Taxonomic Study of Five Parasitic Polypores of the Hymenochaetaceae Family of TIN Vegetation in Western Burkina Faso

The aim of this work is to inventory and study the lignicolous parasitic macrofungi of the Tin plant formation. The mycological outings from July to September 2018 and 2019, collected forty-four (44) basidiomes through a random sampling device over an area of 40,000 m2 including 1000 m long by 40 m2 wide. The standard methods and techniques used in mycology for taxonomic studies were used to describe and classify the carpophores collected in three families: Hymenochaetaceae, Ganodermataceae and Polyporaceae, into eight genera: Onnia (4.55%), Amauroderma (4.55%), Ganoderma (20.45%), Phellinus (52.27%), Inonotus (4.55%), Phellinopsis (6.82%), Grammothele (2.27%) and Trametes (4.55%). The genera Phellinus and Ganoderma were the most abundant. Finally, eight species were identified: Inonotus cf. ochroporus, Inonotus cf. pachyphloeus, Phellinus cf. cryptarum, Phellinus cf. hartigii, Phellinus cf. hippophaecola;Phellinus cf. robustus, Phellinus cf. igniarius, et Amauroderma cf. fasciculatum. Seven fungal species belong to the family Hymenochaetaceae and only the species Amauroderma cf. fasciculatum is a Ganodermataceae. However, all these fungal species are shown to be parasites of trunks and/or branches of the following woody: Parkia biglobosa (50%), Anogeissus leiocarpus (25%), Annona senegalensis (12.5%) and Mangifera indica (12.5%). Authors attest that the presence of phytoparasitic polypores in a plant formation is an indicator of aging hence the urgency to put in place the appropriate measures to safeguard and restore Tin’s plant formation.

Do brood parasitic Common Cuckoos develop brood patches during the breeding season?

Many birds develop brood patches on their ventral apterium under hormonal regulation to effectively transmit body heat to eggs during incubation.The developed patch has several characteristics,including de-feathering,vascularization,and edema.However,little is known about whether avian brood parasites that do not incubate their eggs exhibit brood patch development during the breeding season.In this study,we measured the size of the ventral apterium in 114 Common Cuckoos(Cuculus canorus)captured in the field throughout the breeding season and examined the appearance of the ventral apterium to confirm the development of brood patches.We also examined whether morphological traits and various factors correlated with the size of the ventral apterium(sternal apterium and abdominal apterium)and how it changed during the breeding season.We found no clear signs of brood patch development in Common Cuckoos captured throughout the breeding season,indicating that they likely did not develop brood patches on the ventral apterium during this period.We also found that ventral apterium size was positively correlated with wing length and body weight.In addition,Common Cuckoos with newly growing feathers on the boundary of the ventral apterium with pteryla were frequently observed as seasons progressed to the end.In conclusion,Common Cuckoos exhibit neither brood patch development nor the vestigial characteristics of ancestral brood patches,except for the growth of feathers on boundary the ventral apterium.Further studies examining brood patches across different groups of avian brood parasites are valuable for enhancing our understanding of the developmental and physiological adaptations of avian brood parasites.

Yr5-virulent races of Puccinia striiformis f.sp.tritici possess relative parasitic fitness higher than current main predominant races and potential risk

Wheat stripe rust,caused by Puccinia striiformis f.sp.tritici(Pst),is one of the most destructive fungal diseases of wheat,and seriously threatens safe production of the crop worldwide.In China,new races historically appeared and rapidly developed to be predominant races and have resulted in ineffectiveness and replacement of wheat resistance cultivars as well as massive reduction in yield.In the present study,the relative parasitic fitness of the two newlyemerged Yr5-virulent races(TSA-6 and TSA-9)were compared with those of four currently predominant Chinese races(CYR31,CYR32,CYR33,and CYR34)based on evaluation on 10 Chinese wheat cultivars.As a result,there were significant differences in the relative parasitic fitness parameters among overall tested races based on multiple comparison(LSD)analysis(P<0.05).The principal component analysis(PCA)of overall parasitic fitness parameters indicated that the sporulation ability,infection and spore survivability,expansion capacity,and potential pathogenicity were the most important parasitic fitness attributes of the tested races.Based on the establishment of extracted three principal components and a comprehensive factor score mathematical models,evaluations of the parasitic fitness attributes of tested races showed that the level of relative parasitic fitness of the tested six races was:CYR32(1.15)>TSA-9(0.95)>TSA-6(0.92)>CYR34(0.29)>CYR31(–1.54)>CYR33(–1.77).The results indicated that two Yr5-virulent races TSA-9 and TSA-6 possessed relative parasitic fitness higher than races CYR34,CYR31,and CYR33,but lower than race CYR32,and have potential risks in developing to be predominant races.Therefore,continual monitoring of both Yr5-virulent races,and their variants is needed.The use of wheat cultivars(lines)with Yr5 resistance gene singly in wheat breeding is essential for being avoided,and is suggested to combine with other effective stripe rust resistance genes.

A review of selected parasitic plants in Nigeria:converting harms to benefits

Parasitic plants are challenging to agricultural crops and forestry development,which are sources of major revenues in several countries,including Nigeria.Nevertheless,parasitic plants are important to human society as they have an abundance of bioactive compounds with pharmacological relevance.Thus,it becomes expedient to know the benefits of these plants and potential means of management.This review discusses four selected parasitic plants in Nigeria,namely Viscum album,Striga hermonthica,Tapinanthus bangwensis and Cuscuta campestris.Relevant information about their pharmacological relevance and biocontrol was obtained from credible databases,including the National Library of Medicine,SCOPUS,and Google Scholar.The review showed that all four plants have been extensively studied for their antioxidant and antitumor properties.Also,antimicrobial and anti-inflammatory activities are common pharmacological values among parasitic plants.These are largely due to the presence of abundant beneficial classes of phytocompounds.Furthermore,there is an increasing number of biocontrol studies on the use of microorganisms,such as Phaeobotryosphaeria visci,Sphaeropsis visci,Pandoraea pulminicol,Colletotrichum gloeosporioides,and Fusarium oxysporum in controlling and managing these seemingly disastrous plants.It is hoped that this review will spur further studies into the conservation and proper management of parasitic plants using strategically developed biocontrol.

Harmonics in the Squirrel Cage Induction Motor Analytic Calculation-Part Ⅰ: Differential Leakage, Attenuation, Asynchronous Parasitic Torques

The magnetic field generated in the air gap of the cage asynchronous machine and the harmonics of the magnetomotive forces creating that magnetic field, as well as the related differential leakage, attenuation, asynchronous parasitic torques have been discussed in great detail in the literature, but always separately, for a long time. However, systematization of the phenomenon still awaits. Therefore, it is worth summarizing the completeness of the phenomena in a single study – with a new approach at the same time-in order to reveal the relationships between them. The role of rotor slot number is emphasized much more than before. An existing, commonly used, but still impractical basic figure has been modified to more clearly demonstrate the response of the rotor for the harmonics of the stator. The need to treat differential leakage, asynchronous parasitic torques and attenuation together will be demonstrated: new formula for asynchronous parasitic torque is derived;the long-used characteristic curves for differential leakage and attenuation used separately so far was merged into one, correct curve in order to provide a correct design guide for the engineers.

Cadmium(Cd)exposure through Hyphantria cunea pupae reduces the parasitic fitness of Chouioia cunea:A potential risk to its biocontrol efficiency

Heavy metal contamination has been regarded as an environmental variable that affects the efficiency of pest biological control,but the parasitic fitness of parasitoids under heavy metal stress is poorly understood.Herein,the effect of Cd exposure through the host pupa of Hyphantria cunea on the parasitic fitness of Chouioia cunea was investigated,and the mechanism by which Cd exposure affects the interaction between H.cunea and C.cunea from the perspective of innate immunity in host insect and the oxidative status in the parasitoid offspring was explored.Our results indicated that Cd can be transferred from the H.cunea pupae to the parasitoid offspring,and the transfer coefficient reflected biological amplification.There were no significant differences in the rates of parasitism success and offspring emergence between the untreated and Cd-treated groups.However,after parasitizing Cd-accumulated pupae,the parasitic fitness of offspring wasps(e.g.,the number,individual size and life span)decreased significantly.Under Cd exposure,the cellular and humoral immunity of H.cunea pupae decreased significantly.Compared with the untreated group,the H_(2)O_(2)content of parasitoid offspring in the Cd-treated group was significantly increased.Cd exposure significantly inhibited superoxide dismutase activity in parasitoid offspring,but the contents of ascorbic acid and glutathione were significantly increased by Cd stress.Taken together,these results indicate that Cd exposure reduces the cyclic utilization efficiency of C.cunea on H.cunea pupae.The oxidative status of parasitoid offspring triggered by Cd exposure could be responsible for the reduced parasitic fitness of C.cunea on Cd-accumulated H.cunea pupae.

Harmonics in the Squirrel Cage Induction Motor,Analytic Calculation Part Ⅱ:Synchronous Parasitic Torques,Radial Magnetic Forces

The magnetic field generated in the air gap of the cage asynchronous machine and the harmonics of the magnetomotive forces creating that magnetic field,as well as the synchronous parasitic torques,radial magnetic forces have been discussed in great detail in the literature,but always separately,for a long time.However,systematization of the phenomenon still awaits.Therefore,it is worth summarizing the completeness of the phenomena in a single study–with a new approach at the same time-in order to reveal the relationships between them.The role of rotor slot number is emphasized much more than before.New formulas derived for both synchronous torques and radial magnetic forces are used for further investigation.It will be shown that both phenomena in subject must be treated together.Formulas will be provided to take into account attenuation.Design guide will be provided to avoid dangerous rotor slot numbers.It will be shown that the generation of synchronous torques and radial magnetic forces do not depend–in this new approach-on the slot combination,but on the rotor slot number itself.

Evaluation of Soybean Genotypes (Glycine max L. Merr.) Susceptibility to Parasitic Nematodes in Western Part of Burkina Faso

Parasitic nematodes have been reported as one of the major constraints to soybean production worldwide. The majority of nematodes are so-called “free-living” and feed mainly on bacteria, fungi, protozoa and other nematodes. In Burkina Faso, the presence of parasitic nematodes has been reported in crops such as rice and sorghum. The objective of this study was to identify the genera and species of nematodes associated with soybean production in Burkina Faso. Investigations were carried out on 24 genotypes of a medium-maturity group of soybean at the Farako-Ba research station. Soil samples were taken from the trial soil before its installation. At harvest, soil samples with roots were taken from each genotype in the elementary plots. The composite sample is represented by 4 lots of soil samples with roots. Extractions and counts of nematodes were performed on the different lots. In total, 7 genera of plant-parasitic nematodes associated with soybean were identified. Among these genera, Pratylenchus (100% of infected genotypes), Helicotylenchus (97.28%) and Scutellonema (94.44%) were the most prevalent in terms of frequency and abundance. Some soybean genotypes were less susceptible to the genus Pratylenchus is known to be highly pathogenic in soybean. These were mainly the genotypes TGX2025-10E, TGX2023-3E and TGX2025-14E.

Prevalence and Sensitization and Intestinal Parasitic Infestation of Vernal Keratoconjunctivitis in School Children of Kinshasa

Background: There is no study that estimates the prevalence of vernal keratoconjunctivitis and the association between vernal keratoconjunctivitis and intestinal parasitic infestation in our setting. Purpose: This study aimed to estimate the vernal keratoconjunctivitis prevalence, describe the profile of sensitization and determine the association between vernal keratoconjunctivitis disease and intestinal parasitic infestation in school children of Kinshasa during the scholar year from 2022 to 2023. Methods: An observational, cross-sectional study was performed from September 2022 to June 2023. The children with vernal keratoconjunctivitis were recruited by using the four-stage probability sampling technique. Children attending in the school children of Kinshasa with vernal keratoconjunctivitis were enrolled in the classroom and underwent a clinical examination and skin prick test for 11 allergens and stool examination direct with microscope in the Laboratory. Data were entered in Microsoft Sheets using SPSS version 20.0. The Chi-square test was used to compare the sex, age groups, home environment (grow trees and/or flowers around the yard), dampness in the house, keeping pets (cat and/or dog), number of people per household, number of people sharing a bedroom and intestinal parasitic infestation. The significant level was set to a value of p Results: A total of 28,800 students from four-stage probabilist sampling technique in school of Kinshasa were included, and 2100 students had symptoms according to the vernal keratoconjunctivitis-related symptom questionnaire. Children with vernal keratoconjunctivitis were enrolled and the mean age ± standard was 7.2 ± 3.7 years, with a prevalence of 7.2% and gender was three boys for one girl. All vernal keratoconjunctivitis children recruited in urban and rural part had 33.1% positive skin prick test (SPT) and 67.9% showed polysensitization. Children an urban part was more sensitized than rural respectively with Dermatophagoides pteronyssinus 28.1% vs 28.9%, p = 0.00001, Blomia tropicalis. 15.9% vs 14.9%, p = 0.00001 and cockroach 12% vs 13%, p = 0.00001 in both parts. Vernal keratoconjunctivitis children in rural part were more affected to the intestinal parasite than urban with Ascaris lumbricoides 14% vs 18.3%, p = 0.0006, followed by Ancylostoma duodenale 9.5% vs 12.5%, p = 0.003, Anguillule 7.9% vs 10.1%, p = 0.001, Oxyure 5.7% vs 8.2%, p = 0.0001 and Trichuris trichiura 2.6% vs 3.3%, p = 0.0009. Conclusion: This study outlines that the prevalence of vernal keratoconjunctivitis was 7.2% and 33.1% of children attending for vernal keratoconjunctivitis in school children had a positive skin prick test to at least one allergen, in particular for Dermatophagoides pteronyssinus, Blomia tropicalis and cockroach. The most common intestinal parasitic infestation was Ascaris lumbricoides, Ancylostoma duodenale, Anguillule and Trichuris trichiura.

A novel method to collect sperm from brood parasitic cuckoos:Urodeum stimulation(UroS)method

Sperm competition has been studied in numerous species as a representative example of postcopulatory sexual selection,where sampling sperm from male is the most basic and important step.Sperm collection can be tricky in birds,however,because unlike mammals,the genitals of birds are generally latent in the cloacal region and their characteristics vary among species.Various methods to collect sperm from different birds have been tested,such as cloacal massage,feces collection,and electro-stimulation,but their applicability varies depending on species.In this study,we introduced the urodeum stimulation method(UroS method)to collect sperm from Cuculus cuckoos,such as the Common Cuckoo(C.canorus).These species are expected to have interesting patterns of pair bonding and sperm competition because of their unique breeding strategy called brood parasitism;however,it remains unexplored.In this study,we described the application of our new method to expel semen from male common cuckoos,measured the volume of semen collected,checked the presence of sperm in the semen sample,and finally estimated its success rate among 82 males.Samples were successfully collected from 76 cuckoos(approximately 93%)and the colors and volumes of the samples were very diverse.Sperm was present in 43 of these samples(57%),showing a sperm observation rate approximately twice as high as that of the conventional cloacal massage method.We believe that this novel method will contribute to a better understanding of postcopulatory sexual selection in avian brood parasites and facilitate the process of sperm collection and artificial insemination in other medium-sized birds.

Unveiling the parasitic-reaction-driven surface reconstruction in Ni-rich cathode and the electrochemical role of Li_(2)CO_(3)

Nickel-rich transition-metal oxides are widely regarded as promising cathode materials for high-energydensity lithium-ion batteries for emerging electric vehicles. However, achieving high energy density in Ni-rich cathodes is accompanied by substantial safety and cycle-life obstacles. The major issues of Ni-rich cathodes at high working potentials are originated from the unstable cathode-electrolyte interface, while the underlying mechanism of parasitic reactions towards surface reconstructions of cathode materials is not well understood. In this work, we controlled the Li_(2)CO_(3) impurity content on LiNi_(0.83)Mn_(0.1)Co_(0.07)O_(2) cathodes using air, tank-air, and O_(2) synthesis environments. Home-built high-precision leakage current and on-line electrochemical mass spectroscopy experiments verify that Li_(2)CO_(3) impurity is a significant promoter of parasitic reactions on Ni-rich cathodes. The rate of parasitic reactions is strongly correlated to Li_(2)CO_(3) content and severe performance deterioration of Ni83 cathodes.The post-mortem characterizations via high-resolution transition electron microscope and X-ray photoelectron spectroscopy depth profiles reveal that parasitic reactions promote more Ni reduction and O deficiency and even rock-salt phase transformation at the surface of cathode materials. Our observation suggests that surface reconstructions have a strong affiliation to parasitic reactions that create chemically acidic environment to etch away the lattice oxygen and offer the electrical charge to reduce the valence state of transition metal. Thus, this study advances our understanding on surface reconstructions of Nirich cathodes and prepares us for searching for rational strategies.

Lack of response to conspecific juvenile vocalizations in two avian brood parasites

Juveniles of interspecific avian brood parasites need to locate and recognize conspecifics to continue their life cycle after being reared by individuals of another species.However,little is known about the recognition mechanisms and cues involved in this critical stage of their lives.It has been proposed that adult parasites could show some kind of parental behavior by actively searching and interacting with conspecific young,which in turn could serve the juveniles to learn and/or reinforce the learning of conspecific characteristics.Since acoustic communication is one of the main channels used by birds,if such form of parental behavior by adult avian brood parasites does exist,adult cowbirds should recognize and respond positively to vocalizations of conspecific juveniles.We experimentally tested whether adult shiny Molothrus bonariensis and screaming M.rufoaxillaris cowbirds respond positively towards acoustic signals of conspecific juveniles using two playback experiments,one conducted in semi-captivity and the other in the field.In both cases,we presented 3 types of playbacks to adults of both cowbird species:vocalizations of shiny cowbird juveniles,vocalizations of screaming cowbird juveniles,and white noise as a control.In the experiment in semi-captivity,no significant differences were found between treatments.In the field experiment,no conspecifics approached the playback area,but hosts of the species whose playback was played were attracted to the loudspeaker.In conclusion,our results do not support the predictions we tested from the parental behavior hypothesis and indicate that adult shiny and screaming cowbirds do not respond positively to acoustic signals of conspecific juveniles,at least not to the type of signals used in our experiments.

Parasites of the liver:A global problem?

Parasitic liver diseases can be caused by trematodes,cestodes,nematodes,and protozoa.This pathology is significant because millions of people in different parts of the world have liver parasites,which can manifest themselves in the development of inflammation,liver cysts,cholecystitis,cholelithiasis,pancreatitis and liver cirrhosis that are often threatening their lives.The International Agency for Research on Cancer considers three species of trematodes,Schistosoma haematobium,Opisthorchis viverrini and Clonorchis sinensis,to be carcinogens.Complex modern examination methods,in some cases including extensive screening of large populations,are required for diagnosing liver parasites.Treatment of parasitic liver diseases is differentiated and can involve a combination of surgical and therapeutic measures.There is no doubt that the clinical and epidemiological scale allows one to regard parasitic liver diseases as a global healthcare problem.

Diversity of parasitic cuckoos and their hosts in China

In this exposé we provide the first review of host use by brood parasitic cuckoos in a multiple-cuckoo system in China, based on our own long-term field data and a compilation of observations obtained from the literature. In total, we found that 11 species of cuckoos utilized altogether 55 host species. These hosts belong to 15 families, in which Sylviidae, Turdidae and Timaliidae account for 22.6%, 20.8% and 17.0% of parasitism records, respectively. The Common Cuckoo (Cuculus canorus) had the widest range of host species, accounting for 45.5% of the total number of parasitized species (25 in 10 families) of all parasitism records and is the most frequent brood parasite in the country. Cuckoo species differed in their egg coloration and the extent of egg polymorphism with most of them, e.g. the Common Cuckoo, the Lesser Cuckoo (C. poliocephalus) and the Plaintive Cuckoo (Cacomantis merulinus) laying well mimetic eggs with respect to their hosts based on human being’s visual observations, while others such as the Large Hawk-cuckoo (C. sparverioides), the Himalayan Cuckoo (C. saturatus) and the Asian Emerald Cuckoo (Chrysococcyx maculatus) usually laid non-mimetic eggs. The use of cuckoo hosts and egg color variation in China are compared with those in other parts of their ranges in Asia.

Artificial Breeding Technology of Cuban Fly and Its Parasitic Ability on Chilo infuscatellus

[Objective] The artificial breeding technology of Cuban fly （Lixophaga diatraeae） and its parasitic ability on Chilo infuscatellus was studied.[Method] Through artificial inoculation experiment,the effects of different inoculation proportions between maggot and Galleria mellonella larvae on the growth and development of Cuban fly were studied.Through indoor low temperature storage tests,effects of different temperatures on the emergence rate of Cuban fly were studied;and the effects of different ecological conditions （humidity,sunshine） on the emergence rate of Cuban fly and its parasitic ability on Chilo infuscatellus were studied through indoor and field comparison experiment.[Result] The optimum inoculation proportions between maggot and G.mellonella larvae were 3：1 and 4：1,pupa production amounts were 279 and 327,respectively;short storage under the temperature of 10℃ had small effect on the emergence rate of Cuban fly,while the storage time should not exceed 15 d.Indoor and field parasitic test showed that Cuban fly had strong parasitic ability on C.infuscatellus,the parasitic rate reached 33.3%-50.0%;the parasitic rates during elongation stage and maturation stage were 47.8% and 41.7%,respectively,while they almost could not parasite during seedling stage.[Conclusion] The results provided scientific basis for artificial breeding of Cuban fly in large scale and its field release technology.

Analysis of the Biological Characteristics of a Parasitical Fungus in Chrysosplenium absconditicapsulum J. T. Pan Leaves

[Objective] This study aimed to uncover the biological characteristics of a parasitical fungus in Chrysosp/enium absconditicapsu/um J. T. Pan leaves. [Method] PDA medium was used to isolate the fungus from C. absconditicapsulum leaves; PDA medium, modified KB medium and Czapek medium were adopted to cultivate the isolated strain. [Result] Colonies of the strain were stretched, white, fedora- shaped with smooth and wavy edges, and showed diameter growth on PDA medi- um, modified KB medium and Czapek medium. At the late stage of culture, the colonies turned into cyanish brown on the above media. Spores were black and born on the surface of colonies on PDA medium with blackened medium. While on modified KB medium and Czapek medium, they were born at the edge of colonies with blackened medium. The spores varied in a wide range of shapes, mostly ob- clavate, sometimes spherical or ellipsoidal. The conidia were muriformly septate with transverse or longitudinal or oblique septations. The pseudo-beaks were short and cylindrical. [Conclusion] According to relevant literatures, the isolated strain is a fungus in Alternaria, Dematiaceae, Hylohomycetales, Hyphomycetes, Deuteromycotina.

Investigation of Biological Characteristics of Parasitic Fusarium Fungi from Tibetan Cordyceps sinensis

[Objective] This study aimed to investigate the biological characteristics of parasitic Fusarium fungi from tibetan Cordyceps sinensis. [Method] A Fusarium strain was isolated from fresh tibetan Cordyceps sinensis as the experimental material, to observe the morphologies of Fusarium mycelium and spores. [Result] The isolated Fusarium fungus strain grew lushly on rice medium, with white and villiform myceliurn, and the villous stroma appeared in colors from beige to pink. After cultivated at （18 ± 4） ℃ for 14 d, the Fusarium strain produced milky white protrusions containing pale yellow chlamydospores, which can be divided into microconidiums and macroconidiums based on the different sizes. According to Ainsworth＇s classification system, the isolated strain belongs to Fusarium, Tuberculariales, Hyphomycetes, adelomycete subphylum. Further observation identified three types of macroconidium, and two of them showed distinct morphology, which was not described in Ainsworth＇s classification system. [Conclusion] The structure of the strain isolated from tibetan Cordyceps sinensis is significantly different from that of Fusariurn fungi recorded in relevant literatures, which requires further investigation.

Countermeasures of Goat Parasitic Diseases in Xiangxi Tujia and Miao Autonomous Prefecture

Xiangxi Tujia and Miao Autonomous Prefecture is located in western Hunan province with abundant pastures,suitable for husbandry.However,parasitic diseases become an obstacle for goat industry development.In the research,based on parasite damages,epidemic variety and characters,some prevention measures were proposed,as follows：improving goat raising and management,rotation grazing,reinforcement of disinfection and quarantine,and regular parasite expelling,providing references for goat farming in Xiangxi.

栗疫菌(Endothia parasitica)致病毒素的初步研究

栗疫菌(Endothia parasitica)引起的板栗疫病是森林植物检疫对象之一。病原菌在侵染植物的过程中产生的毒素一向被认为是致病的重要因子。本实验以PD液体培养基为基础,通过震荡和静止两种培养方式,采用浸渍法和针刺法对板栗叶片和小枝进行了生物测定。研究显示板栗小枝和叶片可产生典型的症状,证明栗疫菌能产生具生物活性的毒性物质(毒素),PD培养液适于菌株的生长和毒素的产生。震荡培养比静止条件更利于产毒,浸渍法处理后第二天板栗小枝和叶片都表现典型的病斑和萎蔫症状,针刺法处理后第一天便表现出典型症状,说明针刺法比浸渍法效果更明显、叶片比小枝更敏感。

Why do brood parasitic birds lay strong-shelled eggs?

Brood parasitic birds constitute a model system for the study of coevolution.Such parasites are unique by having evolved unusually thick eggshells for their body size.ick eggshells have been hypothesized to evolve as 1) a means of preventing damage to parasite eggs when the brood parasite lays its egg at a distance from the host clutch(the laying damage hypothesis);2) a consequence of host puncture ejection(the puncture resistance hypothesis);3) a means for the brood parasite to allocate calcium to development of a disproportionately large skeleto-muscular system in evicting parasite chicks(the chick vigour hypothesis);or 4) a means of protecting the cuckoo embryo from microorganisms in the nest of the host(the anti-bacterial protection hypothesis).Here we review the literature studying the evolutionary mechanisms promoting thick eggshells in avian brood parasites,and provide proposals for future studies to test their validity.Available data are insu cient to rigorously test exclusive predictions and assumptions of these not necessarily exclusive hypotheses,although the laying damage and the puncture resistance hypotheses seem to currently be the most well supported alternatives.We discuss how quanti cation of rejection modes(grasp ejection,puncture ejection and desertion) may disclose the validity of the puncture resistance hypothesis,and nally we provide perspectives for future research on testing this speci c hypothesis.