Megalophallus deblocki n. sp. (Digenea: Microphallidae) from Rostrhamus sociabilis (Vieillot) (Aves: Accipitridae) in Paraguay

A new species in the little-known digenean fauna of Paraguayan birds is described in detail, especially in relation to its terminal genitalia. The new form, Megalophallus deblocki n. sp., is a microphallid from the intestine of the snail kite Rostrhamus sociabilis (Vieillot). It is differentiated in detail from its congeners, but differs mainly in having a substantially larger phallus (e.g. in relation to the ventral sucker), a smaller ventral sucker and smaller eggs. Comments are included on the functional morphology of the terminal genitalia.     

Pseudocapillaria (Discocapillaria) margolisi n. subg., n. sp. (Nematoda: Trichuroidea) from freshwater fishes of West Bengal,India

A new nematode,Pseudocapillaria (Discocapillaria) margolisi n. subg., n. sp., from the freshwater fishesPuntius conchonius, P. sophore andAmblypharyngodon mola of West Bengal, India is described. The presence of a ventral lobe-like elevation with two papillae and the absence of a dorsal cuticular membrane on the male tail are referred to as distinguishing features of the new subgenus. The parasite is also characterised by small body size, short and non-annulated stichocytes, a distinctly expanded and folded lobular rim of the proximal end of the spicule, and eggs with protruding polar plugs, all features in which it differs distinctly from other species of the genusPseudocapillaria.     

Phenology of Parasetigena silvestris (Diptera: Tachinidae), gypsy moth (Lymantria dispar) (Lepidoptera: Lymantriidae) larval parasitoid and its efficiency for parasitisation

Parasetigena silvestris is a univoltine, solitary, larval endoparasitoid which lays its eggs on the surface of gypsy moth larvae. Field collection of the host larvae (2nd through 5th instar) from an artificially established gypsy moth population were made to compare stage specific parasitism between larvae without and with P. silvestris tachinid eggs. The tachinid oviposition rate detected was highest in second instar larvae, and then decreased as larvae developed toward full maturity. The opposite was true for tachinid parasitoid emergence which had no emergence from second through third host instar larvae. Fourth instar gypsy moth larvae, however, experienced significantly higher parasitism by P. silvestris in the larvae with eggs than those without the eggs. The braconid wasp Cotesia melanoscelus caused significantly higher parasitism in early instar larvae with P. silvestris eggs than in those without the eggs. The tachinid prefers to lay more eggs on parasitised larvae by the braconid even though the braconid is a superior competitor to the fly during multiparasitism. Factors influencing parasitism rates by P. silvestris such as host-parasitoid synchronisation and the multiparasitism interaction with C. melanoscelus are discussed.     

A new species of Trichogramma (Hymenoptera: Trichogrammatidae) parasitic on eggs of the alderfly Sialis melania (Neuroptera: Sialidae) from Japan,with comments on its phylogeny and male wing polymorphism

A new species of Trichogramma that parasitizes Sialis melania eggs is described as Trichogramma tajimaense Yashiro, Hirose and Honda, sp. nov. from Japan. Its phylogenetic position is based on a DNA‐based analysis, and data regarding its male wing polymorphism are also presented. The view that T. tajimaense is closely related to T. semblidis, another parasitoid of Sialis eggs, is supported by the results of a phylogenetic analysis, as well as by the biological and morphological similarities between both species. Trichogramma tajimaense is also similar in male wing polymorphism to T. kurosuae, a gregarious egg parasitoid of the lepidopteran Ivela auripes, as both Trichogramma species exhibit male wing trimorphism (fully alate, brachypterous and apterous forms) in contrast to the male wing dimorphism (fully alate and apterous forms) of T. semblidis. However, no phylogenetic analysis reveals a close relationship between T. tajimaense and T. kurosuae, and a difference exists between these two species in the mean percentage of flightless (brachypterous and apterous) males that emerge from a host egg mass; 96% of T. tajimaense males are incapable of flight, whereas about 50% of T. kurosuae males are flightless. Because all or almost all males of T. semblidis parasitizing Sialis eggs are apterous, T. tajimaense is more similar to T. semblidis than to T. kurosuae in the proportion of flightless males. In addition, male wing polymorphisms of Trichogramma in relation to mating systems could also show a similarity between T. tajimaense and T. semblidis when considering both species as quasi‐gregarious parasitoids of Sialis eggs.     

Escape of Lygus hesperus (Heteroptera: Miridae) Eggs from Parasitism by Anaphes iole (Hymenoptera: Mymaridae) in Strawberries: Plant Structure Effects

Herbivorous insects in natural and agricultural systems experience variation in parasitoid attack on different plant species due to direct and indirect plant influences on parasitoids. Lygus hesperus is a native polyphagous mirid that suffers up to 100% parasitism by the native egg parasitoid Anaphes iole in certain weed hosts, but with inundative releases in commercial strawberries, we achieve <65% L. hesperus suppression. We examined L. hesperus egg distribution in individual strawberry plants and parasitism by A. iole of eggs in different strawberry plant structures to determine whether plant-related factors affected parasitoid performance in strawberries. L. hesperus laid more eggs (46.5% of all eggs laid) in the fruit (between the achenes [seeds] in the fleshy receptacle) than in the petiole (23.3%), leaflet (20.3%), peduncle (6.2%), or calyx (3.7%). In a no-choice test, parasitism by A. iole was higher in the petiole (96.7%), calyx (91.9%), and leaflet (85.2%) than in the fruit (51.8%), in which the achenes appeared to hinder parasitoid access to host eggs. In addition, in young fruits in which the interachene distance was minimum, parasitism was considerably lower (25.4%) than in fruits in which receptacle swelling had resulted in interachene distances that were medium (65.7% parasitism) or large (77.1% parasitism). Our results suggest that strawberry fruits can provide refugia from parasitism by A. iole and that maximum protection occurs when the achenes are contiguous. The presence of refugia in strawberries limits the impact of augmentative biological control with A. iole, highlighting the need for its integration with other strategies to effectively suppress L. hesperus in strawberries.     

Resistance to freezing temperatures in Aedes (Ochlerotatus) albifasciatus (Macquart) eggs (Diptera: Culicidae) from two different climatic regions of Argentina

Aedes (Ochlerotatus) albifasciatus (Macquart) has the capacity to proliferate in different kinds of climates within its distribution range in South America. With the aim of studying local thermal adaptations of eggs, we exposed egg stocks from two climatically different localities: temperate humid pampa (Buenos Aires) and cold arid Patagonian (Sarmiento), to freezing conditions and then evaluated the effect on some features at this level. First, we thermally described the substrate where this species lays its eggs in the arid region. A typical thermal condition during winter was 10 h at ?12° C. Second, we evaluated the effect of freezing on primary hatching (vs total hatching) and embryo survival. We also compared the proportion of embryonated eggs from both populations. The proportions of embryonated eggs were not different between localities, with averages of 78% and 83% in Sarmiento and Buenos Aires, respectively. Survival was equally successful after freezing in the two localities with an average range between 94–99%. Whether or not the eggs from Buenos Aires and Sarmiento were under freezing conditions, hatching was more than 98% after the first flooding. The results suggest that eggs of Ae. albifasciatus from Sarmiento and Buenos Aires have the same ability to survive at extreme temperatures (<0° C), showing a regional thermal adaptation rather than a local one.     

Refrigeration of Riptortus clavatus (Hemiptera: Alydidae) eggs for the parasitization by Gryon japonicum (Hymenoptera: Scelionidae)

Gryon japonicum (Ashmead) (Hymenoptera: Scelionidae) is a solitary egg parasitoid of Riptortus clavatus (Thunberg) (Hemiptera: Alydidae) one of the most important pests in soybean in Korean and Japan. Refrigeration of R. clavatus eggs for up to 120 days was evaluated as a method of mass production of G. japonicum. The refrigeration reduced the eclosion of eggs, thus no nymph emerged after 30 days of egg refrigeration. Increased duration of host acceptance behaviors by G. japonicum and some detrimental effects on parasitism rate, developmental time, longevity, and adult size of the parasitoid were found in refrigerated host eggs. However, all the biological parameters of G. japonicum were unaffected by the refrigeration of up to 30 days. Gryon japonicum parasitized 16 and 14 host eggs daily that were refrigerated for 15 and 30 days, respectively, which did not differ from parasitization of fresh host eggs. Furthermore, refrigeration of host eggs did not reduce the reproduction of the emerged adult parasitoids and emergence and sex ratio of their progeny. Gryon japonicum also parasitized 14 and 13 refrigerated host eggs per day kept at 26.3°C and 78.7% RH for 2 and 4 days of post-refrigeration without significant reduction, respectively. These results show that refrigeration of R. clavatus eggs can be a good method for mass rearing of the parasitoid, and the host eggs killed by cold storage can be supplemented in the field to boost field parasitism.     

Dimensions and composition of eggs from captive bustards (Gruiformes: Otididae): houbara (Chlamydotis undulata), rufous‐crested (Eupodotis ruficrista), and kori (Ardeotis kori)

This study sought to increase understanding of the size and composition of eggs from two subspecies of houbara bustard (Chlamydotis undulata macqueenii and C. u. undulata). Eggs from the rufous‐crested bustard (Eupodotis ruficrista) and kori bustard (Ardeotis kori) were also examined for comparison. Infertile eggs were collected from captive birds; egg mass and linear dimensions were recorded, and egg component masses were determined wet and dry. Significant differences were observed in the composition of the eggs from the two houbara subspecies. Despite being smaller in size, eggs from the macqueenii subspecies had a relatively larger yolk (and relatively less albumen) than eggs from the undulata subspecies. The relative composition of the rufous‐crested and kori bustard eggs showed patterns similar to that of the undulata eggs. For the houbara bustards, changes in initial egg mass (IEM) were associated with changes in egg length more than egg breadth, and changes in egg length and breadth appeared to be due more to increases in albumen mass than to increases in yolk mass. Zoo Biol 21:337–346, 2002. © 2002 Wiley‐Liss, Inc.     

Reproductive behavior and morphology of Paraleptophlebia spinosa (Ephemeroptera: Leptophlebiidae): implications of variation in copula duration

The reproductive behavior and genital morphology of a leptophlebiid mayfly Paraleptophlebia spinosa Ueno were studied in a population inhabiting a mountain stream in Kyoto, central Japan. Males formed swarms along gravel shores, caught females in the air, and mated on the ground. The distribution of the oviposition sites coincided with that of the swarming sites along the stream shore. The lobes of the male penis were characterized by a shallow pocket opening on the ventral side. The female vestibule formed a square-shaped chamber into which eggs were released from the oviducts. The number of eggs carried by females caught during copulation in the field showed a greater variation than the number of eggs of virgin females. Copula duration was strongly correlated with the number of eggs carried by the female. Significantly short copula duration with spent females (egg loading less than 20% of the estimated fecundity) may indicate that males could identify spent females. Copula duration with partially loaded females (egg loading between 20% and 80% of fecundity), however, was not shorter than that with fully loaded females. Male mating tactics with respect to copula duration and the possibility of kinematic sperm displacement are discussed with reference to the behavioral and morphological characteristics of the species. Received: September 3, 1999 / Accepted: December 9, 1999     

Host-plant effects on Parasyrphus melanderi (Diptera: Syrphidae) feeding on a willow leaf beetle Chrysomela aeneicollis (Coleoptera: Chrysomelidae)

Abstract.

• 1 Generalist predators are repelled by chrysomelid (Chrysomela spp., Phratora vitellinue L.) larval defensive secretions that are obtained from salicin in their host plants. But little is known about the effect of these secretions on specialist predators.
• 2 In this study, we describe the feeding behaviour of a fly, Parasyrphus melanderi Curran (Diptera: Syrphidae), which feeds on Chrysomela aeneicollis Schaeffer (Coleoptera: Chrysomelidae). Parasyrphus melanderi lays its eggs on C.aeneicollis egg clutches, and its larvae consume C.aeneicollis eggs and larvae.
• 3 Chrysomela aeneicollis hatching rates were significantly lower (20%) on clutches with fly eggs than on clutches without them (40%). Half of the clutches with one fly egg had survival rates below 5%, and when two fly eggs were present (four clutches), the entire clutch was consumed.
• 4 In nature, P.melanderi eggs were 3 times more abundant on a salicylaterich willow species S.orestera Schneider, than on the medium-salicylate S.geyeriana Anderss. (1.8 v 0.6 eggs per clutch). On 18% of the S.orestera clones, all the beetle clutches contained fly eggs. In laboratory-choice tests, P.melanderi larvae fed equally rapidly on C.aeneicollis larvae that were chemically defended (feeding on S.orestera) as on larvae that produced no secretion (feeding on the salicylate-poor S.lutea Nutt.). This predator does not appear to be deterred by C.aeneicollis's defensive secretion. We discuss the implications of specialist predators on determining host suitability to herbivorous insects.

     

Reproductive Behaviour and Parental Care of Helobdella striata (Hirudinea,Glossiphoniidae): a Leech that Feeds its Young

The leech Helobdella striata Kutschera (1985) is a protandrous hermaphrodite. It copulates by hypodermic injection: a spermatophore is attached to the skin of the partner and sperm injected through it. During their male phase, the leeches copulate repeatedly and with different partners. In the female phase, 3 to 7 cocoons, each containing 2 to 20 eggs, are produced from the female gonopore and attached to the ventral side of the parent. The larvae which hatch from these eggs cling to the ventral side of the parent. After they have used up their yolk supply and have developed into juvenile leeches they remain attached to the parent for a further three weeks. Helobdella striata capture Tubifex worms and give them to the young they carry. This access to food allows the juveniles to grow from a size of 1 mm to 6 mm length while being carried and protected by the parent. H. striata reared in isolation produce young; at present it is not known whether they reproduce by parthenogenesis or by self-fertilization. The probable phylogenetic development of parental care patterns in the Hirudinea is reviewed.     

The function of the caudal keel inPercina (Percidae)

Synopsis Unique to darters of the subgenusOdontopholis ofPercina andPercina (Imostoma)antesella is the development of a caudal keel in breeding males. The keel is a semicircular extension of the ventral surface of the caudal peduncle and anterior lower caudal fin. The reproductive behavior of species ofPercina implies an adaptive function related to the burial and fertilization of eggs. The caudal keel appears to serve as a plow-share which, in conjunction with an elongated anal fin, facilitates the transfer of sperm from the male's genital opening to eggs buried in the substrate by the female.     

Triumphalisnema bialulaundatum n. sp. (Oxyurida: Robertiidae) from a passalid beetle from Papua New Guinea

A new species ofTriumphalisnema is described and illustrated from the gut of a passalid beetle,Cetejus peltostictus, collected from rotting wood in Papua New Guinea.T. bialulaundatum n. sp. is easily distinguished fromT. lenkoi, the type-species, by the much shorter dorsal and ventral alae (starting posterior to the vulva inT. bialulaundatum, but well anterior inT. lenkoi) and also by a peculiar ornamentation of the eggs. Scanning electron micrographs of the genus are provided for the first time. A diagnosis of the genusTriumphalisnema is included.     

Transmission of injected DNA sequences to multiple eggs of Metaseiulus occidentalis and Amblyseius finlandicus (Acari: Phytoseiidae) following maternal microinjection

The persistence of DNA injected into two species of adult female phytoseiids and its transmission to serial eggs deposited by them was assessed by the polymerase chain reaction (PCR). The effect of DNA concentration on persistence and transmission was examined in Metaseiulus occidentalis. M. occidentalis females were microinjected with plasmid DNA at three different concentrations (250, 500, 750 ng L^–1) and allowed to deposit one to five eggs before the females and their last eggs were analyzed. Plasmid DNA was found in 82% of the females assayed and in 70% of all the eggs analyzed (including the fifth eggs produced after microinjection). Transmission of DNA to multiple eggs was also examined in Amblyseius finlandicus. Females of this species are less traumatized by microinjection allowing analysis of transmission over a more extended number of eggs. Females were microinjected and allowed to deposit eggs until their death. DNA from every fifth egg was analyzed by the PCR. PCR products were amplified from 51% of the eggs and from all egg classes except the 30th egg. The persistence and presence of plasmid DNA in both eggs and females suggests that (1) maternal microinjection is a more efficient method for DNA delivery than traditional egg microinjection, (2) it may be possible to isolate transformants from fewer maternally-microinjected females than originally expected, and (3) maternal microinjection could be useful as a DNA delivery system in other phytoseiids.     

Catatropis hatcheri n. sp. (Digenea: Notocotylidae) from Heleobia hatcheri (Prosobranchia: Hydrobiidae) and notes on its life-cycle in Patagonia, Argentina

A new species of Catatropis Oghner, 1905 from a freshwater Neotropical prosobranch snail, Heleobia hatcheri (Hydrobiidae), is described. Naturally infected snails were collected from Nahuel Huapí Lake in Andean Patagonia. The characteristics of the larval stages are also presented. Experimental adults were recovered from the distal region of the intestinal caeca of chicks and ducklings and natural adults from a wild duck Anas platyrhynchos. Adults of Catatropis hatcheri n. sp. can be distinguished from all other species of the genus in having 10–12 (11) ventral glands in each lateral row, the cirrus-sac extending back to between the first third and the middle of the body, the metraterm shorter than the cirrus-sac, a previtelline field of 1,258–1,544 (1,396), vitelline follicles reach back to the anterior border of the testes with some follicles extending slightly lateral to them, only external testicular margin lobed and genital pore in median line just posterior to the intestinal bifurcation. In addition, the eggs have one filament on each pole, the rediae contain one or two mature cercariae, and the cercariae are tri-oculate, with a long tail and encyst in the environment.     

Effects of embryonic responses to clutch mates on egg hatching patterns of Pentatomidae (Heteroptera)

Stink bugs and shield bugs of the family Pentatomidae (Heteroptera) generally produce a clutch of densely deposited eggs. In a few species of this family, embryos hatch in response to some form of cues associated with the preceding hatching to synchronize egg hatching with clutch mates. The aim of the present study is to obtain a family‐wide understanding of the extent to which the hatching response to clutch mates accelerates hatching within egg clutches. Accordingly, the hatching patterns in intact egg clutches and eggs individually detached from egg clutches are compared in eight species among different genera. In Halyomorpha halys, hatching is significantly and highly synchronized by the effect of the hatching response: when eggs are not attached to each other, the hatching rate is only 3.8% at 15 min and exceeds 95% at 200 min. By contrast, when eggs are attached to each other, the hatching rate reaches more than 95% at 15 min. Hatching is also significantly synchronized by the hatching response in Nezara viridula (which shows relatively high hatching synchronization) and in Piezodorus hybneri and Plautia stali (both of which show milder hatching synchronization). Synchronization of hatching is not found to be promoted by a hatching response in Aelia fieberi, Dolycoris baccarum, Eurydema rugosum or Palomena angulosa. These findings reveal that the hatching response varies depending on the species in Pentatomidae, with a wide spectrum of effects on the hatching patterns of the egg clutches.     

A new species of Saturnius Manter, 1969 (Digenea: Hemiuridae) from Mediterranean mullet (Teleostei: Mugilidae)

A new hemiurid digenean, Saturnius gibsoni n. sp., is described from the stomach lining of Mugil cephalus L. off Oran, Mediterranean coast of Algeria. Characteristic morphological features of the new species include small size of the body which is comprised of six pseudosegments, small ventral sucker, weakly developed mound-shaped flange at the level of the ventral sucker, and eggs being large in relation to the size of the body. Saturnius gibsoni n. sp. resembles S. minutus Blasco-Costa, Pankov, Gibson, Balbuena, Raga, Sarabeev & Kostadinova, 2006 and two unidentified Saturnius spp. in the small size of the body and most metrical features. However, in spite of the presence of five transverse septa resulting in six pseudosegments and the range overlap of some metrical features, the ventral sucker in S. minutus is much larger, the ventral sucker muscular flange is more prominent, the last pseudosegment is narrower in relation to body width and more rounded, and the eggs are smaller (mean 21 × 10 vs 25 × 12 μm). Furthermore, the partial sequences of the 28S rRNA gene region (domains D1–D3; 1,195 nt) obtained from two isolates of S. gibsoni n. sp. differed by 11 nt (0.9%) from that of S. minutus. Both unidentified forms of Saturnius are clearly distinguishable from S. gibsoni n. sp. by the presence of six stout, transverse muscular septa, forming seven pseudosegments (vs five septa forming six pseudosegments). Bayesian inference analysis of partial 28S rDNA sequences based on a total of 15 species from the families Hemiuridae and Lecithasteridae depicted the Bunocotylinae Dollfus, 1950 as a strongly supported basal clade, with Bunocotyle progenetica (Markowski, 1936) as the closest sister taxon to Saturnius spp.     

The Effectiveness of Trichogramma chilonis,Trichogramma pretiosum and Trichogramma brasiliense (Hymenoptera: Trichogrammatidae) as Parasitoids of Helicoverpa armigera (Lepidoptera: Noctuidae) on Sunflower (Helianthus annuus) and Redgram (Cajanus cajan)

The performance of three species of trichogrammatids on the pest, Helicoverpa armigera was evaluated in the laboratory and screenhouse conditions in Karnataka, India during 1996-97. Laboratory studies indicated that Trichogramma chilonis and Trichogramma pretiosum were more effective parasitoids of H. armigera than Trichogramma brasiliense. In screenhouse conditions, T. chilonis was the most effective parasitoid of H. armigera eggs on sunflower plants in comparison to the other two trichogrammatid species. When releasing 50?000 per ha on sunflower and redgram, T. chilonis parasitised 50.1 and 11.4% H. armigera eggs, respectively. The position of H. armigera eggs on different plant parts of sunflower had no effect on parasitism by T. chilonis. However, parasitism by the same trichogrammatid among different plant parts of redgram varied significantly. It parasitized 43.4 and 18.7% H. armigera eggs on leaves and flowers, respectively, and significantly fewer, 3.9%, on pods (P&lt;0.05). The growth stage of redgram plants also had an effect on parasitism by T. chilonis, parasitism being extremely low on plants with pods.     

Pelagic eggs and larvae of Coelorinchus kishinouyei (Gadiformes: Macrouridae) collected from Suruga Bay, Japan

Pelagic eggs and larvae of the macrourid fish Coelorinchus kishinouyei, collected from Suruga Bay, southern Japan and subsequently identified by 16S rRNA gene nucleotide sequences, are described. The spherical eggs, 1.18–1.31 mm in diameter, contained a single oil globule, 0.28–0.33 mm in diameter, and had hexagonally patterned ornamentation on the chorion, 0.017–0.022 mm in width. Melanophores were present on the embryo, yolk and oil globule after the blastopore had closed. Within 1 day after hatching, the body axis of the yolk-sac larvae was bent slightly at the anterior trunk region. During this stage many melanophores formed on the head, trunk, tail, yolk and oil globule, along with small irregular wrinkles on the dorsal and ventral finfolds. Pelagic eggs (after the caudal end of the embryo had detached from the yolk) and yolk-sac larvae also developed xanthophores on the embryo and yolk, and head, trunk, dorsal and ventral finfolds just before tail tip, and yolk, respectively. The pelagic larvae had a short tail, stalked pectoral-fin base and no elongate first dorsal and pelvic-fin rays. Three clusters of melanophores were present on the tail (anterior two embedded to muscle and one just before tail tip subsequently lost with development) and a cluster around the anus (beyond 3.9 mm head length). Nucleotide sequence analyses of comparative adult specimens appeared to confirm a previous proposal that C. productus is a junior synonym of C. anatirostris.