The purpose of this study was to identify factors at various time points in life that are associated with surviving to age 90. Data from men enrolled in a cohort study since 1948 were considered in 12-year intervals. Logistic regression models were constructed with the outcome of surviving to age 90. Factors were: childhood illness, blood pressure (BP), body mass index (BMI), chronic diseases, and electrocardiogram (ECG) findings. After 1996, the Short Form-36 was added. A total of 3,976 men were born in 1928 or earlier, and hence by the end of our study window in 2018, each had the opportunity of surviving to age 90. Of these, 721 did live to beyond his 90th birthday.The factors in 1948 which predicted surviving were: lower diastolic BP, lower BMI, and not smoking. In 1960, these factors were: lower BP, lower BMI, not smoking, and no major ECG changes. In 1972, these factors were lower BP, not smoking, and fewer disease states. In 1984, these factors were lower systolic BP, not smoking, ECG changes, and fewer disease states. In 1996, the factors were fewer disease states and higher physical and mental health functioning. In 2008, only higher physical functioning predicted survival to the age of 90. In young adulthood, risk factors are important predictors of surviving to age 90; in mid-life, chronic illnesses emerge, and in later life, functional status becomes predominant.

The influence of banana weevil, Cosmopolites sordidus (Germar)(Coleoptera: Curculionidae), population density on oviposition rates and larval survivorship was studied in the laboratory at the Kawanda Agricultural Research Institute in Uganda. This study was undertaken to elucidate the relationship between density-dependent factors and rates of banana weevil increase in the field. Oviposition substrates (corm pieces) were offered to a range of densities of weevils maintained in buckets. Mean oviposition rates per female at densities of 10, 20 and 40 females per bucket were 29, 37 and 53%, respectively, lower than that at a density of 5 females. Nevertheless, total oviposition for the same groups was 1.4, 2.5 and 3.7 times higher than that of the 5-female group. Providing fresh corms daily instead of every five days did not increase oviposition. Larval survivorship was slightly higher at lower densities of immatures following insertion of different densities of eggs or first instars into banana corms. The results suggest that density-dependent factors can influence oviposition rates of individual weevils and survivorship of immatures, but appear to exert only modest influence in reducing banana weevil population growth. More likely, high mortality of weevil immatures under field conditions and/or higher rates of adult mortality and emigration than previously postulated contribute to the slow population build-up of this pest.

Les écosystèmes aquatiques sont des milieux privilégiés pour les transports d'organismes, les échanges entre individus, les évolutions rapides de communautés, combinés à la propagation rapide de signaux physiques et chimiques dans l'environnement. Les réseaux microbiens, composés d'une grande variété de micro-organismes (des bactéries au phytoplancton et aux protozoaires) dans divers états physiologiques, sont la base du fonctionnement de ces écosystèmes. L'identification des micro-organismes présents, et de leurs activités in situ, sont des défis technologiques permanents pour le microbiologiste. Les différentes évolutions technologiques concernent : i) L'amélioration des techniques de dénombrement des bactéries vivantes. ii) L'adaptation des techniques de cytométrie (en image et/ou en flux) associées à des marqueurs fluorescents au comptage des micro-organismes in situ. Ces comptages peuvent concerner la présence d'une espèce ou d'une fonction métabolique (association de l'immunofluorescence avec la microscopie ou la cytométrie de flux, ou encore utilisation de sondes phylogénétiques fluorescentes à différents niveaux taxonomiques). iii) La combinaison des techniques décrivant l'état et les fonctions des microflores (biomasse, production, vitesse et rendement de croissance, diverses activités métaboliques intervenant dans les cycles biogéochimiques et/ou les processus de pollution ou de bioremediation) avec des techniques de chimie analytique fine décrivant le milieu naturel (HPLC, chromatographie gazeuse, spectrométrie de masse). iv) La recherche au niveau cellulaire de la réponse bactérienne aux conditions de stress par la mise en évidence de systèmes protéiques nouveaux.

The development time and survival of the castor whitefly, Trialeurodes ricini Misra were measured at four constant temperatures. The duration of the egg stage varied from 15 days at 20°C to 4.6 days at 35°C. No eggs hatched at a constant 40°C. The minimum temperature threshold for egg development was calculated to be 17°C. The total development time from egg to adult ranged from 54.4 days at 20°C to 16.8 days at 30°C. Development of the egg and the first-to fifth-instar larva required 63 and 180 degree-days respectively above the threshold value. Immature survival increased from 64.5% at 20°C to 92.8% at 30°C. Trialeurodes ricini is well adapted to high temperatures and may extend its distribution if mean world temperatures increase as a result of global warming.

Survival and development of Chilo partellus were studied on five sorghum cultivars (IS-18363, IS-18520, ICS-1, ICS-2 and IS-4660) in the laboratory at Mbita Point Field Station, Kenya, at 26 ± 2°C and 65 ± 5% RH. Larval developmental period differed significantly on different cultivars. Number of instars was numerically greater for the females than for the males on all cultivars. Average pupal weight varied with sex; females were twice as heavy as males. The pupal period was longer for males than for females on all cultivars, with the exception of ICS-1, where the pupal period of males was equal to that of females. Ovipositional period was significantly longer on IS-18520 (5.18 ± 0.30 days) than on other cultivars. The shortest ovipositional period (3.70 ± 0.27 days) was recorded on IS-4660. There were no statistically significant differences in adult longevity. Sex ratio of the moths also did not affect the adult longevity of C. partellus reared on the five sorghum cultivars. The variations found in the development of C. partellus on different cultivars were attributed to the nutritional value of the food source.

Juveniles of the common dentex (Dentex dentex) (2.4 g mean weight), were grown over a 6 week period, fed exclusively on a commercial sea bream diet or an isocaloric moist pellet diet, which was produced on site. Ambient temperature (24.4-26.2 °C) and oxygen content (4.8-5.9 mg/L), as well as the relatively low stocking density (max. 2.62 kg/m3) provided favourable rearing conditions. Survival (63.8% vs 51.6%), specific growth rates (6.1% vs 4.5%) and food conversion efficiency (115.8% vs 76.3%) were considerably elevated in the group fed on moist pellets. The growth performance parameters recorded are considered to be favourable for aquaculture requirements. Agonistic behaviour (particular biting of the tail) was found to be the main cause of the continuous mortality that occurred in both feed groups (78% and 64.8% of total mortality in the dry- and moist-pellet group, respectively). These biting attacks targeted the smallest individuals in a tank, whose mean individual weight made up 49-62% (with dry pellet diet) and 28.9-46.6% (with moist pellet diet) of the respective mean weights. The results indicate a strong relationship between nutrition, size variation and agonistic behaviour in the rearing of cornmon dentex juveniles.

The aquaculture production of all-female triploid (sterile) populations is recognized as being of potential advantage for many species of fish where sexual maturation is not desired. All-female triploids have been produced by inducing triploidy in eggs that had been fertilized with monosex female sperm. However, monosex stocks to produce this type of sperm are currently available only for a limited number of economically important species. To circumvent this problem, an alternative method would be the direct fertilization of tripoid embryos. In Pacific salmon, pressure shocks applied shortly after fertilization have consistently resulted in high yields of tripoids, and feminization by direct estrogen treatment has also been shown to be highly effective if applied shortly after hatching. In this study, coho salmon eggs were made triploid by a pressure shock of 633 kg/cm2 for 4 min, applied 20 min after fertilization and incubation at 10 °C. Some of the resulting embryos were then feminized with estradiol-17β in single 2-hour immersion treatments at 400 μg/liter, administered 1 and 8 days after hatching. Six months later, when the fish were juveniles, analysis of the DNA content of erythrocytes by flow cytometry revealed a 100% induction of triploidy, while histological examination of the gonads showed 82% females, which were completely devoid of oocyte development and thus genetically sterile. These manipulations reduced survival during early stages of development but survival became stable later. Together, these results suggest that the production of sterile fish by direct feminization of induced triploids could be of particular advantage for those species in which all-female stocks are yet not available or difficult to obtain.

Larvae of the African River Prawn Macrobrachium vollenhovenii, indigenous to West Africa, were reared at various salinities (0-32‰). A salinity range of 16-24‰ was found most suitable with highest survival and growth, and lowest number and duration of instars. Freshwater was lethal already to zoea I - larvae. A mass culture experiment demonstrated the aquaculture potential of this Macrobrachium species. Larval rearing to postlarvae was possible applying the same methods as for M. rosenbergii. Detailed descriptions of rearing techniques are provided.

Tropical African ticks are found on their hosts throughout the year, but at varying infestation levels. These population changes, for most of the time, have been associated with climatic changes. Their development is inversely related to temperature. Several workers reported that development failed for a number of tick species at temperatures below 15°C, suggesting a possible lower temperature threshold for tick development. The upper development limit for most of the tropical rhipicephalids appear to be 37°C.

Ticks are particularly susceptible to attack during lethargic pre-moulting and the weak post-moulting period. Many biological features enable them, however, to survive especially well. They lay numerous eggs and withstand a comparatively wide temperature and humidity range with greater ease. They survive for months or years without food.

Their degree of host specificity varies from genus to genus or within subgroups of various genera. The requirement of two or more kinds of hosts often with divergent habits, limits their distribution to certain faunal areas.

This paper reviews our current knowledge on development and survival of ixodid ticks under tropical field conditions including some laboratory studies.

Whitefish (Coregonus lavaretus L.) larvae from Léman (= Lake Geneva) and Lake Bourget (France) have been successfully mass reared in tanks of 50-60 l when fed exclusively on dry experimental and commercial diets. In spring water at 10 °C for three initial densities (100-200-400/l) tested, the survival at 35 days fluctuated generally between 30 and 50%. The final number and biomass harvested has been improved by the use of higher water temperature (14 °C) or by stocking with high initial density (200-400/l) at 10 °C. In Lake Leman, temperature appeared to be the key factor controlling the results of coregonid larvae rearing in submerged illuminated net cages (6 m3) stocked with 50 000 yolk sac fry and harvested at the end of spring. The results fluctuated greatly when stocking was too early (middle of February to beginning of March). They were improved by delaying stocking, to the period "mid-Marc - carly April" for yolk sac fry or to "end of March-April" when fry prefed on dry diet were used.

Common carp larvae were fed artificial diets over 28 days at about 24 °C. Diets were based on yeast and either beef liver or casein. Survival rates of larvae were 76-92% with liver diets and 87-96% with casein diets. Larval growth was superior with liver diets (mean final weights 720-880 mg) than with casein diets (130-340 mg). Within-tank coefficient of variation of body weight increased with mean weight according to a generalized S-shaped curve. The skewness coefficient tended to increase with the mean weight, with higher values in the casein-fed group than in the liver-fed group. It is concluded that liver is not strictly indispensable for carp larvae diets and may be replaced by less complex components.

In field conditions in South Australia hatching of eggs of Ectropis excursaria showed a morning and an afternoon peak. In the laboratory, hatching coincided with “lights-on” stimulus at 20°C, 10:14 and 12:12 L:D. Increase or decrease of temperature by 5°C shifted the start of hatching to late scotophase while increasing photoperiod shifted a substantial proportion of hatching to later in photophase. Survival of first instars was linearly related to saturation-deficit of the atmosphere.

Survival and growth performances of autotriploids in rainbow trout (Salmo gairdneri) and three types of triploid hybrids between female rainbow trout and brown trout males (Salmo trutta,) coho salmon males (Oncorhynchus kisutch) and brook trout males (Salvelinus fontinalis) were analysed relatively to the parental species in freshwater farming conditions. At the end of the immature period, autotriploids exhibit moderate but significant depression relative to the control for both survival (about 25% depression) and growth (10 to 15% depression). Most of this depression is established during the first three months of life, triploids appearing very similar to the control later on. At the onset of sexual maturation at 2 years old, relative value of triploids becomes higher than that of the control, for both survival and growth. Long term evaluation (2+ or 3+) balances in favor of triploids with particular advantage for triploid females. Triploid hybrids exhibit much more important depression in early survival (up to 60%). Later on, their survival remains always lower than those of parental controls. Their growth performances are intermediate between their two parental species. Despite a relative advantage for these groups during the onset of sexual maturation in control groups, especially for growth, long tem evaluation is in favor of diploid rainbow trout, but in some specific cases.