The indirect influence of potential mates on survival and reproduction of Tyrophagus curvipenis (Acari: Acaridae).

The social-sexual environment is well known for its influence on the survival of organisms by modulating their reproductive output. However, whether it affects survival indirectly through a variety of cues without physical contact and its influence relative to direct interaction remain largely unknown. In this study, we investigated both the indirect and direct influences of the social-sexual environment on the survival and reproduction of the mite Tyrophagus curvipenis (Acari: Acaridae). The results demonstrated no apparent influence of conspecific cues on the survival of mites, but the survival and reproduction of mated female mites significantly changed, with the females mated with males having a significantly shortened lifespan and increased lifetime fecundity. For males, no significant difference was observed across treatments in their survival and lifespan. These findings indicate that direct interaction with the opposite sex has a much more profound influence on mites than indirect interaction and highlight the urgent need to expand research on how conspecific cues modulate the performance of organisms with more species to clarify their impacts across taxa.

Sex-specific response to delayed and repeated mating in spider mite Tetranychus urticae.

Sexual interaction is an important activity that determines the reproductive schedule of organisms and can ultimately influence the fitness traits of both sexes. Although the influence of sexual interaction on the fitness of females has been extensively determined, little is known about the effects on males, which often have different mating strategies and optimal mating regimes from those of females. To understand how mating regimes (timing and frequency) modulate the fitness in both sexes, we used spider mite (Tetranychus urticae) to investigate the influence of delayed mating and repeated mating on the fitness of male and female. For females, the unmated and the delayed mating females outlived those mated immediately after adult emergence. The repeated mating shortened the lifespan of females that mated at 1-day-old, but not that mated 7-day-old. However, no significant variation in lifespan was observed for males across different mating regimes. We found although delayed mating significantly reduced the daily reproductive rate of the females, there was no significant difference in lifetime reproduction of females across treatments because the delayed mating females increased their reproductive lifespan as a compensation. Our study highlighted that the time and frequency of sexual interaction showed a sex-specific consequence on male and female spider mites, indicating that sexual interaction incurs a higher cost to females which have a much lower optimal mating frequency than males.

Sex dimorphism of life-history traits and their response to environmental factors in spider mites.

Sex dimorphism is ubiquitous in the animal kingdom and can be influenced by environmental factors. However, relatively little is known about how the degree and direction of sex difference vary with environmental factors, including food quality and temperature. With the spider mites from the family Tetranychidae as subjects, the sex difference of life-history traits in responses to host plant and temperature were determined in this meta-analytic review. Across the 42 studies on 26 spider mite species (N = 8057 and 3922 for female and male mites, respectively), female spider mites showed longer developmental duration than the males in all except two species. The direction of sex difference in development was consistent regardless of temperature and host plant. The 16 spider mite species in 33 studies generally showed female-biased longevity, with an overall effect size of 0.6043 [95%CI = 0.4054-0.8031]. Host plant significantly influenced the sex difference in longevity, where the males lived longer than females below 22.5 ℃, but the reverse was true at higher and fluctuating temperature. Host plant also influenced the magnitude of sex difference in longevity, with females living longer than males when reared on herbs but not on trees. This study indicated that life-history traits are highly variable between sexes under temperature and host plant influence, highlighting that environmental conditions can significantly shape the direction and magnitude of sexual dimorphism of life-history traits.

The sex- and duration-dependent effects of intermittent fasting on lifespan and reproduction of spider mite Tetranychus urticae.

BACKGROUND: Intermittent fasting (IF) is receiving increasing attention as an alternative to continuous restriction of calories because of its benefits in aging-related disease prevention and lifespan extension. However, whether both sexes with sexual dimorphism have similar response to IF have rarely been assayed. In this study, we determined how different durations of IF influence lifespan and whether males and females differed in their responses to IF. We also tested whether there is a trade-off between lifespan and lifetime reproduction in females under IF. METHOD: We used spider mite Tetranychus urticae, with female-biased sexual size dimorphism (SSD), as our model species to investigate the survival and lifespan difference of both sexes at different durations of IF regimes, and explore the association between longevity and fecundity in females within and across treatments. RESULTS: The lifespan of females increased before intermediate level of IF and then decreased afterwards, but males showed a decreasing trend in lifespan when subjected to IF. Within each treatment, female longevity was positively associated with their fecundity. However, the females fed ad libitum had a higher lifetime fecundity with a shorter lifespan, whereas mites fed 50% IF outlived ad libitum fed ones with lower fecundity because of the later onset of reproduction and lower daily fecundity, showing clear survival and reproduction trade-off when variation of resource availability enhanced across treatments. CONCLUSION: We showed sex-specific response to IF in lifespan, indicating that sexes with SSD have different optimal level of IF. These findings showed trade-off between survival and reproduction between treatments but not within treatments, suggesting that variation in resource availability is the necessary precondition for life history trade-off, and IF extends lifespan of females at the cost of reproductive success.

Development, lifespan and reproduction of spider mites exposed to predator-induced stress across generations.

Predator-induced stress shows pronounced effects on prey by inducing behavioural, morphological, and physiological responses. Increasing evidence shows that these antipredator responses may also lead to changes in life-history traits such as aging and lifespan. However, little is known about how predator cues influence the fitness of preys and their transgenerational effects. Parental spider mites (Tetranychus urticae) were either raised on a leaf disc with or without cues from a natural predator (Phytoseiulus persimilis). The results showed that predator cues prolonged the development of both sexes, shortened female adult lifespan but not that of males, and reduced lifetime reproductive outputs of the females. The studies with offspring from both cues-exposed and control mothers demonstrated that parental effects were significant in the early developmental stage of offspring, but not in later life stages. The lifespan of offspring was strongly negatively affected by the predator-induced stress when they were directly exposed but not the stress-experienced by their mothers. Additionally, the parental effects in the earlier life stage were sex-specific, with delayed hatching in daughters (but not sons) when parents were exposed to predator-induced stress. This cross-transgenerational study indicated that there were deleterious effects of predator-induced stress on aging and lifespan of prey for both parents and their offspring, although the parental effects appeared to be weak (in the early stage of offspring but diminished in adult stage). This study highlighted the sex-difference of prey in response to predator-induced stress and sex-dependent parental effects on the offspring.

Current and future invasion risk of tomato red spider mite under climate change.

Tomato red spider mite Tetranychus evansi Baker and Pritchard (Acari: Tetranychidae) is a phytophagous pest that causes severe damage to Solanaceous plants worldwide, resulting in significant economic losses. In this study, the maximum entropy model was used to predict the potential current (1970-2000) and future (2021-2060) global distribution of the species based on its past occurrence records and high-resolution environmental data. The results showed that the mean values of the area under the curve were all >0.96, indicating that the model performed well. The three bioclimatic variables with the highest contributions were the coldest quarterly mean temperature (bio11), coldest monthly minimum temperature (bio6), and annual precipitation (bio12). A wide range of suitable areas was found across continents except Antarctica, both currently and in the future, with a much larger distribution area in South America, Africa, and Oceania (Australia), dominated by moderately and low suitable areas. A comparison of current and future suitable areas reveals a general trend of north expansion and increasing expansion over time. This study provides information for the prevention and management of this pest mite in the future.

Distribution patterns of Phytoseiulus persimilis in response to climate change.

BACKGROUND: The biological control agent Phytoseiulus persimilis is a commercialized specialist predator of two agricultural pest mite species Tetranychus urticae and Tetranychus evansi. Biocontrol of these pest species by P. persimilis has achieved success in biological control in some areas. However, the lack of precise information about the influence of global climate change on the worldwide distribution of this biocontrol agent hampers international efforts to manage pest mites with P. persimilis. With 276 occurrence records and 19 bioclimatic variables, this study investigated the potential global distribution of P. persimilis. RESULTS: The results demonstrated that the Maximum Entropy (MaxEnt) model performed well, with the area under the curve being 0.956, indicating the high accuracy of this model. Two variables, the minimum temperature of the coldest month (Bio_6) and precipitation of the coldest quarter (Bio_19) were the most important environmental variables that influenced the distribution of P. persimilis, contributing more than 30% to the model, respectively. The suitable area currently occupies 21.67% of the world's land area, spanning latitudes between 60°S and 60°N. Under shared socio-economic pathway (SSP) 5-8.5 (high-carbon emissions), the low suitable area would increase by 1.31% until the 2050s. CONCLUSION: This study successfully identified that south-eastern China, parts of countries in the Mediterranean coastal regions, including Libya, Algeria, Portugal, Spain, and France, are climatically favorable regions for P. persimilis, providing valuable information about the potential areas where it can be effectively exploited as biocontrol agents in classical biological control programs to manage pest spider mites environmentally friendly. © 2024 Society of Chemical Industry.

Maternal Care Behavior and Its Consequences in Competition.

Parental care behavior has evolved as a life history strategy to improve reproductive success, particularly in organisms facing challenging environments. However, the variation in maternal care, such as egg-guarding behavior in response to the social environment and the associated ecological consequence of competition, remains largely unknown. This study addresses a gap in current knowledge by examining the plasticity of maternal care behavior in the predatory mite C. eruditus and its impact on offspring survival and intra- and interspecific competition. Our results demonstrated that the reproductive females frequently exhibit egg-guarding behaviors, with enhanced maternal care efforts when the interspecific competitor is present. Egg masses are significantly more vulnerable to predation in the absence of maternal care. Guarding females increased egg survival rates and adversely influenced the survival of both con- and heterospecific competitors, with higher mortality rates being detected. Our findings highlight the ecological significance of maternal care behaviors and suggest that releasing C. eruditus and Neoseiulus cucumeris (Oudemans) together is not recommended for pest management in storage products.

The endosymbiont Serratia symbiotica improves aphid fitness by disrupting the predation strategy of ladybeetle larvae.

Aphids, the important global agricultural pests, harbor abundant resources of symbionts that can improve the host adaptability to environmental conditions, also control the interactions between host aphid and natural enemy, resulting in a significant decrease in efficiency of biological control. The facultative symbiont Serratia symbiotica has a strong symbiotic association with its aphid hosts, a relationship that is known to interfere with host-parasitoid interactions. We hypothesized that Serratia may also influence other trophic interactions by interfering with the physiology and behavior of major predators to provide host aphid defense. To test this hypothesis, we investigated the effects of Serratia on the host aphid Acyrthosiphon pisum and its predator, the ladybeetle Propylaea japonica. First, the prevalence of Serratia in different A. pisum colonies was confirmed by amplicon sequencing. We then showed that harboring Serratia improved host aphid growth and fecundity but reduced longevity. Finally, our research demonstrated that Serratia defends aphids against P. japonica by impeding the predator's development and predation capacity, and modulating its foraging behavior. Our findings reveal that facultative symbiont Serratia improves aphid fitness by disrupting the predation strategy of ladybeetle larvae, offering new insight into the interactions between aphids and their predators, and providing the basis of a new biological control strategy for aphid pests involving the targeting of endosymbionts.

Age-specific mortality and fecundity of a spider mite under diet restriction and delayed mating.

Numerous experimental life-history studies on aging are mainly baised on two classical models-fruit fly Drosophila melanogaster (Meigen) and nematode Caenorhabditis elegans (Maupas)-with relatively little attention given to other organisms with different life-history characters. Two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) differs from many other arthropods in that the females continue their growth in the early adult stage and can reproduce sexually and asexually. In this study, the influences of dietary restriction and delayed mating on the aging patterns of the spider mite were examined with the prevailing survival and reproduction trade-off hypothesis of aging being tested. Significant sex-specific responses of the spider mites were found. The females showed longevity extension on diet restriction (fasting for 2 days in every 4 days) compared with their counterparts being fed ad libitum, and after delayed mating for 9 days, while the males displayed a decrease in lifespan when experiencing diet restriction but were not significantly influenced by delayed mating. Path analysis was used to investigate the relationship between mite survival and reproduction traits, including longevity, female lifetime reproduction, age at first reproduction, early reproductive efforts and late reproductive efforts, yielding no evidence for trade-offs between these life-history traits. The additive effects of dietary restriction and delayed mating in lifespan extension of female spider mites were confirmed, proving that diet restriction is a robust anti-aging intervention, and that later onset of reproduction can prolong adult lifespan in females.

Where are primary type specimens of new mite species deposited?

A list of type depositories of new mite species published in two journals (Systematic & Applied Acarology and Zootaxa) during the last five years (2012-2016) is presented in this paper. The 1370 new species are deposited unevenly among 134 collections. The top collection is the Zoological Institute of the Russian Academy of Sciences, St. Petersburg, Russia (145 species), which alone accounts for 10% of the total new species, and the top ten collections accounted for 48% of the total. The average number of new species per collection is 10 and over three quarters of the collections are below the average. Just over half (51%) of the collections are in Europe. However, overall there were still more new species deposited in collections in developing counties (741) than developed countries (629). The top country for type depositories of new mite species for each continent is: Russia (199 species) for Europe, Brazil (134 species) for South America, Iran (133 species) for Asia, Australia (87 species) for Oceania, USA (80 species) for North America and South Africa (36 species) for Africa. The top European collections hold type specimens mostly of foreign origin, whereas those of South America, Asia, Africa and Australasia hold type specimens mostly originating from their own countries.

Hotspots of mite new species discovery: Sarcoptiformes (2013-2015).

A list of of type localities and depositories of new species of the mite order Sarciptiformes published in two journals (Zootaxa and Systematic & Applied Acarology) during 2013-2015 is presented in this paper, and trends and patterns of new species are summarised. The 242 new species are distributed unevenly among 50 families, with 62% of the total from the top 10 families. Geographically, these species are distributed unevenly among 39 countries. Most new species (72%) are from the top 10 countries, whereas 61% of the countries have only 1-3 new species each.  Four of the top 10 countries are from Asia (Vietnam, China, India and The Philippines).

[A new method of processing quantitative PCR data].

Today standard PCR can't satisfy the need of biotechnique development and clinical research any more. After numerous dynamic research, PE company found there is a linear relation between initial template number and cycling time when the accumulating fluorescent product is detectable.Therefore,they developed a quantitative PCR technique to be used in PE7700 and PE5700. But the error of this technique is too great to satisfy the need of biotechnique development and clinical research. A better quantitative PCR technique is needed. The mathematical model submitted here is combined with the achievement of relative science,and based on the PCR principle and careful analysis of molecular relationship of main members in PCR reaction system. This model describes the function relation between product quantity or fluorescence intensity and initial template number and other reaction conditions, and can reflect the accumulating rule of PCR product molecule accurately. Accurate quantitative PCR analysis can be made use this function relation. Accumulated PCR product quantity can be obtained from initial template number. Using this model to do quantitative PCR analysis,result error is only related to the accuracy of fluorescence intensity or the instrument used. For an example, when the fluorescence intensity is accurate to 6 digits and the template size is between 100 to 1,000,000, the quantitative result accuracy will be more than 99%. The difference of result error is distinct using same condition,same instrument but different analysis method. Moreover,if the PCR quantitative analysis system is used to process data, it will get result 80 times of accuracy than using CT method.

Comparison of clinical outcome of low-dose and high-dose rabbit antithymocyte globulin induction therapy in renal transplantation: a single-center experience.

BACKGROUND: To explore a better balance between efficacy and complications, we respectively compared the clinical outcome of low-dose and high-dose rATG induction therapy with a control group in renal transplantations from March 2009 to March 2012. MATERIAL AND METHODS: 281 kidney transplant recipients were included in 3 groups. The low-dose group (n=39) received rATG 1 mg/kg on the first day and 0.5 mg/kg on the next consecutive 3 days post-transplantation. The high-dose group (n=30) received rATG 1 mg/kg for 6 days. The control group (n=212) received no induction therapy. All patients were treated with Prednisolone, Mycophenolate mofetil, cyclosporine A, or tacrolimus capsules. Acute rejection rates, renal function, CMV infection, patient survival, and the adverse effects of rATG were reviewed. RESULTS: The acute rejection rate was significantly lower in the rATG group compared with the control group (low-dose 17.9% vs. control 35.4%, P=0.03, and high-dose 16.7% vs. control 35.4%, P=0.038). There was no statistically significant difference in 3-year survival and graft survival rates among the groups. Renal function early recovery was similar in the rATG and the control group. The CMV infection rate in the high-dose rATG group was higher than the low-dose rATG and the control group (p=0.037 and p=0.002, respectively). rATG induction therapy was associated with thrombocytopenia in our series, especially in the high-dose rATG group. CONCLUSIONS: Low-dose rATG induction may be superior to high-dose rATG induction therapy in renal transplantation.

[The effect of human placenta-derived mesenchymal stem cells on cord blood CD8(+);T cells activation, cellcycle and secretion of IL-17].

AIM: To study the effect of human placenta-derived mesenchymal stem cells (hPMSCs) on cord blood CD8(+);T cell activation, cell cycle and secretion of IL-17, and to provide the theoretical basis for it application in the cell-based therapies. METHODS: hPMSCs were isolated from mature placenta by the method of digestion. Then hPMSCs were cultured, expanded in vitro, and were used in test after the third passage. CD8(+);T cells were sorted from cord blood with immunomagetic beads. FCM was used to analyze the expression of early activation phenotype, cell cycle of cord blood CD8(+);T cells and cytokine secretion. RESULTS: CD8(+);T cells stimulated by PHA in the presence of hPMSCs were arrested at G0/G1 phase. The expression of the early activation marker CD25 and CD69 of cord blood CD8(+);T cells was inhibited in the presence of hPMSCs. While, IL-17secretion of cord blood CD8(+);T cells stimulated by PMA was increased. CONCLUSION: hPMSCs can suppress the activation of cord blood CD8(+);T cells by altering T cell cycle; up-regulate the level of IL-17 secreted by cord blood CD8(+);T cells.