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721.
Foraging behaviour of Scymnus coccivora Ayyar against cotton mealybug Phenacoccus solenopsis Tinsley
Sweetee Kumari Sachin S. Suroshe Dinesh Kumar Neeraj Budhlakoti Venkanna Yana 《Saudi Journal of Biological Sciences》2021,28(7):3799-3805
Predation is one of the significant biotic mortality factors reducing the insect pest population as functional response and the numerical response of the predator are the key factor regulating the population dynamics of predator prey species. This study is aimed to evaluate the functional response of all the developmental stages of Scymnus coccivora Ayyar (Coleoptera: Coccinellidae) against the different densities of cotton mealybug, Phenacoccus solenopsis (Tinsley) (Hemiptera: Pseudococcidae) and the numerical response of female predator. Experiments were carried out in controlled environment laboratory conditions at 25 ± 1 °C temperature, 60 ± 5% relative humidity and photoperiod of 16 h. Number of eggs consumed, number of eggs laid and the Efficiency of Conversion of Ingested food (ECI) were recorded daily. Results from the study revealed that all the developmental stages of S. coccivora exhibited a Type II response. Different parameters such as attack rate (a’), handling time (Th) and the maximum rate of predation were estimated using Roger’s random attack equation and Holling Disc equation in which Rogers random attack equation was found best fit. Female has shown the highest attack rate (a’) followed by IVth instar grub, male, IIIrd, IInd and Ist instar grub. With low handling time, IVth instar grub has shown maximum predation rate of 76.40 per day followed by female (75.86), male (58.79), IIIrd (22.84), IInd (19.65) and Ist instar grub (15.39). The numerical response increase was curvilinearly related to different prey densities with the highest number of eggs (11.8 ± 3.44) produced at highest prey density (160). The Efficiency of Conversion of Ingested food (ECI) was highest (64.49 ± 8.03) at prey density of 10. Understanding the factors that lead to variation in functional response of predator in natural population will advance our understanding of the effects of predation on individual and the effectiveness of coccinellid predators as biocontrol agent against cotton mealybug. 相似文献
722.
N. J. D. Nagelkerke J. Oosting A. A. M. Hart 《Biometrical journal. Biometrische Zeitschrift》1986,28(4):491-494
A comparison is made between two approaches to testing goodness of fit of Cox's regression model for survival data. The first approach is based on the inclusion of time dependent covariates, whereas the second one is based on the autocovariance of successive contributions to the derivative of the loglikelihood. It appears that the second test is most appropriate for testing in situations where the structure of the departure from proportional hazards is not known a priori. An approximate expression for the relative efficiency of the two test procedures is presented. 相似文献
723.
Spring wheat (Triticum aestivum) is a staple food providing sources of essential proteins for human. In fact, gene expressions of wheat play an important role in growth and productivity that are affected by drought stress. The objective of this work focused on analysis gene feature on spring wheat represented by nucleotide and gene expressions under drought stress. It was found that the higher codon adaptation index was in both wheat root and L-galactono-1, 4-lactone dehydrogenase. It was also found that guanine and cytosine content were high (55.56%) in wheat root. Whereas, guanine and cytosine content were low (41.28%) in L-galactono-1, 4-lactone dehydrogenase. Moreover, the higher relative synonymous codon usage value was observed in codon CAA (1.20), GAA (1.33), GAT (1.00), and ATG (1.00) in wheat root and thus about 62.95% of the total variation in relative synonymous codon was explained by principal component analysis. Additionally, high averages frequency number of codon were (above 15.76) in Met, Lys, Ala, Gly, Phe, Asp, Glu, His, and Tyr; whereas, low averages were in remaining amino acids and majority (90%) of modified relative codon bias values was between 0.40 and 0.90. Shortly, calculations and analysis of codon usage pattern under drought stress would help for genetic engineering, molecular evolution, and gene prediction in wheat studies for developing varieties that associate with drought tolerance. 相似文献
724.
725.
Keizi Kiritani 《Population Ecology》1970,12(1):19-34
Polymorphism in adult colour pattern of Nezara viridula is determined on the genetic basis. The basic colour patterns of adult are classified into four types, i. e. G, O, R and F. No appreciable differences between these types were observed in respect to various physiological traits of nymphs and adults, except that type G seems to be superior in reproductive ability but to be inferior in ability of surviving winters at least to types R and F. Inter-generation changes in percentage frequency of G type were examined from 1959 to 1967 covering more than 30 generations. Percentage frequencies of G types prior to the severe winter of 1962–3 fluctuated greatly around a mean of 87.9%, while they did to a lesser extent than before with a mean of 85.0% after the winter. Unexpected high percentages of G type were recorded frequently in summer generations, viz. 1st and 2nd. On the other hand, the relative frequencies of G and O types decreased after hibernation in contrast to the increases in those of F and R. This sort of changes in genetic composition related to the winter of 1962–3 was observed in several populations segregated from each other. This seasonal alternation of selective activity in the environments is considered to be responsible for retention of the polymorphism. Alternative possible causes, i. e. difference in habitat preference, non-random mating and selective predation by predators among polymorphs, may safely be rejected as irrelevant to the mechanism in maintaining polymorphism. The polymorphism of this insect seems to be in a transient state rather than balanced one contributing little to population regulation, but the persistence of N. viridula in the periphery range may be assisted by retention of the polymorphism. 相似文献
726.
727.
Synopsis Sampling in six estuaries of the east coast of James and Hudson Bays between 1973 and 1977 has revealed latitudinal differences
in the composition of fish communities. Arctic and subarctic marine species are more prominent in estuaries of Hudson Bay.
Fewer species are found northwards with 35 species in lower rivers and estuaries of James Bay and only 24 in those of Hudson
Bay, for a total of 38 species. Climate, postglacial dispersion and restricted space are proposed as causes of the observed
distribution of fishes.
Send reprint request to this address 相似文献
728.
Relative expression ratios are commonly estimated in real-time qPCR studies by comparing the quantification cycle for the target gene with that for a reference gene in the treatment samples, normalized to the same quantities determined for a control sample. For the “standard curve” design, where data are obtained for all four of these at several dilutions, nonlinear least squares can be used to assess the amplification efficiencies (AE) and the adjusted ΔΔCq and its uncertainty, with automatic inclusion of the effect of uncertainty in the AEs. An algorithm is illustrated for the KaleidaGraph program. 相似文献
729.
《Journal of enzyme inhibition and medicinal chemistry》2013,28(5):461-469
AbstractHuman poly(ADP-ribose)polymerase (PARP) was expressed in the yeast line JELl under the control of a GAL promoter. Proteins were extracted and human recombinant PARP purified to apparent homogeneity. The pharmacological profile of this human enzyme was characterised in terms of the effects of known inhibitors of PARP belonging to various chemical families and this was compared with that of the rat enzyme purified from rat testes. using the same purification protocol. The rat and the human enzymes appeared very similar in terms of their sensitivities to those selected inhibitors. 相似文献
730.