Host Abdomen Research Articles

Anatomical, phenological and genetic aspects of the host-parasite relationship between Andrena vaga (Hymenoptera) and Stylops ater (Strepsiptera).

Stylops ater is an endoparasite of the mining bee Andrena vaga with extreme sexual dimorphism and hypermetamorphosis. Its population structure, parasitization mode, genetic diversity and impact on host morphology were examined in nesting sites in Germany to better understand this highly specialized host–parasite interaction. The shift in host emergence due to stylopization was proven to be especially strong in A. vaga. Around 10% of bees hosted more than 1 Stylops, with at maximum 4. A trend in Stylops' preference for hosts of their own sex and a sex-specific position of extrusion from the host abdomen was found. Invasion of Andrena eggs by Stylops primary larvae was depicted for the first time. Cephalothoraces of female Stylops were smaller in male and pluristylopized hosts, likely due to lower nutrient supply. The genes H3, 18S and cytochrome c oxidase subunit 1 were highly conserved, revealing near-absence of local variation within Stylops. Ovaries of hosts with male Stylops contained poorly developed eggs while those of hosts with female Stylops were devoid of visible eggs, which might be due to a higher protein demand of female Stylops. Male Stylops, which might have a more energy-consuming development, led to a reduction in head width of their hosts. Host masculinization was present in the leaner shape of the metabasitarsus of stylopized females and is interpreted as a by-product of manipulation of the host's endocrine system to shift its emergence. Stylopization intensified tergal hairiness, most strongly in hosts with female Stylops, near the point of parasite extrusion, hinting towards substance-induced host manipulation.

蓝色长盾金小蜂对橡副珠蜡蚧的控制作用

PDF HTML阅读 XML下载 导出引用 引用提醒 蓝色长盾金小蜂对橡副珠蜡蚧的控制作用 DOI: 10.5846/stxb202110092804 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 海南省自然科学基金项目（321RC623）；国家现代农业产业技术体系项目（CARS-33-GW-BC2）；热科院基本业务费项目（1630042017002） The control efficiency of Scutellista caerulea Fonscolombe on Parasaissetia nigra Nietner Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:蓝色长盾金小蜂Scutellista caerulea Fonscolombe是橡胶树重要害虫橡副珠蜡蚧Parasaissetia nigra Nietner的一种外寄生性天敌。为了明确蓝色长盾金小蜂对橡副珠蜡蚧的控害潜能，为该寄生蜂的进一步利用提供数据支撑。在室内通过体视镜下解剖观察寄生蜂在寄主腹下是否产卵测定了不同温度、寄主发育阶段下蓝色长盾金小蜂的寄生功能反应、寻找效应和自身密度干扰效应。温度设置有21、24、27、30、33、36℃共6个处理，寄主发育阶段设初期成虫（1-2 d成虫）、褐色期成虫（体色褐色，产卵前3-4 d成虫）、黑色期成虫（体色黑色，产卵1-2 d成虫）三个处理。结果显示：蓝色长盾金小蜂对橡副珠蜡蚧的寄生功能反应符合Holling-Ⅱ型和Holling-Ⅲ型模型，在21-36℃范围内，33℃时该蜂寄生效能最大，为44.4201，21℃时最小，为9.2458；在橡副珠蜡蚧为初期成虫-黑色期成虫范围内，寄生效能由大到小为黑色期成虫>褐色期成虫>初期成虫，分别为18.9044、13.7410、7.2002。采用Hassell-Varley干扰模型对不同温度下蓝色长盾金小蜂受自身密度干扰的寄生作用率进行拟合，表明蓝色长盾金小蜂在寄生时存在种群内个体间自我干扰情况。温度会影响蓝色长盾金小蜂的搜寻和自我干扰，在21-33℃范围内，33℃搜寻常数和干扰常数达到最大值，分别为0.6116、0.7535。当温度为33℃，寄主发育阶段为黑色期成虫时，蓝色长盾金小蜂对橡副珠蜡蚧有较强的控制能力，自身干扰作用最强。 Abstract:Scutellista caerulea Fonscolombe is an ectoparasitic enemy of Parasaissetia nigra Nietner, an important pest of rubber trees. This study aims to clarify the control efficiency of S. caerulea on P. nigra and provide data support for its further utilization. The functional response, searching efficiency and mutual interference of this parasitoid were measured indoors by dissecting to see if the wasp laid eggs under the host's abdomen at different temperatures and host developmental stages. There were 6 treatments for temperature, including 21, 24, 27, 30, 33, 36℃, and three treatments were used for the developmental stages of the hosts, early adult (1 to 2 d adult), brown adult (brown body color, 3 to 4 d before spawning), black adult (black body color, adults 1-2 days after laying eggs). The results showed that the functional response of S. caerulea to P. nigra matched the Holling-Ⅱ and Holling-Ⅲ models. In the range of 21-36℃, the control efficiency of S. caerulea on P. nigra was the maximum at 33℃, 44.4201 and the minimum at 21℃, 9.2458, and both models show that at 33℃, the upper limit of parasitism is the largest, which were 45.7 and 19.2, respectively. The control efficiency to the different development stages of P. nigra were:the largest in the black stage, followed by the brown adult, and the smallest in the early adult stage, which were 18.9044, 13.7410, and 7.200, respectively. And both models show that when P. nigra was black adult stage, the upper limit of parasitism was the largest, which were 15.7 and 12.2, respectively. Both models show that when P. nigra was early adult stage, the upper limit of parasitism was the lowest, which were 5.2 and 4.4. In addition, the Hassell-Varley interference model was used to fit the parasitic action rate of S. caerulea interfered by its own density under different temperatures, which indicated that S. caerulea had self-interference among individuals in the population when they parasitized. Temperature affected the search and self-interference of S. caerulea. In the range of 21-33℃, the search constant and interference constant reached their maximum values at 33℃, which were 0.6116 and 0.7535, respectively. In summary, when the developmental stage of P. nigra is the black adult, and the temperature is 33℃, S. caerulea has the stronger ability to control P. nigra, and the mutual interference is the strongest. 参考文献 相似文献 引证文献

Behavioural strategy of the ectosymbiotic crab (Sestrostomasp.) during ecdysis of the crab and its upogebiid shrimp host

AbstractMoulting is essential for crustacean growth, but is one of the causes of mortality, because a crustacean cannot move during and just after its ecdysis. In the cases of ectosymbiotic crabs, escape from the host's hostile response may also be a problem during its own ecdysis. In this study,Sestrostomasp. (Varunidae), an ectosymbiotic crab which clings to the ventral abdomen of upogebiid shrimps with legs that can walk, was studied to clarify how the crab moults and maintains association with the host. Five cases of crab ecdysis were observed, where the crab moulted with its legs clinging to the host abdomen, without detaching from the host body. Time required for moulting was 14–21 min. Shedding of the old exoskeleton (active phase) took only 40–59 s.Sestrostomasp. detached from the host abdomen and waited in the burrow tube during shrimp ecdysis. The crab then reattached at the same location on the host when shrimp moulting was complete. Our results suggest thatSestrostomasp. are able to maintain a symbiotic relationship with the same shrimp host after its own ecdysis as well after ecdysis of its host.

Parasitism in Theridion sp. (Araneae: Theridiidae) by Zatypota riverai Gauld, 1991 (Hymenoptera: Ichneumonidae: Pimplinae)

The hymenopteran genus Zatypota Förster, 1869 (Ichneumonidae: Pimplinae, Ephialtini) comprises highly specialized koinobiont ectoparasitoids of spiders and is the largest genus of the Polysphincta group of genera in the world, with more than 50 described species. The vast majority of species of Zatypota are parasitoids of the spider family Theridiidae. In this study, we present information about a new interaction between the parasitoid spider wasp Zatypota riverai Gauld, 1991 and the host spider Theridion sp. Walckenaer, 1805 (Theridiidae) with information about host weight selection. We collected 102 non-parasitized adult and subadult females of Theridion sp. and six spiders with larvae of Z. riverai attached to host's abdomen. The pupal development takes about 8–11 days, though the development time of the pupa varies with the sex of the wasp. All larvae collected in the field completed their life cycle on the host spiders, even though all of the hosts were small, indicating that the host biomass was sufficient for larval development and no larger-sized spiders are needed. Moreover, larger Theridion probably pose a greater risk because they are more likely to be successful at wasp predation, even if they offer a greater resource to the larva.

Host-parasitoid interactions between the solitary bee Centris analis (Apidae: Centridini) and conopid flies (Diptera: Conopidae).

Natural enemies are one of the main mortality factors in bees and wasps attacking either immature stages or adults of their hosts. Dipterans of the genus Physocephala (Diptera: Conopidae) are parasitoids that attack adult bees during their field activities, and the parasitoid larvae develop inside the host abdomen. However, little is known about the biology of these natural enemies and their interactions with their solitary bee hosts. This study is aimed at analyzing attacks by conopid flies in one of their hosts, the solitary bee species Centris analis (Apidae: Centridini), and the consequences in the nesting behavior of this bee species. Higher incidences of parasitism occurred during the hot/wet season, and seven fly species attacking C. analis were identified. Of the fifty-six females observed during their nesting activities, seven of them were parasitized. These females showed alterations in their nesting behavior, depositing extra oil on the plug of finished nests and building plugs in empty cavities. The behavioral changes observed in these females began during larval stage L1 of the parasitoid. In the last stages of parasitoid development (L3 PUP and pupa), the bees ceased their flight activities and entered cavities at the nesting site, remaining there until death.

Using an in vitro system for maintaining Varroa destructor mites on Apis mellifera pupae as hosts: studies of mite longevity and feeding behavior.

Varroa destructor mites (varroa) are ectoparasites of Apis mellifera honey bees, and the damage they inflict on hosts is likely a causative factor of recent poor honey bee colony performance. Research has produced an arsenal of control agents against varroa mites, which have become resistant to many chemical means of their control, and other means have uncertain efficacy. Novel means of control will result from a thorough understanding of varroa physiology and behavior. However, robust knowledge of varroa biology is lacking; mites have very low survivability and reproduction away from their natural environment and host, and few tested protocols of maintaining mites in vitro are available as standardized methods for varroa research. Here, we describe the 'varroa maintenance system' (VMS), a tool for maintaining in vitro populations of varroa on its natural host, and present best practices for its use in varroa and host research. Additionally, we present results using the VMS from research of varroa and host longevity and varroa feeding behavior. Under these conditions, from two trials, mites lived an average of 12 and 14days, respectively. For studies of feeding behavior, female mites inflicted wounds located on a wide range of sites on the host's integument, but preferred to feed from the host's abdomen and thorax. Originally in the phoretic-phase, female mites in VMS had limited reproduction, but positive instances give insights into the cues necessary for initiating reproduction. The VMS is a useful tool for laboratory studies requiring long-term survival of mites, or host-parasite interactions.

Imaginal Disc Transplantation in Drosophila.

Since Ephrussi and Beadle introduced imaginal disc transplantation to Drosophila research in 1936, the method played an important part towards a better understanding of disc patterning, tissue regeneration, and reprogramming phenomena like transdetermination. Despite increasing usage of high-throughput approaches towards solving biological problems this classical manual method is still in use for studying disc development in a semi-physiological context. Here we describe in detail a protocol and provide recommendations on the procedure in particular for analyzing the regenerative potential of imaginal disks. The steps consist of disc dissection and fragmentation, transplantation into the larval or adult abdomen, and the recovery of implants from the host abdomen. Additionally, we also describe how to make the special transplantation needle from a glass capillary.

Zygomycetes: an emerging problem in the clinical laboratory.

This supplement of ‘Mycoses’ is devoted to infections caused by a group of fungi traditionally known as the zygomycetes. The Zygomycota represent an important group of medically important opportunistic fungi, which cause devastating fungal infections in humans and animals with severe underlying immune or metabolic disorders. These infections are increasing in numbers due to the growing populations of patients with uncontrolled diabetes and immunosuppression, as well as the increased use of prophylactic measures against other hospital infections using drugs that are ineffective against Zygomycota organisms. The Zygomycota has been one of the ancestral phyla in the fungal Kingdom. The second class, the Trichomycetes contains phylogenetically diverged groups of organisms united based on their ecological requirement as endocommensals in the digestive tract of the aquatic insect larvae or other arthropods. Under the influence of molecular phylogeny the Zygomycota as a distinct phylum has changed significantly over the past decades. The group disintegrated into the five subphyla of Entomophthoromycotina, Kickxellomycotina, Mortierellomycotina, Mucoromycotina and Zoopagomycotina. These subphyla are too distantly related from each other to compose a single group higher up in the hierarchy. These changes have little impact on medical mycology, since just the umbrella term has disappeared and the major types of mycoses are still distinguishable into: (i) the preponderantly chronic entomophthoromycoses; (ii) the rapidly progressive mucormycoses; and (iii) the few representatives of Mortierellomycotina causing bovine abortion. Clinical parameters in main traits coincide with the above taxonomic and phylogenetic tripartition. The Mucorales is by far the largest order of the lower fungi, with nearly 240 species in 48 genera. In the interest of nomenclatural stability, common generic names such as Mucor and Rhizopus were preserved as presently applied. In their natural habitat the fungi comprise a wide morphological and ecological diversity as saprobes or opportunistic pathogens. The Mucorales are generalistic fungi having importance as biotransforming agents of pharmacological and chemical compounds and are extensively used in the food industry. The same, thermotolerant species – mostly belonging to the genera Lichtheimia, Rhizomucor and Rhizopus – are found to occur as agents of infection. This remarkable duality of good and bad united in the same individual must be explained by properties needed in their natural habitat, which are as yet only fragmentarily understood. The Mucorales are cosmopolitan, and are amongst the most widespread fungi, but regional differences exist in prevalence between different patient populations. The Entomophthorales is an order of mainly pathogenic fungi on insects with highly adapted killing mechanisms. Spores are actively discharged to become airborne and are adhesive knobs to invade between segments of the host's abdomen. These fungi are obviously not adapted to human infection, but nevertheless severe systemic infections in sinus and gastrointestinal tract have frequently been reported from the tropics caused by species found in the intestinal tract of cold-blooded vertebrates. Only limited numbers of species in the genera Basidiobolus and Conidiobolus are involved. This special issue touches numerous aspects of opportunism in Mucorales and Entomophthorales, ranging from clinical aspects and different patient populations to taxonomy and virulence studies.

Misdiagnosis of fetus-in-fetu as meconium peritonitis

Fetus-in-fetu (FIF) is a rare congenital condition in which a fetiform mass is detected in the host abdomen and also in other sites such as the intracranium, thorax, head, and neck. This condition has been rarely reported in the literature. Herein, we report the case of a fetus presenting with abdominal cystic mass and ascites and prenatally diagnosed as meconium pseudocyst. Explorative laparotomy revealed an irregular fetiform mass in the retroperitoneum within a fluid-filled cyst. The mass contained intestinal tract, liver, pancreas, and finger. Fetal abdominal cystic mass has been identified in a broad spectrum of diseases. However, as in our case, FIF is often overlooked during differential diagnosis. FIF should also be differentiated from other conditions associated with fetal abdominal masses.

Parasitic Forms of Halictophagus sp. (Strepsiptera:Halictophagidae) Infesting the Mango Leafhopper, Idioscopus clypealis (Leth) (Hemiptera:Cicadellidae)

The various stages of Halictophagus sp., a strepsipteron parasitoid of the mango leafhopper ldioscopus clypealis (Lethierry), collected over a one-year period were identified and described. Several hundreds to more than a thousand globular white eggs were present in the ovisac of a highly reproductive neotenic female which remains attached to the host. The eggs hatched into first instar larvae or triungulins which exhibited two forms, the C-shaped female with posterior spines and the tubular males without the spines. The tubular males predominate over the C-shaped females at 1.6:1.0 ratio. The neotenic female larviposits the triungulins within the vicinity of potential hopper hosts. The triungulins penetrate the host and develop inside the host abdomen. Two forms of endoparasitic larvae were observed: one was the hard dark-brown C-shaped female larva and the other was the hard dark brown tubular male larva. The latter developed into a soft creamy-white larva which showed hardening and tanning of its anterior region when full grown and before extruding as cephalotheca. On the other hand, a small area along the ventral region of the host abdomen darkens ( dark spot) to indicate a soon to extrude female cephalothorax. The extruded parasitoids had 1.3 cephalotheca: 1.0 cephalothorax ratio. The parasitoid was extrapolated as completing Jts life cycle in 4 months and having two to three overlapping generation cycles in a year.

Life histories of two ichneumonid parasitoids of Cyclosa octotuberculata (Araneae): Reclinervellus tuberculatus (Uchida) and its new sympatric congener (Hymenoptera: Ichneumonidae: Pimplinae)

AbstractIn Japan, two species of the genus Reclinervellus were found to attack a single host spider, Cyclosa octotuberculata (Araneae). One of these, Reclinervellus tuberculatus comb. nov., winters as a tender larva and has at least two generations a year. This species laid its egg on the anterior face of the host's abdomen. Prior to laying an egg the female repeatedly rubbed her ovipositor over the dorsal and lateral surfaces of the host's abdomen near the base for more than 25 min. The hatched larva fixed itself at the position where the egg was laid, and developed by consuming the host's body fluids. The other species, R. masumotoi sp. nov., is closely related to R. tuberculatus but is easily distinguished from it by having a very weakly reclivous Cu vein in the hindwing, a less developed carina of the propodeum, a shorter ovipositor and more blackish coloration of the mesoscutum. Although this species is sympatric with R. tuberculatus and attacks the same host, the position of the egg and larva on the host's body is quite different from that of R. tuberculatus. The egg of this species was laid on the posterior surface of the host's abdomen and the larva matured 10–20 days earlier than those of R. tuberculatus. Via these modes of parasitism R. masumotoi seemed to escape from competition with R. tuberculatus at the stage of oviposition and out‐competed it when a single host individual bore larvae of both species. Previous records of parasitoids reared from C. octotuberculata were reviewed and found to include records of both species.

Are the attachment sites of larval water mites (Acari, Hydrachnidia) on their dipteran hosts suited for host partitioning?

Attachment site patterns for parasitic larvae of spring-dwelling water mites on nematocerans were recorded and evaluated. Emphasis is placed on mite larvae which parasitize chironomid hosts. Species-specific attachment sites on the hosts and site preferences in both thoracically and abdominally attached mite larvae were registered. A comparison between the attachment sites of single larvae and of two or more conspecific larvae parasitizing a single host revealed only small differences in attachment patterns, suggesting that site selection was the result of an innate preference rather than induced by competition. Balanced attachment was more frequent than asymmetrical attachment and dorsal/ventral attachment was found to be host-species-specific. Host partitioning was evident for those parasite-host associations in which one species parasitizes the host's thorax and another parasitizes the host's abdomen. Despite preferences for different attachment sites by the mite larvae, host partitioning was only rarely realized. This is because multiple parasitism was rare in the parasite-host relationships studied. We conclude that host partitioning caused by differences in attachment site preferences is likely for chironomid hosts but should be proven in a habitat with higher mite diversity, where competition would play a more important role.

Mating of Xenos vesparum (Rossi) (Strepsiptera, Insecta) revisited

The controversial mating of the strepsipteran Xenos vesparum was studied to investigate the possible sperm routes for fertilization. The female, which is a neotenic permanent endoparasite of Polistes wasps, extrudes only its anterior region, the "cephalothorax," from the host abdomen. This region has an opening where both mating and larval escape occur. Observations with scanning and transmission electron microscopy revealed spermatozoa not only in the hemocoel, but also in the "ventral canal" (an extragenital duct peculiar to strepsipteran females) and in the "genital ducts" (ectodermal invaginations connecting the ventral canal to the hemocoel) of recently mated females. Xenos vesparum spermatozoa can reach the oocytes either through the hemocoel as a result of a hypodermic insemination, or by moving along the extragenital ducts, which are later used by first instar larvae to escape. The hypothesis of hypodermic insemination is reconsidered in the light of behavioral and ultrastructural evidence.

Australian species of Chordodes (Nematomorpha) with a description of two new species, remarks on the genus Chordodes and its life history

Only seven species of freshwater Nematomorpha (Gordiida) are known from Australia, four of which belong to the genus Chordodes. This paper describes two new species: C. queenslandi and C. brevipilus. Chordodes queenslandi is characterized by a polymorphism of crowned areoles which appear as two types with distinct distribution patterns. Chordodes brevipilus is characterized by crowned areoles with very short apical filaments. One specimen previously determined as C. modiglianii (Camerano, 1892) belongs to C. queenslandi. Chordodes jandae Camerano, 1895 is redescribed according to the terminology introduced for C. queenslandi and C. brevipilus. Two further species, C. annulatus Linstow, 1906 and C. undulatus Linstow, 1906 do not belong to Chordodes. The newly reported specimens were collected emerging from praying mantids in the vicinity of water and escaped by contact of the host's abdomen with water. The active movement of mantids towards water suggests an internal stimulus of the nematomorph parasite to its host.

Factors that determine the positions where Pseudoxenos iwatai Esaki (Strepsiptera: Stylopidae) extrudes from the host abdomen

Factors that determine the positions where Pseudoxenos iwatai Esaki (Strepsiptera: Stylopidae) extrudes from the host abdomen

Morphological discrimination between first instar larvae of four euphorine parasitoids

Four parasitoids of the subfamily Euphorinae are common in New Zealand pasture. These are Microctonus aethiopoides, M. hyperodae, M. zealandicus and Dinocampus coccinellae. There is overlap in these parasitoids' host ranges and, although adults of these species can be identified morphologically, their larval stages have not yet been compared. This contribution provides morphological descriptions of the head capsules of 1st instar larvae that enable the four parasitoid species to be distinguished. Diagnostic characteristics are the shape of the mandible and the pattern of sclerotisation on the hypopharynx. Post 1st instar larvae can be identified by retrieving the shed 1st instar head capsule from the host abdomen.

Parasites of Larval Black Flies (Diptera: Simuliidae) and Environmental Factors Associated with Their Distributions

A total of 26,673 midto late-instar larval black flies were collected from 115 stream sites in South Carolina. Host larvae with patent, externally visible infections of nematodes, fungus, or microsporidia were identified to species either morphologically or cytologically. Six parasite taxa were identified: nematodes of the family Mermithidae; the fungus Coelomycidium simulii; and the microsporidia Janacekia debaisieuxi, Polydispyrenia simulii, Amblyospora bracteatalvarians, and Caudospora simulii. Of 43 species of black flies, 25 harbored at least one of these parasite taxa. Records from museum specimens increased the number of infected host species in South Carolina to 34 species. Prevalence of patent infections for each parasite taxon was low, ranging from 0.1 to 6.5% of all larvae. The distribution of nematodes among stream sites was nonrandom and correlated with season, host abundance, and stream-site conditions. The association of nematode distributions with stream parameters might reflect environmental influences on the nematodes during their free-living period and on host susceptibility to infection. Additional keywords: Mermithidae, Coelomycidium simulii, microsporidia Larval black flies (Diptera: Simuliidae) are a major component of the macroinvertebrate fauna in streams and rivers (Adler & McCreadie 1997). They anchor themselves to a silken pad spun on solid substrates (e.g., rocks, trailing vegetation) and filter food from the water column or graze it from the substrate. Larval and pupal development is temperature dependent and requires from one week to half a year (Crosskey 1990). After emergence from the pupa, females of most species mate, acquire sugar for energy and a vertebrate bloodmeal for egg maturation, and find a suitable stream for oviposition. Larvae are hosts of a variety of parasites, especially mermithid nematodes (Mermithidae), microsporidian protozoans (Microspora), and the chytrid fungus Coelomycidium simulii DEBAISIEUX. Preparasitic mermithid nematodes crawl about on the stream substrate and use a protrusible stylet to penetrate the host body (Molloy 1981). Infected host larvae are recognized by the presence of one or more coiled worms visible through the abdominal cuticle. Mermithids either exit and kill the host while it is still in the larval stage or pass into the adult stage, exiting shortly thereafter (Crosskey 1990). Postparasitic worms molt to adults, mate, and deposit eggs in the streambed (Poinar 1981). a Author for correspondence. E-mail: jmccrd@clemson.edu Microsporidian infections cause pathological changes, primarily to the host fat body (Weiser & Undeen 1981). Patent infections are recognized by the presence of large, irregular cysts that distend the host abdomen. Life cycles of microsporidia that attack black flies are not well understood, but larval hosts become infected both by transovarial transmission and by ingesting the free-living spores (Crosskey 1990). Spores might require some form of environmental conditioning before they become infective, and alternate hosts might be required to complete the life cycle (Jamnback 1973; Lacey & Undeen 1987). Larvae with patent infections of the fungus C. simulii are packed with minute, spherical thalli throughout the body cavity. Thalli give rise to spores that are released into the water column after the death of the host (Tarrant 1984). An intermediate host might be required to complete the life cycle (Lacey & Undeen 1987). In the present study, we survey selected parasites of larval black flies in South Carolina. Given that nematodes have free-living stages, we ask whether these parasites occupy a restricted range of stream conditions within the broader range of conditions under which their hosts are found. In other words, can occurrence (presence/absence) of nematodes in a particular host species, at a particular location, be predicted This content downloaded from 157.55.39.84 on Wed, 15 Jun 2016 06:30:20 UTC All use subject to http://about.jstor.org/terms Parasites of larval black flies by local stream conditions? Our objective is to examine factors that can explain parasite distributions, with the tenet that patterns of distribution can provide insight into the basic ecology of these organisms. Other parasites (microsporidia, C. simulii) were collected in numbers too low to address these questions.

The Genus Gibellula on Spiders from Taiwan

Four species of Gibellula were found on spiders in Taiwan. Gibellula leiopus and G. pulchra are redescribed; G. unica, a new species, and G. clavulifera var. major, a new variety, are described. A key to the Taiwanese Gibellula species is given. The most distinguishing feature of G. unica is the concurrent or independent production of phialidic or polyblastic conidiogenous cells of, respectively, Gibellula and Granulomanus synanamorphs on the same well differentiated distinctly verrucose conidiophore. Gibellula clavulifera var. major is primarily characterized by a white, solitary, whiplashlike synnema arising from the tip of host abdomen, and from which the bi-, ter-, or rarely monoverticillate penicilli are initiated. The verticillate conidiogenous cells on the well differentiated conidiophores are of two types, one phialidic bearing catenate, fusiform to broadly fusiform conidia; the other holoblastic, with distinct denticles bearing solitary, long, bacilliform conidia. Gibellula unica is compared to the morphologically similar species G. brunnea, G. clavata, and G. mirabilis; and G. clavulifera var. major is compared to G. clavulifera var. clavulifera, and G. clavulifera var. alba.

The genus Gibellula on spiders from Taiwan

Four species of Gibellula were found on spiders in Taiwan. Gibellula leiopus and G. pulchra are redescribed; G. unica, a new species, and G. clavulifera var. major, a new variety, are described. A key to the Taiwanese Gibellula species is given. The most distinguishing feature of G. unica is the concurrent or independent production of phialidic or polyblastic conidiogenous cells of, respectively, Gibellula and Granulomanus synanamorphs on the same well differentiated distinctly verrucose conidiophore. Gibellula clavulifera var. major is primarily characterized by a white, solitary, whiplashlike synnema arising from the tip of host abdomen, and from which the bi-, ter-, or rarely monoverticillate penicilli are initiated. The verticillate conidiogenous cells on the well differentiated conidiophores are of two types, one phialidic bearing catenate, fusiform to broadly fusiform conidia; the other holoblastic, with distinct denticles bearing solitary, long, bacilliform conidia. Gibellula unica is compared to the morphologically similar species G. brunnea, G. clavata, and G. mirabilis; and G. clavulifera var. major is compared to G. clavulifera var. clavulifera, and G. clavulifera var. alba.

Life history and immature stages ofRhyncophoromyia maculineura, an ant-parasitizing phorid fly (Diptera: Phoridae) from Peru

Third-instar larva, puparium and life history of Rhyncophoromyia maculineura are described. Females of this species parasitize injured workers of Camponotus sericeiventris and possibly also those of Dolichoderus lugens. Larvae develop in the host abdomen, one per host. Limited life history data indicate that this way of life might be shared by other species of this genus.