Incubation

About: Incubation is a research topic. Over the lifetime, 5748 publications have been published within this topic receiving 126541 citations.

[The effect of the period of egg quiescence on the life cycle of Aedes aegypti (Linnaeus, 1762) (Diptera, Culicidae) under laboratory conditions].

Abstract: The influence of the period of egg quiescence on the life cycle of Aedes aegypti (Linnaeus, 1762) (Diptera, Culicidae) was studied under laboratory conditions in order to improve the management of vector control. The eggs are known to be the most resistant stages during development, allowing a long survival of the mosquitoes under unfavorable climatic conditions. The experiments were performed in a biological chamber kept at 28 +/- 1 degrees C temperature, with 80 +/- 5% relative humidity and 12 hours of photophase. Data about the influence of different periods of quiescence on eclosion, larval and pupal development and the developmental cycle are presented. We observed a highly significant effect of the period of quiescence on larval eclosion. The period of quiescence had no influence on the duration of larval or pupal incubation. Eggs originating from the same period of quiescence showed significantly different periods of incubation. The larvae emerged in groups defined by the period of incubation. This group effect was significant during the cycle. In 99.8% of the cycles the variation was determined by incubation.

Transient and permanent effects of suboptimal incubation temperatures on growth, metabolic rate, immune function and adrenocortical responses in zebra finches.

Abstract: In birds, incubation temperature can vary by several degrees Celsius among nests of a given species. Parents may alter incubation temperature to cope with environmental conditions and/or to manipulate embryonic development, and such changes in incubation behavior could have long-lasting effects on offspring phenotype. To investigate short- and long-term effects of suboptimal incubation temperatures on survival and physiological functions in zebra finches, eggs were incubated at 36.2, 37.4 or 38.4°C for the entire incubation period. The post-hatch environment was identical among the treatment groups. We found that hatching success was lowest in the 38.4°C group, while post-hatch survival was lowest in the 36.2°C group. Incubation temperature had sex-specific effects on offspring phenotype: incubation temperatures affected body mass ( M b ) but not physiological parameters of males and conversely, the physiological parameters but not M b of females. Specifically, males from the 38.4°C group weighed significantly less than males from the 36.2°C group from the nestling period to adulthood, whereas females from different incubation temperature groups did not differ in M b . In contrast, females incubated at 36.2°C had transient but significantly elevated basal metabolic rate and adrenocortical responses during the nestling and fledgling periods, whereas no treatment effect was observed in males. Innate immunity was not affected by incubation temperature in either sex. These results suggest that a 1°C deviation from what is considered an optimal incubation temperature can lower offspring performance and offspring survival.

Transformation of 14C glucose and starch in soil

Abstract: To gain information about the breakdown and synthesis of carbohydrate, incubations of soil with 14C-stareh and 14C-glucose were studied under laboratory conditions. Carbon dioxide was liberated equivalent to 60–80 per cent of the substrate during incubation of soil with glucose (14 days) and with starch (84 days). The carbohydrate content of the hydrolysate of the substrate-soil mixture returned almost to the initial soil value within 35 days of incubation with 0.5 per cent starch, and within 7 days with 1 per cent glucose. The total glucose in the mixtures rapidly decreased but the amounts of other sugars present showed little change during incubation. To obtain the specific activities of sugars present in the hydrolysate various methods of separation were used including charcoal column, Celite column, and paper chromatography of the free sugars, and resin column chromatography of their borate complexes. With both substrates there was a rapid redistribution of 14C amongst the sugars. Galactose and mannose acquired considerable activity in all cases, rhamnose and fucose became labelled in one experiment, but arabinose and xylose were not labelled. This pattern of distribution remained unchanged with further incubation and glucose remained the most highly labelled sugar (70–80 per cent of total sugar radioactivity) for as long as the incubations were studied.

Influence of organic matter decomposition on soluble carbon and its copper-binding capacity.

Abstract: Bulk and low molecular weight (LMW) (<1 kDa) water-extractable carbon were collected from fresh and microbially degraded wheat straw (Triticum aestivum L.) and crimson clover (Trifolium incarnatum L.) residues to monitor early-stage humification over an 8-wk incubation. Copper complexation parameters were determined for both bulk and LMW water-extractable C for both plant materials in a separate 1-wk incubation. Humification progressed through increasing molar absorptivity (A285) and phenolic and total acidity (TA), and through an increase in average molecular size and degree of polymerization as determined by ultrafiltration and changes in fluorescence peak locations. Such dynamic transformations demonstrate that while humification is a bulk property, with C breakdown and stabilization occurring simultaneously and continuously in soil, its early stages can be effectively monitored for fresh plant residues. Significant changes consistently occurred during the first 7 d of the incubation and were more pronounced for LMW fractions than bulk extracts. For both residues, water-extractable C extracted initially and following a 7-d incubation desorbed and complexed 0.11 to 0.55 mmol resin-bound Cu g(-1) C. Low molecular weight water-extractable C generated the higher values within this range, and values increased consistently following incubation. Potential concerns regarding LMW soluble Cu complexes include percolation through soils or runoff into adjacent water bodies as well as effects on plant root development.

Enhancement or Modulation of the Vector Competence of Ochlerotatus vigilax (Diptera: Culicidae) for Ross River Virus by Temperature

Abstract: Two different doses of Ross River virus (RR) were fed to Ochlerotatus vigilax (Skuse), the primary coastal vector in Australia; and blood engorged females were held at different temperatures up to 35 d. After ingesting 104.3 CCID50/mosquito, mosquitoes reared at 18 and 25°C (and held at the same temperature) had higher body remnant and head and salivary gland titers than those held at 32°C, although infection rates were comparable. At 18, 25, and 32°C, respectively, virus was first detected in the salivary glands on days 3, 2, and 3. Based on a previously demonstrated 98.7% concordance between salivary gland infection and transmission, the extrinsic incubation periods were estimated as 5, 4, and 3 d, respectively, for these three temperatures. When Oc. vigilax reared at 18, 25, or 32°C were fed a lower dosage of 103.3 CCID50 RR/mosquito, and assayed after 7 d extrinsic incubation at these (or combinations of these) temperatures, infection rates and titers were similar. However, by 14 d, infection rates and titers of those reared and held at 18 and 32°C were significantly higher and lower, respectively. However, this process was reversible when the moderate 25°C was involved, and intermediate infection rates and titers resulted. These data indicate that for the strains of RR and Oc. vigilax used, rearing temperature is unimportant to vector competence in the field, and that ambient temperature variations will modulate or enhance detectable infection rates only after 7 d extrinsic incubation. Because of the short duration of extrinsic incubation, however, this will do little to influence RR epidemiology, because by this time some Oc. vigilax could be seeking their third blood meal, the latter two being infectious.