Estimation of the biological age in females of the taiga tick (Ixodes persulcatus: Ixodidae) by changing of fat resources in the organism

The method of estimation of the biological age in hungry tick females by revealing of the degree of lipid inclusions in the cells of the midgut and of the fat body is assumed. In order to estimate the degree of fat reserves in hungry females, live ticks were dissected and fragments of their internal organs were vitally stained with the saturated solution of Sudan III in 70% ethanol. Three age-specific groups were established, including (I) young females whose intestines and fat body were filled with fat inclusions; (II) mature females whose fat reserves were partially expended; and (III) old females possessing solitary fat inclusions in their midgut and fat body.     

Susceptibility of the fat reserves of mice to natural challenges

Summary Many small rodents living in the wild neither store food nor forage during the daytime. Thus they can feed only at night. Imposing this restriction upon young female laboratory mice maintained at 22°C yields a dramatic daily cycle in their fat stores. Energy is rapidly stored as fat while feeding, and then rapidly utilized during the non-feeding period. Almost one-third of the extractable whole body fat is lost during a 14 hour non-feeding period. Less fat is stored while feeding at 11°C. Thus missing a single feeding period at this cooler temperature results in a total depletion of fat stores. In an ultimate sense then, the daily challenge of surviving with such a paucity of fat reserves probably presents as great a problem to the small mammal as does the thermoregulatory cost of small body size itself. Strategies for solving this problem apparently vary immensely from population to population and from locale to locale.     

Trapping oestrid parasites of reindeer: the relative age, fat body content and gonotrophic conditions of Cephenemyia trompeand Hypoderma tarandifemales caught in baited traps

Abstract. Dissection of flies caught in northern Norway revealed that only mated, gravid females of H.tarandi (L.) and larviparous C.trompe (Modeer) were caught in host-mimicking C0₂-baited traps. Trapped females had the same gonotrophic and fat body (FB) conditions as females caught on and around reindeer. Most trapped females of both species were of middle to old age, having only one-half to no FB reserves left and only a few to moderate numbers of eggs or larvae remaining. Most young females trapped also had previously oviposited or larviposited at least once, and some newly eclosed, mated females were present throughout the fly season. Based on the known location of reindeer herds, it was evident that trapped flies that had recently oviposited or larviposited had dispersed into the trapping area from 25–100 km away. Declining FB reserves sustained wild-caught C.trompe females (and in utero larvae) in the laboratory for 14 days and H.tarandi females for 18 days. Reserve FB also was depleted during long flights. Females of both species that flew for the longest times (5.1–11.7 h) on a laboratory flight mill had low FB reserves, but nearly maximum numbers of eggs or larvae. Conversely, most females that flew for less than 5 h on the flight mill had little or no FB remaining, and few eggs or larvae. The large FB reserves accumulated as larvae feed in the vertebrate host enable the non-feeding adults to survive and infect their hosts even after prolonged periods of flight-inhibiting climatic conditions.     

Changes in the age structure of populations of ixodid ticks (Ixodes persulcatus: Ixodinae) in the territory of St. Petersburg and its environs

The age structure of the natural populations of adult Ixodes persulcatus ticks in St. Petersburg and its environs was assessed on the basis of fat reserves in tick midgut and fat body.     

Onset of vitellogenin production and vitellogenesis,and their relationship to changes in the midgut epithelium and oocytes in the tickDermacentor variabilis

InDermacentor variabilis (Say), the onset of vitellogenin production and vitellogenesis (up-take of vitellogenin into oocytes) began during the rapid-engorgement feeding period. Mating was required for both vitellogenin production and vitellogenesis to complete the tick's life cycle. Complete immunological identity, as measured by Ouchterlony's double diffusion test, existed between vitellogenin from the fat body, midgut and hemolymph, and vitellin from the ovaries and eggs. Antivitellin antibody did not react with host hemoglobin nor with fat body, midgut, and ovary extracts from feeding females prior to rapid engorgement, feeding unmated females, or unfed or fed males. Some unmated females fed for 13 days and then hand-detached from the host eventually began oviposition after going through a preoviposition period. In these ticks, organ extracts from the midgut, fat body and ovary reacted with antivitellin antibody. The presence or absence of presumed vitellogenic cells in the midgut and yolk bodies in oocytes corresponded with the presence or absence of vitellogenin and vitellogenesis as measured by Ouchterlony's test. Presumed vitellogenic cells increased in size during the preoviposition period. These cells reached their greatest size during the time when the most eggs were being produced, and then declined in size toward the end of oviposition. Vitellogenin was deposited directly into developing yolk bodies in oocytes and was not processed through lysosomes. Feeding was the process that initiated the formation of eggshell cuticle. Detachment from the host was required for the initiation of oviposition.     

Age-related changes in natural populations of Ixodes pavlovskyi (Ixodinae) from Novosibirsk and its environs

The age structure of I. pavlovskyi natural populations from Novosibirsk and its environs was investigated on the basis of fat reserves in the midgut and the fat body of the ticks.     

Rhipicephalus sanguinius: localization of vitellogenin synthesis by immunological methods and electron microscopy

In ovipositing Rhipicephalus sanguinius (Latrelle), complete immunological identity existed between vitellogenin from the midgut, fat body, and hemolymph and vitellin from eggs. This supported the hypothesis that the same vitellogenin was synthesized by both the midgut and fat body, then released into the hemolymph and transported to the ovary. Vitellogenin was taken up unaltered by the oocytes during vitellogenesis to become vitellin. Antivitellogenin did not react with host (dog) hemoglobin. Transmission electron microscopy showed specialized cells with large amounts of rough endoplasmic reticulum, Golgi complexes, and secretory granules in the midgut and fat body of ovipositing females that were absent in the midgut and fat body of fed males. It is suggested that these cells synthesize vitellogenin.     

Seasonal variation in body composition and morphology of adult muskrats in central Saskatchewan, Canada

We quantified seasonal variation in body composition and morphology of adult muskrats ( Ondatra zibethicus ) inhabiting freshwater marsh environments in central Saskatchewan, Canada. The study areas were characterized by long and cold winters extending over six months during which muskrats were restricted to foraging under ice. A total of 162 adult muskrats were collected during nine sampling periods across the year. The large accumulation of fat reserves (16% of body mass) during winter and the concurrent decline in protein mass suggested a reduced maintenance requirement associated with the presence of energy-rich food resources. Dietary fibre content increased significantly during mid-summer and was manifested by changes in gut morphology. Mobilization of fat reserves during summer months by both sexes reflected high energetic demands for reproduction. Males depleted fat reserves soon after spring break-up, while near-exhaustion of fat reserves in females occurred 4–6 weeks later, during lactation. Pregnant females contained significantly greater fat and protein reserves compared to non-pregnant and lactating females. The dynamics of body reserves in muskrats should be viewed as an integral part of the sex-specific life-history traits of this important herbivore species of marsh environments.     

Timing of eclosion affects diapause development, fat body consumption and longevity in Osmia lignaria, a univoltine, adult-wintering solitary bee

Most insects from temperate areas enter diapause ahead of winter. Species diapausing in a feeding stage and accumulating metabolic reserves during permissive pre-wintering conditions are expected to enter diapause shortly before the onset of winter. In contrast, species diapausing in a non-feeding stage are expected to lower their metabolism as soon as possible to avoid excessive consumption of metabolic reserves. The solitary bee Osmia lignaria winters as a non-feeding adult within its cocoon, but previous studies show important weight losses and increased winter mortality in populations pre-wintered for extended periods. We measured respiration rates to assess diapause initiation and maintenance during pre-wintering, and tested whether timing of adult eclosion affected fitness by measuring fat body depletion, winter mortality and post-winter longevity. We worked with different cohorts of a population reared under natural conditions, and manipulated pre-wintering duration in a population reared under artificial conditions. In agreement with our expectation, O. lignaria lower their metabolic rates within a few days of adult eclosion, but nonetheless suffer strong weight loss during pre-wintering. Early developing individuals suffer greater weight loss and fat body depletion, and have short post-winter longevity. Although, we found no differences in winter mortality among treatments, our results indicate that increased mortality may occur in years with late winter arrivals. We discuss fundamental ecophysiological differences between adult and prepupal diapause within the Megachilidae, and hypothesize that species wintering as adults will be more negatively affected by a situation of extended summers under a scenario of global warming.     

Juvenile hormone metabolism in the plasma,integument, midgut,fat body,and brain during the last instar of the tobacco hornworm,Manduca sexta (L.)

Juvenile hormone (JH) III esterase and JH III epoxide hydrolase activity was found in the integument, midgut, fat body, and brain during last instar development of the tobacco hornworm, Manduca sexta. JH esterase activity was primarily located in the cytosol in these tissues while the majority of the JH epoxide hydrolase activity was found in the microsomes. A prewandering (on day 3) and postwandering (on day 8) peak in plasma JH III esterase activity occurs in the last instar of gate I M. sexta. The JH esterase activity profile in integument, midgut, fat body, and brain followed a similar pattern to that of the plasma. The only exception to this was the absence of the postwandering, prepupal (on day 8) JH esterase peak in the fat body. The topical application of the juvenoid, (RS)-methoprene, failed to induce fat body JH esterase activity but increased activity in the plasma, integument, midgut, and brain in M. sexta prepupae. These results indicate that the source of plasma JH esterase activity is not always the fat body as previously hypothesized. The developmental profile of tissue JH epoxide hydrolase activity was also similar to that of JH esterase suggesting that both enzymes may be regulated partly by the same factors and that JH epoxide hydrolase may also have an important, previously unrecognized functional role in JH regulation and insect metamorphosis. Multiple isoelectric forms of tissue-specific JH esterases and JH epoxide hydrolases were found in integument, midgut, fat body, and brain. The JH esterases in these tissues had isoelectric points more acidic than that for plasma. Tissue α-naphthyl acetate esterase, developmental profiles, and inhibitor sensitivity to 3-(octylthio)-1,1,1-trifluoropropan-2-one differed significantly from that for JH esterase, suggesting that they represent different enzymes. ©1992 Wiley-Liss, Inc.     

Absorption and tissue distribution of cholesterol in Manduca sexta

In Manduca sexta larvae, radioactive free cholesterol is absorbed directly from the midgut into mucosal cells where it is stored both in the free form (87% in males and 93% in females) and esterified form (13% in males and 7% in females). Subsequently, cholesterol is transported to fat body via lipophorin in the hemolymph exclusively in the free form. In fat body, the distribution of cholesterol between the free and esterified form varied significantly between genders and developmental stages. Except for the larval stage, males and females were able to store cholesterol in both free and esterified forms in the fat body and in the adult stage cholesterol ester accounted for more than 75% of the stored cholesterol. Placement of radioactive cholesterol at different locations in the gut-foregut, midgut, and hindgut-demonstrated that the midgut is the site where cholesterol is absorbed and released into the hemolymph. Cholesterol-labeled lipophorin injected into larval hemolymph was cleared from the hemolymph with a half-life of 10.2 h. After 17 h, most of the cleared radioactivity was recovered in the fat body (38%). Arch.     

Lipid dynamics in the viperine snake, Natrix maura, from the Ebro Delta (NE Spain)

Body reserves play a major role in several aspects of vertebrate biology. Accurate identification and quantification of body reserves constitute a useful contribution to the better understanding of the energetic costs of reproduction and the implication of food availability in life history traits of organisms. In this study, lipid content in fat bodies, liver and muscle of the viperine snake (Natrix maura) were measured along an active season. Samples were collected monthly from a natural population of the Ebro Delta Natural Park (NE Spain). This methodology pointed out that lipids stored in fat bodies were the main energetic source during reproduction. In addition, lipids stored in liver appeared to be critical for vitellogenesis, while lipids stored in muscle turned out to be a supplementary energetic resource to fuel reproductive effort. Relationships between changes in body reserves and prey availability in canals of the Ebro Delta were also considered. In males, lipid reserves presented a positive correlation with food availability. On the contrary, lipid reserves in female viperine snakes decreased during vitellogenesis even though food availability increased in this period, which suggests a quick transfer of body lipids to clutch. In April, when rice fields of the Ebro Delta were dry and aquatic prey was scarce for viperine snakes, males and females presented a lower lipid content in fat bodies, liver and muscle than they did in other months, showing a clear link between prey availability and body reserves during food shortage. Thus, patterns of variation in fat levels indicated that Natrix maura is a capital breeder since it acquires resources in advance and stores them until they are invested during the reproductive period. Nevertheless, the shortage in April forces Natrix maura to turn into a facultative income breeder to fuel vitellogenesis. Finally, fat reserves in body components were compared with an estimate of body condition calculated by the residuals from the regression of body mass on body length. In male viperine snakes, the estimate of body condition was correlated with fat levels, revealing that this index is useful to measure condition in living individuals. On the contrary, body condition in females was not correlated with fat levels, which suggests that it is not appropriate to infer condition in female viperine snakes since it depends on the reproductive status of the individuals.     

Flying to feed or flying to mate: gender differences in the flight activity of tsetse (Glossina palpalis)

Abstract. To test the prediction that female and male tsetse should differ in their behaviour and the partitioning of their energy budgets to maximize their respective reproductive outputs, we investigated experimentally the relationship between blood intake, fat content and flight activity in virgin and mated female flies, following the same procedure as in a previous study on males.Those flies whose fat content was raised to higher levels by being fed more frequently performed more flight activity, but all females showed very little activity until day 4 after their last blood meal, thereby using only a small fraction of their fat reserves.This contrasted markedly with the large amount of flight performed by males on day 3, resulting in the depletion of their fat reserves.The difference is interpreted with respect to females flying only to find food approximately once every 3 days (and larviposition sites approximately once every 9 days), compared with males flying to find as many mates as possible during the earlier part of the feeding cycle when their energy reserves are high and feeding is a low priority.     

Correlated response in body condition and energy mobilisation in rabbits selected for litter size variability

A divergent selection experiment on litter size variability (high and low lines) was performed in rabbits over seven generations. The aim of this study was to evaluate the correlated responses to selection in body condition and fat reserves mobilisation. Litter size variability was estimated as phenotypic variance of litter size within female after correcting for the year-season and the parity-lactation status effects. A total of 226 females were used in this study, of which 158 females were used to measure body condition and energy mobilisation. Body condition was measured as BW and perirenal fat thickness. Females were stimulated with the adrenergic isoproterenol. Mobilisation capacity of fat reserves was measured by the lipolytic potential, defined as the increment in non-esterified fatty acids (NEFA) levels from basal concentration until adrenergic stimulation at mating, delivery and 10 days after delivery of the second reproductive cycle. Females were classified as survivor or non-survivor when they were culled for sanitary reasons or died before the third kindling. Data were analysed using Bayesian methodology. Survivor females presented higher BW than the non-survivor females at delivery (238 g, P=1.00) and 10 days after delivery (276 g, P=1.00). They also showed higher perirenal fat thickness at 10 days after delivery (0.62 mm, P=1.00). At delivery, basal NEFA levels was lower in survivor than non-survivor females (−0.18 mmol/l, P=1.00), but their lipolytic potential (∆NEFA) was higher (0.08 mmol/l, P=0.94). Body weight was similar between lines in survivor females. Perirenal fat thickness was lower in the high line than in the low line at delivery (−0.23 mm, P=0.90) and 10 days after delivery (−0.28 mm, P=0.92). The high line exhibited higher NEFA (0.10 mmol/l, P=0.93) and lower ∆NEFA (−0.08 mmol/l, P=0.92) than the low line at delivery. The low line showed a favourable correlated response to selection on body condition and fat reserves mobilisation. In conclusion, the low line selected for litter size variability seems to adapt better to adverse conditions, as it has a greater capacity to mobilise energy reserves at delivery than the high line. Females that adequately manage their body reserves and perform energy mobilisation correctly have a lower risk of dying or being culled.     

摄入异烟肼对家蚕幼虫体内谷胱甘肽氧化还原循环和谷胱甘肽S-转移酶活性的影响

为了建立家蚕Bombyx mori的药物筛选和毒性评价模型, 以剂量为2 000 mg/kg的抗结核模药异烟肼饲喂家蚕5龄第3天幼虫后检测其中肠和脂肪体的抗氧化解毒相关代谢的变化。结果表明： 雌蚕中肠组织中, 总谷胱甘肽(GSH+2GSSG)、 还原型谷胱甘肽(reduced glutathione, GSH)和氧化型谷胱甘肽(oxidized glutathione, GSSG)含量均呈现迅速上升再缓慢下降趋势; 谷胱甘肽S 转移酶(glutathione S-transferase, GST)活性升高到较大值后逐渐降低; GSH/GSSG的比值下降表明, 在72 min后中肠组织向氧化态转移。脂肪体组织中, 总谷胱甘肽、 GSH和GSSG含量变化均呈现迅速下降再迅速上升的趋势; GST活性达到最大值后逐渐降低后趋于平稳; GSH/GSSG比值升高表明, 在72 min后脂肪体组织向还原态转移。无论雌蚕还是雄蚕, 总谷胱甘肽、 GSH和GSSG含量以及GST活性均是脂肪体高于中肠。雌蚕的总谷胱甘肽含量、 GSH和GSSG含量高于雄蚕, 但雄蚕的GST活性高于雌性。结果说明, 摄入异烟肼引起了家蚕幼虫体内谷胱甘肽氧化还原状态的改变和酶活性的变化, 在这个过程中脂肪体起主要解毒代谢作用。     

The role of the fat body, midgut and ovary in vitellogenin production and vitellogenesis in the female tick, Dermacentor variabilis.

Polyclonal antibodies directed against D. variabilis vitellin were utilized for immunocytochemistry at the ultrastructural level. We localized vitellogenin (Vg) in rough endoplasmic reticulum cisternae, secretory granules and secreted products of fat body trophocytes and midgut vitellogenic cells from feeding and ovipositing females. Vg was localized in the oocyte Golgi bodies and in the yolk bodies of both feeding and ovipositing females. Uptake of exogenous Vg was indicated by the presence of immunospecific gold probe in coated pits and coated vesicles at the apical plasma membrane of oocytes from females in rapid engorgement and oviposition. In unmated females little detectable evidence of Vg uptake by developing oocytes suggests that mating and host detachment signal the beginning of vitellogenesis. We conclude that fat body trophocytes, midgut vitellogenic cells and oocytes are involved in the synthesis and/or processing of Vg and that feeding is the signal associated with the initiation of Vg synthesis and/or processing.     

Changes in body condition of hibernating bats support the thrifty female hypothesis and predict consequences for populations with white-nose syndrome

White-nose syndrome (WNS) is a new disease of bats that has devastated populations in eastern North America. Infection with the fungus, Geomyces destructans, is thought to increase the time bats spend out of torpor during hibernation, leading to starvation. Little is known about hibernation in healthy, free-ranging bats and more data are needed to help predict consequences of WNS. Trade-offs presumably exist between the energetic benefits and physiological/ecological costs of torpor, leading to the prediction that the relative importance of spring energy reserves should affect an individual''s use of torpor and depletion of energy reserves during winter. Myotis lucifugus mate during fall and winter but females do not become pregnant until after spring emergence. Thus, female reproductive success depends on spring fat reserves while male reproductive success does not. Consequently, females should be “thrifty” in their use of fat compared to males. We measured body condition index (BCI; mass/forearm length) of 432 M. lucifugus in Manitoba, Canada during the winter of 2009/2010. Bats were captured during the fall mating period (n = 200), early hibernation (n = 125), and late hibernation (n = 128). Adult females entered hibernation with greater fat reserves and consumed those reserves more slowly than adult males and young of the year. Consequently, adult females may be more likely than males or young of the year to survive the disruption of energy balance associated with WNS, although surviving females may not have sufficient reserves to support reproduction.     

2-十三烷酮对棉铃虫细胞色素P450的诱导作用

将2-十三烷酮按0.005%～0.01%（重量比）的浓度加到棉铃虫人工饲料中,连续诱导3代,测定棉铃虫中肠和脂肪体中细胞色素P450(cyt-P450)含量以及与标准配基（正丁醇、吡啶、苯胺、环己烷）形成的氧化型结合光谱。2-十三烷酮诱导品系的中肠cyt-P450与CO结合光谱的最大吸收峰在449 nm处,脂肪体cyt-P450与CO结合光谱的最大吸收峰在450.7 nm处。中肠cyt-P450除了在450 nm附近存在一个吸收峰外,在通入CO后依次在414、415、418 nm附近出现吸收峰,随后该峰消失,随着时间的推移（第31次扫描）在420 nm处又开始出现一个弱吸收峰。2-十三烷酮诱导品系的中肠、脂肪体cyt-P450与4种标准配基形成的差光谱与对照相比在峰型上存在着不同程度的差异。中肠cyt-P450与正丁醇形成双峰双谷的光谱;脂肪体cyt-P450与正丁醇形成的光谱最大吸收峰在416.61 nm处,波谷在424.91 nm处;中肠cyt-P450和脂肪体cyt-P450与吡啶形成的光谱为典型的Ⅱ型光谱,而与环己烷形成的光谱为不典型Ⅰ型光谱;中肠和脂肪体的cyt-P450与苯胺形成典型的Ⅱ型光谱,最大吸收峰分别在443.30和428.92 nm处,最小吸收分别在402.30和401.00 nm处。     

The piRNA response to BmNPV infection in the silkworm fat body and midgut

Bombyx mori nucleopolyhedrovirus (BmNPV) is a DNA virus that causes huge losses to the silkworm industry but the piRNA responses during BmNPV infection in the silkworm remain uninvestigated. Here, silkworm piRNA profiles of uninfected and BmNPV-infected fat body and midgut were determined by high-through sequencing in the early stages of BmNPV infection. A total of 2675 and 3396 genome-derived piRNAs were identified from fat body and midgut, respectively. These genome-derived piRNAs mainly originated from unannotated instead of transposon regions in the silkworm genome. In total, 572 piRNAs were associated with 280 putative target genes in fat body and 805 piRNAs with 380 target genes in midgut. Compared to uninfected tissues, 322 and 129 piRNAs were significantly upregulated in BmNPV-infected fat body and midgut, respectively. In addition, 276 and 117 piRNAs were significantly downregulated. Moreover, differentially expressed (DE) piRNAs during BmNPV infection differed significantly between fat body and midgut. Putative DE piRNA–targeted genes were associated with “response to stimulus” and “environmental information processing” in fat body after infection with BmNPV, which may indicate an active piRNA response to BmNPV infection in fat body. This study may lay the foundation for future research of the potential roles of the piRNA pathway and specific piRNAs in BmNPV pathogenesis.     

Energetics of reproduction in female and male greater snow geese

Arctic-nesting geese are classified as capital breeders (i.e., birds that rely largely on endogenous reserves to meet the high nutrient requirement of clutch formation) as opposed to income breeders (those that rely directly on ingested food). However, some evidence has suggested that energy reserves of greater snow geese (Chen caerulescens atlantica) are not sufficient to meet these costs. We tested whether greater snow geese were capital breeders and examined the consequences on their reproductive strategy. We collected 48 females and 47 males from arrival at the breeding colony on Bylot Island (NWT) to the postlaying stage, and determined fat and protein content in somatic and reproductive tissues. Rapid follicular growth was initiated only after arrival on the breeding ground. Somatic fat of females tended to increase during the prelaying and laying stages at the same time that most of the fat was deposited in developing follicles. Decrease in somatic fat in postlaying females was mostly related to its use for meeting metabolic requirements during early incubation. Hence, almost all fat invested in the clutch came from food intake, not endogenous reserves. Somatic protein was maintained during prelaying but decreased during laying, suggesting that some protein reserves were deposited in the eggs. There was no relationship between somatic fat and the number of developing follicles (incubating females excluded) but a relationship was found with somatic protein. Clutch size was not related to body size. In males, somatic fat, which was similar to females at arrival, was almost completely depleted by the postlaying stage. Male somatic protein remained stable. Male somatic reserves were not related to the somatic reserves, clutch size or nutrient investment in reproduction of their mate. We conclude that, in female greater snow geese, little fat reserves (if any) were used for egg formation though some protein reserves were used, whereas males relied heavily on their fat reserves during the same period. This is probably a consequence of the long and costly migration between the last staging area and the breeding grounds.