Faster Rate Of Development Research Articles

Life History Traits in Hippodamia convergens (Coleoptera: Coccinellidae) after Selection for Fast Development

Individuals of the convergent lady beetle Hippodamia convergens Guérin-Méneville, selected for a fast developmental rate (intensely selected line) through five generations, were assessed for unintended selective effects on adult weight and longevity, survivorship, food consumption, fecundity, and population growth parameters. Beetles from an intensely selected line were compared with beetles from a moderately selected line and field-collected wild types. After selection, survivorship from first instar to adult emergence at 18, 22, and 26°C was improved by 9.4, 8.5, and 22.2%, respectively, in the intensely selected line. Selection of individuals for fast development did not affect adult weight (19.6 mg), fecundity (344 eggs), longevity (53 days), nor third-fourth instar consumption of aphids (106 mg of pea aphids). Also, the intrinsic rate of increase ( r m ) and number of beetle generations per year were calculated for the intensely selected line, the moderately selected line, and wild-type beetles. The r m was higher for the intensely (0.099) than for the moderately selected line (0.091) and wild type (0.092). A degree-day model demonstrated that the intensely selected line may complete 3.9 and 5.3 generations in Corvallis and Hermiston, Oregon, respectively. The moderately selected line and wild-type populations would only complete 3.4 and 3.2 generations in Corvallis, respectively, and 4.6 and 4.5 generations in Hermiston, respectively.

Development of Pseudocalanus elongatus (Copepoda, Calanoida) cultured at different temperature and food conditions

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 119:99-110 (1995) - doi:10.3354/meps119099 Development of Pseudocalanus elongatus (Copepoda, Calanoida) cultured at different temperature and food conditions Klein Breteler, W. C. M., Gonzalez, S. R., Schogt, N. The pelagic copepod Pseudocalanus elongatus Boeck was bred 3 times from nauplius stages I and II to maturity at 5, 10, 15 and 20*C and at 4 different rations of autotrophic and heterotrophic food. The rate of development of the copepods increased with increasing temperature and food supply. The shortest generation times (from egg to adult) were 59 d at 5*C and 19 d at 15*C. The generation time nearly doubled when food concentration was very low. At 20*C mortality rates were high and development did not proceed faster than at 15*C. At all food levels the stage duration was generally constant (nearly isochronal), but the last 1 or 2 developmental stages took longer. The relationship between development time and temperature is described by Belehrádek's functions at different food levels. This relationship predicts a generation time of approximately 45 d during spring bloom conditions in the North Sea and about 30 d during summer due to food limitation. Field estimates from the literature are too scarce to evaluate the presumption of food limitation during summer conditions. Some evidence of a low critical food level was found compared to other North Sea copepod species. Together with a fast development rate at low temperatures, this may explain the numerical dominance of P. elongatus in the North Sea and the northeast Atlantic Ocean. Pseudocalanus . Copepods . Cultivation . Development . Temperature . Food Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 119. Publication date: March 23, 1995 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1995 Inter-Research.

Life history divergence of sympatric diploid and polyploid populations of brine shrimp Artemia parthenogenetica.

In order to study how polyploidy affects life history patterns in animals, we have examined sympatric diploid and polyploid brine shrimp (Artemia parthenogenetica) from China, Italy and Spain under laboratory conditions. At optimal temperature and salinity (25°C and 90 ppt), diploids from the three populations had much higher intrinsic rates of increase, higher fecundity, faster developmental rates, and larger brood sizes than their sympatric polyploids. The Chinese and Italian populations were selected for further analysis to determine the life history responses of diploids and polyploids to temperature and salinity changes. Under intermediate and high salinities, Chinese and Italian polyploids produced most of their offspring as dormant cysts while their sympatric diploids produced most of their offspring as nauplii. This relationship is reversed in the Spanish diploid-polyploid complex. For the Chinese population at 25° C, pentaploid clones had higher developmental rates than diploid clones at 35 ppt; at 90 ppt, diploid clones had higher developmental rates than the pentaploids. Italian diploids and tetraploids had different responses to variation in both temperature (25° C and 31° C) and salinity (30 ppt and 180 ppt). Our results demonstrate that relative fitness of the two cytotypes is a function of environmental conditions and that sympatric diploids and polyploids respond differently to environmental changes. Chinese and Italian polyploids are expected to have lower fitness than their sympatric diploids when the physical environment is not stressful and when intraspecific competition is important. However, polyploids may have advantages over sympatric diploids in stressful habitats or when they encounter short-term lethal temperatures. These results suggest that polyploid Artemia have evolved a suite of life-history characteristics adapting them to environments that contrast to those of their sympatric diploids.

Aeolian processes and sand encroachment problems in Kuwait

The surface of Kuwait is carved in a calcretized clastic sequence of Miocene-Pleistocene age, mostly covered by a thin blanket of recent aeolian deposits. Fast rate of development and increase of human activities contributed to denudation of the vegetative cover and exposure of dry, loose sediments to wind action. At present, Kuwait is intensively subjected to aeolian actions manifested by frequent occurrences of sand and dust storms. This dictated the need for regional understanding of the magnitude of the aeolian processes, their behavior with man-made establishments, and their long- and short-term impacts. A comparison between the nature and distribution of recent surface sediments in Kuwait in 1979 and 1990 shows significant changes that reflect the work of aeolian processes during this period. The direct impact of the enhancement of aeolian action is represented by the increase in the rate of sediment transport. Transportation of fine-grained particles in suspension frequently occurs during dust storms usually initiated in southern Iraq. The particles migrate over Kuwait as thick dust clouds and finally settle in the northern part of the Arabian Gulf. Bedload transport of sand, or saltation, frequently occurs during summer whenever wind speed reaches 5.4 m/s. The average annual sand drift rate in Kuwait is about 20 m 3 (m width) −1 yr −1, the majority of the drift occurring during the period May–August, to the southeast. Bedform transport or sand dune movement is also recognized in Kuwait. Sand dunes mostly occur as small barchans of about 3 m height. The measured rate of movement of these barchans varies with height. A barchan of average height usually moves about 20 m in nine monthes (January–August). The remarkable high rate of sand transport and the increase in development activities in the desert areas, are responsible for the enhancement of the sand encroachment problems in Kuwait. Almost all installations, roads, and farms are significantly affected by the accumulation of considerable amounts of aeolian sand. These problems have pronounced adverse environmental and economic impacts.

Effect of temperature on development and survival of eggs of Halotydeus destructor (Tucker) (Acari: Penthaleidae)

Abstract The effect of temperature on the rate of development of post - aestival diapause and winter (non-diapause) eggs of Halotydeus destructor (Tucker) was determined under a range of constant temperatures. Rates of development changed in a linear fashion over a wide range of temperatures (5-30°C) for winter eggs and over a narrower range (10-22.5°C) for post-diapause eggs. Estimates of lower developmental thresholds were 3.7°C for post-diapause eggs and 5.6°C for winter eggs. Fastest rate of development (22% per day) occurred at 27.5°C for winter eggs and at 22.5°C (8.7% per day) for post-diapause eggs. Requirements of 156.3 and 105.9 DD (degree days) were estimated for postdiapause and winter eggs, respectively. Survivorship was high (70–100%) for both egg types at most temperatures.

Dose-Response Relation, Neuromuscular Blocking Action, Intubation Conditions, and Cardiovascular Effects of Org 9273, a New Neuromuscular Blocking Agent

The ED50 and the ED90, the time-course of the neuromuscular block, the intubation conditions, and the cardiovascular effects of Org 9273, a new steroidal nondepolarizing neuromuscular blocking agent, have been evaluated in 41 anesthetized patients. From cumulative dose-response curves the ED50 and ED90 were calculated to be 175 and 300 micrograms/kg, respectively. The time-course of neuromuscular blockade after 300- and 500-micrograms/kg doses of Org 9273 appeared to be similar to that of equipotent doses of vecuronium. The neuromuscular block was characterized by a fast initial rate of block development. High-dose Org 9273 (1 mg/kg = 3-4 times the ED90) had a clinical duration comparable to an intubating dose of pancuronium, but a considerably more rapid onset and recovery index. Three hundred micrograms per kilogram and 500 micrograms/kg Org 9273 produced good to excellent intubation conditions 1 min after administration. Org 9273 in a dose of 0.5-2 times the ED90 produced no cardiovascular changes; however, 3-4 times the ED90 increased heart rate 20%-25% (P less than 0.001), probably due to a vagolytic effect.

Differences in the effects of parental age on offspring life history between tropical and temperate populations of milkweed bugs (Oncopeltus spp.)

We compare the effects of parental age on several offspring life history traits in two milkweed bug populations: a typically univoltine population ofOncopeltus fasciatus from the Sacramento Valley of California and a typically multivoltine population ofO. cingulifer from Monteverde, Costa Rica. Reared under identical conditions (27°C, 12 h light: 12 h dark photoperiod), these bugs exhibit significant differences in the effects of parental age on offspring life history. As they age,O. fasciatus females from Sacramento lay clutches of eggs of decreasing average weight and a decreasing proportion of their eggs produce offspring that survive to adulthood. Those offspring which do survive have a significantly faster developmental rate and females have a larger body size at adult eclosion. AsO. cingulifer from Monteverde age, they also produce lighter eggs, but there is no significant change in the offspring developmental rate, survival or female adult body size. We suggest that these results are largely explicable as the consequence of different parental investment strategies associated with the predictable relationship between parental age and time of season inO. fasciatus but not inO. cingulifer. AsO. fasciatus from Sacramento age, they may be increasing their investment per developing offspring so as to increase the probability that nymphs hatching late in the season will reach a prereproductive adult diapause before the first killing frost.

Optical power supply for fiber-optic hybrid sensors

Systems for optical power supply are of central importance for the concept of fiber-optic hybrid sensors. We present our systems for optical power supply which are capable of giving up to 150 mW of electrical power to the sensor head. Such a system for optical power supply consists of a combination of optical and electronic modules, namely a suitable optical power source, an optical fiber as power link and an optical energy converter with voltage control unit. This concept of a fiber-optic power supply in combination with a fiber-optic hybrid sensor covers many of the advantages given by a pure optical sensor. The galvanic isolation between the measuring circuit and the electronic evaluation unit is notable and implies use at higher voltages with high immunity to interference (EMI) of the data transmission line. A key element for our fiber-optic power supply is a specially developed photo-element array (PEA) for optical–electrical power conversion. Conversion efficiencies of 10–15% ith silicon material and up to 30% with GaAs material have been achieved. The available voltage with our single photoelement array (SPEA) can be up to 8 V. With a multiple photoelement array (MPEA) the voltage is switchable between 8 and 32 V. An application example for a complete fiber-optic hybrid sensor is given. With the fast rate of development of electronic and optoelectronic components, further improvements and a broad range of practical applications can be expected. An outlook to possible future improvements is given.

Effect of temperature and photoperiod on pupal development rates inPlanotortrix octoDugdale* (Lepidoptera: Tortricidae)

Abstract The pupal development rate of Planotortrix octo was monitored at 17 and 21°C at photophases of 0, 2, 6, 12, 14, 16, 18, and 24 h. Development rate was faster at 21°C and females developed significantly faster than males. A negative correlation between development rate and photophase was observed, with this being most marked at 17°C. Superimposed on this was a faster development rate at intermediate photophases (12–16 h). This is discussed in relation to a possible circadian mechanism for control of both larval and pupal development.

Effect of Temperature on the Development of the Blackfaced Leafhopper (Homoptera: Cicadellidae)

A laboratory investigation examined the effects of temperature on development of Graminella nigrifrons (Forbes) using seedling johnsongrass as the host. Daily development for each life stage was calculated. Results indicate no significant differences between developmental rates of male and female G. nigrifrons eggs at the temperatures studied. Male nymphs, however, exhibited significantly faster developmental rates than female nymphs. Using estimated thresholds of development of eggs and female nymphs, it was determined that three generations of the leafhopper per year were likely in central Kentucky.

Genetic variability and components of fitness in hatchery strains of rainbow trout

Two fitness components, development rate and egg size, were examined in six hatchery strains of rainbow trout, Oncorhynchus mykiss (syn. Salmo gairdneri Richardson), with different amounts of enzyme heterozygosity. The average expected heterozygosities per strain ranged from 4 to 8%, based upon an electrophoretic analysis of the protein products of 42 loci. Strains with higher heterozygosities had faster development rates, as measured by hatching time, than strains with lower heterozygosity. Concordance between hatching time and another measure of development rate, degree of yolk‐sac resorption, suggests that hatching time is a valid measure of embryonic development rate in salmonid fishes. Earlier‐hatching embryos were longer and heavier at the time of yolk‐sac resorption than later‐hatching fish. Females from more‐heterozygous strains also had a tendency to have larger eggs. These data suggest that genetic variation is an important biological resource to be conserved in hatchery stocks.

Occurrence of protandry and a female-biased sex-ratio in a sponge-associated water mite (Acari: Unionicolidae)

The sex ratio of aUnionicola crassipes-type mite from a pond in Alberta, Canada, was found to be significantly female-biased at the time of adult emergence. Male mites emerged earlier, but were later surpassed in number by the females. This protandry seems more likely to be due to the smaller size of the males and hence their faster developmental rate than to any mating advatage the male mites gain by early emergence. It is possible that group selection acting on the productivity of mite colonies with different proportions of low-sex-ratio producers has selected for female-bias. Water mites are not known to exhibit any atypical modes of reproduction (e.g.arrhenotoky), nor is it known whether pre-adult maleU. crassipes have a greater mortality rate than females, so the mechanism behind the skewed ratio is not known.

Release and establishment ofAphidiusspp. (Hymenoptera: Aphidiidae), parasitoids of pea aphid and blue green aphid in New Zealand

Abstract Three Aphidius spp. parasitoids of the lucerne aphids, pea aphid (P A) and blue green aphid (BGA), were introduced into New Zealand from 1977 to 1982. A. eadyi spread rapidly and now occurs in all the main lucerne-growing areas. In comparison, A. ervi was difficult to establish, failing to persist after several initial recoveries, but was eventually established from releases of se:parate strains in the North and South Islands, replacing A. eadyi as the predominant parasitoid in the North Island. Despite large releases, A. smithi has not established. A. ervi shows a preference in the field for BGA, but in the laboratory it demonstrated the ability to adapt from PA to BGA in two generations. Laboratory experiments showed that A. eadyi has a higher fecundity and faster development rate than A. ervi indicating that it competes better for PA. However, the polyphagy of A. ervi may be significant in its increasing predominance in the field. Comparisons are drawn with North American results.

Life history consequences of feeding versus non-feeding in a facultatively non-feeding toad larva.

Bufo periglenes, a toad endemic to montane Costa Rica, produces an unusually small clutch of large, yolk-rich eggs. The toads breed in small ephemeral pools that are unpredictable in duration and may be low in food availability. Two congeners, Bufo coniferus and Bufo marinus, occur nearby, breed in more permanent bodies of water that offer more food, and exhibit the typical toad pattern of large clutches of small eggs. Tadpoles of all three species feed on detritus and suspended organic material. By raising tadpoles of the three species individually with and without food I investigated the relationship between egg size (yolk provision) and tadpole survival. All of the unfed B. coniferus and B. marinus tadpoles grew little and died soon after developing to the hindlimb bud stage. On the other hand, all of the unfed B. periglenes tadpoles metamorphosed successfully, demonstrating that the tadpoles are facultatively non-feeding; developmental time from hatching to metamorphosis was significantly shorter for unfed tadpoles than for fed tadpoles, but fed individuals were significantly larger at transformation. Faster developmental rate and larger body size at transformation are both advantageous for frogs and toads, but cannot be attained simultaneously. Large egg size may afford flexibility in unpredictable environments. In pools where food is available, tadpoles presumably eat, take longer to metamorphose, but are larger at transformation than tadpoles developing in nutrient-poor sites. Small body size at transformation (a consequence of not eating) has potential costs, but the large quantity of yolk provided by a large egg enhances the probability of metamorphosis in food-limited environments.

Emergence of Baltic salmon, Salmo salar L., in relation to temperature: a laboratory study

Emergence pattern and developmental status at emergence of Baltic salmon fry from the Umeälven hatchery stock (63°50′N, 20°25′E) were studied at 6, 10 and 12°C in the laboratory. The number of days and degree days from hatching to 50% emergence decreased exponentially with increasing temperature. Synchronization of emergence increased with temperature. Optimal temperature for incubation of yolk‐sac alevins was 10°C, which resulted in the largest fry at emergence and the lowest death rate. Fry kept at 6°C had the lowest mean weight and at 12°C the highest death rate. The fry emerged at an earlier developmental state with more yolk at 12°C than at 6°C. The Baltic salmon had a faster developmental rate during the gravel‐phase, as compared to more southern Atlantic salmon populations.

Adaptive significance of developmental rate in rainbow trout: an experimental test

We examined the survival, size, and agonistic behaviour of faster and slower developing rainbow trout (Salmo gairdneri) in an artificial stream channel with a simulated redd. The analysis was performed at two levels: between three full-sib families genetically marked at a hexosaminidase locus, and within families segregating for a regulatory allele Pgml-t(b) that is associated with faster developmental rate. The families differed significantly in their hatching times but showed little variation in emergence times. Fishes with the Pgml-t(b) allele hatched and emerged significantly earlier than their full-sibs without the allele. Despite the mortality of at least 50% of emerged fishes in the selection experiment, there was no significant difference in survival between either the three families or fishes with different genotypes at the Pgml-t locus. However, fishes from the faster developing family and those with the Pgml-t(b) allele had significantly higher levels of agonistic behaviour and had a tendency to be larger than slower developing individuals.

Varietal resistance to stem borer pests of rice management in West Africa: A review

Major rice stem borers in W. Africa were discussed and scientific investigations relating to varietal resistance were reviewed. Impediments militating against a faster rate of development of this area of research in W. Africa were highlighted. A call was made to accord greater emphasis and priority to research on varietal resistance since in the long run it will become the most important rice crop management tactic feasible for the majority of West African small scale rice fanners.

Genetic Diversity and Linkage Disequilibrium in Drosophila melanogaster With Different Rates of Development

We have examined eight enzyme polymorphisms in groups of Drosophila melanogaster flies with fast, intermediate and slow development. The allelic frequencies are similar in all three developmental classes, but the distribution of the genotypes among the classes is significantly heterogenous for the three loci on the second chromosome. When the total sample of 300 individuals is examined, significant gametic disequilibrium appears in 3 out of 13 pairs of genes located on the same chromosome and in 4 out of 15 pairs of genes located on different chromosomes. This 25% incidence of disequilibrium between pairs of genes is larger than previously observed in other natural populations (but similar to the incidence observed in laboratory populations). The greater frequency of significant gametic disequilibrium in our study is probably due to the larger number of genomes sampled.-Some models specifically predict that individuals with faster rates of development (i.e., greater fitness) should be more heterozygous (and exhibit more linkage disequilibrium) than individuals with slower development. This hypothesis is not supported by our results.

Modelling the Effects of Accelerated Development and Reduced Fecundity on the Population Dynamics of Aquatic Diptera

The population dynamics of aquatic insects were simulated using a stage-projection matrix model. Transition elements, some of which were specified by nonlinear and stochastic functions, represent the joint probability of development and survivorship from time t to t + 1. For the simulation, stage-specific survivorship was kept unchanged and only development rate and fecundity were altered. The simulation predicts that the intrinsic capacity for population growth (rm) and equilibrium levels of abundance (K) should increase with both faster development rate and higher fecundity, independent of stage-specific mortality. As a test of the effect of accelerated development on population growth, abundance of insects emerging from experimental stream channels was compared in ambient temperature and heated channels. Development was faster in the heated channels, and abundance was greater for 9 of the 11 species compared. These results indicate that changes in development rate, in addition to changes in fecundity, must be considered when predicting the population effects of an altered thermal regime.

Temperature requirements of the chrysanthemum leaf miner,Chromatomyla syngenesiae [Dipt.: Agromyzidae], and its ectoparasitoid,Diglyphus isaea [Hym.: Eulophidae

The development rate from egg to adult for ♂ and ♀Chromatomyia (Phytomyza) syngenesiae andDiglyphus isaea increased linearly between 19 and 25°C.D. isaea had a faster developmental rate thanC. syngenesiae between 19 and 25°C but therer was no difference at 16°C. FemaleD. isaea required 154.6 D° above the theoretical threshold of 12.80°C and maleD. isaea 152.4 D° above 12.9°C for total development from egg to adult emergence. FemaleC. syngenesiae needed 207.0 D° above 12°C and ♂ and 211.0 D° above 11.6°C for total development.