Quantitative relationships between the ingestion of protein-rich material and ovarian development in the Australian sheep blowfly,Lucilia cuprina (Wied.)

The mature ovaries accounted for about 25% of dry weight and 30% of the protein content of wild-type (anautogenous) females of L. cuprina which had fed ad lib. on liver. The protein content of gravid females was 50% greater than at emergence. Protein ingested during the adult stage, therefore, plays an important role in ovarian maturation. The protein content of the ovaries of females fed measured amounts of liver exudate was from 37 to 52% of the amount of protein ingested.

Only limited ovarian development occurred in females fed only protein (high MW fraction of liver exudate or bovine serum albumin). The presence, in addition, of low MW components (low MW fraction of liver exudate or a salt mixture) was necessary for ovarian maturation. Quantitative feeding showed that the high and low MW fractions of liver exudate were, respectively, superior to bovine serum albumin and the salt mixture, which was based on the cation analysis of the low MW fraction of the exudate.     

The effect of sugar meals and body size on fecundity and longevity of female Aedes communis(Diptera: Culicidae)

Abstract. Starved females of Aedes communis (DeGeer) had significantly shorter mean lifespans than females with access to one blood meal and/or sugar meals. For the starving females, lifespan was significantly correlated with wing length. This correlation was not found in sugar- and/or blood-fed females. Fructose and sucrose had similar effects on mosquito lifespan. The 25% and 50% (w/w) solutions of each, increased mean lifespans to 37.8 ± 7.2 and 34.9 ± 9.1 days, respectively. A 10% solution, of either sugar, was significantly inferior, mean lifespan 23.2 ± 10.2 days. The initial sugar meal was very important for female longevity. Subsequent meals aided in ovarian development. One sugar meal, one blood meal, and several sugar meals during oogenesis was found to be the optimal diet for the female mosquitoes in this study.     

Physiological aspects of multiple blood feeding in the malaria vector Anopheles tessellatus

The malaria vector Anopheles tessellatus is able to take several blood meals in a gonotrophic cycle. The fecundity is largely dependent on the first blood meal and is not generally increased by subsequent blood meals during a gonotrophic cycle. Larval rearing densities influenced adult body size. There is an inverse relationship between wing length and larval rearing densities. Smaller mosquitoes produced from larvae reared at higher densities had reduced body reserves of protein, lipid and carbohydrates. At emergence, ovarian development in An. tessellatus is in the previtellogenic stage and it remained at this stage until the intake of a blood meal. The number of ovarian follicles is related to wing length and, irrespective of adult body size, An. tessellatus developed oocytes to maturity with a single blood meal. This is attributed to the availability of metabolic reserves above the threshold level required for further development of oocytes. Mosquitoes that took more than one blood meal had largely digested their previous blood meal and had ongoing vitellogenesis. Blood meals subsequent to the first one apparently contribute mainly to increasing metabolic reserves. The stimulus for a second and third blood meal in An. tessellatus appears to be completion of the digestion of the previous blood meal. There was no evidence that multiple blood meals taken in the first gonotrophic cycle influenced fecundity significantly in the second cycle.     

Antagonistic effects of energy status on meal size and egg-batch size of Aedes aegypti (Diptera: Culicidae).

The effect of sugar feeding on egg-batch size in Aedes aegypti was examined in a way that would distinguish between the roles of a recent sugar meal (full vs. empty crop) and of repeated sugar feeding and digestion (high vs. low energy reserves). Egg numbers of females representing the four combinations of these characteristics (full crop/high reserves, full crop/low reserves, empty crop/high reserves, empty crop/low reserves) were counted during their first gonotrophic cycle. In addition, the sizes of their replete sugar meals and human blood meals were measured to understand the interactions between them. Results demonstrated that blood-fed mosquitoes with full crops and low energy reserves produced the fewest eggs (mean = 56.2); those with empty crops and high energy reserves produced the most eggs (mean = 84.6); and those with the opposite combinations (full/high and empty/ low) had an intermediate fecundity (mean = 75.2 and 76.9, respectively). This ranking of fecundities did not correspond to blood-meal size ranks, owing to direct and indirect effects of energy reserves on meal sizes and egg number. Full-crop females with low reserves ingested the smallest blood meals (mean = 0.62 mg) and had the lowest fecundities. Full-crop females with high reserves ingested more blood (mean = 0.82 mg) and produced more eggs. But empty-crop females with low reserves ingested the largest blood meals (mean = 1.19 mg), yet produced significantly fewer eggs than their high-reserve counterparts, which took smaller blood meals (mean = 0.99 mg). These results demonstrate extremes in the reproductive penalty of crop sugar and the reproductive reward of digested sugar. Energy reserves and an empty crop are similarly valuable in promoting fecundity at the time blood is taken.     

柑桔爆皮虫卵巢发育动态

本研究利用室内饲养成虫,对柑桔爆皮虫的蛹及正常取食和交配、正常取食但未交配以及正常交配但未取食三种处理的雌成虫的卵巢发育进行了系统观察。结果显示：该虫具有1对卵巢,每侧有5根卵巢管。前两种处理的雌虫卵巢管均能正常发育,成虫寿命在30天左右; 没有取食的雌虫寿命只有7天左右,在其卵巢管的生长区和成熟区均无卵形成。根据卵巢的形状、卵的产生过程、卵巢萼内有无卵粒以及卵黄沉积情况等将卵巢发育程度分为6个级别,即发育初期（0级）、卵黄沉积前期(Ⅰ级)、卵黄沉积期(Ⅱ级)、成熟待产期(Ⅲ级)、产卵盛期(Ⅳ级)和产卵末期(Ⅴ级)。每头雌虫最高怀卵量在140粒左右,根据雌虫怀卵量变化趋势,推测正常取食和交配的柑桔爆皮虫雌虫在出孔后10天左右开始产卵,产卵历期可达22天左右。据此提出该虫卵巢管发育到成熟待产期(Ⅲ级)之前（即羽化出孔后10天之内）为出孔成虫的防治适期。     

Gonadal development and diandric protogyny in two populations of Dascyllus reticulatus from Madang, Papua New Guinea

Two Dascyllus reticulatus populations from Madang, Papua New Guinea exhibited diandric protogyny. In both populations, gonads began as undifferentiated, and then developed oocytes in the primary growth stage and an ovarian lumen. From this ovarian state or from more developed ovaries containing oocytes beyond the primary‐growth stage, some gonads developed into testes. The first sign of testicular development was degeneration of oocytes, degeneration of oocytes in the primary growth stage in ovarian gonads and degeneration of oocytes of all growth stages present including the primary growth stage in ovaries, which was then followed by development of spermatogenic tissue. In both populations, most of the fish that had gonads with degenerating oocytes were smaller than the smallest mature females, indicating that development towards testes was mostly initiated in immature gonads containing only pre‐vitellogenic oocytes. On some occasions, however, females as large as other mature females also had gonads with degenerating oocytes, suggesting that development towards testes may have occurred in mature ovaries as well. This latter notion is further strengthened by the discovery of a fish having a gonad that contained both degenerating vitellogenic oocytes and developing spermatogenic tissue. Taken together, these results suggest that D. reticulatus can exhibit diandric protogyny, because testes in D. reticulatus developed from juvenile gonads as well as from mature ovaries.     

Effect of meal viscosity and nutrients on satiety, intragastric dilution, and emptying assessed by MRI

The relationship between the intragastric distribution, dilution, and emptying of meals and satiety was studied using noninvasive magnetic resonance imaging techniques in 12 healthy subjects with four polysaccharide test meals of varying viscosity and nutrient content as follows: 1) low-viscosity nonnutrient, 2) low-viscosity nutrient, 3) high-viscosity nonnutrient, and 4) high-viscosity nutrient. Increasing the nutrient content of the high-viscosity meal delayed gastric emptying from 46 +/- 9 to 76 +/- 6 min (P < 0.004), whereas increasing viscosity had a smaller effect. The volume of secretions within the stomach 60 min after ingestion was higher for the high-viscosity nutrient meal (P < 0.04). A simple model to calculate the total volume of secretion added to the test meal is presented. Color-coded dilution map images showed the heterogeneous process of progressive gastric dilution of high-viscosity meals, whereas low-viscosity meals were uniformly diluted. Fullness was found to be linearly related to total gastric volumes for the nutrient meals (R(2) = 0.98) and logarithmically related for the nonnutrient meals (R(2) = 0.96). Fullness was higher for high- compared with low-viscosity meals (P < 0.02), and with the nutrient meals this was associated with greater antral volumes (P < 0.05).     

瓜实蝇卵巢的发育阶段及分级

瓜实蝇是热带和亚热带地区最重要的经济害虫之一。本研究拟对卵巢发育进行分级,以判断田间捕获的瓜实蝇是否达到性成熟。室内饲养瓜实蝇成虫,对开始羽化至羽化后80 d的不同日龄成虫卵巢进行解剖,并记录了卵巢长度、卵巢宽度、卵巢指数（卵巢长度＆#215;卵巢宽度）和所含卵粒数。将瓜实蝇卵巢发育过程分为4期6个级别,分别为卵黄发生前期（Ⅰ级和Ⅱ级）、卵黄发生期（Ⅲ级和Ⅳ级）、抱卵期（Ⅴ级）、经产期（Ⅵ级）。随着卵巢的发育,Ⅰ～Ⅴ级卵巢长度和宽度迅速增长,卵巢发育成熟开始产卵以后,Ⅵ级卵巢长度和宽度逐渐减小。Ⅰ级和Ⅱ级卵巢长度与宽度大致相等,以后各期卵巢长度均大于宽度。Ⅲ级和Ⅳ级可见清晰的卵室,卵母细胞迅速增长,卵黄逐渐沉积。Ⅴ级可见清晰的卵粒,整个卵巢呈圆柱状。Ⅵ级开始排出卵子,所含卵粒数显著少于Ⅴ级;虽然此级卵巢长度大于Ⅳ级,但卵巢宽度、卵巢指数与Ⅳ级基本一致;Ⅵ级卵巢可见黄体,可结合黄体判定卵巢所处发育级别。本研究对评估粘虫板捕获的瓜实蝇雌虫生理日龄结构有潜在应用价值。     

Reproductive physiology of Anopheles gambiae and Anopheles atroparvus.

When exposed to a human host, Anopheles gambiae started probing 4 h post-eclosion, but 95% successfully blood-fed by 16-20 h with maximal blood volumes of 5- 10 microl per female. When fed sugar, the 95% feeding was not observed until 36-40 h post-eclosion; sugar meals appeared to interfere with blood meals. Similarly in An. atroparvus, maximum volumes were 10 microl when starved but only 6 microl when fed sugar. This species did not bite before 2 d, and 95% biting was by 4 d. Given single blood meals to water-kept An. gambiae, a threshold body size for oogenesis was detected. With wing lengths below 2.8 mm, eggs never matured, but when sugar-fed, females of all sizes matured eggs including the synthesis of maternal deposits. Although sugar feeding interfered with blood feeding, more lipid was transferred to the yolk. In water-kept An. atroparvus only 5% of the females produced eggs. When sugar-fed for 4 d, all females matured eggs, so in this species sugar feeding appeared to be essential for oogenesis. An. gambiae always took multiple blood meals, tested at any time after the first ones, leading to 120 mature eggs/female. Yolk composition was 3.9 mcal protein and 3.8 mcal lipid/oocyte when kept on water, but 2.8 meal protein and 4.3 mcal lipid/oocyte with intermittent sugar meals, thus marking a surprising flexibility in synthesis of yolk protein and lipid that strongly depends on additional carbohydrates sources. Only 80% of water-fed An. atroparvus re-fed 2 d after a first blood meal with small females taking three blood meals but they still showed reduced fecundity. Only the large water-fed females matured eggs, with blood volumes higher than 9-12 microl. When fed sugar, the blood meal input was reduced, but oogenesis was possible, whereas water-fed females required three blood meals to reach the caloric level comparable to pre-feeding sugar-fed females. Water-fedAn. gambiae could survive on daily blood meals alone, but survival was further extended by intermittent sugar meals. When offered a blood donor daily, there was a behavioral difference. Females maintained alone showed a more or less regular 3 d feeding and oviposition activity, while females kept in groups fed daily followed a daily oviposition pattern, suggesting gonotrophic discordance.     

Assessment of cytoplasmic effects on the development of mouse embryonic nuclei transferred to enucleated zygotes

In this study, cytoplasmic effects on the development of nuclear transplant embryos were examined. In addition, the production of offspring from nuclear transplant embryos was attempted. Nuclei from cleavage-stage embryos were transplanted to enucleated zygotes at different cell cycle stages and with different cytoplasmic volumes. A greater developmental rate to the blastocyst stage was observed in reconstituted late stage zygotes that received nuclei from late 2-cell stage embryos than in early stage zygotes (46.3% vs. 16.9%). A further increase in developmental rate to the blastocyst stage (85.5%) and in cell number was obtained in reconstituted late stage zygotes with reduced cytoplasmic volume. However, developmental potential of nuclei from 4- and 8-cell stage embryos was very limited, although they were transferred to enucleated late stage zygotes with reduced cytoplasm. After the transfer of blastocysts derived from nuclear transplant embryos to recipient females, live young were obtained from reconstituted embryos that received nuclei from late 2-cell stage embryos (28.6%). These results confirm that the development of nuclear transplant embryos can be affected by recipient cell cycle stage and cytoplasmic volume. Furthermore, the nuclei from late 2-cell stage embryos in which activation of the embryonic genome had occurred can be reprogrammed to a certain extent when transplanted into enucleated zygotes, especially late stage zygotes with reduced cytoplasmic content.     

Inhibition of testicular growth and development in Manduca sexta larvae parasitized by the braconid wasp Cotesia congregata

Tobacco hornworm larvae parasitized by the gregarious larval endoparasitoid Cotesia congregata exhibited an inhibition in testicular growth and development, the extent of which was determined by the age and developmental stage of the host at the time of parasitization. The degree of parasitic castration, as assessed by measurements of testicular volume, was correlated with the stadium in which parasitization occurred. A mathematical formula requiring the measurement of testicular length, width and depth was used to calculate testicular volume. The use of the depth parameter revealed a negative correlation between host weight and testicular volume in parasitized larvae. Testicular volumes of fifth instar hosts, which had been parasitized in the first stadium, were significantly smaller than those originally parasitized as fourth or fifth instar larvae and were not correlated with parasitoid load. Effects of natural parasitism were not duplicated by injections of C. congregata polydnavirus and venom, topical treatment with the juvenile hormone analog methoprene, or starvation of nonparasitized larvae. Larvae receiving virus plus venom or methoprene grew larger due to delayed wandering and had larger testes than controls. Deleterious effects on host testes may be due to the effects of nutrient competition between the developing parasitoid progeny and the gonads, combined with the juvenilizing effects believed to be caused by the polydnavirus.     

Do protein-limited female Lucilia cuprina (Diptera: Calliphoridae) obtain a nutritional benefit from mating?

Abstract. Cohorts of adult female Lucilia cuprina Wiedemann (Diptera: Calliphoridae) were fed a single 5 μl droplet of liver exudate after which half the females were allowed to mate and the other half left as virgins. Females were housed individually with water and sucrose for between 4 and 7 days after mating. Females were dissected to record the level of ovarian development and the size of their primary oocytes. Mating did not give protein-limited females any significant nutritional benefit in terms of either increased oocyte development, yolk deposition or oocyte size. Hence, it is concluded that male L.cuprina do not provide females at mating with any obvious material benefits beyond their sperm.     

The influence of food concentration and container volume on life history parameters of Diaptomus dorsalis Marsh from subtropical Florida

Two experiments were conducted with a subtropical calanoid, Diaptomus dorsalis Marsh 1907, to determine the influence of food concentration and the volume of medium per copepod (one copepod in each of several containers of different volumes) on post-embryonic development rates, adult body size, clutch size, survivorship and sex ratio. Low concentrations of food (Chlamydomonas reinhardti) decreased development rates, body size, clutch size and survivorship; the sex ratio did not vary significantly from 1:1. Small container volumes had the same effects as low food concentrations, except that naupliar development time was not affected and survivorship showed greater variability. Because the copepod parameters exhibited maximum responses when food was abundant, even in the smallest container volume, it was concluded that container volume did not directly influence these parameters but exerted its effect through food availability.Larger life history stages were affected more than smaller life history stages by low food levels. In part, this was attributed to a laboratory artifact in which depletion of food by larger animals was greater than by smaller animals and, in part, to a real effect of low food concentration. A possible explanation of this real effect came from comparisons of these results to data from D. dorsalis fed phytoplankton from a Florida lake. The comparisons suggested that nauplii may be more efficient feeders on, or utilizers of, small food items such as Chlamydomonas.     

The relationship of age and ovarian development to mating of Delia antiqua (Diptera: Anthomyiidae)

Abstract. The relationship between age and sexual receptivity for male and female onion flies, Delia antiqua (Meigen) (Diptera: Anthomyiidae), and factors affecting ovarian development were examined under various conditions. Confinement in small arenas had a significant negative effect on the rate of oogenesis over the first 10 days of adult life and, in some cases, on the percentage of females inseminated. The rate of oogenesis was not affected by male population density, but high density of females in large arenas appeared to have a priming effect. Few males in single-pair mating bioassays conducted over 24 h were sexually mature at 3–4 days post-eclosion, but > 50% mated when aged 6–7 days. Although females first mated at 3–4 days post-eclosion when confined for 24 h with sexually mature males, most females mated at 6–7 days of age when oocytes in the terminal ovariole position comprised 50% of total egg volume (stage 7 or greater on a 10-stage scale). No females aged 3 days were mated in no-choice and two-choice bioassays with sexually mature males over 24 h. Previtellogenic females (stage 3) were not inseminated, and ovarian development was only correlated weakly ( r = 0.48) with mating. Frequency of mating in mixed-sex groups of twenty flies was comparable with that in single pairs. However, more females were inseminated at 3–4 days, probably as a result of multiple matings by a few precocious males. These results do not support the hypothesis that females mate only when ovarioles are mature.     

Precocene is not a specific antigonadotropic agent in adult female Aedes aegypti

ABSTRACT. In the mosquito, Aedes aegypti , other workers have shown that prior to blood-feeding a pre-vitellogenic period ensues manifested by the growth and differentiation of ovarian follicles. This results in resting stage follicles which will then complete ovarian development after the blood-meal. Allatectomy of newly emerged females prevents follicles from reaching their resting stage and such follicles do not undergo subsequent vitellogenesis after blood-feeding. Precocene II, a plant substance which effectively prevents ovarian development in Oncopeltus fasciatus by causing the irreversible degeneration of the corpus allatum, was applied to newly emerged mosquitoes, and at various times after blood-feeding. Sublethal doses of precocene applied 1 h after adult emergence had no effect on pre-vitellogenic follicular development and did not prevent yolk deposition after the blood-meal. Precocene applied after blood-feeding had two major effects. When administered early, it inhibited trypsin synthesis and retarded ovarian maturation. Animals exposed to it later, exhibited abnormal oviposition. It is proposed that precocene II does not act as an antigonadotropic agent in adult Aedes aegypti , but that it does induce a general toxic state in treated animals.     

Oöcyte resorption during ovarian development in the blowfly Lucilia cuprina

Nulliparous females of a normal anautogenous strain of Lucilia cuprina mature all of their primary oöcytes after feeding ad lib on sheep's liver. Females fed measured inadequate amounts of protein-rich materia either fail to mature any oöcytes or mature less than their full complement. These mature oöcytes are smaller than in ad lib fed females. In females maturing no oöcytes, ovarian development ceases with all oöcytes in a pre-vitellogenic or early vitellogenic stage. When females mature only some of their oöcytes, the remainder are resorbed in early vitellogenesis. Few females mature less than 100 oöcytes, if they mature any at all.     

饥饿和交配对小地老虎飞行肌发育的影响

小地老虎Agrotis ypsilon(Rottemburg)成虫飞行肌的发育常受一些因素影响而发生变化,为探讨饥饿和交配行为对飞行肌发育的影响,通过电子显微镜对雌虫飞行肌(背纵肌)的肌原纤维、线粒体结构进行观察,结果显示:4日龄饥饿雌虫,肌原纤维直径、肌节长度、肌原纤维体积均显著(P<0.05)小于取食的。7日龄饥饿雌虫肌原纤维直径、肌节长度、肌原纤维体积分数较4日龄的差异均不显著(P≥0.05),而7日龄饥饿的肌原纤维直径显著(P<0.05)大于7日龄取食的;羽化10 d后,饥饿雌虫肌节长度显著(P<0.05)大于取食雌虫的,而肌纤维体积分数和线粒体体积分数均却小于后者。7、10、13日龄交配雌虫肌原纤维横切直径分别显著(P<0.05)小于同日龄非交配的;7、10、13日龄交配雌虫肌原纤维体积分数显著(P<0.05)小于非交配的,线粒体体积分数虽然无差异(P≥0.05),但是交配雌虫的早在4日龄便已明显(P<0.05)减小。上述结果表明:正常取食的小地老虎飞行肌4日龄后会发生降解现象;饥饿抑制飞行肌前期发育和中期的降解,而促进成虫末期肌原纤维的分解;交配能促进飞行肌的降解。     

Enzymatic analysis of uricotelic protein catabolism in the mosquito Aedes aegypti

Excess protein ingested by blood meals of mosquitoes is catabolized by a uricotelic pathway. We have established enzyme activity profiles for xanthine dehydrogenase (XDH), the enzyme that catalyzes uric acid synthesis, and related it to intestinal proteolytic activities in female Aedes aegypti mosquitoes.During the first day after eclosion the meconium containing urate and urea of larval/pupal origin is discharged, together with XDH activity. Females of constant body size and of defined age were given measured blood meals by enema. XDH activity and uric acid synthesis correlate with the size of the blood meals. Upon completion of protein digestion and catabolism, XDH is excreted in an active form and its activity returns to the residual level. Maximal XDH activity always precedes intestinal proteolytic activities by a few hours. Regulation of XDH activity appears to be purely metabolic, independent of endocrine factors.Small females fed identical volumes of blood produce fewer eggs than their larger sisters and consequently catabolize a higher proportion of blood protein to uric acid.Old females are less fecund and show smaller investments of protein into yolk than younger ones. Despite reduced XDH activities, they excrete equal amounts of urate as young females. Obviously in young females XDH activity is in excess of biochemical requirements.     

Terminal phase males stimulate ovarian function and inhibit sex change in the protogynous wrasse Thalassoma duperrey

Under experimental conditions, the probability of sex change in the protogynous wrasse Thalassoma duperrey is determined largely by an individual's relative size within a social group. Natural populations, however, contain two distinct male phenotypes that may also play a role in regulating sex change. To investigate potential effects of male phenotype, the ability to change sex, ovarian histology and serum estradiol-17 beta levels were examined in females maintained under controlled social settings. Large females housed with smaller or larger terminal phase males had significantly larger gonadosomatic indices than females housed singly, with other females or with smaller initial phase males. Similarly, ovaries of females housed with terminal phase males showed no histological evidence of sex change, whereas large females from other social groupings were in advanced stages of sex change. These results demonstrate terminal phase males inhibit sex change regardless of their size relative to the female. Furthermore, gonadosomatic indices, ovarian histology, and serum estradiol-17 beta levels of females housed with terminal phase males indicate normal ovarian function whereas ovaries of other treatment groups appear quiescent or are undergoing sex change. Consequently, terminal phase males may be required for normal ovarian development which may, in turn, inhibit sex change in T. duperrey.     

Dynamic egg maturation strategies in an aphid parasitoid

Abstract.  Females of the parasitoid Aphelinus albipodus both lay more eggs on younger stages of their aphid host, Aphis glycines , and contain more mature eggs in their ovaries when held with these younger host stages. This suggests that egg maturation is more rapid in the presence of younger host stages. Three factors explaining the difference in the egg loads of A. albipodus females exposed to various host stages are examined. These are (i) the number of host-feeding meals; (ii) the number of eggs laid; and (iii) the host stage utilized. Together, these factors explain 69% of the variance in A. albipodus egg load. The number of host-feeding meals taken by females is a strong predictor of egg load. More host meals are taken on young hosts, suggesting that host feeding contributes to the trend of faster egg maturation in the presence of younger hosts. Host stage has a strong impact on egg load even when the effect of host feeding is accounted for. There is no evidence for an effect of the oviposition rate on egg load. The results indicate that egg maturation by A. albipodus is dynamic; females mature eggs faster when in the presence of preferred hosts. It is hypothesized that this allows A. albipodus females to more closely match their reproductive effort to reproductive opportunities.