Occasional males in parthenogenetic populations of Asobara japonica (Hymenoptera: Braconidae): low Wolbachia titer or incomplete coadaptation?

Wolbachia are endosymbiotic bacteria known to manipulate the reproduction of their hosts. Some populations of the parasitoid wasp Asobara japonica are infected with Wolbachia and reproduce parthenogenetically, while other populations are not infected and reproduce sexually. Wolbachia-infected A. japonica females regularly produce small numbers of male offspring. Because all females in the field are infected and infected females are not capable of sexual reproduction, male production seems to be maladaptive. We investigated why these females nevertheless produce males. We tested three hypotheses: high rearing temperatures could result in higher offspring sex ratios (more males), low Wolbachia titer of the mother could lead to higher offspring sex ratios and/or the Wolbachia infection is of relatively recent origin and not enough time has passed to allow complete coadaptation between Wolbachia and host. In all, 33% of the Wolbachia-infected females produced males and 56% of these males were also infected with Wolbachia. Neither offspring sex ratio nor male infection frequency was significantly affected by rearing temperature or Wolbachia concentration of the mother. The mitochondrial DNA sequence of one of the uninfected populations was identical to that of two of the infected populations. Therefore, the initial Wolbachia infection of A. japonica must have occurred recently. Mitochondrial sequence variation among the infected populations suggests that the spread of Wolbachia through the host populations involved horizontal transmission. We conclude that the occasional male production by Wolbachia-infected females is most likely a maladaptive side effect of incomplete coevolution between symbiont and host in this relatively young infection.     

Tetracycline treatment and sex-ratio distortion: a role for Wolbachia in the moulting of filarial nematodes?

Filarial nematodes harbour intracellular bacteria of the genus Wolbachia. These bacteria are thought to be beneficial to the host nematode. Indeed, tetracycline treatments reduce the population of Wolbachia in filarial worms and have detrimental effects on the nematode. Even though various antibiotic-curing experiments have been performed on filariae, the actual role of Wolbachia in the biology of these nematodes is not yet clear. To address this issue, we designed a first experiment on a model filaria (Brugia pahangi), maintained in the gerbil (Meriones unguiculatus). In this experiment, timing of tetracycline treatment was set on the basis of the larval stage of the nematode. This first experiment showed that 2 weeks of treatment started after the L(4)-L(5) moult of males, but before the moult of females, led to significant sex-ratio distortion of the nematodes. We thus hypothesised that tetracycline interferes with the moult in B. pahangi. To test this hypothesis, we designed a second experiment in which antibiotic treatments were started (1). before the moult of both sexes, (2). after the moult of males but before the moult of females, or (3). after the moult of both sexes. Treatment 1 determined a reduction of worm recovery with no sex bias. Treatment 2 led to a male-biased sex-ratio. Treatment 3 had no effect on either worm recovery or sex-ratio. These results thus support the hypothesis that tetracycline treatment interferes with the L(4)-L(5) moult of B. pahangi. The nematodes recovered from the treated and control animals were examined for the presence of Wolbachia using both immunohistochemistry and real-time PCR. In general, nematodes from treated animals showed a dramatic reduction in Wolbachia content. In one group, Wolbachia depletion, as observed at the end of the treatment, was followed by a rebound to 'normal' values 160 days later. Prospects for antifilarial therapy using Wolbachia-targeted tetracycline treatments should thus take into account the possibility of Wolbachia rebound.     

去除Wolbachia 对丽蝇蛹集金小蜂繁殖适合度和成蜂寿命的影响

【目的】明确内共生菌 Wolbachia 对丽蝇蛹集金小蜂 Nasonia vitripennis 繁殖适合度和成蜂寿命的影响。【方法】通过给自然感染 Wolbachia 的丽蝇蛹集金小蜂成蜂喂食不同浓度的利福平来消除其体内的 Wolbachia,然后进行10个世代的连续饲养,探究不同浓度利福平对丽蝇蛹集金小蜂体内 Wolbachia 的去除效果和去除 Wolbachia 后对丽蝇蛹集金小蜂繁殖力、性比（雌蜂占子代数量的比值）和成蜂寿命的影响。【结果】低浓度利福平（0.1~0.5 mg/mL）对丽蝇蛹集金小蜂的毒害作用较小,而高浓度利福平（0.7~10.0 mg/mL）对丽蝇蛹集金小蜂的毒害作用较大,但二者均能去除丽蝇蛹集金小蜂体内的 Wolbachia;去除 Wolbachia 后丽蝇蛹集金小蜂的出蜂量显著下降（P <0.01）,子代中性比显著下降（P <0.01）,但寿命无明显差异。【结论】不同浓度利福平均能去除丽蝇蛹集金小蜂体内Wolbachia,但效果不一致;Wolbachia 对丽蝇蛹集金小蜂的出蜂量和子代性比均有显著影响,对成蜂寿命无显著影响。     

Trypanosoma rangeli: effects of physalin B on the immune reactions of the infected larvae of Rhodnius prolixus

Physalins are seco-steroids obtained from plants of the family Solanaceae. Herein, we tested Physalis angulata L purified physalin B as an immunomodulatory compound in 5th-instar larvae of Rhodnius prolixus, which were systemically infected with the H14 Trypanosoma rangeli strain protozoan. In uninfected insects, the effective concentration of physalin B, which inhibited 50% of the blood ingested (ED(50)) volume, was 15.2+/-1.6 microg/ml of the meal. Ecdysis processes and mortality in uninfected larvae, treated orally with physalin B in concentrations ranging from 1 to 10 microg/ml, was similar to that observed in insects not treated with physalin B. However, R. prolixus larvae previously fed on blood containing 1.0, 0.1, and 0.01 microg of physalin B/ml exhibited mortality rates of 78.1, 54.3, and 12.7%, respectively, 6 days after inoculation of T. rangeli (1 x 10(3) parasites/insect), whereas only 7.2% mortality was observed in the control group, injected with sterile culture medium. The insects treated with physalin B (0.1 microg/ml) and inoculated with T. rangeli did not modify the phenoloxidase (PO) activity and total hemocyte count in the hemolymph. However, physalin B treatment caused a reduction in hemocyte micro-aggregation and nitric oxide production and enhanced the parasitemia in the hemolymph. These results demonstrate that physalin B from P. angulata is a potent immunomodulatory substance for the bloodsucking insect, R. prolixus.     

In vitro study of the antimicrobial activity of Brazilian propolis against Paenibacillus larvae

The honey bee disease American foulbrood (AFB) is a serious problem since its causative agent (Paenibacillus larvae) has become increasingly resistant to conventional antibiotics. The objective of this study was to investigate the in vitro activity of propolis collected from various states of Brazil against P. larvae. Propolis is derived from plant resins collected by honey bees (Apis mellifera) and is globally known for its antimicrobial properties and particularly valued in tropical regions. Tests on the activity of propolis against P. larvae were conducted both in Brazil and Minnesota, USA using two resistance assay methods that measured zones of growth inhibition due to treatment exposure. The propolis extracts from the various states of Brazil showed significant inhibition of P. larvae. Clear dose responses were found for individual propolis extracts, particularly between the concentrations of 1.7 and 0.12 mg propolis/treatment disk, but the source of the propolis, rather than the concentration, may be more influential in determining overall activity. Two of the three tested antibiotics (tylosin and terramycin) exhibited a greater level of inhibition compared to most of the Brazilian samples, which could be due to the low concentrations of active compounds present in the propolis extracts. Additionally, the majority of the Brazilian propolis samples were more effective than the few collected in MN, USA. Due to the evolution of resistance of P. larvae to conventional antibiotic treatments, this research is an important first step in identifying possible new active compounds to treat AFB in honey bee colonies.     

Cadmium effects on development and reproduction of Oncopeltus fasciatus (Heteroptera: Lygaeidae)

Newly hatched nymphs of the insect Oncopeltus fasciatus were exposed to various concentrations of CdCl2 administered in drinking water until the end of adult life. Significant nymphal mortalities were observed at concentrations above 30 mg Cd/l (corresponding to the LC50). The duration of the nymphal stages increased in proportion to the Cd concentration; at the lowest Cd concentration of 10 mg Cd/l, the median duration was significantly prolonged by one day, while at the highest concentration of 100 mg Cd/l it was increased by 10 days over the control group. The weight of newly emerged adults lineally decreased with Cd concentration, being reduced to half the weight of controls at 100 mg Cd/l. In addition, a proportionality between delay in development and weight reduction was found in Cd-treated adults. Survival of adult females was decreased at concentrations higher than 10 mg Cd/l, while males were only affected at 30 mg Cd/l or higher doses. Reproduction was the most affected parameter. Oviposition rate, fecundity and fertility of females exposed to 10 mg Cd/l were significantly lower than controls (73%, 58% and 55% relative to controls, respectively). Hatchability of the eggs laid by treated females was also reduced. These results show that development and reproduction of O. fasciatus are seriously impaired at sublethal Cd concentrations.     

Are the diatoms Navicula sp. and Thalassiosira fluviatilis suitable to be fed to the benthic harpacticoid copepod Tisbe biminiensis?

The objective of this study was to compare the influence of the diets of two diatoms, Navicula sp. (benthic) and Thalassiosira fluviatilis (planctonic), on the development, fecundity and survival of the harpacticoid copepod Tisbe biminiensis. In order to determine the optimal concentration of food, 35 egg-bearing females were submitted to six algal concentrations and controls (without food). After 24 h, the content of the recipients was fixed with 4% formalin and then fecal pellets produced by each female were counted and measured. The larval development was studied by surveying 50 nauplii on each diet individually until the adult stage, at intervals of 6 h. The cast exoskeletons were removed to count the number of segments and for measurement. The fecundity was obtained counting the naupliar production every 48 h of groups containing 10 females in different algal concentrations in both diets. The diet influence on fecundity was tested by submitting four groups of 10 females fed on optimal algal concentrations based on the fecal pellet experiments. In the Navicula sp. concentration of 0.4 μg Chl-a/ml, considered to be optimal for fecal pellets production, the diatoms were shown toxic, resulting in a low survival rate and inhibiting the egg production of copepods. The optimal concentration considering fecundity was estimated to be 0.1 μg Chl-a/ml for both diets. Copepods fed on Navicula sp. presented a faster development rate and higher naupliar production compared to copepods fed on T. fluviatilis. Size and survival did not vary significantly among diets. The algal concentration interfered significantly in the reproductive success of females. Both very low and very high algal concentrations reduced reproductive success. Concluding, the benthic diatom Navicula sp. was more favorable to the copepod T. biminiensis than the planktonic diatom T. fluviatilis.     

Bacteria in ovarioles of females from maleless families of ladybird beetles Adalia bipunctata L. (Coleoptera: Coccinellidae) naturally infected with Rickettsia,Wolbachia, and Spiroplasma

Ovarioles were found to be infected with Spiroplasma, Wolbachia, and Rickettsia in Adalia bipunctata females with maleless progeny in different natural populations. Ooplasm was infected with few Wolbachia bacteria. In ooplasm infected by Rickettsia, bacteria were present in small foci. Spiroplasmas were found encapsulated into ooplasm from the wider intercellular spaces between epithelial and oocyte cells. The cytoplasm of follicular epithelia infected with Rickettsia was heavily destroyed, but the nucleus was intact and free from bacteria. The essential feature of follicular epithelium cells from Spiroplasma and Wolbachia infected A. bipunctata females was inclusions of three types: crystalline, filaments, and concentric myelin-like lamellae. Observations of smears prepared from ovaries of A. bipunctata from natural populations revealed a low concentration of bacteria within a microscopy field (less 10 bacteria) in more than 90% of specimens, and only a few ovaries were heavily infected. Two different ways of bacterial invasion of the oocyte are suggested: Spiroplasma-like, through the intercellular spaces in the epithelium and Rickettsia-like, through the cytoplasm of follicular epithelium cells. Bacteria were not found in germarium zones and we suggest that each follicle is infected from haemolymph.     

Experimental study of the embryotropic action of tetracycline]

The general toxic and embryotropic effect of tetracycline was studied on unbred pregnant albino rats. The antibiotic was used in concentrations of 1 and 0.1 mg/m3, the maximum permissible concentration (MPC). The animals were exposed to tetracycline inhalation for 20 days of their pregnancy. On the basis of the results it was concluded that tetracycline in the concentration at the level of the MPC, i.e. 0.1 mg/m3 had under the experimental conditions a negative effect on the pregnant animals. In concentrations of 1 and 0.1 mg/m3 it had in addition an embryotropic effect. It was also shown that the pregnant animals were more sensitive to the antibiotic than the non-pregnant ones.     

Larval Apis mellifera L. (Hymenoptera: Apidae) mortality after topical application of antibiotics and dusts

Beekeepers apply various dusts to honey bee, Apis mellifera L., colonies to dislodge parasitic mites and control bacterial brood diseases. Anecdotal reports by beekeepers indicate that the antibiotic oxytetracycline (OTC) can be toxic when applied in powdered sugar to cells containing immature bee brood, but it was not known whether the purported toxicity is caused by the antibiotic or the sugar carrier. Additionally, the toxicity of various dusts, proposed for parasitic mite control, is poorly known. In the current studies, we tested OTC and two other antibiotics (tylosin and lincomycin, candidate compounds for use in honey bee colonies) in a powdered sugar carrier for larval toxicity. We also tested for larval toxicity, several dusts that have been proposed for mite control. OTC caused significant brood mortality of approximately 80% at the concentrations used in the hive (200 mg in 20 g sugar). In contrast, tylosin and lincomycin at the 200 mg dose were both similar to untreated controls, and only five times that concentration (1000 mg) caused significant brood mortality of approximately 65%. The addition of dusts, wheat flour, talc, and a commercially available protein supplement, BeePro, resulted in mortality levels between 65 and 80%, similar to that seen with OTC. The common antibiotic carrier, powered confectioners sugar, was nontoxic. The use of 100 unsealed brood cells was demonstrated to be a reliable means of assessing potential adverse affects of dry compounds on larval honey bees. Two new candidate antibiotics for use in honey bee colonies were less toxic to larval bees than the currently labeled antibiotic, OTC.     

Root mass distribution patterns under standardised conditions in species of Chionochloa and Festuca from New Zealand

The vertical biomass allocation patterns of roots grown under standardised conditions were determined for species representing the major New Zealand indigenous grass genera Chionochloa and Festuca. Ten ramets, each of 2–3 tillers from garden collections of each species were grown in irrigated vertical sand columns in a glasshouse, and harvested after 168 days. Chionochloa teretifolia, Chionochloa macra, and Chionochloa crassiusucula, characteristic of alpine environments failed to produce new roots and died. However, most of the Chionochloa taxa (Chionochloa beddiei, Chionochloa pallens, Chionochloa rigida ssp. rigida, Chionochloa rubra ssp. cuprea, Chionochloa vireta), developed extensive new roots that reached the base of the one metre sand column. Roots of Chionochloa cheesemanii and Chionochloa conspicua reached 80–90 cm depth. Two Festuca taxa (Festuca actae, Festuca luciarum) had roots to 1 m depth, and roots of Festuca coxii, Festuca matthewsii ssp. latifundii, Festuca matthewsii ssp. matthewsii, Festuca multinodis, and Festuca novae-zelandiae grew to 70–90 cm depth. The edaphic specialists (Festuca deflexa, Chionochloa spiralis, Chionochloa defracta) were all shallow rooting.Species of Festuca maintained at least 40% of the root mass in the upper 10 cm of the column and most of the Chionochloa taxa had less than 40% of root mass in the upper zone. Genotype level variation in root mass less than 10 cm deep was greater in Chionochloa than in Festuca, and least in the edaphic specialist grasses.     

Seasonal variation in antifouling activity of crude extracts of the brown alga Bifurcaria bifurcata (Cystoseiraceae) against cyprids of Balanus amphitrite and the marine bacteria Cobetia marina and Pseudoalteromonas haloplanktis

Previous studies have demonstrated that macroalgae from Brittany (France) contain products with antifouling activity against marine bacteria, fungi, diatoms, seaweeds and mussels. Little is known regarding the ecological function of these compounds and insufficient attention has been paid to evaluating the possible temporal variation in antifouling activity. Studies of chemical defenses in both terrestrial and marine organisms suggest that organisms vary widely in the production of chemical defenses associated with physical (temperature, light) and biological (e.g. grazing pressure) factors, season and geographical location. The present study aimed to investigate the antifouling activity of crude extracts of monthly collections of the brown alga, Bifurcaria bifurcata, against two marine bacteria, Cobetia marina and Pseudoalteromonas haloplanktis, and cypris larvae of the barnacle, Balanus amphitrite. The toxicity of the extracts was determined with a B. amphitrite nauplius assay.The antimicrobial activity of the extracts was found to be subject to seasonal variation, with the highest level of activity recorded from samples collected between April and September. Results of the anti-settlement experiments showed that the extracts of B. bifurcata (when tested from 0 to 100 μg/ml) can be divided into three groups on the basis of their minimum inhibitory concentrations (MICs): (1) extracts from plants collected from September to March reduced settlement at nontoxic concentrations (50-100 μg/ml); (2) extracts from plants collected from April to July (which were the most active extracts) reduced settlement significantly when tested at >5 μg/ml, but were toxic at 100 μg/ml; (3) the extract prepared from plants harvested in August was inhibitory at >25 μg/ml, but was toxic at 100 μg/ml. Toxicity tests on nauplii showed that LC₅₀ values of samples from the September to March collections were >100 μg/ml, demonstrating that they were nontoxic to nauplii. In contrast, samples obtained from the April to August collections were toxic to nauplii; the most toxic ones being from algae collected in May (LC₅₀=55.6 μg/ml) and in June (LC₅₀=38.3 μg/ml).The antifouling activity of extracts thus reached a peak in summer corresponding to maximal values for water temperature, light intensity and fouling pressure. It remains to be investigated whether this activity has an ecological role in the alga.     

Food consumption by Chilo partellus (Lepidoptera: Pyralidae) larvae infected with Beauveria bassiana and Metarhizium anisopliae and effects of feeding natural versus artificial diets on mortality and mycosis

Second and third instar Chilo partellus larvae were infected with Beauveria bassiana and Metarhizium anisopliae (both at 1x10(8)conidia/ml) and daily consumption of maize leaves was measured. Infection by the fungi was associated with reduced mean daily food consumption. Reduction in food consumption became evident 3-4 days after treatment with the fungi for second instar larvae and 4-5 days for third instar larvae. Four conidial concentrations, 1x10(5), 1x10(6), 1x10(7), and 1x10(8)conidia/ml, were tested against second instar larvae. Food consumption dropped by 70-85% when the second instar larvae were treated with the fungi at 1x10(8)conidia/ml. Reduction in food consumption by C. partellus larvae infected with B. bassiana and M. anisopliae may offset the slow speed of kill of the fungi. The effect of artificial versus natural diets on mortality and mycoses of second instar larvae treated with the fungi at 1x10(8)conidia/ml was determined. Larvae provided with artificial diet suffered little mortality and mycoses than larvae provided with maize leaves. The LT(50) was longer for larvae provided with artificial diet.     

Feeding and breeding aspects of Stomoxys calcitrans (Diptera: Muscidae) under laboratory conditions

Bionomic aspects of Stomoxys calcitrans (Linnaeus, 1758) (Diptera: Muscidae) were studied under laboratory conditions. For this reason, laboratory-rearing techniques were optimized at the National Veterinary School of Toulouse. The colony was maintained at 25 ± 2 °C, 50 ± 10% RH under a 12-hour light cycle and observed daily. The size of each adult cage is 30 x 30 x 30 cm and designed to house about 500-1,000 flies. The average cycle from egg to adult was 19.2 ± 1.7 days. The mean longevity of imagos was 9.3 ± 5.8 days and not significantly different between sexes. Stable flies were split into two groups; the first was fed with blood, honey and water, and the second was fed only with honey and water. The mean weight of a blood meal was 11.1 ± 3.8 mg with no significant differences between males and females. The mean longevity of non-blood fed flies was found to be significantly higher (10.4 ± 3.9 days) than those fed with blood. The maximum lifespan was shorter for non-blood fed males (17 days) and females (18 days) than for those fed with blood (females: 24 days, males: 23 days). Under these laboratory conditions, S. calcitrans rearing was successfully established. In the end, the number of expected generations of S. calcitrans and the net reproduction rate were estimated to be 11.8 generations/year and 16.2 living females per female respectively.     

Effects of beauvericin on Schizaphis graminum (Aphididae)

The effects of beauvericin, a toxic fungal metabolite common contaminant of maize and wheat, on aphid fitness were studied in three consecutive generations of females. Aphids were reared on wheat leaves inserted into a sandy substratum wetted with a solution of beauvericin. Ingestion of this solution through leaves did not significantly decrease the lifespan of females of all generations as compared to controls. However, the mean number of offspring from the third generation of treated females was significantly smaller than those in controls. Furthermore, treated second and third generation females produced a greater number of abortive embryos. Histological analysis revealed abundant DAPI and Feulgen positive material in the cytoplasm of some bacteriocytes of treated third generation females. This material was attributed to the endosymbionts of bacteriocytes. Tests by contact were also carried out and revealed a significantly lower survival of treated first instar aphids as compared to controls 18h after the start of the trial.     

蝇蛹金小蜂的交配行为及雄蜂交配次数对雌蜂繁殖的影响

多数昆虫能够进行多次交配,随寄生蜂雄蜂交配次数的增加,雄蜂体内精子减少,雌蜂获得的精子数量减少,产下更多的单倍体卵,发育为雄性后代;一些单寄生性的寄生蜂雌蜂一生仅能够交配1次。描述了蝇蛹金小蜂雌雄蜂的交配行为,探讨了雄蜂交配次数对雌蜂后代产量等的影响以及雌蜂的可交配次数。结果表明,交配过程包括求偶、交尾前期、交尾和交尾后期;雄蜂已交配的次数并不能够显著影响其配偶的寿命、产卵期和后代总数量,但显著影响到其配偶的雌、雄后代数量和性比。随雄蜂交配次数的增加,与之交配的雌蜂的后代雄性百分比显著增大,雌蜂在产卵期内更早地出现较多雄性后代,体内精子不足的现象更加明显。无论已交配的蝇蛹金小蜂雌蜂在产卵期中是否出现精子不足,均不能再次完成交配。     

Effect of food type and concentration on the survival,longevity, and reproduction of Daphnia magna

The freshwater microalgae Ankistrodesmus falcatus and Scenedesmus incrassatulus, at three concentrations (6, 12 and 18 mg l⁻¹ t, dry weight), were tested as diets for Daphnia magna cultured in reconstituted hard water, at 19 ± 1 °C. Effects on survival, and reproductive characteristics were evaluated during a complete life-cycle. Test animals fed with the highest food concentration had the lowest survival, longevity, number of clutches, and average inter-brood times, but the total offspring was similar to that obtained with the lowest food concentration, for the same species of alga. Average longevity ranged from 40 to 85 days, with a minimum of 24 and a maximum of 119 days. The average inter-brood time ranged from 4.2 to 5.8 days, the highest values being observed at the lowest food concentration. The average total offspring was maximum for the intermediate concentrations of both algae. The maximum number of clutches ranged from 9 to 23, with the lowest values being observed at the highest food concentration. Even though both microalgae had similar effects on survival and reproduction, and the greatest differences observed were related to food concentration, it seems that S. incrassalulus is a comparatively better food for D. magna. The most suitable food level should be determined prior to carrying out chronic bioassays, and it is also an important factor in cultures for obtaining neonates for toxicological tests.     

Ovarian hydrobursitis in female camels (Camelus dromedarius): the role of Chlamydophila abortus and a trial for medical treatment

The occurrence of Chlamydophila abortus in female camels affected with ovarian hydrobursitis and a trial for medical treatment were studied. A total of 111 cases were included in two experiments. In Experiment 1, sera from 51 affected cases were tested for C. abortus antibody using enzyme-linked immunosorbent assay (ELISA). In Experiment 2, 60 female camels affected with bilateral ovarian hydrobursitis were divided into treated and control groups (n = 30 each). Based on the bursal diameter, females of both groups were subdivided into those having small (< 5 cm), medium (5-7 cm) or large (> 7 cm) bursae. Treated group received 20 mg/kg body weight oxytetracycline intramuscular, 4% lotagen intrauterine, and 500 μg cloprostenol intramuscular. Controls did not receive any treatment. All females were observed for 90 days non-return rate (NRR) and calving rate (CR). Antibodies against C. abortus were observed in 44/51 (86.3%) of the affected females. The 90 days NRR of the treated and control groups were 13/30 (43.3%) and 0/30 (0.0%), respectively, (P = 0.001), while the CR were 10/30 (33.3%) and 0/30 (0.0%), respectively, (P = 0.01). Based on bursal size, the 90 days NRR were 11/15 (73.3%), 2/7 (28.6%) and 0/8 (0.0%) for treated females having small, medium and large bursa, while the CR were 9/15 (60%), 1/7 (14.3%), and 0/8 (0.0%), respectively, (P = 0.01). In conclusion, it seems that C. abortus may be responsible for the spreading of the ovarian hydrobursitis syndrome in dromedaries. Small sized bursa could be medically treated.     

Pollen as a source of food for egg parasitoids of the genus Trichogramma (Hymenoptera: Trichogrammatidae)

The value of corn pollen as a food source for Trichogramma brassicae Bezdenko (Hymenoptera: Trichogrammatidae) was assessed in the laboratory by testing the effect of different pollen diets on the longevity, capacity of parasitism and other life-table parameters. T. brassicae females that fed on corn pollen and water (wet filter paper dusted with pollen) lived significantly longer (4.97 days) than females that fed on water alone (2.67 days), but significantly shorter than those feeding on honey alone (8.37 days) or corn pollen and honey (8.23 days), respectively, in the absence of host eggs. The presence of European corn borer eggs (Ostrinia nubilalis Huebner, Lepidoptera: Pyralidae) significantly increased longevity. With host eggs available, female T. brassicae that fed on corn pollen and water lived significantly longer (4.9 days) than on water alone (2.60 days), but significantly shorter than on honey alone (12.33 days) or corn pollen and honey (12.17 days), respectively. The cumulative lifetime fecundity was 82.53 offspring pupae when fed on pollen and water, which was significantly higher than 61.70 for water alone but lower than feeding on honey alone (95.70) or corn pollen and honey (99.97), respectively. Compared to water alone, corn pollen and water increased the net reproduction rate (R₀), intrinsic rate of increase (r_m), and finite rate of increase (λ), and reduced the doubling time (T₂), but had no effects on the emergence rate, sex ratio, and mean generation time (T_c). In another set of experiments, 13 out of 30 females reduced the number of pollen grains offered to them. The average number of pollen grains utilized per female in this 48-h test 2.46±0.40 (mean±SE). Hence, T. brassicae used corn pollen as food that significantly increased longevity and fecundity of the tested females. Pollen and honey supplied a complete diet for T. brassicae, compared to pollen and water or water alone.     

Wolbachia感染对拟澳洲赤眼蜂寿命、生殖力和嗅觉反应的影响

研究了通过共享同一寄主卵,短管赤眼蜂Trichogramma pretiosum体内共生的Wolbachia被水平传递到拟澳洲赤眼蜂T. confusum体内后,Wolbachia对新宿主拟澳洲赤眼蜂的影响。结果表明： Wolbachia的侵染能使拟澳洲赤眼蜂进行不完全的产雌孤雌生殖,增加拟澳洲赤眼蜂子代雌性比例,但却导致了雌蜂寿命缩短和繁殖力降低的生理损失。Wolbachia感染的当代处女蜂及其建立的种群连续5代(F₁～F₅),其子代雌蜂百分率分别为79.17%、76.60%、68.66%、72.58%、68.15%和64.06%,基本上呈现出逐代降低的趋势,并越来越接近对照的63.85%。处女蜂及F₁～F₅代雌蜂的平均寿命分别为4.33、5.50、5.60、6.68、7.32和7.50天,而未感染交配雌蜂寿命为7.59 天;处女蜂及F₁～F₅代雌蜂平均产卵量分别为11.33、70.00、86.41、93.90、102.92和124.38粒/雌,除F₅代外,均显著低于未感染交配雌蜂的产卵量134.81粒/雌。用四臂嗅觉仪测定了Wolbachia新宿主拟澳洲赤眼蜂对寄主小菜蛾的嗅觉反应,结果表明Wolbachia的侵染具轻微干扰拟澳洲赤眼蜂嗅觉反应的负面影响。未感染Wolbachia的拟澳洲赤眼蜂及Wolbachia供体短管赤眼蜂对寄主小菜蛾具较强的嗅觉反应,其雌蜂在小菜蛾腹部鳞片正己烷提取液和小菜蛾卵表正己烷提取液处理区内滞留时间显著或极显著长于对照区。而感染Wolbachia的拟澳洲赤眼蜂F₂代和F₃代雌蜂,尽管在小菜蛾腹部鳞片正己烷提取液处理区内滞留时间比对照区长,但没有达到显著水平;其F₂代雌蜂在小菜蛾卵表正己烷提取液处理区内滞留时间与对照区相比,也没有达到显著水平。随Wolbachia在拟澳洲赤眼蜂种群中垂直感染代数的增加,拟澳洲赤眼蜂对寄主小菜蛾的嗅觉反应恢复正常,在Wolbachia感染后的 F₄～F₆代,雌蜂在两种提取液处理区内的滞留时间均显著或极显著长于对照区。