples.With this information,we examined differences in the diet composition between oxpecker species and localities,as well as the co-occurrence between host and arthropod species.Our findings revealed that oxpeckers predominantly source their diet from mammals,ticks,and flies;however,ticks and flies rarely co-occur in the diet of an individual.We observed variability among individuals in their feeding ecology,which is strongly correlated with locality and,to a lesser extent,with the mammal host.We noted a high degree of mobility between hosts within relatively short periods,with 32%of the samples showing traces of at least two mammal hosts.This study illustrates the dynamic foraging behavior of these specialized symbiotic birds,shedding light on their potential role in pest control services and disease transmission.
基金The Fundação para a Ciência e Tecnologia(FCT-MEC,Portugal)under contract No.UIDB/04326/2020 awarded to Gerardo Zardithe South African Research Chairs Initiative(SARChI)of the Department of Science and Technology and the National Research Foundation of South Africa under contract No.64801 awarded to Christopher McQuaid+1 种基金the Fund of European Union’s Horizon 2020 Research and Innovation Programme under the Marie Skłodowska-Curie contract No.101034329the WINNINGNormandy Program supported by the Normandy Region for Gerardo Zardi.
文摘Marine heatwaves(MHWs)caused by anthropogenic climate change are becoming a key driver of change at the ecosystem level.Thermal conditions experienced by marine organisms across their distribution,particularly towards the equator,are likely to approach their physiological limits,resulting in extensive mortality and subsequent changes at the population level.Populations at the margins of their species’distribution are thought to be more sensitive to climate-induced environmental pressures than central populations,but our understanding of variability in fitness-related physiological traits in trailing versus leading-edge populations is limited.In a laboratory simulation study,we tested whether two leading(Iceland)and two trailing(Spain)peripheral populations of the intertidal macroalga Corallina officinalis display different levels of maximum potential quantum efficiency(Fv/Fm)resilience to current and future winter MHWs scenarios.Our study revealed that ongoing and future local winter MHWs will not negatively affect leading-edge populations of C.officinalis,which exhibited stable photosynthetic efficiency throughout the study.Trailing edge populations showed a positive though non-significant trend in photosynthetic efficiency throughout winter MHWs exposure.Poleward and equatorward populations did not produce significantly different results,with winter MHWs having no negative affect on Fv/Fm of either population.Additionally,we found no long-term regional or population-level influence of a winter MHWs on this species’photosynthetic efficiency.Thus,we found no statistically significant difference in thermal stress responses between leading and trailing populations.Nonetheless,C.officinalis showed a trend towards higher stress responses in southern than northern populations.Because responses rest on a variety of local population traits,they are difficult to predict based solely on thermal pressures.
文摘The rates at which birds use energy may have profound effects on fitness, thereby influencing physiology, behavior, ecology and evolution. Comparisons of standardized metabolic rates (e.g., lower and upper limits of metabolic power output) present a method for elucidating the effects of ecological and evolutionary factors on the interface between physiology and life history in birds. In this paper we review variation in avian metabolic rates [basal metabolic rate (BMR; minimum normothermic metabolic rate), summit metabolic rate (Msum; maximal thermoregulatory metabolic rate), and maximal metabolic rate (MMR; maximal exercise metabolic rate)], the factors associated with this variation, the evidence for functional links between these metabolic traits, and the ecological and evolutionary significance of avian metabolic diversity. Both lower and upper limits to metabolic power production are phenotypically flexible traits, and vary in association with numerous ecological and evolutionary factors. For both inter- and intraspecific comparisons, lower and upper limits to metabolic power production are generally upregulated in response to energetically demanding conditions and downregulated when energetic demands are relaxed, or under conditions of energetic scarcity. Positive correlations have been documented between BMR, Msum and MMR in some, but not all studies on birds, providing partial support for the idea of a functional link between lower and upper limits to metabolic power production, but more intraspecific studies are needed to determine the robustness of this conclusion. Correlations between BMR and field metabolic rate (or daily energy expenditure) in birds are variable, suggesting that the linkage between these traits is subject to behavioral adjustment, and studies of the relationship between field and maximal metabolic rates are lacking. Our understanding of avian metabolic diversity would benefit from future studies of: (1) the functional and mechanistic links between lower and upper limits of metabolic power output; (2) the environmental and ecological cues driving phenotypically flexible metabolic responses, and how responses to such cues might impact population responses to climate change; (3) the shapes of metabolic reaction norms and their association with environmental variability; and (4) the relationship of metabolic variation to fitness, including studies of repeatability and heritability of minimum and maximum metabolic power output [Current Zoology 56 (6): 741-758, 2010].
基金This study was supported by Researchers Supporting Project(No.RSP-2020/25),King Saud University,Riyadh,Saudi Arabia.
文摘The present study was to investigate the copepodid species infecting rosy goatfish Parupeneus rubescens,one of the most economically important fishes in the Arabian Gulf.A copepodid species identified from the examined fish specimens belongs to the Taeniacanthidae family and is labeled as Taeniacanthus yamagutii Shiino,1957,mainly depending on its morphological,morphometric,and ultrastructural characteristics,in particular the presence of maxilliped claw with a conspicuous digitiform process at the base,the terminal process of the second maxilla stout,and a setiform element at the tip of each exopod spine of legs 2-4.In order to ensure the accurate identification and exact taxonomic characterization of this species,the 28S rRNA gene sequence was analyzed.The result revealed that the present copepodid species belong to the Taenicanthidae family and has a close relationship with Taeniacanthus yamagutii(gb|KR048852.1)in the same taxon.The present study demonstrated that the rosy goatfish is a host for Taeniacanthus species,which will be helpful to prevent this parasitic infection.
文摘Mimosa diplotricha is an invasive perennial, scrambling, thorny, leguminous shrub of neotropical origin widely acknowledged as a major economic, agricultural and ecological burden in its introduced ranges. Although the plant is thought to have been present in Nigeria for well over two decades, its mode and time of introduction is uncertain. In spite of the continuing spread of, and the menace caused by M. diplotricha in Nigeria, no attempt has been made to map the distribution of the plant countrywide. Therefore, we conducted a countrywide survey between 2007 and 2009, sponsored by the Weed Science Society of Nigeria (WSSN) to determine the spread and status of Mimosa diplotricha in Nigeria. A further objective of this paper was to review literatures on Mimosa diplotricha in Nigeria and elsewhere to enable comparison. In this paper, we report on the spread, distribution and problems of Mimosa diplotricha in Nigeria based on the field monitoring surveys conducted. The distribution of this invasive plant in Nigeria has been mapped and is presented together with its ecology and problems being caused. Since the early 1990s, the weed has started to spread and invade many parts of the country causing significant damage to many natural and semi natural ecosystems. The different control options used by farmers to control Mimosa diplotricha in Nigeria are discussed. Based on the successful control of this invasive plant using the biocontrol agent, Heteropsylla spinulosa in countries such as Australia and Papua New Guinea (PNG), we discussed the biological control prospects for the management of Mimosa diplotricha in Nigeria. Such control attempts stands to benefit from international collaborations between Nigerian institutions and a host of others in Australia, PNG and/or Brazil. Finally three major causes for the massive and continuing spread of this weed in Nigeria are presented with recommendations for the Nigerian government and institutions to: 1) formulate policies and legislations regarding the control and management of invasive alien plant species which is currently nonexistent;2) enlighten the general public on the dangers of invasive alien plant species such as Mimosa diplotricha;and 3) initiate actions such as early detection and rapid response (EDRR) and biological control in order to prevent further spread of, and invasion by invasive plant species including Mimosa diplotricha.
基金support fromthe U.S. National Park Service,the Royal Swedish Academy of Sciences and Siléns FoundationHunters in the Kotzebue area kindly provided us with harvest materialon wolverines,caribou and moose+1 种基金Dan Stevenson and the local staff at the U.S.National Park Service office in Kotzebue for logistical supportto Gene Peltola for help during aninitial stage of the Noatak wolverine project
文摘Knowledge of carnivore diets is essential to understand how carnivore populations respond demographically to variations in prey abundance. Analysis of stable isotopes is a useful complement to traditional methods of analyzing carnivore diets. We used data on δ^13C and δ^15N in wolverine tissues to investigate patterns of seasonal and annual diet variation in a wolverine Gulo gulo population in the western Brooks Range, Alaska, USA. The stable isotope ratios in wolverine tissues generally reflected that of terrestrial carnivores, corroborating previous diet studies on wolverines. We also found variation in δ^13C and δ^15N both between muscle samples collected over several years and between tissues with different assimilation rates, even after correcting for isotopic fractionation. This suggests both annual and seasonal diet variation. Our results indicate that data on δ^13C and δ^15N holds promise for qualitative assessments of wolverine diet changes over time. Such temporal variation may be important indicators of ecological responses to environmental perturbations, and we suggest that more refined studies of stable isotopes may be an important tool when studying temporal change in diets of wolverines and similar carnivores [ Current Zoology 55 (3): 188- 192, 2009].
文摘Exposure to mercury can cause immune, sensory, neurological, motor and behavioral dysfunctions similar to traits associated with autism spectrum disorders (ASDs), and these similarities extend to neuroanatomy, neurotransmitters and biochemistry. It also affects antioxidant system in the cell, resulting in loss of membrane integrity and finally cellular necrosis (Abdel Moneim, 2015).
基金the Deanship of Scientific Research at King Saud University for funding the study through the research group project No.RG-198
文摘Objective In this study, the ameliorative effects of gold nanoparticles (gold NP) on the renal tissue damage in Schistosoma mansoni (S. mansoni)-infected mice was investigated. Methods High-resolution transmission electron microscopy was used for the characterization of NP. The gold NP at concentrations of 250, 500, and 1000 μg/kg body weight were inoculated into 5. mansoni-infected mice. Results The parasite caused alterations in the histological architecture. Furthermore, it induced a significant reduction in the renal glutathione levels; however, the levels of nitric oxide and malondialdehyde were significantly elevated. The parasite also managed to downregulate KIM-I, NGAL, MCP-1, and TGF-8 mRNA expression in infected animals. Notably, gold NP treatment in mice reduced the extent of histological impairment and renal oxidative damage. Gold NP were able to regulate gene expression impaired by 5. Mansoni infection. Conclusion The curative effect of gold NP against renal toxicity in 5. mansoni-infected mice is associated with their role as free radical scavengers.
文摘This study aimed to make an inventory of fruit fly species in Burundi, by use of parapheromones. The trapping by parapheromones is a method used to capture fruit fly species. Four types of parapheromones were used, namely, methyl eugenol, cuelure, terpinyl acetate and trimedlure. In total, 70,115 individuals were captured, of which, 68,728 individuals (or 98.02%) were fruit flies, while 1,387 individuals (1.98%) were non-fruit flies. The majority of Tephritidae has been captured by methyl eugenol with 62,538 individuals (90.97%), followed by cuelure with 3,621 individuals (5.27%). Terpinyl acetate and trimedlure have captured 1,900 and 669 individuals, respectively. The effectiveness of parapheromones has varied from one locality to another. In fact, methyl eugenol showed efficiency in the city of Bujumbura, Rumonge, Kigwena and Cibitoke located at an altitude between 780 m and 887 m; cuelure in Bubanza and Kayanza at an altitude between 1,101 m and 2,219 m; trimedlure and terpinyl acetate at Mwaro at an altitude of 1,640 m. From the point of view of abundance of species caught, Bactrocera dorsalis dominates with 62,349 individuals (90.72%), and it is in the Bujumbura city that this species has been captured in abundance.
基金the Deanship of Scientific Research at King Saud University for funding the work through the research group project,No.PRG-1436-02
文摘Lead (Pb) is one of the most common environmental toxicants, exposure to which can cause significant neurotoxicity and an associated decline in brain function. This study investigated the possible neuroprotective role oflndigofera oblongifolia leaf methanolic extract (IOLME) against lead-induced neurotoxicity. Rats were intraperitoneally injected with lead acetate, with or without IOLME (intragastric administration for 5 days), and the neuroprotective effect of IOLME was assessed by measuring the lead concentration, redox status (lipid peroxidation, nitric oxide and glutathione), enzymatic antioxidant activities (superoxide dismutase, catalase, glutathione peroxidase and reductase), PCR assays of apoptosis markers (Bax and Bcl-2) and histopathology of the brain. The increases in the lipid peroxidation, nitric oxide, and apoptosis, the decreases in the glutathione level and the activity of antioxidant enzymes, and the altered histology of the brain induced by lead acetate were mitigated in the brain of rats pre-treated with IOLME. These findings indicate that IOLME has beneficial effects and it mitigates lead acetate-induced neurotoxicity via its antiox-idant and anti-apoptotic activities.
文摘This study assessed the influence of a freshwater pulse on selected physico-chemical and biological variables in a permanently open freshwater deprived southern African estuary. In the absence of the freshwater pulse a reverse gradient in salinity was evident with hypersaline (salinity > 40) conditions prevailing in the upper reaches of the estuary. Total chlorophyll-a (chl-a) concentration during this period ranged from 0.25 to 0.60 μg·l-1. The mean total zooplankton abundance and biomass in the absence of freshwater during the daytime was 666 ind·m-3 (SD ± 196) and 12.4 mg·dwt·m-3 (SD ± 3.3), respectively. During the night time the mean total zooplankton abundance was 3121 ind·m-3 (SD ± 1203) and the biomass 21.8 mg·dwt·m-3 (SD ± 196). The total zooplankton abundance during the dry season was numerically dominated by the copepod nauplii and the calanoid copepod, Pseudodiaptomus hessei, which contributed up to 76% of the total zooplankton counts. The freshwater pulse was associated with the establishment of a horizontal gradient in salinity along the length of the estuary and a significant increase in the total chl-a concentration (range from 0.74 to 11.75 μg·l-1) and zooplankton biomass (range from 23.7 to 76.6 mg·dwt·m-3) (p ally, there was a marked increase in the total zooplankton abundances and biomass within the estuary. A distinct shift in the zooplankton community composition was evident with the copepod, Acartia longipatella numerically dominating the zooplankton counts.
基金Supported by Natural Science Foundation of Hainan Province(NO:311055)Doctoral Start-up Research Fund of Qiongzhou University(No:QYXB201009)+1 种基金Co-operation Fund between University and Locality of Sanya City(No:2010YD22)Fund for Zoology Major Course of Hainan Province
文摘The polymerase chain reaction combined with direct sequencing was employed to deduce the variety of the grey-rumped pheasant populations in China. Totally 1079 basepair sequences of mitochondrial DNA (mtDNA) control-region gene were analyzed from 121 grey-rumpod pheasants obtained from 13 Chinese lo- calities, 76 variable sites resulted in 91 haplotypes. These populations possessed a high level of genetic diversity, indicating that during their evolution effective population size and polymorphism were not reduced by climatic fluctuations in the Pleistocene ice ages. Phylogenetie analysis indicates that all populations were clustered into two groups, western and eastern. The degree of population differentiation presumably results from a low gene flow ( N, = 0. 33, F,, = 0. 60, P 〈 0. 001 ) between the two groups, and the divergence occurred in the years (2.1 ×10^5 - 2.2 × 105 ). The genetic structure of grey-rumped pheasants in China ap- pears to be the result of the uplift of Qinghai-Tibet Plateau, the existence of Qinling Mountains and Liupan Mountains and cyclical climatic oscillations during the late Pleistocene.
文摘Morphometric studies of 3D micro CT-scanned images can provide insights into the evolution of the brain and sensory structures but such data are still scarce for the most diverse mammalian order of rodents.From reviewed and new data,we tested for convergence to extreme aridity and high elevation in the sensory and brain morphology of rodents,from morphometric data from micro-CT X-ray scans of 174 crania of 16 species of three distantly re-lated African murid(soft-furred mice,Praomyini,laminate-toothed rats,Otomyini,and gerbils,Gerbillinae)clades and one North American cricetid(deer mice and white-footed mice,Peromyscus)clade.Recent studies demon-strated convergent evolution acting on the oval window area of the cochlea(enlarged in extremely arid-adapted species of Otomyini and Gerbillinae)and on endocranial volume(reduced in high elevation taxa of Otomyini and Peromyscus).However,contrary to our predictions,we did notfind evidence of convergence in brain struc-ture to aridity,or in the olfactory/respiratory system(turbinate bones)to high elevation.Brain structure differed,particularly in the petrosal lobules of the cerebellum and the olfactory bulbs,between Otomyini and Gerbillinae,with extreme arid-adapted species in each clade being highly divergent(not convergent)from other species in the same clade.We observed greater“packing”of the maxillary turbinate bones,which have important respiratory functions,in Peromyscus mice from high and low elevations compared to the high-elevation African Praomyini,but more complex patterns within Peromyscus,probably related to trade-offs in respiratory physiology and heat exchange in the nasal epithelium associated with high-elevation adaptation.
文摘Chrysomya megacephala (Fabricius,1794) occurs on every continent and is closely associated with carrion and decaying material in human environments.Its abilities to find dead bodies and carry pathogens give it a prominence in human affairs that may involve prosecution or litigation,and therefore forensic entomologists.The identification,geographical distribution and biology of the species are reviewed to provide a background for approaches that four branches of forensic entomology (urban,stored-product,medico-criminal and environmental) might take to investigations involving this fly.
基金The financial assistance of the National Research Foundation(NRF)of South Africa(grant number SFH160619172260)to Ngitheni Nyoka is hereby acknowledged.Opinions expressed and conclusions arrived at are those of the authors and are not necessary to be attributed to the NRF.
文摘Terrestrial and aquatic ecosystems are increasingly threatened by pesticide pollution resulting from extensive use of pes-ticides,and due to the lack of regulatory measures in the developing world,there is a need for affordable means to lessen environmental effects.This study aimed to investigate the impact of biochar amendment on the toxicity of imidacloprid to life-cycle parameters and biomarker responses of the earthworm Eisenia fetida.E.fetida was exposed to 10%biochar-amended and non-amended OECD artificial soils spiked with 0,0.75,1.5,2.25 and 3 mg imidacloprid/kg for 28 days.An LC50 of 2.7 mg/kg was only computed in the non-amended soil but not in the biochar-amended soil due to insignificant mortality.The EC50 calculated in the non-amended soil(0.92 mg/kg)for reproduction(fertility)was lower than the one computed in the biochar amended(0.98 mg/kg),indicating a decrease in toxicity in the biochar-amended substrate.Significant weight loss was observed at the two highest imidacloprid treatments in the non-amended soil and only at the highest treatment in the biochar-amended substrate,further highlighting the beneficial effects of biochar.Catalase activity decreased significantly at the two highest concentrations of non-amended soil.Yet,in the amended soil,the activity remained high,especially in the highest concentration,where it was significantly higher than the controls.This indicated more severe oxidative stress in the absence of biochar.In all non-amended treatments,there was a significant acetylcholinesterase inhibition,while lower inhibition percentages were observed in the biochar-amended soil.In most endpoints,the addition of biochar alleviated the toxic effects of imidacloprid,which shows that biochar has the potential to be useful in soil remediation.However,there is still a need for field studies to identify the most effective application rate of biochar for land application.
文摘Accurate age estimates of immature necrophagous insects associated with a human or animal body can provide evidence of how long the body has been dead.These estimates are based on species-specific details of the insects’aging processes,and therefore require accurate species identification and developmental stage estimation.Many professionals who produce or use identified organisms as forensic evidence have little training in taxonomy or metrology,and appreciate the availability of formalized principles and standards for biological identification.Taxonomic identifications are usually most readily and economically made using categorical and qualitative morphological characters,but it may be necessary to use less convenient and potentially more ambiguous characters that are continuous and quantitative if two candidate species are closely related,or if identifying developmental stages within a species.Characters should be selected by criteria such as taxonomic specificity and metrological repeatability and relative error.We propose such a hierarchical framework,critique various measurements of immature insects,and suggest some standard approaches to determine the reliability of organismal identifications and measurements in estimating postmortem intervals.Relevant criteria for good characters include high repeatability(including low scope for ambiguity or parallax effects),pronounced discreteness,and small relative error in measurements.These same principles apply to individuation of unique objects in general.