Hyperparasitism of intrasnail stages of Fasciola hepatica by a mosquito microsporidian parasite

Laboratory studies were conducted to investigate the infective behavior of Nosema algerae spores when ingested by Fasciola hepatica free of F. hepatica-infected snails (Lymnaea cubensis). Among the F. hepatica-infected snails exposed to N. algerae, 38.09% harbored microsporidia-infected F. hepatica rediae. The F. hepatica-free snails exposed to N. algerae as well as the controls did not become infected. Light microscopical studies of Giemsa-stained microsporidia distinguished this organism from microsporidia previously described in trematode larvae. Based on the infectivity studies and morphological data, it was concluded that N. algerae, a mosquito pathogen, was transmitted to intrasnail stages of F. hepatica.     

下垂虫草的重寄生现象及重寄生菌的鉴定

在安徽省岳西县鹞落坪自然保护区,发现了1种寄生于下垂虫草(Ophiocordyceps nutans)的重寄生菌。通过形态特征观察和ITS序列分子生物学分析,将其鉴定为枝多头霉(Polycephalomyces ramosus)。其孢梗束着生于下垂虫草子实体的可孕部,顶部膨大呈球形。本种具有产生单个卵形的A型分生孢子的顶侧生排列的A型瓶梗和能形成分生孢子链的B型瓶梗,并在培养基上的气生菌丝和孢梗束的柄部都观察到梭形、链生的B型分生孢子。GenBank中相关种的ITS序列与拉丁名可能有误。     

'Divergent male ontogenies' in Aphelinidae (Hymenoptera: Ghalcidoidea): a simplified classification and a suggested evolutionary sequence

A classification of the different types of divergent male ontogeny in Aphelinidae is proposed to replace the little known and cumbersome systems previously published. All the Aphelinidae in which conspecific males and females have different host relationships, i.e. those that have divergent ontogenies, are here designated heteronomous parasitoids. Females of these species are primary endoparasitoids of Homoptera. The males of (i) diphagous parasitoids are primary ectoparasitoids of the same host species exploited by their females, (ii) heteronomous hyperparasitoids develop hyperparasitically, and (iii) heterotrophic species are endoparasitoids of lepidopterous eggs. Heteronomous hyperparasitoids can be classified further as obligate autoparasitoids, facultative autoparasitoids or alloparasitoids. All the species of heteronomous aphelinids whose biologies are known are listed according to the new classification, and the evolutionary sequence of these unusual host relationships is discussed.     

Cryptophiale sphaerospora sp. nov. occurring onJanetia synnematosa

Cryptophiale sphaerospora sp. nov. is described and illustrated based on a single collection attached to a synnematous fungus,Janetia synnematosa, from a dead bamboo culm. It differs from other species ofCryptophiala in having spherical to subspherical conidia and a cerebroid layer of phialides. The overall morohology of this species is smaller than that of previously described species.     

Pseudaulacaspis cockerelli (Cooley) hyperparasitizing Dendrophthoe falcata (L.f) Ettingsh

Here, we first report hyperparasitism of Honey Suckeled Mistletoe, Dendrophthoe falcata var. falcata (Loranthaceae) by Pseudaulacaspis cockerelli (Diaspididae). The infected mistletoe was found parasitising branches of the Senna siamea host. Pear-shaped white spots were observed on abaxial and adaxial leaf surfaces, stem and few on the haustorial surfaces of the mistletoe. Close inspection revealed a yellowish-brown spot on individual white spots. These were identified on the basis of morphological features as Cockerell Scales hidden in the white-spot like self-secreted waxy armours. No incidence of such an infection was seen on any part of the mistletoe host, Senna siamea.     

Natural occurrence of ampelomyces intracellular mycoparasites in mycelia of powdery mildew fungi

This is the first extensive investigation that quantifies natural mycoparasitic relationships in the phyllosphere. The presence of Ampelomyces spp. was quantified in naturally occurring powdery mildew fungi collected in Hungary and Romania between 1992 and 1995. A total of 570 samples was studied representing 27 species (nine genera) of the Erysiphaceae infecting 41 host plant genera. The incidence of Ampelomyces spp., determined as the proportion of samples in which intracellular pycnidia were present, varied between 4.3 and 68.8% in the host fungal genera studied. The intensity of mycoparasitism, defined as a percentage of the powdery mildew mycelia parasitized by Ampelomyces , ranged from 0.15 to 65%. Both the incidence and the intensity of mycoparasitism showed the lowest values in Blumeria graminis (DC.) Speer collected from wild and cultivated monocotyledons, while the highest values were found in Arthrocladiella mougeotii (Lév.) Vassilkov infecting Lycium halimifolium Mill. plants. The paper reports for the first time the natural occurrence of Ampelomyces in Sawadaea bicornis (Wallr.:Fr.) Homma on maple.     

Biology ofEpidinocarsis [=Apoanagyrus] lopezi [Hymenoptera: Encyrtidae] an exotic parasite of cassava mealybug,Phenacoccus manihoti [Homoptera: Pseudococcidae] in Nigeria

The biology ofEpidinocarsis (=Apoanagyrus) lopezi (DeSantis) was studied under fluctuating laboratory conditions of 24–31°C and 79–90% R.H. It is a solitary internal parasite. There are 4 tailed larval instars. The total developmental time from egg to adult ranged from 11–25 days, average 18 days. The duration of each developmental stage was: egg 2 days, 1 st instar 1 day, 2nd instar 1 day, 3rd instar 2 days, 4th instar 2 days, prepupa 4 days and pupa 6 days. Males mated several times, females mated once. Mated females produced both males and females, unmated females produced only males. Mated ovipositing females lived for 13 days while non-ovipositing mated females lived for 25 days. Parasitization decreased with increasing host density from 30% at a density of 10 hosts/plant/female to 11% at a density of 50. There was virtually no pre-oviposition period. Based on 10 females, the highest mean daily progeny production was 10. Females have an average oviposition period of 11 days and an average of 67 adult progeny. The sex-ratio was 1∶2.3 in favour of females.     

Spatial and temporal diversity in hyperparasitoid communities of Cotesia glomerata on garlic mustard,Alliaria petiolata

1. Interactions between two trophic levels can be very intimate, often making species dependent on each other, something that increases with specialisation. Some specialised multivoltine herbivores may depend on multiple plant species for their survival over the course of a growing season, especially if their food plants are short‐lived and grow at different times. Later generations may exploit different plant species from those exploited by previous generations. 2. Multivoltine parasitoids as well as their natural enemies must also find their hosts on different food plants in different habitats across the season. Secondary hyperparasitoid communities have been studied on cocoons of the primary parasitoid, Cotesia glomerata (Hymenoptera: Braconidae), on black mustard (Brassica nigra) – a major food plant of its host, the large cabbage white (Pieris brassicae) – which grows in mid‐summer. 3. Here, hyperparasitoid communities on C. glomerata pupal clusters were studied on an early‐season host, garlic mustard, Alliaria petiolata, over ‘time’ (one season, April–July) in six closely located ‘populations’ (c. 2 km apart), and within two different ‘areas’ at greater separation (c. 100 km apart). At the plant level, spatial effects of pupal ‘location’ (canopy or bottom) on the plant were tested. 4. Although large‐scale separation (area) did not influence hyperparasitism, sampling time and small‐scale separation (population) affected hyperparasitism levels and composition of hyperparasitoid communities. Location on the plant strongly increased proportions of winged species in the canopy and proportions of wingless species in bottom‐located pupae. 5. These results show that hyperparasitism varies considerably at the local level, but that differences in hyperparasitoid communities do not increase with spatial distance.     

Tetrastichine aphid hyperparasitoids (Hymenoptera: Eulophidae) in Japan

A small collection of aphid hyperparasitic species of Tetrastichinae obtained by rearing mummified aphids in Japan were examined. In addition to the two already known species, three more species were confirmed to occur in Japan. A key to these five Japanese species and their hosts (primary parasitoids, aphids and plants) are provided. The modes of hyperparasitism and host associations of tetrastichine aphid hyperparasitoids are discussed.     

Impact of superparasitism time intervals on progeny survival and fitness of an egg parasitoid

1.Superparasitism influences the fitness of female parasitoids and their progeny, and increasing time interval between oviposition bouts generally reduces survival probabilities of the second clutch. However, the timing of superparasitism may, under certain conditions, favour the second clutch. 2. This study investigated the effects of superparasitism time intervals on survival and fitness of both clutches, allowing the egg parasitoid Trichogramma euproctidis to parasitise previously parasitised Ephestia kuehniella host eggs at different time intervals. 3. In short intervals (0–1 h), a significant advantage was found for the second clutch over the first clutch (93.1% survival). In contrast, the second clutch was outcompeted by the first clutch in 17–19 h and 27–29 h intervals. Females deposited their eggs into larvae (intraspecific hyperparasitism) in a 39–41 h interval with a probability of survival of 57.1%. Females mostly refused to hyperparasitise pupae (～80% rejection at 124–126 h), and when they did, their progeny never survived. 4. Hyperparasitism significantly increased parasitoid mortality in both clutches from less than 20% (superparasitism only) to over 35%. 5. Except on newly laid eggs (0–1 h), superparasiting females were frequently observed attempting to stab immatures of all stages (from 36.4% to 89.4% of all ovipositions depending on treatment), but infanticide only appeared to succeed on larvae (39–41 h). 6. When the second clutch survived, emerging parasitoids were smaller than control individuals, probably due to resource depletion. 7. These results suggest that T. euproctidis females can detect that a host has been previously parasitised but they cannot perceive superparasitism time intervals.     

Impact of selected pesticides on field population dynamics of parasitic Hymenoptera (Pteromalidae) in caged-layer poultry manure in southern California, U.S.A.

Field studies were conducted at caged-layer poultry facilities in southern California, U.S.A., to determine the effect of selected pesticides on beneficial Pteromalidae. Weekly parasite sampling was conducted using sentinel Musca domestica L. pupae to assess changes in parasitization in relation to pesticide treatment. Sites were sampled weekly for 5 weeks before treatment and for 8-10 weeks post-treatment. Treatments were applied twice to six hen houses (four treated plus two controls) at each of two sites. Treatments were: (1) dimethoate (0.5%), spot-treatment to wet areas only (approximately 5-10% of manure surface); (2) dimethoate (0.5%), entire manure surface; (3) cyromazine (0.1%), entire manure surface; and (4) permethrin (0.05%) applied to all hens in the house for northern fowl mite [Ornithonyssus sylviarum (Canestrini and Fanzago)]. The two discrete pesticide applications during an 8-day period had no significant effect on activity of Muscidifurax spp. and Spalangia spp. at either site.     

Biological Control ofMonilinia laxaandFusarium oxysporumf. sp.lycopersiciby a Lytic Enzyme-ProducingPenicillium purpurogenum

Biological control experiments were conducted with the lytic enzyme-producing fungusPenicillium purpurogenumagainst the plant pathogensMonilinia laxaandFusarium oxysporumf. sp.lycopersici.Applications ofP. purpurogenumto peach shoots previously inoculated withM. laxareduced lesion length and extent of pathogen colonization of shoots by 90 and 80% (P ≤ 0.05), respectively, comparable to the level of disease control obtained with the fungicide captan. Disease severity in tomato plants inoculated withF. oxysporumf. sp.lycopersiciwas decreased by 30% (P ≤ 0.05) with the biological treatment. The fungusP. purpurogenumproduced β-1,3-glucanase and chitinase activities in liquid culture that were inducible by cell walls and live mycelium ofM. laxabut not ofF. oxysporumf. sp.lycopersici.Crude filtrates or crude enzyme preparations ofP. purpurogenumcultures with lytic enzyme activities produced lysis of hyphae and spores ofM. laxaandF. oxysporumf. sp.lycopersici.These lytic effects were strong inM. laxaand ended in complete dissolution of mycelium. The induction of lytic enzymes byM. laxaand the effects of lytic enzymes on mycelia of the pathogens in relation to the different degrees of biological control obtained are discussed.     

农杆菌介导的绿木霉遗传转化及重寄生缺陷突变体的筛选

绿木霉(Trichoderma virens)是一种重要菌寄生真菌,该菌已广泛应用于多种病害的生物防治上。本研究构建了双元载体pCATPH-I(GenBank登录号为：KC252999),并利用该载体成功实现了农杆菌介导的绿木霉遗传转化,转化效率可达385~460个转化子/106绿木霉分生孢子。转化子的PCR和遗传稳定性分析表明, T-DNA已整合进该菌的基因组中且在无选择压力的条件下能够稳定遗传。利用该转化体系成功建立了超过2000个转化子的转化子库,通过转化子与病原真菌立枯丝核菌(Rhizoctonia solani)对峙培养在该转化子库中成功筛选到两个重寄生缺陷突变体,D441和A281。本研究的完成可为绿木霉的功能基因组学及重寄生分子机制的研究打下基础。     

Assessing trophic interactions in a guild of primary parasitoids and facultative hyperparasitoids: stable isotope analysis

Facultative hyperparasitism is likely to be the most common form of intraguild predation among parasitoids. However, difficulties associated with studying facultative hyperparasitoids in the field have hampered a thorough understanding of their trophic ecology. In this study, we used a combination of stable isotope analysis and published natural history information to infer trophic interactions in a guild of field-collected primary parasitoids and facultative hyperparasitoids that attack a gall-making midge on Baccharis pilularis. Our three a priori hypotheses were: (1) stable isotope values should increase incrementally from the host plant to higher trophic levels; (2) the two species of ectoparasitoids should exhibit higher stable isotope signatures than the two endoparasitoids, and; (3) the two facultative hyperparasitoids should exhibit stable isotope signatures that fall between zero and one trophic level steps above that observed for the primary parasitoids. Food webs inferred from stable isotope data generally agreed with previously published accounts of community structure. As expected, both δ¹³C and δ¹⁵N were progressively enriched in the heavy isotope from the host plant to the herbivorous midge to the parasitic wasps. Multivariate analysis of stable isotope data revealed that the two primary ectoparasitoids occupied a similar trophic niche, but were significantly different from the primary endoparasitoids. We attribute this result to “coincidental intraguild predation” by ectoparasitoids that develop on already-parasitized midge larvae. One of the facultative hyperparasitoids, Zatropis capitis, exhibited a stable isotope signature approximately one trophic step above the primary parasitoids. Unexpectedly, the second facultative hyperparasitoid, Mesopolobus sp., appeared to be developing as a primary parasitoid at all sites. Coupled with independent assessments of community structure, stable isotope analysis validated trophic links constructed by previous researchers and identified potential taxon-specific differences in trophic interactions for two facultative hyperparasitoids in the B. pilularis gall community.Electronic Supplementary Material Supplementary material is available to authorised users in the online version of this article at .     

The influence of parthenogenesis-inducing Wolbachia on the oviposition behaviour and sex-specific developmental requirements of autoparasitoid wasps

Parthenogenesis-inducing (PI) Wolbachia are bacteria that cause incipient male eggs of parasitoid wasps to develop as females. These microbes may invade populations and lead to fixation of parthenogenesis. In this study, the consequences of fixation of PI Wolbachia on evolution of behaviour and development were addressed in three species of whitefly parasitoids in the genus Encarsia. Most sexual Encarsia are obligate autoparasitoids. In these haplodiploid wasps, fertilized, female-producing eggs are laid in whitefly or scale insect nymphs, while unfertilized, male-producing eggs are laid in immature parasitoids within the homopteran integument. The oviposition behaviour and progeny developmental requirements of unmated females of a sexual autoparasitoid species were compared with two species that were fixed for PI Wolbachia. All species were treated with antibiotics, effectively ‘curing’ the asexual species of Wolbachia infection. As expected, unmated females of the sexual species, E. pergandiella, laid few eggs in whiteflies relative to immature parasitoids, and males emerged exclusively from parasitoids. In contrast, females of one of the parthenogenetic species, E. formosa, laid few eggs in parasitoids relative to whiteflies, and male progeny emerged exclusively from whiteflies. Females of the second parthenogenetic species, E. hispida, were intermediate in their oviposition behaviour. Females laid eggs in both wasps and whiteflies. However, all of the males except one emerged from the whiteflies. The results suggest that the association of autoparasitoids and PI Wolbachia may result in dramatic evolutionary change of both host selection behaviour and developmental requirements of the infected wasps.     

Differential Flower Herbivory and Gall Formation on Males and Females of Neea psychotrioides, a Dioecious Tree

The goal of this study was to determine whether there exists intersexual differences in the degree of herbivore attack on a tropical, dioecious tree. Neea pychotrioides is a Costa Rican tree that experiences at least two types of attack on its reproductive structures: flower herbivory and gall formation on inflorescences. Although female trees were more common than males in the two study populations (overall sex ratio = 1.5 females/male), male flowers were more likely to be eaten by lepidopteran larvae. Similarly, inflorescence-borne, fly-induced galls were more frequent on males. Ten families of insects from three orders (Diptera, Hymenoptera, Lepidoptera) occupied the galls with varying levels of parasitism and hyperparasitism occurring within. Although the sexes were not significantly different in vegetative size, males had larger floral displays (more inflorescences and larger flowers) that may have acted as attractants to herbivores and gallmakers. The results are consistent with the hypothesis that flower damage and the energetic costs of producing galls exert a greater expense to males, ultimately resulting in death, and over time, a skewing of the sex ratio.     

European field collections and Canadian releases ofCeranthia samarensis (Dipt.: Tachinidae), a parasitoid of the gypsy moth

A programme to collect, import and release into Canada the gypsy moth parasitoid,Ceranthia samarensis (Diptera: Tachinidae) is described. The parasitoid's potential for biological control in Canada is also discussed. The parasitoid was collected in Europe by exposing experimental gypsy moth larvae in areas where local gypsy moth populations were at low densities. Following field exposure, the host larvae were returned to the laboratory and parasitoids reared from them. This technique has shown thatC. samarensis is the suffers 7–16% hyperparasitism. From 83–90% of theC. samarensis typically enter diapause as pharate adults within the puparia. Laboratory tests of post-exposure host rearing conditions indicate that constant temperatures disrupt the normal parasitoid diapause and that this effect can not be offset by use of either static long or short photoperiods or natural daylengths. Shipping and cold-storage procedures for puparia are described. Post-storage time to emergence of adultC. samarensis decreased with longer cold storage periods and with higher post-storage incubation temperatures. Emergence requires 112 degree-days above a threshold of 8°C after a period of at least 8 months cold storage. Releases of adultC. samarensis into field cages at four locations in southern Ontario are documented. While dissection of host larvae from the field cages has failed so far to demonstrate evidence of parasitism, we remain hopeful that some establishment of the parasitoid has occurred.      

Behavioural plasticity in the stinging act of female ectoparasitoids

Abstract. The plasticity of the stinging behaviour of female Eupelmidae ( Eupelmus vuilleti Crawford, E. orientalis Crawford Hymenoptera: Eupelmidae) was analysed through the interrelationships of a parasitic community living on larval stage of Callosobruchus maculatus Fabricius (Coleoptera: Bruchidae). In traditional African grainstores, Eupelmus females have at their disposal all the larval stages of their host. Their exploitation is revealed by the sting observed on the host caused by the ovipositor of parasitoid females. This stinging behaviour begins immediately on the adult female's emergence, and thereafter there is a daily increase in the number of hosts stung. Stinging activity is linked to the age of the available hosts, but not all of the hosts available are exploited by the two species studied. This absence of total exploitation could indicate a threshold of activity in the stinging acts which could be in part linked to the secretion activity of the poison glands of parasitoid female.
In females of E. vuilleti and E.orientalis the stinging act is usually associated with egg-laying. The relationship between stinging and egg-laying is stronger in more advanced larval stages of the host.
In the presence of parasitized hosts, females of E. orientalis and E.vuilleti can exhibit hyperparasitism. The majority of larvae (i.e. primary parasitoid) that have been hyperparasitized have been stung and a large number of them are completely inactive. However, E. vuilleti females deposited their eggs in the available space of the pupation chamber of the host. The neonatal larvae from these scattered eggs could exploit any available host without the female having 'prepared the ground' at the time of egg-laying.
In Eupelmidae, all this happens as if there were a complementary action between the females and the neonate which could, if necessary, reinforce and/or compensate for the deficiencies in the host exploitation by the female.