Length Of Developmental Period Research Articles

Estimating the Susceptibility of Four Wheat Cultivars to the Saw-Toothed Grain Beetle Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae).

The quality and quantity of wheat are severely affected by insect infestation during storage. Excessive use of chemical pesticides has resulted in several environmental issues, in addition to the emergence of pesticide-resistant strains. Extensive research has been conducted to determine sustainable alternatives, such as the selection and cultivation of insect-resistant crop varieties. The aim of this study was to determine the degree of susceptibility of four wheat cultivars, namely, Albelad, Aldwasair, Australia, and Najran (NJ), to Oryzaephilus surinamensis (L.) using four parameters: F1 progeny, length of developmental period, Dobie's index of susceptibility (DI), and percentage weight loss (PWL). Albelad was highly susceptible (DI =17.44) to O. surinamensis, followed by Najran (DI =8.42) and Australia (DI =6.18) (susceptible and moderately susceptible, respectively), whereas Aldwasair was moderately resistant (DI =4.67). Furthermore, there were significant positive correlations between DI and the mean number of F1 progeny (R2 = 0.98) and between DI and grain weight loss (R2 = 0.95). However, a significantly negative correlation (R2 = −0.86) was observed between DI and beetle developmental period. These findings will aid the development of breeding programs to maintain the quality and quantity of wheat grains during storage.

Variability in the Emergence Point of Transpersonal Experience in the Life Cycle

AbstractIt is shown in this article that many positions that are usually considered incompatible or antagonistic can be synthesized into a unified framework, creating a model of transpersonal development based around plurality and complexity. The model focuses on evolutionary developmental biology (particularly the process of heterochrony) as well as around psychological theories. A large degree of variability in the nature of transpersonal experience in the life cycle is to be expected, due to differences in both the “timing of onset” of transpersonal characteristics and the “length of developmental period.” Numerous developmental patterns are identified, using the work of some prominent transpersonal theorists

Levels of Resistance to the Whitebacked Planthopper, Sogatella furcifera (Homoptera: Delphacidae), in Rice Varieties with Different Resistance Genes

Levels of Sogatella furcifera (Horvath) resistance among varieties with different resistance genes were measured by the seedbox screening technique, and by the following biological criteria: insect feeding rate, oviposition rate, egg hatchability, survival, length of development period, and population growth. There were distinct differences in the levels of S. furcifera resistance among varieties with the different genes. The population growth test was the most useful test to assess the levels of resistance among varieties. IR2035-117-3 having two resistance genes, Wbph1 + Wbph2 , was the most resistant variety as indicated by the population growth study.

Effects of insecticide resistance on biotic potential of the house fly (Diptera: Muscidae).

Biotic potential (length of developmental period and fecundity) was measured for one susceptible (S) and four organophosphate insecticide-resistant (R) strains of Musca domestica L. and for RS heterozygotes. The R strains showed an 11 to 43% decrease in biotic potential relative to the S strain. The decrease was associated with reduced fecundity in all R strains and an increase in developmental time in two of them. In contrast, the biotic potential of RS heterozygotes, which are resistant, was seldom different from the S strain. Therefore, the R gene is dominant for expression of resistance but recessive for adverse effects on biotic potential. This may result in the occurrence of a balanced polymorphism in field situations. The implications of these findings for resistance managment are discussed.

Comparative Resistance of Multiple Insect-Resistant Soybean Genotypes to the Soybean Looper12

Four soybean, Glycine max (L.) Merr., plant populations with Mexican bean beetle, Epilachna varivestis Mulsant, and corn earworm, Heliothis zea (Boddie), resistance derived from PI227687 and PI229358 were evaluated for resistance to the soybean looper, Pseudoplusia includens (Walker), in the laboratory, field, and greenhouse. Foliage of plants from N77-9002 and N77-9003, derived from PI227687, was less preferred for feeding than that of N77-9004 and N77-9005, derived from PI229358, in laboratory leaf disc tests. P. includens larval field plot populations were slightly higher in N77-9004 and -9005 than in N77-9002 and -9003. In laboratory no-choice tests, the most resistant subline of N77-9003 was more resistant than the most resistant subline of each of the other three populations, based on larval weight, length of developmental period, and percent mortality. P. includens larvae fed PI227687 foliage suffered 100% mortality, both early (days 3 to 7) and late (days 18 to 25) in larval life, whereas larvae fed PI229358 foliage suffered 50% mortality only in instars immediately preceding pupation. Weights of P. includens larvae fed postbloom PI227687 foliage were 42% less than those fed prebloom foliage, compared with weight differences of 32% for larvae fed post- and pre-bloom PI229358 foliage.

Confused Flour Beetle1 Growth and Development Stimulated by Eating Eggs or Adults of the Indian Meal Moth2,3

After 16 days of larval growth, females and males of the confused flour beetle, Tribolium confusum Jacquelin duVal, held in the laboratory at 29°C and 60% RH in flour supplemented with eggs of the Indian meal moth, Plodia interpunctella (Hubner), weighed 3.55±0.S9 (SE) and 3.33±0.42 mg, respectively; females and males in flour supplemented with dead moths weighed 3.05±0.33 and 2.72±0.17 mg, respectively; and females and males in unsupplemented flour weighed 2.28±0.27 and 1.96±0.22 mg, respectively. Maximum weights of the larvae on the 3 diets did not differ significantly. Males and females did not differ in the length of developmental period, but the developmental period on the 3 diets differed: by the 20th day 50% of the larvae had pupated in flour supplemented with eggs; but it took 22 days for larvae in flour supplemented with moths, and 25 for larvae in unsupplemented flour. Supplemented diets did not affect duration of the prepupal stage (1.1±0.4 days) or pupation (7.2±0.4 days). The 1st day that at least 50% of the adults had emerged was day 28.0±0.6 for larvae in flour with eggs, day 29.0±1.6 for larvae in flour with moths, and day 32.0±1.0 for larvae in unsupplemented flour.

Quantitative l-arginine requirements of larvae of the saw-toothed grain beetle, Oryzaephilus surinamensis (L.) (Coleoptera, Silvanidae)

A dietary requirement for l-arginine by larvae of the saw-toothed grain beetle, Oryzaephilus surinamensis (L.), was demonstrated. Based on criteria of survival to the pupal stage, adult emergence, and length of development period, the optimum concentration of l-arginine in the diet was shown to be about 0·67 per cent. The arginine requirement of this organism could be satisfied by substitution with two or three times the equimolecular amount of l-citrulline. l-Ornithine could not replace l-arginine in the diet and was inhibitory even in the presence of more than a minimal concentration of l-arginine. Although creatine could be substituted to some extent for dietary arginine, the results suggest that this is not necessarily the end-product of arginine metabolism in this organism.

Studies on Beetles of the Family Ptinidae IX.—A Laboratory Study of the Biology ofPtinus tectusBoield

Ptinus tectusoccurs on a large range of foodstuffs in all types of storage places, in warehouse refuse and in the nests of birds. It is widely distributed in cool and temperate areas but is very rarely found in hot climates. In Britain it can survive the winter when exposed in a Stevenson screen to outdoor shade conditions.P. tectusis seldom found on imported cargoes inspected aboard ship, but many British warehouses carry a population of the species resident in the fabric of the premises.The larva is able to bore through cellophane, card and textiles and can also make impressions on wood. The fully fed larva spins a cocoon on the fabric of containers and buildings. Holing of packages and contamination by silk of high grade produce form the chief economic losses caused by the species, but occasionally large populations are found, sufficient to reduce the food value of produce. Unlike the larvae, adult beetles cannot penetrate sound linen bags, but lay eggs through the meshes.In a series of consecutive experiments, performed identically as far as possible, variations in the length of developmental period and in emergence weight of adult beetles were greater than would be expected by chance. The variations could not be related to any single observed or suspected inconsistency of technique or environment. It is desirable therefore to conduct comparative experiments simultaneously.