Experimental data on the life-cycle of Petasiger grandivesicularis Ishii, 1935 (Trematoda: Echinostomatidae)

Larval stages of an echinostome were found in Planorbis planorbis in a brackish water lake on the Black Sea coast of Bulgaria. The cercaria is a large-tailed form with 19 collar spines. The life-cycle was completed in the laboratory using aquarium-reared fishes (Lebistes reticulatus, Puntius tetrazona tetrazona, P. pentazona pentazona, P. nigrofasciatus, Carassius auratus auratus and Xiphophorus helleri) as second intermediate hosts and canaries as definitive hosts. The redia, cercaria, metacercaria and experimentally reared adults are described. The species is determined as Petasiger grandivesicularis Ishii, 1935, and its cercaria is compared in detail with those of related forms. A key to the known large-tailed echinostome cercariae from the Palaearctic Region is presented.     

Observations on the morphology and life-cycle of Procerovum varium (Onji & Nishio, 1916) (Trematoda: Heterophyidae)

The life-cycle of Procerovum varium (Digenea: Haplorchiinae) was studied experimentally and the morphology of stages in the life-cycle has been described and illustrated. Infections with adult flukes were found in the pond heron Ardeola grayii and heavy infections with metacercariae were found, attached to the liver of the fish Oryzias melastigma (Oryziatidae) occurring in a freshwater stream situated in Visakhapatnam, India. The cercariae developing in the snail Thiara tuberculatapossessed typical haplorchiine features and were characterised by the presence of numerous cystogenous glands. Early stages of metacercarial development occurred free in the muscles of the fish intermediate host. The larvae reached the liver at 5 days post-infection, encystment commenced 2 days later and 15-day-old metacercariae were found to be infective to chicks, ducks and mice that served as suitable experimental hosts. The adult flukes obtained from natural and experimental infections showed many intraspecific variations, especially in the size and shape of the expulsor which depend on the quantity of sperm it contains. The validity of various species described in the genus and differentiated on the basis of differences in the size of the expulsor has been examined. It is concluded that only three species of the genus, namely P. varium, P. cheni and P. calderoni, are valid. "P. sisoni" of Chen (1949) is confirmed as a synonym of P. varium. P. varium is reported for the first time from India.     

Multivariate analyses of morphometrical features from Apatemon gracilis (Rudolphi, 1819) Szidat, 1928 and A. annuligerum (v. Nordmann, 1832) (Digenea: Strigeidae) metacercariae

Only two species of the strigeid subgenus Apatemon (Apatemon) sensu Sudarikov (1959), Apatemon gracilis (Rudolhi, 1819) and A. annuligerum (von Nordmann, 1832), are known to infect British fishes. A. annuligerum is poorly characterised, with few life-cycle data available, since only the adult and metacercarial stages have been described. Both of these life-stages demonstrate only minor morphological differences from those of A. gracilis. The multidimensional approach of principal components analysis (PCA) was employed to determine the intra- and inter-specific morphological variation that exists for metacercariae of these species. Analyses revealed that metacercarial morphometrics cannot confidently discriminate between Apatemon gracilis and A. annuligerum specimens. Indeed, levels of intra-specific variation present between A. gracilis metacercariae originating from different piscine hosts were as marked for certain populations as those between the two nominal species. Individual populations of A. gracilis metacercariae differed most in the relative dimensions of their internal organs, whereas variation between the two nominal species was primarily in length-related variables. A. gracilis specimens originating from Welsh and Scottish stoneloach represented two populations with the most comparable total body lengths, yet clustered separately. Conversely, A. gracilis metacercariae infecting rainbow trout and salmon parr differed markedly in size, but demonstrated minimal composite morphological variation. Much, if not all, of the variation described between populations and species of parasites can be attributed to host or to metacercarial location within a particular host. These findings and the lack of strong life-cycle data for A. annuligerum place some doubt on its validity as a species discrete from A. gracilis.     

Cercaria patellae Lebour, 1911 developing inPatella vulgata is the cercaria ofEchinostephilla patellae (Lebour, 1911) n. comb. (Digenea,Philophthalmidae)

The echinostome cercaria,Cercaria patellae Lebour, 1911, which develops in the limpetPatella vulgata (Prosobranchia, Diotocardia, Patellidae), was investigated by light and scanning microscopy. The highest prevalence of limpets with rediae/cercariae occurred on bare rocks on the upper part of the shore. The prevalence was higher in larger snails and in those which had an orange foot-sole. The cercariae penetrated into other gastropods,Aplysia punctata (Opisthobranchia, Cephalaspidea, Aplysiidae),Acanthodoris pilosa (Opisthobranchia, Nudibranchiata, Lamellidorididae) andP. vulgata. No differences in size were found between metacercariae which naturally infected onlyP. vulgata and five-day-old metacercariae from experimental infections. Inin vitro experiments excystation of metacercariae from natural infections took place as a passive process after a double treatment with pepsin and trypsin which caused the dissolution of the cyst wall. After metacercariae from natural infections were fed to one-day-old chickens, the young adults developed. Detailed morphometrical data on rediae, cercariae and metacercariae are compared with previously published measurements of living specimens. Chaetotaxy demonstrated a distinct distribution of tegumental papillae of cercariae, resembling that of the Echinostomatidae or Philophthalmidae. Scanning electron microscopy of adults revealed short, blunt spines anteriorly, while flattened serrated spines occurred on the posterior tegument. Morphometry revealed no major differences to previously published data. Considering all ecological data and comparing the morphological data with those of previous publications by different authors, we conclude thatC. patellae Lebour, 1911, the cercaria in the limpet, is a developmental stage of a digenean in the intestine of the oystercatcherHaematopus ostralegus and should be referred toEchinostephilla patellae (Lebour, 1911) n. comb.     

Predation of the apefly,Spalgis epius (Lepidoptera: Lycaenidae) on citrus mealybug,Planococcus citri (Hemiptera: Pseudococcidae)

The citrus mealybug, Planococcus citri (Risso) (Hemiptera: Pseudococcidae) is a serious pest of economically important crops worldwide. The apefly, Spalgis epius (Westwood) (Lepidoptera: Lycaenidae) is a potential predator of various species of mealybugs. Earlier investigation on its daily preying capacity and preference for prey stages on P. citri is incomplete. Hence, a study was conducted to find out the daily prey consumption ability and preference for prey stages by different larval instars of S. epius reared on P. citri in the laboratory. Through the 8-day developmental period with four larval instars, the daily prey consumption of S. epius increased from the first to the seventh day and decreased on the eighth day prior to the prepupal stage. Generally, there was a significant difference in the prey consumption on different days. When the prey stages were offered separately, the first to fourth instar larva of S. epius consumed, respectively, a mean of 199.6, 722.6, 1908.8, and 4625.6 eggs or 21.5, 77.0, 168.5, and 670.5 nymphs or 3.2, 7.2, 16.0, and 35.1 adults of P. citri. When an S. epius larva was fed on P. citri eggs, nymphs and adults separately, it consumed a mean of 7456.7 eggs, 937.6 nymphs, or 62.3 adults during its entire development. When the prey stages were offered all together, a single S. epius larva consumed 2618.4 eggs, 170.4 nymphs, and 39.7 adults of P. citri throughout its entire development. The study revealed that S. epius is a voracious predator of P. citri and thus could be utilized as a major biological control agent.     

Larval survival,host plant preferences and developmental responses of the diamondback moth Plutella xylostella (Lepidoptera: Plutellidae) on wild brassicaceous species

The diamondback moth Plutella xylostella (L.) (Lepidoptera: Plutellidae) is an important pest of cultivated brassicaceous crops worldwide. The host plant preferences, developmental biology and survival and longevity of P. xylostella are relatively well understood on commercial crop species; however, its relationship with brassicaceous weeds is poorly known. Sinapis arvensis L., Erysimum cheiranthoides L. and Capsella bursa‐pastoris (L.) Medicus are among the most common brassicaceous weeds worldwide and can serve as important bridge hosts of P. xylostella. In this study, preference and performance of P. xylostella were compared on these weed species. In free‐choice situations, females deposited 5.5 and 18.8 times more eggs on S. arvensis than on E. cheiranthoides and C. bursa‐pastoris, respectively. Survival from neonate to pupa and from pupa to adult was highest on S. arvensis and E. cheiranthoides and lowest on C. bursa‐pastoris. Development was fastest, foliage consumption was greatest, pupae and silk cocoons were heaviest, adult body masses and longevities were highest and forewings were largest for both females and males when reared as larvae on S. arvensis. Realized fecundity of new generation adults was highest for individuals reared on S. arvensis compared to those reared on E. cheiranthoides or C. bursa‐pastoris. Relative growth rates of pupae and adults were highest on S. arvensis, suggesting that this plant species is a high‐quality host for P. xylostella compared with other species tested. Potential impacts of these wild brassicaceous species on P. xylostella populations are discussed.     

Behavioral responses of Poecilia vivipara (Osteichthyies: Cyprinodontiformes) to experimental infections of Acanthocollaritrema umbilicatum (Digenea: Cryptogonimidae)

The swimming behavior of Poecilia vivipara was evaluated using an image analysis system comparing laboratory-reared uninfected fish before and after experimental infection with different intensities of cercariae of the trematode Acanthocollaritrema umbilicatum. Two experiments were performed, each with 30 fish which were individually exposed to 30 and 50 cercariae, respectively, shed from experimentally infected molluscs, Heleobia australis. Before and after (17–27 days) infection, the behavior of each fish was monitored in terms of Distance travelled, Ambulatory time, Stereotypic time, Resting time and Average speed. At the end of the experiments, the fish were dissected to count the number of metacercariae recovered. In the experiment with 30 cercariae, fish with 2–10 metacercariae did not exhibit any significant differences in their swimming activity, but those with 11–22 metacercariae had a significantly enhanced Stereotypic time and a reduced Time Resting. In the experiment with 50 cercariae, fish with 5–22 metacercariae had an enhanced Distance travelled and a reduced Average speed; highly significant differences occurred with regard to all behavioral parameters when considering the subgroup 23–36 metacercariae: Distance travelled, Stereotypic time, Resting time, Ambulatory time and Average speed. The swimming behavior of P. vivipara changed influenced by an intensity-dependence on metacercariae of A. umbilicatum, supporting the prediction that parasites are able to alter the behavior of their hosts.     

Identification of Diplostomum spp. in the retina of perch Perca fluviatilis and the lens of roach Rutilus rutilus from the Baltic Sea — an experimental study

Metacercariae of the genus Diplostomum dwelling in the retina of perch Perca fluviatilis and the lens of roach Rutilus rutilus were identified on the basis of adults obtained by feeding various piscivorous birds of the families Laridae, Anatidae and Phasianidae with metacercariae on an experimental basis. Both morphological studies of the metacercariae and adults obtained from the intestine of the infected birds, as well as the suitability in these hosts, indicated that we were dealing with two different species of Diplostomum. The perch form was recognised as D. baeri Dubois, 1937. Although metacercariae of this species matured both in herring gull Larus argentatus and common tern Sterna hirundo, the principal final host seemed to be goosanders Mergus merganser. In contrast, the lens form in roach was identified as D. spathaceum (Rudolphi, 1819) and it seemed to be restricted to birds of the family Laridae. These experimental results agree with parasitological findings from birds infected in the wild.     

Metazoan parasites of African annual killifish (Nothobranchiidae): abundance,diversity, and their environmental correlates

Estimates of biodiversity and its global patterns are affected by parasite richness and specificity. Despite this, parasite communities are largely neglected in biodiversity estimates, especially in the tropics. We studied the parasites of annual killifish of the genus Nothobranchius that inhabit annually desiccating pools across the African savannah and survive the dry period as developmentally arrested embryos. Their discontinuous, non‐overlapping generations make them a unique organism in which to study natural parasite fauna. We investigated the relationship between global (climate and altitude) and local (pool size, vegetation, host density and diversity, and diversity of potential intermediate hosts) environmental factors and the community structure of killifish parasites. We examined metazoan parasites from 21 populations of four host species (Nothobranchius orthonotus, N. furzeri, N. kadleci, and N. pienaari) across a gradient of aridity in Mozambique. Seventeen parasite taxa were recorded, with trematode larval stages (metacercariae) being the most abundant taxa. The parasites recorded were both allogenic (life cycle includes non‐aquatic host; predominantly trematodes) and autogenic (cycling only in aquatic hosts; nematodes). The parasite abundance was highest in climatic regions with intermediate aridity, while parasite diversity was associated with local environmental characteristics and positively correlated with fish species diversity and the amount of aquatic vegetation. Our results suggest that parasite communities of sympatric Nothobranchius species are similar and dominated by the larval stages of generalist parasites. Therefore, Nothobranchius serve as important intermediate or paratenic hosts of parasites, with piscivorous birds and predatory fish being their most likely definitive hosts.     

Taxonomic status, redescription, and surface ultrastructure of Ascocotyle (Phagicola) pindoramensis n. comb. (Digenea: Heterophyidae)

Pygidiopsis pindoramensis Travassos, 1928, is redescribed from the holotype and specimens obtained from experimental infections of hamsters with metacercariae of the naturally infected poeciliids Poecilia vivipara and Phalloptychus januarius from Rio de Janeiro, Brazil. Ascocotyle (Phagicola) pindoramensis (Travassos, 1928) n. comb. is proposed, based on the presence of a solid, tapering muscular posterior prolongation of the oral sucker and Ascocotyle (Phagicola) mollienisicola (Sogandares-Bernal and Bridgman, 1960) is synonymized with A. (P.) pindoramensis because of the identical morphology and measurements of adults and metacercariae, similar spectrum of fish intermediate hosts (poeciliids), and the same site of infection of the metacercariae. Trematodes designated as Pygidiopsis pindoramensis, previously reported from Argentina and Mexico, represent another species of Pygidiopsis Looss, 1907, because they possess circumoral spines and their oral sucker is devoid of the posterior muscular prolongation. Data on the surface morphology of metacercariae and adults of A. (P.) pindoramensis are inferred from scanning electron microscopy observations.     

Variation in the morphology of adult Apatemon gracilis Rudolphi, 1819 (Digenea: Strigeidae) reared in different avian hosts

Adult Apatemon gracilis (Rudolphi, 1819) were reared experimentally in three different avian hosts: herring gulls Larus argentatus Gmelin, domestic chicks Gallus gallus (L.) and eider ducklings Somateria mollissima (L.). Comparisons of size, body proportions and fecundity were made between these and specimens obtained from a naturally infected goosander Mergus merganser L. The eider duck proved to be a suitable experimental host, rearing adults of comparable size and fecundity to those from the natural host. The growth and development of the parasite in domestic chicks and herring gulls were significantly reduced. Similar conditions are likely to exist in the natural environment and this should be taken into consideration when choosing experimental hosts for use in the laboratory or when identifying species.     

Age‐based life history parameters and status assessments of by‐catch species (Lethrinus borbonicus,Lethrinus microdon,Pomacanthus maculosus and Scolopsis taeniatus) in the southern Arabian Gulf

Life history and demographic parameters for Lethrinus borbonicus, Lethrinus microdon, Pomacanthus maculosus and Scolopsis taeniatus in the southern Arabian Gulf were estimated using a combination of size frequency, biological and size‐at‐age data. Defined structural increments consisting of alternating translucent and opaque bands in transverse sections of sagittal otoliths were validated as annuli. The maximum age estimates ranged from 5 years for Scolopsis taeniatus to 36 years for Pomacanthus maculosus. The size‐at‐age relationships were highly asymptotic in form with the majority of growth being achieved early in life. There were significant differences in the growth characteristics between sexes for Pomacanthus maculosus, with males approaching a larger asymptotic size at a faster rate than females. With the exception of Scolopsis taeniatus, the mean age at which fish became vulnerable to capture was lower than the mean age at first sexual maturity. The stocks of L. microdon, P. maculosus and S. taeniatus were exploited within sustainable limits, conversely, L. borbonicus was found to be overexploited and recruitment overfishing may have occurred as the relative spawner biomass per recruit was below 30% of the unexploited state.     

Rearing phonotactic parasitoid flies [Diptera: Tachinidae,ormiini, ormia spp.]

Females of ormiine tachinids fly to their hosts' calling songs and deposit larvae on the host or nearby. Two species,Ormia ochracea (Bigot) andO. depleta (Wiedemann), were reared for at least 8 generations, making them the first ormiines to be laboratory-propagated. Both were reared on natural hosts:Gryllus spp. field crickets (principallyG. rubens) forO. ochracea, andScapteriscus spp. mole crickets forO. depleta. Commercially rearedAcheta domesticus tested as hosts were less satisfactory. Hosts were parasitized manually or by confinement with flies or planidia (infective larvae). Transparent, cylindrical, sleeved cages were designed to accommodate parasitized hosts and pupae and adults ofO. ochracea. Cages were joined to allowO. ochracea to cycle through its stages with minimum handling and care. Parasitized hosts and pupae ofO. depleta were held in containers of damp sand; adults were held in cages developed forO. ochracea. Adults of both species were maintained on applesauce, sugar cubes, powdered milk, and water. The life cycle ofO. ochracea was about 31 days and ofO. depleta about 36 days, with the principal difference being the time required for planidia to complete development. InO. ochracea the adults emerged synchronously but inO. depleta males preceded females. In both species sex ratio was generally I: 1 and females lived slightly longer than males.O. depleta from our laboratory colony have been released for biological control of mole crickets.      

Catatropis chilinae n. sp. (Digenea: Notocotylidae) from Chilina dombeiana (Gastropoda: Pulmonata) and notes on its life-cycle in Patagonia,Argentina

A new species of Catatropis from a freshwater pulmonate snail of the family Chilinidae, which is endemic to South America, is described. Naturally infected Chilina dombeiana were collected from several localities in Andean Patagonia. The characteristics of the larval stages are presented. Experimentally reared adults, located in the distal portion of the intestinal caeca, were recovered from chickens and ducks. Adults of Catatropis chilinae n. sp. can be distinguished from all other species in having 9-11 (10) ventral glands, a cirrus-sac extending between the first third and the middle of the body, a metraterm slightly shorter or equal to the cirrus-sac, vitelline follicles reaching forward to the middle of the body, lobed testes, and a genital pore closely posterior to the caecal bifurcation. Eggs bear polar filaments only at the anopercular end. Rediae have only one or two cercariae. Shed cercariae are trioculate with a long tail and encyst in the environment, and metacercariae become infective 72 hours after encystment. This species is widely distributed between 40°10 S and 43°09 S and it is the first Catatropis species recorded for the Chilinidae and for Argentina.     

Studies on the life-cycle of Ganeo tigrinus Mehra & Negi, 1928 (Digenea)

The life-history stages of Ganeo tigrinus Mehra & Negi, 1928 infecting the Indian bull frog Hoplobatrachus tigerinus (Daudin) are described, those from cercaria to egg-producing adult having been established in the laboratory. Non-virgulate xiphidiocercariae are released by the planorbid snail Indoplanorbis exustus (Deshayes). Metacercariae occur in the haemocoel of dragonfly nymphs and become infective to the frog H. tigerinus within 15 days. The pre-patent period is 45 days. Growth and development of both metacercariae and adults are described in detail. Comments on the systematic position of Ganeo Klein, 1905 are included.     

Immature stages of Pangaeus (Pangaeus) serripes (Westwood) (Hemiptera-Heteroptera: Cydnidae: Cydninae), associated with figs in Mexico

The immature stages of Pangaeus (Pangaeus) serripes are described for the first time. Immature stages are illustrated and notes about their biology are included. Morphological features of the legs of the nymphs are associated with the fossorial habit of the Cydninae. Both adults and nymphs have been reared and found feeding on fallen fruits and seeds of several species of figs in Mexico.     

Beitrag zur Kenntnis der Wirte vonOpius-Arten (Hymenopter,Braconidae)

Summary This paper deals with a collection of about 225 samples of the genusOpius (Hymenoptera, Braconidae) reared from dipterous hosts. 40 species have been identified, two of which (O. griffithsi andO. heringi) are new. Full data (hosts, host-plant, locality, date of collection and emergence, number of specimens) is given for the species that were examined.      

Use of Alternative Food Plants Exclusively by Adult Male Froghoppers (Homoptera: Cercopidae)1

Male-specific associations of adult froghoppers (Homoptera: Cercopidae) with alternative food plant hosts is reported. Four accounts from the field and one from the literature are presented: Iphirhina quota on Bourreria costaricensis (Boraginaceae), Huaina inca on Solanaceae sp., Prosapia simulans and Prosapia sp. (near P. bicincta) on Ilex haberi (Aquifoliaceae), and Prosapia bicincta on Ilex cornuta and Ilex opaca. In three cases host use is limited to adults while in two cases use is limited to only adult males. In four cases adults feed on plants that differ taxonomically, structurally and ecologically from hosts normally utilized by all life stages. These associations are not considered aggregations per se because froghoppers are not clustered and because these associations cannot be explained by the usual criteria supporting the adaptiveness of insect aggregations. Indirect evidence suggests that these unusual hosts may be unavailable to nymphs and not sought by females. This passive lack of opportunity by nymphs and females, in tandem with an active selection/attraction by males, is a plausible explanation for the existence of male-specific hosts.     

The effect of host plant on larval survivorship of the Alaskan swallowtail butterfly (Papilio machaon aliaska)

The Alaskan swallowtail butterfly, Papilio machaon aliaska (Lepidoptera: Papilionidae), uses three plant species as host plants. Cnidium cnidiifolium (Turcz.) Schischk. belongs to the family Apiaceae, the ancestral host‐plant family of the P. machaon group. Artemisia arctica Less. and Petasites frigidus (L.) Franch, in contrast, belong to the distantly related Asteraceae family and were colonized relatively recently by this group of butterflies. Previous work has shown that larval survival is highest on the novel host plants when natural enemies are present in the field. Here I examine whether P. m. aliaska fitness varied when individuals were reared on the three host plants in a common environment, free of environmental and ecological complications such as predation. I collected 12 P. m. aliaska females and measured their reproductive success when their progeny were reared on each of the three host plants. I assessed larval fitness on each of the hosts by recording the percentage pupation and percentage emergence as well as by measuring pupal mass. I found that larvae reared on the ancestral host plant, C. cnidiifolium, had higher fitness than did larvae reared on either of the novel host plants, A. arctica or P. frigidus. Larvae reared on C. cnidiifolium were more likely to pupate, achieved a greater pupal mass, and had higher emergence rates than larvae reared on the novel hosts. I interpret these results to mean that, in the absence of predation, the ancestral host plant is a better host for P. m. aliaska larvae than either novel host and I contend that this result does not appear to support the hypothesis that P. m. aliaska populations in central Alaska are divided into host races.     

Pathology and first report of natural eye infection with the trematode Philophthalmus gralli (Digenea,Philophthalmidae) in Tinamus major (Tinamiformes,Tinamidae), Costa Rica

The eye-fluke Philophthalmus gralli (Philophthalmidae Looss, 1899) was found in six birds known as great tinamous (Tinamus major) reared in a wild animal shelter located in Alajuela, Costa Rica. The birds presented conjunctival hyperemia, blepharitis, anorexia and weakness. Some of them suffered from unilateral blindness and ocular loss. After morphometric analysis, the specimens showed characteristics compatible with the digenean trematode P. gralli. The clinical signs of infection were resolved by manual removal of the adults, treatment with praziquantel and relocation into an environment without a natural water source. In order to determine if an ongoing cycle of this pathogen was present in the shelter, the habitat of the birds was inspected for the presence of infected intermediate hosts and contaminated water and objects. It was found that the snails Melanoides tuberculata acted as the intermediate host, and reared the infectious stages toward other animals, as shown by the reproduction of ocular philophthalmiasis in chickens artificially infected with excysted metacercaria. Moreover, three out of every ten snails found in the place were infected with rediae of P. gralli, raising the possibility of the dispersion of the parasite into new environments as well as the imminent zoonotic risk. The finding of P. gralli in Costa Rica is the first official report in Central America.