The mating system of Dryobalanops aromatica in three different forest types and a seed orchard was quantified by allozyme analysis of progeny arrays using a mixed-mating model. The primary forest (Bukit Sai) had the highest multilocus outcrossing rate (tm=0.923 +/- 0.035), followed by logged forest (Lesong; tm=0.766 +/- 0.056) and artificial forest (FRIM; tm=0.661 +/- 0.066) with seed orchard showing the lowest (Tampin; tm=0.551 +/- 0.095). Deviations from the mixed mating model were evident from differences in pollen and ovule allele frequencies, and heterogeneity of pollen pools in all three different forest types and the seed orchard. A high rate of outcrossing in primary forest (tm=0.92) may indicate that the species is self-incompatible, but a lower value in the seed orchard (tm=0.55) might suggest further that the self-incompatibility system is weak. The outcrossing rate was greater in the primary forest (tm=0.92) than in logged forest (tm=0.77). It is argued that this might be a consequence of the lower density of flowering trees and alteration of pollinator foraging behaviour in logged forest. Higher values of correlated mating (rp) and biparental mating (tm - ts) in primary forest (0.08 and 0.39, respectively) in comparison with logged forest (0.03 and 0.11, respectively) demonstrate that logging activities might reduce the seeds produced through consanguineous mating. Compared with primary forest, it is argued that lower rates of outcrossing in artificial forest (tm=0.67) and seed orchard (tm=0. 55) might be attributed to lack of flowering synchrony and insufficient number of pollinators. The high level of correlated mating (rp=0.43) and biparental mating (tm - ts=0.12) in the seed orchard may further suggest that the seed orchard was established using related seed sources.
Five mark-release-recapture experiments with wild caught Ma. uniformis were conducted in an open swamp area at Batang Berjuntai in Selangor, 40 km from Kuala Lumpur, Malaysia, between May 1983 and January 1985. A total of 64 (0.14%) from the 45,950 females released were recaptured feeding on humans and cattle and resting in cattle-sheds. Substantially fewer (0.03% to 0.09%) females were recaptured from releases of blood-fed females than from releases of unfed females (0.20% to 0.23%). More than 70% of all recaptures were taken within a radius of 1.5 km around the point of release and the longest detected flight was 3.5 km. The mean dispersal distance for blood-fed and unfed females was 1.445 +/- 1.06 and 1.706 +/- 1.03 km, respectively. However, there was no significant difference in the overall mean dispersal of the two groups of females (p greater than 0.05). The duration of the gonotrophic cycle in the field was between 3 to 4 days. Daily survivorship estimates (0.783-0.867) based on the recapture rates of date specific marked females was comparable to that estimated vertically from the dissection of unmarked females (0.751-0.795). These experiments revealed the remarkable flying ability of Ma. uniformis and the importance of reinvasion must be recognized when control operations are restricted to small areas.
The mosquito, Aedes albopictus, has recently become established in a number of cities throughout the United States. An initial survey of allozyme and genotypic frequencies in U.S. populations (Black et al., 1988) revealed an extensive amount of local differentiation of populations and suggested that much genetic drift may have accompanied colonization. A study of gene flow was initiated in native habitats of Ae. albopictus in Malaysia to determine if the result observed in the U.S. was a consequence of colonization or simply followed the natural breeding structure of the species. Allelic and genotypic frequencies were monitored at ten enzymatic loci in 11 populations from peninsular Malaysia and Borneo. Multiple populations were sampled within the districts of Kuala Lumpur and Kuala Trengganu. Peninsular Malaysian and Borneo populations were strongly genetically differentiated. Allele frequencies were significantly different among and within districts in both regions. Variance in allele frequencies among all collections was partitioned into the variance among regions, districts within regions and collections within districts. Almost all of the variance within regions was attributable to local differentiation suggesting that genetic drift is an important component of the natural breeding structure of this species. This indicates that the large amounts of local differentiation found in U.S. populations was not a consequence of recent colonization.
Malacca Strait (MS) has an important role and potential for many countries. It is a major transportation route for oil and commodities across continents. In addition, various activities such as shipping, fishing, aquaculture, oil drilling, and energy are also carried out in MS. Tides strongly affect the MS environment so that it becomes a major parameter in MS management. This paper is the first study, which presents MS tidal hydrodynamics based on a baroclinic and nonhydrostatic approach. Tidal hydrodynamics in MS and the surrounding waters were assessed using tidal forces, temperature, salinity, and density. This study analyzes the amplitude, phase, current ellipses, and semi-major axis of the tides. These variables are obtained from the simulation results of the three-dimensional numerical models of M2 tides and combined tides (M2, S2, N2, K1, and O1) with nonhydrostatic models. Then the results obtained are verified by observation data. Amplitude and phase of the tidal wave in MS originate from two directions, namely the northern part of MS (Andaman Sea) and the South China Sea (SCS). Tides from the north of MS propagate into the MS, while tides from the SCS travel to Singapore Waters (SW) and the south of MS. This causes a complex residual flow in SW and shoaling in the middle of MS. Shoaling in the middle of MS is characterized by a large amplitude and semi-major, as in B. Siapiapi. The results of this analysis show that tidal waves are dominated by semidiurnal types rather than diurnal types. The M2 current ellipse has dominantly anticlockwise rotation along the west of the MS, while along the east of MS, it has generally a clockwise rotation.
The evolutionary history and classification of epiphyllous cryptogams are still poorly known. Leptolejeunea is a largely epiphyllous pantropical liverwort genus with about 25 species characterized by deeply bilobed underleaves, elliptic to narrowly obovate leaf lobes, the presence of ocelli, and vegetative reproduction by cladia. Sequences of three chloroplast regions (rbcL, trnL-F, psbA) and the nuclear ribosomal ITS region were obtained for 66 accessions of Leptolejeunea and six outgroup species to explore the phylogeny, divergence times, and ancestral areas of this genus. The phylogeny was estimated using maximum-likelihood and Bayesian inference approaches, and divergence times were estimated with a Bayesian relaxed clock method. Leptolejeunea likely originated in Asia or the Neotropics within a time interval from the Early Eocene to the Late Cretaceous (67.9 Ma, 95% highest posterior density [HPD]: 47.9-93.7). Diversification of the crown group initiated in the Eocene or early Oligocene (38.4 Ma, 95% HPD: 27.2-52.6). Most species clades were established in the Miocene. Leptolejeunea epiphylla and L. schiffneri originated in Asia and colonized African islands during the Plio-Pleistocene. Accessions of supposedly pantropical species are placed in different main clades. Several monophyletic morphospecies exhibit considerable sequence variation related to a geographical pattern. The clear geographic structure of the Leptolejeunea crown group points to evolutionary processes including rare long-distance dispersal and subsequent speciation. Leptolejeunea may have benefitted from the large-scale distribution of humid tropical angiosperm forests in the Eocene.
The life table developmental attributes of laboratory colonies of wild strains of Aedes albopictus and Aedes aegypti were analyzed and compared based on the age-stage, two-sex life table. Findings inclusive in this study are: adult preoviposition periods, total preoviposition period, mean intrinsic rate of increase (r), mean finite rate of increase (λ), net reproductive rates (R0), and mean generation time (T). The total preadult development time was 9.47 days for Ae. albopictus and 8.76 days for Ae. aegypti. The life expectancy was 19.01 days for Ae. albopictus and 19.94 days for Ae. aegypti. Mortality occurred mostly during the adult stage. The mean development time for each stage insignificantly correlated with temperature for Ae. albopictus (r = -0.208, P > 0.05) and (r = -0.312, P > 0.05) for Ae. aegypti. The population parameters suggest that Ae. albopictus and Ae. aegypti populations are r-strategists characterized by a high r, a large R0, and short T. This present study provides the first report to compare the life parameters of Ae. albopictus and Ae. aegypti strains from Penang island, Malaysia.
Introduction: Aedes albopictus is known for its aggressiveness towards human and recently expanded to more coun- tries outside the native regions. Thus, the demographic parameters of Aedes albopictus are important to determine the characteristics of this species mosquitoes in terms of the reproduction rates and dispersal distance. Materials and Methods: This study, was performed using a Shah Alam strain of Aedes albopictus originally collected in twenty district areas of the central zone of Shah Alam. This research applies field work-study with a cross-sectional design to investigate the demographic parameters of Aedes albopictus. The demographic evaluation of Aedes albopictus was conducted under the control environment in insectarium. Results: Investigation on the demographic parameters of Aedes albopictus clearly showed that there is a significance different observed in the total number of mosquito eggs produced in both high and low incidence rate IR areas (p=0.03). In contrast, other parameters showed insignificant value between high and low IR areas. Conclusion: The key to control the mosquito vectors population is by tracking the vector’s life cycle including its survival. Therefore, the outcome of this study may provide as a baseline to esti- mate the dengue outbreak in the current episystem.
COVID-19 is an emerging and rapidly evolving pandemic around the world, which causes severe acute respiratory syndrome and results in substantial morbidity and mortality. To examine the transmission dynamics of COVID-19, we investigate the spread of this pandemic using Malaysia as a case study and scrutinise its interactions with some exogenous factors such as limited medical resources and false detection problems. To do this, we employ a simple epidemiological model and analyse this system using modelling and dynamical systems techniques. We discover some contrasting findings with respect to the observations of basic reproduction number: while it is observed that R0 seems to provide a good description of transmission dynamics in simple outbreak scenarios, this quantity might mislead the assessment on the severity of pandemic when certain complexities such as limited medical resources and false detection problems are incorporated into the model. In particular, we observe the possibility of a COVID-19 outbreak through bistable behaviour, even when the basic reproduction number is less than unity. Based on these findings, we caution policy makers not to make their decisions solely based on the guidance of the basic reproduction number only, which clearly could cause trouble.
This article presents the assessment of time-dependent national-level restrictions and control actions and their effects in fighting the COVID-19 pandemic. By analysing the transmission dynamics during the first wave of COVID-19 in the country, the effectiveness of the various levels of control actions taken to flatten the curve can be better quantified and understood. This in turn can help the relevant authorities to better plan for and control the subsequent waves of the pandemic. To achieve this, a deterministic population model for the pandemic is firstly developed to take into consideration the time-dependent characteristics of the model parameters, especially on the ever-evolving value of the reproduction number, which is one of the critical measures used to describe the transmission dynamics of this pandemic. The reproduction number alongside other key parameters of the model can then be estimated by fitting the model to real-world data using numerical optimisation techniques or by inducing ad-hoc control actions as recorded in the news platforms. In this article, the model is verified using a case study based on the data from the first wave of COVID-19 in the Republic of Kazakhstan. The model is fitted to provide estimates for two settings in simulations; time-invariant and time-varying (with bounded constraints) parameters. Finally, some forecasts are made using four scenarios with time-dependent control measures so as to determine which would reflect on the actual situations better.
Survival and fertility characteristics of the brown planthopper (BPH), Nilaparvata lugens were assessed in the laboratory and field. Life tables and population parameters of the BPH were constructed in an environment with unlimited food supply and that was free of natural enemies. The highest mortality occurred in the immature stage, especially in the first and second instars. The life table analysis showed that the population density of BPH decreased gradually. The survival ratio of male to female was 0.512:0.488. The females lived for a maximum of 20 days. The trend of oviposition showed a peak at around the tenth day of the female life. The highest number of eggs produced per female per day was 9.63. The intrinsic rate of increase (rm) in egg production per female per day was 0.0677 and the daily finite of increase (λ) was 1.0688 females per female per day, with a mean generation time (T) of 34.05 days. The net reproductive rate (Ro) of the population was 10.02. The population doubling time (DT) was 10.42 days.
Mating studies were conducted on 78 isolates of Fusarium species section Liseola from rice, sugarcane and maize. From the crosses with tester strains of Gibberella fujikuroi species complex, 64.1% (50 out of 78 isolates) were cross-fertile with tester strains of mating populations A to E. The results of the mating studies showed that of the 50 isolates, 19 belonged to mating population A (Gibberella moniliformis), 18 to mating population B (Gibberella sacchari), 4 to mating population E (Gibberella subglutinans), 6 to mating population D (Gibberella intermedia) and 3 to mating population C (G. fujikuroi). Identification of several mating populations from rice, sugarcane and maize could be important biological entities under field conditions.
Helopeltis antonii is the major pest affecting cashew plants in Indonesia and causes potential damage to the plant. The development of the population was influenced by the fecundity and fertility of their eggs. The effect of mating on the eggs’ fecundity and the fertility of H. antonii was studied. Laboratory studies at Wonogiri Estate Service in Ngadirojo District, Wonogiri, Indonesia investigated the sexual maturity, the influence of female to male sex ratio on the females’ fecundity and longevity, and the influence of mating frequency to fecundity and the eggs hatchability of H. antonii. The study reveals that H. antonii females and males are ready to mate when they are two days old. The number of eggs laid and the longevity of the females’ lives were not significantly affected by the sex ratio; however, female to male sex ratios of 2:1 and 1:2 tended to produce a greater number of eggs. The fecundity of the female was not significantly influenced by the number of times the female mated. Unmated females laid fewer eggs than females paired with a mature male. The study shows that females need to mate to produce fertile eggs.
Mating studies were conducted on 78 isolates of Fusarium species section Liseola from rice, sugarcane and maize. From the crosses with tester strains of Gibberella fujikuroi species complex, 64.1% (50 out of 78 isolates) were cross-fertile with tester strains of mating populations A to E. The results of the mating studies showed that of the 50 isolates, 19 belonged to mating population A (Gibberella moniliformis), 18 to mating population B (Gibberella sacchari), 4 to mating population E (Gibberella subglutinans), 6 to mating population D (Gibberella intermedia) and 3 to mating population C (G. fujikuroi). Identification of several mating populations from rice,sugarcane and maize could be important biological entities under field conditions.
Serotypes B: 2 and E: 2 of Haemorrhagic septicaemia found in Asia and Africa cause an economically important disease that affects cattle and buffaloes. The disease has a feature of short clinical course and high morbidity and mortality rates. However, animals surviving HS are usually characterized by decrease productivity. There is paucity of knowledge in the involvement of the reproductive system and its organizer hormones in animals afflicted with HS. Therefore, this review aimed to gather information and provide more details on reproductive pathophysiology and its modifications in buffaloes and cattle as a result of P. multocida B: 2 infections.
Shoot and inflorescence are central physiological and developmental tissues of plants. Flowering is one of the most important agronomic traits for improvement of crop yield. To analyze the vegetative to reproductive tissue transition in Jatropha curcas, gene expression profiles were generated from shoot and inflorescence tissues. RNA isolated from both tissues was sequenced using the Ilumina HiSeq 2500 platform. Differential gene expression analysis identified key biological processes associated with vegetative to reproductive tissue transition. The present data for J. curcas may inform the design of breeding strategies particularly with respect to reproductive tissue transition. The raw data of this study has been deposited in the NCBI's Sequence Read Archive (SRA) database with the accession number SRP090662.
The overall reproductive process consists of both the human sex organs which include the male and female reproductive system. The ability to produce offsprings that have similar characteristic as their parents is the goal of reproduction. The sexual type of reproduction takes place in human and both male and female reproductive system is required. Male reproductive system is mainly concerned with production of semen (whitish viscous fluid emitted from the male reproductive tract that contains sperm and fluids) and transferring it into the female reproductive tract. In this review, we will discuss the latest findings in the research pertaining the male reproductive system and its contribution towards the research in advancement of reproductive physiology.
Torch ginger (Etlingera elatior) is a herbaceous clumping plant. It is a multifunctional crop that has been used for culinary, medicinal, antibacterial agent, ornamental and floral arrangement purpose. However, from the literature, no work has been carried out to study its growth and development morphological characteristics. It is important to understand the developmental morphology of the torch ginger plant for research purpose, commercial usage and apply proper production practices by growers for higher yields and profits. Therefore, the aim of this study was to determine the time course of morphological changes during the growth and development of torch ginger. Results showed that it took 155 days from leafy shoot emerging from rhizome until senescence of inflorescence. The growth and development of torch ginger plant were divided into vegetative and reproductive phases. The vegetative phase mainly involved the growth activities of leafy shoot. The transition of vegetative to reproductive phase happened when the inflorescence shoot emerged from the rhizome. In the reproductive phase, the growth and development of the inflorescence were categorized into four phenological stages which were peduncle elongation, inflorescence emergence, flowering and senescence. The growth pattern of the leafy shoot and inflorescence demonstrated a monocarpic plant growth habit with the remobilization of photoassimilates from senescing plant parts to developing true flowers that caused whole-plant senescence. Further research is needed to study the mechanisms that regulate flowering and senescence in torch ginger plant.
AISYAH ABU BAKARRed palm weevil (RPW), Rhynchophorus ferrugineus has been reported as a serious pest of coconut, sago palm and date palm in many parts of the world. In Malaysia, RPW is a lethal pest of coconut in Terengganu and sago palm in Sarawak. However, very limited information about the reproductive performance of RPW is available, specifically in Malaysia. In the present study, the reproductive performance of RPW reared on sago palm (Metroxylon sagu) were studied using nine pairs of virgin RPW under laboratory conditions. The number of eggs laid and eggs viability were recorded daily until females could not produce eggs. The total number of eggs laid were 3081 and the average number of eggs deposited by a female was 342.3+0.97 eggs (ranged from 270 to 396). The percentage of hatchability was 52.4% and out of the total 1614 hatched eggs, only 118 individuals (7.3%) were survived until late instar. However, no significant differences in fecundity, hatchability and total survived larvae in different RPW pairs were observed. Females longevity was found to be strongly influenced by the number of eggs laid; the higher number of eggs laid, the shorter is the life span of the female. This study is important to understand the biological aspects of RPW, as a first step to develop effective control strategy of the pest.
Sound and its reception are crucial for reproduction, survival, and population maintenance of many animals. In insects, low-frequency vibrations facilitate sexual interactions, whereas noise disrupts the perception of signals from conspecifics and hosts. Despite evidence that mosquitoes respond to sound frequencies beyond fundamental ranges, including songs, and that males and females need to struggle to harmonize their flight tones, the behavioral impacts of music as control targets remain unexplored. In this study, we examined the effects of electronic music (Scary Monsters and Nice Sprites by Skrillex) on foraging, host attack, and sexual activities of the dengue vector Aedes aegypti. Adults were presented with two sound environments (music-off or music-on). Discrepancies in visitation, blood feeding, and copulation patterns were compared between environments with and without music. Ae. aegypti females maintained in the music-off environment initiated host visits earlier than those in the music-on environment. They visited the host significantly less often in the music-on than the music-off condition. Females exposed to music attacked hosts much later than their non-exposed peers. The occurrence of blood feeding activity was lower when music was being played. Adults exposed to music copulated far less often than their counterparts kept in an environment where there was no music. In addition to providing insight into the auditory sensitivity of Ae. aegypti to sound, our results indicated the vulnerability of its key vectorial capacity traits to electronic music. The observation that such music can delay host attack, reduce blood feeding, and disrupt mating provides new avenues for the development of music-based personal protective and control measures against Aedes-borne diseases.
The influence of local conditions and remote climate modes on the interannual variability of oil palm fresh fruit bunches (FFB) total yields in Malaysia and two major regions (Peninsular Malaysia and Sabah/Sarawak) is explored. On a country scale, the state of sea-surface temperatures (SST) in the tropical Pacific Ocean during the previous boreal winter is found to influence the regional climate. When El Niño occurs in the Pacific Ocean, rainfall in Malaysia reduces but air temperature increases, generating a high level of water stress for palm trees. As a result, the yearly production of FFB becomes lower than that of a normal year since the water stress during the boreal spring has an important impact on the total annual yields of FFB. Conversely, La Niña sets favorable conditions for palm trees to produce more FFB by reducing chances of water stress risk. The region of the Leeuwin current also seems to play a secondary role through the Ningaloo Niño/ Niña in the interannual variability of FFB yields. Based on these findings, a linear model is constructed and its ability to reproduce the interannual signal is assessed. This model has shown some skills in predicting the total FFB yield.