Maximum Longevity Research Articles

Lifespan of male and female APP/PS1 and APPNL-F/NL-F mouse models of Alzheimer's disease.

Alzheimer's disease (AD) disproportionately affects women, yet most preclinical research studies are male-centric. We performed lifespan analyses of male and female AD mouse models (APP/PS1 and APPNL-F/NL-F) and their shared genetic background control (C57BL/6). Survival curves support significant sex differences between within genotypes. Minimal longevity revealed increased age in male APP/PS1, and decreased age in APPNL-F/NL-F mice. Maximal longevity revealed an increased average age in males. Furthermore, median lifespan differed between sex and genotype. This study supports sexual dimorphic survival in two mouse models of AD, emphasizing the need to examine mechanisms and treatments in both sexes.

Growth, reproduction and resource allocation in the Norwegian lemming Lemmus lemmus (L.) under controlled conditions

Lemmings from a laboratory colony did not show statistically significant differences in growth between the sexes up to an age of 50 days. After this, growth slowed down, but adult individuals continued to gain weight, some reaching more than 100 g. Reproductive females gained more weight than non-reproductive. Maximal longevity was between 2 and 3 years. The Norwegian lemming has high reproductive potentials. Females became sexually mature at about 3 weeks of age, even down to two weeks, and remained sexually active until the last periods of life. With 8 mammae and an average litter size of 4, our material confirmed the one-half rule. Litter size up to 16 was recorded. With post-partum oestrus, litters were born at 21 day intervals. Pregnancy and lactation therefore overlapped. Resource allocation between the mother’s demands and those of the two sets of progeny, is achieved partly because the lactation period is so much shorter than the gestation period. Thus competition for energy is reduced. We did not observe any negative effects of the presence of sucklings on the ensuing litter. Even with concurrency in pregnancy and lactation the female herself gained some weight. The Norwegian lemming is thus capable of rapid population growth.

Body Mass Shapes Most Life History Traits and a Fast-Slow Continuum in Amphibians.

Amphibians have the least studied life histories among vertebrates, although they have unique and the most diverse life histories within this group. We compiled a new dataset on adult body mass and 16 other life history traits of 2069 amphibian species across three orders (1796 frogs, 236 salamanders, 37 caecilians). These traits characterise fecundity, offspring development from egg deposition to metamorphosis and adult life. We established allometric models on traits for all amphibians and each of the three orders to assess a potential scaling of traits to body mass and then checked whether allometric slopes were consistent with two different metabolic scaling exponents. Further, we examined a possible fast-slow continuum in all amphibians, as well as in each of the two orders frogs and salamanders by applying principal component analysis (PCA) to five traits. Our allometric models indicated a positive scaling to body mass for 11 traits across all amphibians, 12 in frogs, and 10 in salamanders, and for five out of eight traits analysed in caecilians. Allometric slopes on most traits characterising offspring development were not significant. All slopes did not support a three-quarter metabolic scaling exponent, whereas slopes on age at maturity and maximum longevity were consistent with an amphibian metabolic scaling exponent of 0.88. As in fishes, reptiles, birds, and mammals, the first axes of our PCAs indicated a body mass-dependent fast-slow continuum in amphibians. Amphibian species of slow life histories have larger body masses, later sexual maturities and longer lifespans and lay more and larger eggs than species of fast life histories, a pattern also known from reptiles. The second axes indicated a trade-off between egg size and number. As this trade-off was nearly independent of body mass, we hypothesise that amphibians have occupied a broad range of ecological niches without evolutionary changes in body mass.

The Middle Mesial Canal: Combined Endodontic and Restorative Treatment Approach - A Case Report

The management of the middle mesial canal (MMC) in mandibular first molars presents considerable challenges during endodontic treatment due to its complex anatomy. Challenges may arise throughout various stages of treatment, including canal location, instrumentation, and obturation. The inability to identify and shape this canal can lead to endodontic failure and post-treatment apical periodontitis. Therefore, understanding this aberrant root canal anatomy and its clinical implications during the various stages of endodontic treatment is essential for successful management, including the selection of the optimal coronal restoration to enhance the efficacy of the obturation’s coronal seal and to ensure the restoration’s maximal longevity. This case report describes the diagnosis and successful endodontic and restorative management of an MMC in a mandibular first molar.

Influence of life-history traits on mitochondrial DNA substitution rates exceeds that of metabolic rates in teleost fishes

Abstract Understanding the molecular relevance of metabolic rate (MR) is crucial for unveiling the mechanisms driving the evolution of animals. In this study, we investigated the association between mitochondrial DNA characteristics and both resting and maximal MRs in conjunction with life-history traits among 139 species of teleost fish. We gathered fish MR data from various sources and procured sequences of 13 mitochondrial protein-encoding genes. We calculated the absolute substitution rate for entire nucleotide sequences and 4-fold degenerate sites of each gene, along with encoding amino acid sequences. Using the phylogenetic comparative method, we then explored the associations between MR and mitochondrial DNA absolute substitution rate. Additionally, we screened MR-associated single nucleotide variants in mitochondrial DNA. The findings indicate no positive correlation between MRs and any substitution rate values of both combined sequences and individual mitochondrial protein-coding genes, refuting the MR hypothesis. Instead, both maximum body size and longevity correlated negatively with molecular substitution rates, suggesting their influences on both mutation and fixation within mitochondrial genes in fish. Results also revealed significant correlations between base variation at ATP6_169 and both resting MR and maximum MR, identifying the unique ATP6_169G in Scombridae fish, which results in an extremely low isoelectric point (pI) value of the ATP6 protein. Considering its functional significance, the ATP6_169G in Scombridae fish might link to their lifestyle characterized by fast locomotion and high metabolic demands alongside a slower molecular evolutionary rate.

Germline mutation rate predicts cancer mortality across 37 vertebrate species

Abstract Cancer develops across nearly every species. However, cancer occurs at unexpected and widely different rates throughout the animal kingdom. The reason for this variation in cancer susceptibility remains an area of intense investigation. Cancer evolves in part through the accumulation of mutations and, therefore, we hypothesized that germline mutation rates would be associated with cancer prevalence and mortality across species. We collected previously published data on germline mutation rate and cancer mortality data for 37 vertebrate species. Germline mutation rate was positively correlated with cancer mortality (P-value = 0.0008; R² = 0.13). Controlling for species average parental age, maximum longevity, adult body mass, or domestication did not improve the model fit (ΔAIC < 2). However, this model fit was better than a model controlling for species trophic level (ΔAIC > 2). The increased death rate from cancer in animals with increased germline mutation rates may suggest underlying hereditary cancer predisposition syndromes similar to those diagnosed in human patients. Species with higher germline mutation rates may benefit from close monitoring for tumors due to increased genetic risk for cancer development. Early diagnoses of cancer in these species may increase their chances of overall survival, especially for threatened and endangered species.

Impact of diet composition of <I>Corcyra cephalonica</I> (Lepidoptera: Pyralidae) on the development and reproduction of <I>Trichogramma chilonis</I> (Hymenoptera: Trichogrammatidae)

Utilizing parasitoids for augmentative biological control frequently depends on the physiological state of the parasitoids and the pest population density at the time of release. Trichogramma chilonis Ishii (Hymenoptera: Trichogrammatidae) is commonly used as an egg parasitoid for biological insect pest control via augmentation and field release. A crucial component of mass production programmes is the host’s nutritional compatibility. So, the investigations were carried out to study the effect of diet composition of Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae) on developmental and reproductive parameters of Trichogramma chilonis Ishii. The T. chilonis was reared on Corcyra cephalonica fed on different diets (D1-D7) in the laboratory at 25℃±1℃ with 75±5% RH. Based on pooled data of two generations T. chilonis had shown significantly highest parasitization of 85.80%, adult emergence percentage 75.00% and sex-ratio 1.62:1 on rice moth eggs obtained from Maize (48.5%) + Sorghum (48.5%) + Groundnut (3%) diet (D5). Trichogramma adult’s emergence was observed earlier (3.10 days) on the host’s eggs reared on the Bajra (100%) diet (D1). In case of adult longevity, the maximum longevity of 7.70 days was recorded on the host’s egg obtained from the D5 diet over the others. These findings may help to improve the developmental and reproductive performance of T. chilonis and an optimized D5 diet may be useful for mass rearing of this egg parasitoid.

Response to Discretising and validating Keyfitz' entropy for any demographic classification

Abstract In recent years, demographers have parsed variation in survivorship into two distinct components: the shape and the pace of ageing. The pace of ageing is defined by measures of longevity such as mean life expectancy or maximum longevity, whereas measures of the shape of ageing attempt to classify different shapes of the survivorship curve. We recently published a paper pointing out that a commonly used discretization of a shape measure, Keyfitz' entropy, does not correctly classify survivorship curves into negatively and positively senescing curves (de Vries et al., 2023). In that paper, we also suggested an alternative, accurate discrete‐time version of Keyfitz' entropy. de Vries et al. (2023) ended with two open questions, both of which have been answered by Giaimo (2024) now: (1) Can a discrete‐time entropy measure of survivorship be generalized beyond age‐based population models? Giaimo (2024) introduce a new formula that achieves this. (2) Will a discretization of Keyfitz' derivation of his measure as the elasticity of lifespan to a uniform change in mortality lead to the same formula as a discretization of Keyfitz' result? Giaimo (2024) answers: no. Here, we briefly discuss the implications of the results obtained by Giaimo (2024), and the implementation of his new formula into the Rpackage Rage, which is widely used for comparative demographic studies. We showcase the strength of the new method by reanalysing a comparison of Keyfitz' entropy to another shape measure. We find that the comparison is significantly altered by using Giaimo's new Keyfitz' formula. This example strengthens Giaimo's (2004) words of warning in approaching discretizations with attentiveness.

Caloric Restriction and Intermittent Fasting: possible strategies for delaying brain aging in humans and animals

Calorie restriction (CR) is the strategy that hasdemonstrated a significant impact on slowing thebiological rate of aging and increasing both averageand maximum longevity in a variety of animals. Adiet plan known as intermittent fasting (IF) calls foreating habits that involve prolonged periods of lowor no-calorie intake. The morphology, architecture,vasculature, and cognition of the brain are known tochange as the organism ages. Oxidative stressplays a crucial role in the aging of the brain. Theeffects of oxidative stress include mitochondrialdysfunction, protein modification, membrane lipidperoxidation, nuclear DNA oxidation, and mitochondrial and mitochondrial DNA oxidation.These effects hasten brain aging, neuronal loss, andcognitive impairment. Cognitive ability, long-termmemory, and dementia are improved by CR andIF, which are beneficial for brain andneurodegenerative illnesses. The presented reviewarticle explores recent findings on how two dietaryapproaches, CR and IF, can support healthy agingand improve brain function. We will also explorehow the most studied CR mimetics affect aging andhow they might be used as treatments to promoteneuroprotection.

Caribbean deepwater snappers: Application of the bomb radiocarbon age estimation validation in understanding aspects of ecology and life history.

Reef fishes have been utilized as food fish throughout the U.S. Caribbean and Gulf of Mexico waters for centuries, with increasing fishing effort in recent decades. As a result, many species have experienced declines in landings, including deepwater snappers such as queen snapper Etelis oculatus and blackfin snapper Lutjanus buccanella. However, little to no peer-reviewed published research exists on basic life history parameters for either species. Confirming the accuracy of an age estimation method for a fish species is essential for ensuring sustainable fisheries management. This is because in the assessment of fisheries species population age-based parameters, including longevity, age at sexual maturity, growth rate, mortality, age-specific reproductive output, and lifetime reproductive output, are important in understanding overall life history strategies of managed stocks. The past stock assessment on U.S. Caribbean queen snapper utilized an estimated longevity of 8 y, derived from length frequencies for fish from St. Lucia. Blackfin snapper has an estimated longevity of 27 y based on a relatively small study from offshore waters of the southeastern U.S. The focus of our investigation was to estimate maximum longevity of two data-poor species in the U.S. Caribbean. The accuracy of ageing methods was tested via bomb radiocarbon age estimation validation and effects of depth on Δ14C in otolith cores and eye lens core values were examined. Results from our work indicate a maximum validated age of 45 y for queen snapper, and 43 y for blackfin snapper. Our findings indicate queen snapper and blackfin snapper are long-lived (> 40 y). The resulting Δ14C comparison between eye lens cores and otolith cores has important implications for the study of age validation, specifically when deepwater species are involved.

Physiological components of seed quality in runner‐type peanut during seed formation

AbstractSeed is one of the most expensive costs in peanut (Arachis hypogaea L.) production, and the use of high‐quality seed is important to provide the greatest yield potential. Physiological seed quality, represented by a combination of germination, vigor, desiccation tolerance, and longevity, is progressively acquired during seed formation. When all components reach their maximum, seeds achieve the highest physiological quality. The objectives of this study were to identify the acquisition pattern of the physiological components of seed quality, to determine the timing in which the maximum physiological quality is achieved during seed formation, and to define the timing in which seeds acquire and further break primary dormancy in peanut. A 3‐year field study was conducted using the cultivar Georgia‐06G. Plants were inverted when growing degree days reached 2500 for all fields, and a maturity board profile was used to classify the pods into the maturity classes. Seeds were split into two groups, treated and non‐treated, with ethephon to break potential primary dormancy. Water content, germination, vigor, desiccation tolerance, and longevity were tested in the seeds. Seed mass maturity was reached in the “orange” class. Maximum germination and vigor were achieved between “brown 1” and “brown 2”. Primary dormancy was acquired between “orange” and “brown 1” and broken after artificial drying. Maximum desiccation tolerance was observed in “brown 1”, whereas maximum longevity was achieved only in “black 2”. Considering all physiological quality components, peanut seeds achieved the maximum physiological quality between “brown 1” and “brown 2”.

Age Structure and Body Size of the Plateau Brown Frog (Rana kukunoris) in the Jiuzhaigou National Nature Reserve and Potential Climatic Impacts on Its Life History Variations

Jiuzhaigou National Nature Reserve (JNNR) is a renowned World Biosphere Reserve and UNESCO-designated World Nature Heritage Site. The age structure and body size of a population are crucial for assessing the quality of habitats in which a population lives and are essential for the vertebrate conservation and management, especially for amphibians. Unfortunately, information about the life history traits of amphibians is currently unavailable in JNNR. Herein, we first estimated the age structure and body size of Rana kukunoris, which is endemic to the Eastern Qinghai-Xizang Plateau. Then, we compared our data with 28 reported populations along an elevation gradient (1797–3450 m) and investigated how life history traits respond to climatic variations. Our results indicated the following: (1) For individuals from JNNR, the maximum longevity is 8 years, age at sexual maturity (ASM) is 2 years, suggesting a favorable ecological environment in JNNR. Notably, females are significantly larger than males due to the age factor. (2) The average age and ASM show a positive correlation with elevation. However, when the elevation exceeds 3000 m, the average SVL initially increases and then decreases due to the harsh environmental conditions at higher elevation. (3) Temperature and/or UV-B have a significant impact on the average age, ASM, and average SVL variations of R. kukunoris, suggesting adaptive potential of this species via life history variations in light of environmental changes. These accounts provide antecedent information about the life history traits of amphibians in JNNR, and provide insights into the driving factors of the life history variations of the plateau brown frog.

Competitive ability of dwarf bamboo (Sasa borealis) through long‐term clonal growth in mixed dwarf bamboo communities in the understory of a temperate deciduous forest

AbstractWe investigated the clonal competition of three co‐occurring dwarf bamboo species, Sasa borealis, Sasa nipponica, and Sasaella ramosa, for 32 years in an old‐growth beech forest in central Japan. A study plot (10 m × 24 m) was established to examine the culm dynamics of these species. Sasa borealis had a competitive advantage over the other species. It invaded the other bamboo populations at a rate of 0.84–0.89 m/y from 1988 to 2020, while S. nipponica invaded at a rate of 0.17 m/y until 2003. After that, S. nipponica started to retreat at a rate of 0.85 m/y along with the invasion of S. borealis until 2020. The invasion rate of S. borealis did not change before and after the competition with S. nipponica. Our results showed that it would take 13.9–14.8 years from S. borealis invasion for S. nipponica to disappear. The density of S. ramosa decreased but it did not disappear from the plot because it retreated at a slow rate of 0.08 m/y. Sasa borealis almost achieved its potential maximum culm density, but the other two bamboo species did not. If stable conditions were maintained, S. borealis would continue to invade, dominate, and eliminate the other bamboo species. The ecological traits of dwarf bamboo species, such as the maximum density, size, and longevity of culms, are good indicators for assessing their competitiveness. Our findings demonstrate that dwarf bamboo species are actually replaced by another bamboo species in the forest understory during a long period.

Durability of Lumber Pretreatment Compared to Posttreatment Processes

Aim of study: In terms of treatment, it is essential to consider the correct use of preservatives and epoxy resin. Lumber pretreated with these substances can protect the wood from biodegradation or insect attack for exceeding three-year life expectation periods. Methods: To further increase durability and structural integrity, Posttreatment like painting or lamination on wood surfaces helps keep moisture out and carries a higher yield compared to traditional methods. In addition, chemical treatments to make timber resistant to fungal infestations as well has been gaining traction recently which makes it possible for lumber to be used in even more applications safely than ever before. Results: Thus, proper treatment plays a major role when considering the implications of using lumber as a resource both structurally and functionally over time. Conclusion: Lumber remains one of the most sought-after resources due to its versatility; likewise finding ways how impart maximum longevity necessitates research into new treatments available so that we can optimally exploit such abundant supplies without compromising the durable nature of good quality timber source.

Unveiling growth and reproduction of a giant Patagonian galaxiid: an experimental rearing study

ABSTRACT Understanding the life history of understudied native and threatened fishes is crucial to develop conservation strategies for freshwater ecosystems. Puye grande (Galaxias platei) is an endemic freshwater fish of Patagonia with little known about its life history traits. To bridge this information gap, comprehensive studies under controlled conditions could expand our basal understanding of puye grande’s life history. We conducted a long-term experimental study using one cohort of puye grande throughout its lifespan. We collected 423 postlarvae individuals from the Riñihue Lake (southern Chile) and reared them for 11 years under captivity. We documented the maximum longevity of this species as 11 years, with a survival rate of 0.47% for the entire study period. Hatchery-reared individuals showed isometric growth (b = 2.75). Parameters of the von Bertalanffy growth model were asymptotic total length L ∞ = 20.80 cm, growth coefficient K = 0.75 yr−1, and theoretical age at-length zero t 0 = 0.45 yr, including both sexes. Puye grande showed an iteroparous life history, with the first spawning event occurring at age 2+ and consecutive spawning events occurring mainly in fall and winter. Females had a mean (standard deviation) total fecundity of up to 58 500 (23 331) eggs individual−1 and a mean relative fecundity in fall of 621 (109) eggs g−1 wet mass; males had a mean spermatic density of 28.41 (4.18) × 109 spermatozoa mL−1. The embryonic development until eclosion occurred 432 h post fertilization (hpf) at 12 °C. Our valuable baseline findings about the life history of puye grande can contribute to future strategies for managing and conserving galaxiids under global environmental change in Patagonia.

Differential adult lifespan and starvation stress responses in laboratory evolved bivoltine silkworm breeds of Bombyx mori l.

Silkworm breeding is majorly focused on balancing the progress of productive trait to generate profitability.However, with recurrent commercialization and utilization of such productive trait through heterosis may decline with drastic climatic variations. In order to achieve and generate profitability in sericulture, paradigm shift is essential through transition from balanced breeding to sustainable breeding via selection of breeding lines with better adult moth longevity which confers the benefits by coping with stressful environment. In the present investigation, CSR bivoltine silkworm breeds were screened to understand the adult moth longevity among them which have attained two decades of evolution. Differential longevity was recorded among the selected breeds. The maximum and minimum longevity was observed in CSR 51 and CSR17 respectively than other breeds. The short-listed breeds were exposed to starvation stress, wherein, interestingly, the CSR51 was highly tolerant compared to other breeds and CSR17 being short-lived was susceptible to starvation stress. The data obtained suggest that the relatively longer lifespan may be rendering more tolerance towards the starvation stress mediated lethality, as evident by the induced starvation stress assay. This would help us to focus on the generation of long-lived breeding lines with better longevity which could intrinsically determine for better abiotic and biotic stress tolerance.

Deadwood on clearcut sites during 20 years after harvests: The effects of tree retention level and prescribed burning

Deadwood is essential for species diversity in forests. Forest management has led to the shortage of deadwood in managed forests and, consequently, to the decline of biodiversity. Prescribed burning and tree retention during harvests may promote deadwood formation, but the long-term effectiveness of these methods is not known. We examined patterns of tree mortality and deadwood dynamics following tree retention and prescribed burning in Finnish boreal forests in a large-scale replicated field experiment with two factors: retention level (10 or 50 m3/ha) and burning (burned or unburned). We monitored 2744 trees individually for 20 years. Deadwood input was initially high after the treatments, since nearly all retention trees on the burned sites and about one third of the trees on the unburned sites died within four years. For the rest of the monitoring period, deadwood input was much lower since the mortality rate of retention trees decreased to a level similar to the background mortality rate. After 20 years from the treatments, deadwood volume varied from about 40 m3/ha on the burned sites with 50 m3/ha retention to about 5 m3/ha on the unburned sites with 10 m3/ha retention. Prescribed burning altered deadwood composition e.g. via the complete mortality of fire-susceptible tree species. Still, deadwood diversity was mainly affected by retention level. Lastly, prescribed burning generated high numbers of snags, which fell rather quickly, with an estimated maximal longevity of 49 years. We conclude that the combination of a high retention level and prescribed burning produces high volumes of diverse deadwood, and thereby has the potential to support the conservation of deadwood-associated biodiversity in managed forests. However, the stand-scale continuity of deadwood throughout the forestry rotation period is still uncertain. The application of management methods should be adjusted at the landscape level to ensure the continuity of deadwood habitats.

Prolonging Vase Life of Gladiolus (Gladiolus grandiflorus L.) var. Arka Amar with Various Preservative Solutions

Background: Arka Amar is a most popular variety of gladiolus which is used as cut flower and cut flowers are highly perishable materials and pregnable to large post-harvest losses. There is an immense post-harvest losses in value of cut flowers which is seen all along the marketing channels and it can be up to 40-50%. So, an experiment was carried out to find out the best combination of preservative solutions to enhance the vase life of Gladiolus (Gladiolus grandiflorus L.) var. Arka Amar. Methods: In this laboratory study during March 2022 to April 2022, different preservative solutions were analyzed to find out the maximum longevity of spikes. The experiment was laid out in C.R.D. with nine different combinations of sucrose, Al2 (SO4)3, AgNO3 and citric acid including control (distilled water). Result: The study revealed that the treatment T9 (Sucrose 2% + AgNO3 50ppm + citric acid 100 ppm) increased the percentage of water uptake both in weight and volume basis, minimize the days taken for opening of 1st floret (4.83 days), increase the length (7.41 cm) and diameter (13 cm) of floret, increase the percentage of opening of florets/spike (96.92%), maximize the longevity of floret (22 days) and flowering duration of spike (14.66 days). Visual scoring on appearance (8.71) and freshness (8.93) were also found significant for the above treatment combination.

ELUCIDATING THE HOST PREFERENCE BY THE PULSE BEETLE <i>CALLOSOBRUCHUS CHINENSIS</i> (L)

Callosobruchus chinensis (Bruchidae: Coleoptera) known as pulse beetle is a serious pest of pulses causing economic losses. The present work reports the effect of pulses on life cycle parameters (oviposition, emergence, longevity, total development period) of Callosobruchus chinensis (L.), and also on the nutritional loss incurred by it. Grains of seven pulses viz. Vigna radiata (green gram), Vigna aconitifolia (moth bean), Cicer arietinum (desi chickpea), Vigna unguiculata (cowpea), Cajanus cajan (pigeon pea), Vigna mungo (black gram) and Pisum sativum (yellow pea) were used as host with three replications. The results exhibit alterations in the developmental period as it was recorded least in green gram (23± 0.58 days) and maximum in peas (42± 1 days). The number of eggs were maximum on pea (310± 2) and least in moth (180± 2). Maximum longevity was recorded on green grams (16 days) and least on pea (9± 1 days). A significant correlation between weight loss and adult emergence was observed. Loss of nutritional content like protein and carbohydrate was significant.

Biological characteristics and parasitization potential of Encarsia formosa Gahan (Hymenoptera: Aphelinidae) on the whitefly, Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae), a pest of greenhouse crops in north-western Indian Himalayas

BackgroundThe greenhouse whitefly, Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae) constitutes key pests of greenhouses and field crops, which have developed pesticide resistance over the years. It has emerged as a difficult pest to manage owing to its indiscriminate exposure to higher dosages of insecticides. The use of natural enemies is environmentally safe alternative management tactic. Efficacy of Encarsia formosa Gahan (Hymenoptera: Aphelinidae) was determined by studying its biological characteristics on T. vaporariorum.ResultsParasitization by E. formosa was higher on fourth-instar nymphs of the greenhouse whitefly (GHWF) (37.2%), which was at par with that of third instar (36.4%), both differing significantly to the parasitization observed in second instar (19.6%). Total developmental duration of the parasitoid was longer on second instar (33.2 days) than that of fourth instar (29.9 days). Adult longevity was found significantly higher for the adults that emerged from fourth-instar nymphs of GHWF, which was at par to that of third instar and longevity of E. formosa adults was significantly higher in the absence of parasitoid host. The size of parasitoid that emerged from different instars of GHWF varied non-significantly. T. vaporariorum was reared on brinjal, cucumber, French bean, lettuce, tobacco, and tomato plants for mass production of E. formosa. Among them, French bean and tobacco were found to be the best host plants for mass production of E. formosa based on higher parasitization (37.2%). Total developmental period varied from 26.4 to 27.3 days on different host plants, the variations being non-significant. The maximum adult longevity was observed on cucumber (8.0 days) in the absence of host, and the adult size of parasitoid varied non-significantly. Results on host to parasitoid ratio of 5:1, 10:1, 20:1, 40:1 and 80:1 revealed that parasitization rate varied from 61.2 to 95.0% with maximum parasitization recorded in host–parasitoid proportion of 20:1 and minimum in 80:1. The total developmental duration varied non-significantly among all the proportions (15.1–15.4 days). Adult longevity was higher in the proportion of 40:1 (6.5 days), which was at par to the proportion of 5:1 (6.2 days), 20:1 (6.2 days), 80:1 (6.2 days) and 10:1 (6.1 days) in the absence of the host, respectively.ConclusionThis study suggests that augmentative biological control of T. vaporariorum under polyhouse conditions with E. formosa appears to be an effective strategy for the management of this economic pest.