取食蜂蜜对棉铃虫齿唇姬蜂体内主要代谢物质的影响

为揭示食物在齿唇姬蜂Campoletis chlorideae Uchida生命中所起的作用,测定分析饱食蜂蜜和只取食清水的齿唇姬蜂体内糖类、脂肪和蛋白质随日龄增加的变化趋势。结果显示,取食蜂蜜对齿唇姬蜂体内主要代谢物质影响显著。10%蜂蜜水和清水饲养的齿唇姬蜂的雌蜂和雄蜂在刚羽化时体内都含有较高水平的糖原、总糖、脂肪和蛋白质。但随着日龄的增加,用清水饲养的雌、雄蜂体内的糖原和总糖含量迅速下降并达到最低水平;而用蜂蜜水饲养的雌、雄蜂随日龄的增加体内的糖原含量没有显著变化,并且与清水饲养的雌、雄蜂相比,其体内总糖含量反而有所上升。用蜂蜜水饲养的齿唇姬蜂的寿命显著长于用清水饲养的齿唇姬蜂。由于蜂蜜中含有丰富的果糖,所以冷蒽酮反应测定显示,用蜂蜜水饲养的齿唇姬蜂体内果糖含量较高,但却不能在清水饲养的齿唇姬蜂体内测出。2种食物处理的齿唇姬蜂在羽化后体内脂肪含量均有下降;并且随日龄的增加,清水饲养的齿唇姬蜂体内脂肪含量的下降速度明显快于蜂蜜水饲养的齿唇姬蜂。取食蜂蜜水的齿唇姬蜂体内蛋白质含量随日龄无显著变化;而用清水饲养的齿唇姬蜂在羽化后体内蛋白质含量随日龄的增长迅速下降并达到最低水平。     

Asymmetric effects of adult nutrition on reproductive success of male and female Diaeretiella rapae (Hymenoptera: Aphidiidae)

The role of diet supplements (honey, water or no supplements) on egg maturation, oviposition strategy and longevity of the parasitic wasp Diaeretiella rapae McIntosh (Hymenoptera: Aphidiidae) is investigated. Parasitoids feed as larvae on hosts to acquire nutrition for growth and development, and further gain additional resources during their adult stage by feeding on either host or nonhost resources. The additional resources acquired by adults can help them to increase their reproductive activity or life expectancy, or both. Diaeretiella rapae females emerge with some developed eggs and no additional resources are required for egg maturation or successful oviposition. Females are able to oviposit and produce viable offspring immediately after emergence, and the number of eggs left in the ovaries of females decreases with subsequent oviposition, suggesting that ovigeny index of D. rapae is inclined towards pro‐ovigenic status. When unmated males and females are offered honey solution, females are attracted to it, whereas males display courtship and make mating attempts but then feed on honey after mating. The oviposition efficiency of female D. rapae increases by 30% when they feed on honey compared with when starved. Honey‐fed D. rapae adults live significantly longer (almost twice as long) than starved adults. Honey‐fed females deprived of hosts live longer than those offered hosts regularly. The positive effects of honey‐feeding on longevity are greater in females than in males. Taken together, the results of the present study suggest that the provision of additional resources to adult D. rapae parasitoids could enhance their life expectancy and parasitism efficiency in biological control programmes.     

引进花角蚜小蜂成虫的寿命和羽化节律

通过室内饲养和连续观察,研究了食物、温度对引进花角蚜小蜂成虫寿命的影响及其羽化的时间节律.结果表明：食物对该寄生蜂成虫寿命有极显著影响,喂食20％蜂蜜或20％蜂蜜＋新鲜松针可将雌虫寿命从不喂食的1.5 d延长到14.8 d和17.3 d,将雄虫寿命从不喂食的1.5 d延长到11.3 d和12.3 d.喂食20％蜂蜜条件下,温度也表现出极显著影响,23 ℃和26 ℃下雌、雄成虫的寿命均明显较长,32 ℃下均最短,相同温度下雌虫的寿命显著长于雄虫.日周期中,雌虫主要在11:00-15:00羽化,18:00以后基本不羽化;雄虫主要在9:00-12:00羽化,17:00以后基本不羽化.在花角蚜小蜂的主要羽化期7-9月,7月羽化量最大 ,此后8、9月呈波浪式递减;单日羽化的成虫中,雌虫大多占80％以上,雄虫则长期在一个较低水平波动.对比试验发现,花角蚜小蜂在收蜂棚中的出蜂量比在收蜂箱中更大.花角蚜小蜂在羽化前积累的能量十分有限,人工放蜂前提供必要的营养补充将有助于提高生物防治效果.福建和广东夏季的高温、花角蚜小蜂雌成虫和松突圆蚧雌成蚧虫口高峰期不吻合、极高的雌性比例等是影响该寄生蜂种群稳定的潜在因素.收蜂棚有利于大量收集花角蚜小蜂,适合在生产上应用.     

人工饲料中添加脂类和昆虫保幼激素类似物对七星瓢虫取食和生殖的影响

本文定量测定在人工饲料中加入埴物油和ZR512对七星瓢虫成虫(第一代)的生殖、摄食、生长、食物利用和转化的影响。结果表明:成虫取食加0.1%橄榄油和ZR512的人工饲料时产卵率能达到96.7%产卵前期为8天左右。如果在此基础上分别添加1%的玉米油或豆油时能促进雌虫产卵量的进一步增加,成虫的增重百分率随着生长天数增加持续上升,取食这种人工饲养的成虫除产卵量外,在体重、产卵前期、产卵率三方面都达到或接近取食蚜虫时的水平。 人工饲料中加入橄揽油能刺激成虫的取食,在此基础上加入玉米油或豆油能使食物转化效率显著地提高。人工饲料中加入ZR512时能阻止或打破雌虫的生殖滞育,促进生殖活动。     

Effects of sugar feeding on carbohydrate and lipid metabolism in a parasitoid wasp

Lifetime patterns of carbohydrate and lipid metabolism were compared in starved and sucrose‐fed adults of the parasitoid Macrocentrus grandii (Goidanich) (Hymenoptera: Braconidae). As expected, sucrose‐fed individuals lived longer than did starved individuals. Macrocentrus grandii males and females eclosed with levels of simple storage sugars (presumably primarily trehalose) and glycogen that were below maximum levels recorded from sucrose‐fed parasitoids. Both of these nutrients dropped to very low levels in starved individuals within 4 days post‐emergence and were maintained at high levels in sucrose‐fed individuals throughout their lives. Lipid reserves at emergence represented the highest lipid levels for both sexes in the two diet treatments, with levels declining over the lifetimes of males and females from both diet treatments. Our results therefore suggest that dietary sucrose is used to synthesize trehalose and glycogen, but not lipids in M. grandii. Also, in contrast to the patterns observed for the simple sugars and glycogen, lipid levels in starved individuals did not drop below levels observed in sugar‐fed individuals. The average number of mature eggs carried by females at emergence was 33 and increased to approximately 85 in sucrose‐fed and 130 in starved females by the age of 5 d in the absence of hosts. The egg maturation rate was therefore higher in starved than in sugar‐fed females. Potential explanations for this unexpected result are discussed.     

Larval and adult nutrition effects on blood/nectar choice of Culex nigripalpus mosquitoes

Abstract. The impact of nutritional variables on the development of host-seeking and biting behaviours after emergence by female Culex nigripalpus mosquitoes were studied using air-flow olfactometer and close-range biting assays, respectively. Unfed females failed to develop resting stage ovarian follicles. When offered a bird host in the absence of competing stimuli, sugar-fed mosquitoes were significantly more responsive in both host-seeking and biting than unfed controls. In a choice olfactometer assay using nectar odours (honey scented with artificial apple-blossom oil) versus host odours (a bird), unfed females preferred honey over bird odours except when honey odour was weak. After sucrose feeding, females switched from honey to bird preference. This change in behaviour was accompanied by significant accumulation of lipid and by follicular growth to the resting stage. Elevation of host responsiveness after sugar feeding was reversible; starvation ultimately resulted in females preferring honey over bird odours. When the larval diet was restricted by crowding, the wing-length and total lipid of resultant adult females were reduced. Although differences were subtle, unfed bird-responding females tended to have longer wings and more lipid than their honey-responding counterparts.     

Oleuropein supplementation increases urinary noradrenaline and testicular testosterone levels and decreases plasma corticosterone level in rats fed high-protein diet

The effects of oleuropein, a phenolic compound in extra virgin olive oil, on protein metabolism were investigated by measuring testicular testosterone and plasma corticosterone levels in rats fed diets with different protein levels. In Experiment 1, rats were fed experimental diets with different protein levels (40, 25 and 10 g/100 g casein) with or without 0.1 g/100 g oleuropein. After 28 days of feeding, the testosterone level in the testis was significantly higher and the plasma corticosterone level was significantly lower in rats fed the 40% casein diet with oleuropein than in those fed the same diet without oleuropein. The urinary noradrenaline level, nitrogen balance and hepatic arginase activity were significantly higher in rats fed the 40% casein diet with oleuropein supplementation than in those fed the 40% casein diet without oleuropein supplementation. In Experiment 2, the effects of oleuropein aglycone (a major phenolic compound in extra virgin olive oil and the absorbed form of oleuropein ingested in the gastrointestinal tracts) on the secretion of luteinizing hormone (LH) from the pituitary gland, which regulates testosterone production in the testis, were investigated in anesthetized rats. Plasma LH level increased dose dependently after the administration of oleuropein aglycone (P<.001, r= 0.691). These findings suggest that dietary supplementation with 0.1 g/100 g oleuropein alters the levels of hormones associated with protein anabolism by increasing urinary noradrenaline and testicular testosterone levels and decreasing plasma corticosterone level in rats fed a high-protein diet.     

Effect of six sugars on the longevity,oviposition performance and nutrition accumulation in an endoparasitoid,Meteorus pulchricornis (Hymenoptera: Braconidae)

The effects of six sugar resources (fructose, glucose, sucrose, trehalose, raffinose and honey) on the longevity, oviposition performance and nutrition levels of Meteorus pulchricornis, a thelytokous larval endoparasitoid of the common cutworm Spodoptera litura were examined under laboratory conditions. Female adults of M. pulchricornis fed 1 M fructose, glucose, trehalose or sucrose solutions survived longer than those fed on other sugar solutions or water. When provided with honey or sucrose solutions, the female parasitoids laid more offspring than those fed other sugar diets or the control. The body size of offspring driven from honey-, fructose-, sucrose-, and glucose-fed females, along with water-fed group, were larger than the trehalose- and raffinose-fed females. However, the emergence rates of all offspring generated from different sugars- and water-fed females were similar. When separately given honey, sucrose or fructose, M. pulchricornis females accumulated fructose at a higher level than the other groups. Parasitoid wasps fed trehalose solution accumulated the highest level of total sugar. Glycogen levels and lipid content were highest at emergence and then decreased across all diets. In addition, females fed on trehalose had the highest level of glycogen compared to other sugar diets and water control regardless of emergency level. Females fed trehalsoe, fructose, and glucose solutions had a higher level of lipid than those fed other sugar solutions and water at life end. The outcome of this study can benefit both laboratory rearing and management interventions that improve sugar sources for the parasitoid in the field.     

Maternal diets enriched in olive oil regulate lipid metabolism and levels of PPARs and their coactivators in the fetal liver in a rat model of gestational diabetes mellitus

In a rat model of gestational diabetes mellitus (GDM) programmed in the offspring of neonatal streptozotocin-induced (nSTZ) diabetic rats, lipids are accumulated in the fetal liver in a sex-dependent way. Here, we evaluated whether maternal diets enriched in olive oil in rats that will develop GDM ameliorate lipid metabolic impairments in the fetal livers. Pregnant offspring of control and nSTZ diabetic rats (F0) were fed a 6% olive oil-supplemented diet throughout the F1 gestation. We evaluated maternal metabolic parameters as well as lipid content, expression of lipid metabolizing enzymes and protein expression of PLIN2, PPARs and PPAR coactivators in the fetal livers. The offspring of nSTZ diabetic rats developed GDM regardless of the maternal treatment. Hypertriglyceridemia in GDM rats was prevented by the olive oil-enriched maternal treatment. In the livers of male fetuses of GDM rats, the maternal olive oil-supplemented diet prevented lipid overaccumulation and prevented the increase in PPARγ and PPARδ levels. In the livers of female fetuses of GDM rats, the maternal olive oil supplementation prevented the increase in PPARδ levels and the reduction in PGC1α levels, but did not prevent the reduced lipid content. Control and GDM rats showed a reduction of lipid metabolic enzymes in the fetal livers, which was associated with reduced levels of the PPAR coactivators PGC-1α and SRC-1 in males and of SRC-1 in females. These results suggest powerful effects of a maternal olive oil-supplemented diet in the fetal liver, possibly providing benefits in the fetuses and offspring from GDM rats.     

Adult feeding and lifetime reproductive success in the parasitoid Aphytis melinus

The diet of adult females of the parasitoid Aphytis melinus DeBach (Hymenoptera: Aphelinidae) includes host insects and sugar-rich foods such as nectar and honeydew. We compared the contributions of host feeding to longevity and fecundity in A. melinus females in the presence and in the absence of honey meals. First, we assessed the longevity of females that were not allowed to oviposit. While the longevity of females fed honey was significantly increased by host feeding (median ages were 30.5 days for host-fed females and 17 days for females not allowed to host feed), the lifespan of parasitoids not fed honey did not exceed 3 days for any individual and there was no effect of host feeding on longevity in this group. In the second set of experiments, we assessed the fecundity and longevity of females allowed to oviposit. We conducted two experiments, one in which honey was continuously available, and one in which honey was not available. In both experiments, daily observations were made of females that were either allowed to host feed or manually prevented from host feeding. In the presence of honey, host feeding significantly increased both fecundity and longevity, and in the absence of honey, parasitoids died within 2 days and host feeding had no significant effect on either fecundity or longevity. The lifetime fecundity of females fed honey but not hosts exceeded the initial egg complement by 60% on average. Approximately one host per day was used for host feeding whether honey was supplied or not, and each host-feeding meal contributed approximately 3.9 eggs to the lifetime fecundity of honey-fed females. In the last experiment, we compared the rate of egg resorption over a 36-h period in A. melinus females that were deprived of hosts and either fed honey or starved. While no egg resorption was detected in honey-fed females over this time period, starved females resorbed approximately 9 eggs. Thus, the availability of a sugar-rich food interacts strongly with host feeding in influencing longevity and fecundity and has a strong direct effect on egg resorption.     

Effects of diet and activity on lipid levels of adult Mediterranean fruit flies

Abstract. The objectives of this study were to determine whether adult Mediterranean fruit flies, Ceratitis capitata Wiedeman (Diptera: Tephritidae), are capable of synthesizing lipids, and whether adult diet affects this ability.Lipid levels in females fed protein and carbohydrate or carbohydrate alone declined significantly from emergence to the fourth day of life and then rose back to teneral levels on the fifth day, before oviposition took place on the sixth day.In males fed protein and carbohydrate, lipid levels initially declined as males aged and then stabilized.In carbohydrate-fed males lipid levels declined following emergence and recovered somewhat by the sixth day.Lipid levels declined significantly when flies underwent post-emergence starvation, but after substantial feeding on the above-mentioned diets they eventually (within 6–7 days) reached teneral levels in all experimental groups.Multivariate analysis of variance revealed that differences in lipid contents are primarily related to the flies' age, which corresponds to the various sex-specific activities these flies exhibit.Average lipid investment in eggs was found to equal teneral lipid levels in females.Without lipogenic abilities, oviposition would completely deplete female lipid reserves.We conclude that adult medflies are capaple of lipid synthesis, and that this capability is modulated by individual and sex-specific activity patterns.     

Dietary nucleotides influence immune responses and intestinal morphology of red drum Sciaenops ocellatus

Dietary nucleotides have been shown to benefit many physiological and nutritional functions in higher vertebrates and fish. Therefore, a 6-week feeding trial was conducted to evaluate the effects of graded levels of a commercial nucleotide product on growth performance, immune responses and intestinal morphology of juvenile red drum (initial average weight of 7.1 g). The basal diet was formulated to contain 40% protein, 10% lipid and a digestible energy level of 3.5 kcal g^?1. Two levels of nucleotide (Ascogen P^®, 0.5% and 1% of diet) were added to the basal diet with menhaden fishmeal and menhaden oil adjusted to provide isonitrogenous and isolipidic diets. Nucleotide supplementation tended to improve weight gain and survival of red drum, but not at a significant level. Neutrophil oxidative radical anion production and serum lysozyme activity tended to be higher for fish fed diets supplemented with nucleotide, while extracellular superoxide anion production of head kidney macrophages from fish fed diets with 1% nucleotide was significantly (P < 0.05) increased, although no significant differences were observed between fish fed 0.5% nucleotide diet and the basal diet.Nucleotide supplementation significantly (P < 0.05) increased fold height in the proximal intestine, and enterocyte height in the pyloric caeca, proximal and distal enteric sections. A significantly (P < 0.05) higher microvilli height was observed in all evaluated enteric sections of fish fed with diets supplemented with nucleotides. It is therefore possible to use dietary nucleotides supplementation to significantly enhance the intestinal structure of red drum. Likewise, nucleotides in the diet may improve some components of the non-specific immune response of this sciaenid fish.     

Dietary fatty acids and oxidative stress in the heart mitochondria

Our study compared the effects of different oils on oxidative stress in rat heart mitochondria, as well as on plasma parameters used as risk factors for cardiovascular disease. The rats were fed for 16 weeks with coconut, olive, or fish oil diet (saturated, monounsaturated, or polyunsaturated fatty acids, respectively). The cardiac mitochondria from rats fed with coconut oil showed the lowest concentration of oxidized proteins and peroxidized lipids. The fish oil diet leads to the highest oxidative stress in cardiac mitochondria, an effect that could be partly prevented by the antioxidant probucol. Total and LDL cholesterols decreased in plasma of rats fed fish oil, compared to olive and coconut oils fed rats. A diet enriched in saturated fatty acids offers strong advantages for the protection against oxidative stress in heart mitochondria.     

Aspects of the reproductive biology of Pseudaphycus maculipennis (Hym: Encyrtidae), a parasitoid of obscure mealybug,Pseudococcus viburni (Hem: Pseudococcidae)

Laboratory experiments to determine aspects of the reproductive biology of Pseudaphycus maculipennis are described. All experiments were carried out at a constant temperature of 21 ± 2 °C, a 16-h photoperiod and ambient RH. Pseudaphycus maculipennis was shown to be an arrhenotokous, synovigenic, gregarious endoparasitoid of Pseudococcus viburni. Females and males lived for 16 and 11 days, respectively, when fed either honey-agar or mealybug honeydew. Relatively, large instars (third instar or adult females) were preferred for oviposition; mated females parasitized more mealybugs than unmated females, and the progeny sex ratio favored females by 3:1. Egg load increased with age from emergence to day 8, averaging 23 mature eggs/female. Mean realised daily fecundity never exceeded 5, with a mean lifetime fecundity of 46 eggs/female. Parasitised mealybugs remained alive for about 5 days and then mummified. Total development period was 20–21 days (larva 4–5 days, prepupa 3 days, pupa 8–9 days). Development periods of eggs and individual larval instars were not measured. A mean of 3.01 ± 0.1 parasitoids/mealybug were reared after individual parasitism events, increasing through super-parasitism (either self or conspecific) to 9 parasitoids/mealybug when hosts were exposed to competing females. Pseudaphycus maculipennis progeny emerged from the mummies in discrete cohorts over periods ranging from 3 min to 18 h (depending on the number of cohorts).     

Biological and ecological studies of the parasitoidChelonus inanitus [Hym.: Braconidae] in Israel

The effects of certain environmental conditions on the survival ofChelonus inanitus (L.) adults were studied in the laboratory. The longevity of the adults decreased with increase in temperature. The survival of males and females under extreme conditions of temperature and humidity was negatively correlated with the duration of exposure. For short periods of exposure the survival ofC. inanitus adults was influenced by high temperatures, the lethal exposure time decreased when the parasitoids had been exposed to high temperatures. Change in the saturation deficit did not affect the survival rate. Different kinds of food available in the field such as flowers of cotton and alfalfa, cotton nectars and excretion of common aphids, did not prolong the life span ofC. inanitus adults in comparison with parasitoids that had not received food or water. The 50% mortality of males that had been fed on cane-sugar with water, honey, flowers of alfalfa or flowers of cotton, was 15, 23, 5 and 5 days respectively, while these values for females that had been fed on the same type of food were 23, 35, 5 and 3 days respectively.     

Dietary fructose augments ethanol-induced liver pathology

Certain dietary components when combined with alcohol exacerbate alcohol-induced liver injury (ALI). Here, we tested whether fructose, a major ingredient of the western diet, enhances the severity of ALI. We fed mice ethanol for 8 weeks in the following Lieber-DeCarli diets: (a) Regular (contains olive oil); (b) corn oil (contains corn oil); (c) fructose (contains fructose and olive oil) and (d) corn + fructose (contains fructose and corn oil). We compared indices of metabolic function and liver pathology among the different groups. Mice fed fructose-free and fructose-containing ethanol diets exhibited similar levels of blood alcohol, blood glucose and signs of disrupted hepatic insulin signaling. However, only mice given fructose–ethanol diets showed lower insulin levels than their respective controls. Compared with their respective pair-fed controls, all ethanol-fed mice exhibited elevated levels of serum ALT; the inflammatory cytokines TNF-α, MCP-1 and MIP-2; hepatic lipid peroxides and triglycerides. All the latter parameters were significantly higher in mice given fructose-ethanol diets than those fed fructose-free ethanol diets. Mice given fructose-free or fructose-containing ethanol diets each had higher levels of hepatic lipogenic enzymes than controls. However, the level of the lipogenic enzyme fatty acid synthase (FAS) was significantly higher in livers of mice given fructose control and fructose–ethanol diets than in all other groups. Our findings indicate that dietary fructose exacerbates ethanol-induced steatosis, oxidant stress, inflammation and liver injury, irrespective of the dietary fat source, to suggest that inclusion of fructose in or along with alcoholic beverages increases the risk of more severe ALI in heavy drinkers.     

Sugar concentration and timing of feeding affect feeding characteristics and survival of a parasitic wasp

The availability of food sources is important for parasitoid survival, especially for those that inhabit ecosystems where nectar and honeydew are spatially or temporally scarce. Therefore, the value of even a single meal can be crucial for survival. Psyttalia lounsburyi is a parasitoid, and biological control agent, of the olive fruit fly, Bactrocera oleae. In order to improve our understanding of the basic nutritional ecology of P. lounsburyi and its role in survival we evaluated the effect of a single sucrose meal on the longevity of female and male wasps. We measured the duration of feeding, volume ingested, sucrose consumption, energy content, and longevity of wasps provided with different concentrations of sucrose (0.5, 1, and 2 M) at different times after emergence (0, 1, 2 or 3 days after emergence). Our results showed that longevity was significantly influenced by sucrose concentration and timing of feeding. For females, feeding on sucrose increased the likelihood of survival to varying degrees, ranging from 32.3% to 95.4%, compared to water-only controls. The longest duration of feeding was observed for the highest sucrose concentrations and oldest wasps. The amount of sugar ingested and energy uptake increased, up to a point, as sugar concentration increased. Our results suggest that P. lounsburyi derived greatest benefit from the intermediate concentration (1 M) of sucrose provided 2 or 3 days after emergence. Our study emphasizes the importance of finding balance between increasing longevity and limiting the duration of feeding, and concomitant uptake of nutrients, that is fundamental for survival of the wasp in nature.     

Adult diet affects the life history and host-killing behavior of a host-feeding parasitoid

Neochrysocharis formosa (Westwood), an important biocontrol agent of agromyzid leafminers worldwide, is a host-feeding, idiobiont parasitoid. Female wasps have three types of host-killing behaviors: reproductive (parasitism), non-reproductive host feeding (host feeding), and host stinging without oviposition or feeding (host stinging). In this study, we compared the life history and host-killing behaviors of female parasitoids under four adult diets: starvation, hosts only, hosts plus honey (10% w/v honey solution), and honey only. Furthermore, we analyzed the host-feeding and oviposition preferences of adult females in the hosts-only and hosts-plus-honey treatments. Female parasitoids feeding on hosts had significantly increased longevity, higher fecundity, more host-stinging events, and caused a higher total host mortality than parasitoids in the starvation treatment. The honey supplement significantly increased longevity, fecundity, host-stinging events, and total host mortality, as well as average daily fecundity, but did not alter host-feeding events, host-stinging events, or daily total host mortality. However, the honey supplement did reduce the number of daily host-feeding events and induced a shift toward oviposition. Finally, we found that the non-reproductive host killing caused by host feeding and host stinging enhanced the control potential of N. formosa. These results should contribute to a better understanding of the biocontrol efficiency of destructive host feeders.     

母代高脂饮食诱导子代在小鼠生命早期出现糖脂代谢紊乱且具有雄性易感性

目的：探讨孕期和哺乳期的高脂饮食能否导致子代在生命早期出现糖脂代谢紊乱。方法成年雌性C57BL/6J小鼠与正常饮食雄性小鼠进行交配,孕鼠随机分为高脂饮食组和正常饮食组,在孕期和哺乳期喂养高脂饲料或正常饲料,至交配后第一代鼠断乳时（3周龄）观察其糖脂代谢相关性指标以及肝脏病理表现。结果较正常饮食组子鼠相比,高脂饮食子鼠出生体重更低（ P＜0.05）。在断乳时,高脂饮食组雄性子鼠体重较重（ P ＝0.038）,腹腔糖耐量实验30 min和60 min血糖明显升高（P值分别为＜0.001和＜0.01）,糖耐量曲线下面积较大（P＝0.0016）,HOMA-IR值较大（P＜0.05）,雌性子鼠腹腔糖耐量实验在30 min血糖高于正常组（P＜0.01）,而糖耐量曲线下面积和HOMA-IR值在两组之间无明显统计学意义。雄性和雌性子代小鼠空腹胆固醇水平高脂饮食组均高于正常饮食组（ P值分别为＜0.0001和0.0004）,而两组雄性和雌性子代小鼠空腹胰岛素和甘油三酯水平差异均无显著性（ P均＞0.05）。另外,在断乳时高脂饮食子鼠出现肝脏脂肪变性,雌性和雄性子鼠无明显差异。结论母鼠孕期和哺乳期高脂饮食能够诱导子代在生命早期就能出现糖脂代谢紊乱并且雄性子鼠更易出现肥胖、糖耐量异常、胰岛素抵抗。     

Influence of floral resources on sugar feeding and nutrient dynamics of a parasitoid in the field

Abstract.  1. To investigate how floral resources impact feeding and nutrient dynamics of parasitoids, the ichneumonid Diadegma insulare (Cresson) was monitored in cabbage fields with and without buckwheat Fagopyrum esculentum Moench borders. Biochemical analyses of field-collected wasps determined whether sugar feeding occurred, and whether it enhanced nutrient levels and increased parasitism of diamondback larvae Plutella xylostella (L.) from 2000 to 2003. The effects of experimental spatial scale on sugar feeding dynamics were also evaluated in 2001.
2. The majority of D. insulare foraging on cabbage had fed upon sugar, but floral borders did not consistently increase the proportion of sugar-fed wasps or their levels of glycogen and lipid over all 4 years. Floral borders increased sugar storage by females in 2001. More females fed on sugar when experimental plots were separated by at least 800 m compared with 67 m.
3. Feeding on buckwheat nectar vs. honeydew produced by the soybean aphid Aphis glycines Matsumura in surrounding fields was distinguished using the ratio of fructose to total sugars, which was higher in nectar- than in honeydew-fed parasitoids. Floral borders increased the probability that females collected from adjacent crops were nectar-fed in 2002, demonstrating that floral resources were utilised by foraging parasitoids. Diadegma insulare that fed upon any sugar source had higher levels of sugar and glycogen than unfed wasps, and feeding on honeydew appeared to enhance nutrient storage.
4. The prevalence of sugar or nectar feeding by female D. insulare was not correlated with parasitism rates over the 4 years from all plots, but nectar feeding was positively correlated with parasitism rates within floral plots.