Cuticular lipids for species recognition of mole crickets (Orthoptera: Gryllotalpidae): II. Scapteriscus abbreviatus,S. acletus,S. vicinus,S. sp., and Neocurtilla hexadactyla

Qualitative analyses were made from whole-body cuticular extracts of Scapteriscus abbreviatus, Scapteriscus acletus, Scapteriscus vicinus, and Neocurtilla hexadactyla by isothermal and temperature-programmed gas chromatography. Adults of both sexes and nymphs of each species were collected in Florida. The chromatographic profiles of peaks were distinct and easily recognizable for each species, regardless of sex or developmental stage. Distinct sexual differences were found in S. acletus and S. abbreviatus. Specimens of S. abbreviatus from Puerto Rico and S. vicinus from Bolivia produced gas chromatography (GC) traces very similar to those of conspecifics collected in Florida. Evidence is presented to illustrate the potential importance of volatile cuticular lipid analysis as a tool for mole cricket identification. Cuticular extracts of an undescribed short-winged species of Scapteriscus from Bolivia were also examined and produced GC traces unlike those of any other species analyzed to date.     

Pathogenicity of Steinernema scapterisci to Selected Invertebrates

Steinernema scapterisci was more pathogenic to insects tested in the order Orthoptera than to those in the orders Lepidoptera or Hymenoptera; it was not pathogenic to earthworms. The nematode also infected and killed the mole crickets Scapteriscus acletus and S. vicinus when released four successive times at 10-day intervals in containers of soil infested with the nematode.     

Suitability ofScapteriscus moles crickets [Ort.: Gryllotalpidae] as hosts ofEuphasiopteryx depleta [Dipt.: Tachinidae]

Euphasiopteryx depleta (Wied) flies successfully developed in the mole cricketsScapteriscus borellii Giglio-Tos andScapteriscus vicinus Scudder, as well as in the short-tailed cricket,Anurogryllus sp., after artificially placing larvae under their pronota. Using this technique, no relation was found between the number of larvae placed on each cricket and the resulting number of puparia obtained from the cricket. In all cases, the number of flies emerging from the puparia was small, with females failing to mature reproductively. AsE. depleta has been reared from field collectedScapteriscus spp., the exact reasons for lack of maturation remain unknown.Anurogryllus sp. can be considered a probable alternate host forE. depleta.      

Integration of insect parasitic nematodes (Rhabditida steinernematidae) with insecticides for control of pest mole crickets (Orthoptera: Gryllotalpidae: Scapteriscus spp.)

To develop a successful integrated pest management program for pest mole crickets (Orthoptera: Gryllotalpidae: Scapteriscus spp.), it is important to ascertain the compatibility of infective juveniles of insect parasitic nematodes and chemical insecticides. Aqueous solutions of five pesticides (acephate, bifenthrin, deltamethrin, fipronil, and imidacloprid) used in turfgrass to control mole crickets were tested for compatibility with Steinernema scapterisci Nguyen & Smart (Rhabditida: Steinernematidae) in the laboratory. Survival of S. scapterisci was >95% in solutions of acephate, bifenthrin, and imidacloprid. Infectivity of S. scapterisci in adult Scapteriscus vicinus Scudder was >60% in acephate and bifenthrin; however, infectivity was <40% in imidacloprid. The entomopathogenic nematode was compatible with most insecticides tested without significantly reduced survival or infectivity.     

Characterization of an iridovirus isolated from the southern mole cricket,Scapteriscus vicinus

A new iridovirus has been detected from diseased southern mole crickets, Scapteriscus acletus, collected in Brazil during the spring of 1986. This icosahedral virus measuring 146 nm (side-side) to 172 nm (apex-apex) has been purified via Ficoll gradient centrifugation and demonstrated to be infectious to 1st instar Scapteriscus vicinus nymphs. The cytopathology of this virus is typical of the pattern documented for other iridovirus isolates. Characterization of the structural polypeptides by SDS-polyacrylamide gel electrophoresis revealed an array of 3 major and 17 minor polypeptides ranging in molecular weight from 15.1 to 152.0 kDa. Electrophoresis in agarose gels of purified DNA revealed a single band of high molecular weight. Analysis of various restriction endonuclease (REN) digests of this DNA demonstrated it to have an approximate molecular weight of 144 kilobase pairs. Based on differences in the polypeptide profile and REN profiles we believe this virus is distinct from previously characterized invertebrate iridovirus isolates.     

Pocket gophers (Geomys bursarius), vegetation,and soil nitrogen along a successional sere in east central Minnesota

Summary Insect size tactics or developmental strategies are discussed in relation to decisions individuals make about when to mature. Such decisions carry with them costs and benefits in terms of that individual's reproductive success. Whenever size affects fitness, selection should act such that individuals evaluate the costs and benefits due to changes in size and should mature when the ratio of benefit to cost is maximized.Predictions about seasonal changes in adult sizes within a population are tested on two species of mole cricket, Scapteriscus acletus and vicinus. Specifically, individuals maturing in the fall should be larger than average because there is no cost associated with delayed reproduction since reproduction occurs only during spring months. Smaller than average individuals should remain in juvenile stages and get larger before reproducing. Also it is predicted that as the spring reproductive season progresses a greater proportion of smaller individuals should mature because the costs due to delaying reproduction increase. The changes in seasonal distribution of adult sizes of mole crickets support the predictions and suggest that individuals make decisions about when to mature based on costs and benefits associated with changes in size.     

Indian species of the genusMirufens [Hym.: Trichogrammatidae]

An account is given of 4 new species ofMirufens Girault:M. brevifuniculata Khan & Shafee, M.albiscutellum Khan & Shafee,M. magniclavata Khan & Shafee andM. longiclavata Khan & Shafee. A key to Indian species of the genusMirufens is also provided.     

Establishment of the exotic parasiteTetrastichus haitiensis [Hym.: Eulophidae] and recovery of a newTrichogramma [Hym.: Trichogrammatidae] from root weevil egg masses in Florida

The exotic root weevil egg parasite,Tetrastichus haitiensis Gahan, imported from Puerto Rico and released in Florida between 1969 and 1971, was found established on citrus root weevil egg masses in 1978 near Oakhill, Florida. It was also recovered there from field-collected weevil egg masses from June to August 1978 and from citrus bouquets containing egg masses placed in the grove during July and August 1978. In addition, a new species ofTrichogramma was discovered. In the laboratory, this species parasitized egg masses of 4 species of weevils that attack citrus in Florida. These areDiaprepes abbreviatus (L.),Pachnaeus litus (Germar),P. opalus (Olivier) andArtipus floridanus Horn.     

Absorption of glucose,glycine and palmitic acid by isolated midgut and hindgut from crickets

• 1.1. In vitro experiments indicated that midgut and hindgut anterior to the Malpighian tubules are important in absorption and processing of products of digestion in crickets.
• 2.2. Isolated hindguts from crickets (Gryllus assimilis, G. rubens and Scapteriscus acletus) absorbed and released into the incubation medium 20–30% of a load of [¹⁴C]glucose and 29–31% of a load of[¹⁴C]glycine.
• 3.3. Isolated midguts from the same crickets absorbed and released into the incubation medium 30–50% of the glucose and 43–52% of the glycine load.
• 4.4. Radiolabelled palmitate was absorbed into epithelial cells of isolated mid- and hindguts, but little was transported and released into the incubation medium.

     

Revision of the fossil cylindrotomidae (Diptera,Nematocera) from florissant and White River,USA

Fossil species of the genusCyttaromyia Scudder (Diphtera, Cylindrotomidae) described by Scudder in 1877 and 1894 from the Eocene of White River Basin and the Lower Oligocène of Florissant, Colorado, are revised.Cyttaromyia fenestrata Scudder from White River andCyttaromyia princetoniana Scudder are redescribed; the remaining species: C.cancellata Scudder, C.clathrata Scudder and C.oligocena Scudder are regarded as junior synonyms of C.princetoniana.     

Parasites ofSpodoptera exigua,S. eridania [Lep.: Noctuidae] andHerpetogramma bipunctalis [Lep.: Pyralidae] collected fromAmaranthus hybridus in field corn

Three species of lepidopterous larvae were collected fromAmaranthus hybridus L. growing in field corn during 1975 and 1976 at Hastings, Florida.Spodoptera exigua (Hubner) was the predominant species in May.Spodoptera eridania (Cramer) was predominant in June andHerpetogramma bipunctalis (F.) in July and August. Nine native species of parasites, representing theBraconidae, Eulophidae, Ichneumonidae andTachinidae, emerged from these larvae.Meteorus autographae Muesebeck emerged from bothS. exigua andS. eridania. TheTachinidae, Winthemia rufopicta (Bigot),Eucelatori rubentis (Coquillett) andLespensia sp., emerged from mixtures ofS. exigua andS. eridania. Apanteles marginiventris (Cresson),Temelucha sp., andChelonus texanus Cresson emerged from bothS. exigua andH. bipunctalis larvae, andEuplectrus platyhypenae Howard andOphion sp. emerged fromS. eridania. All the species of parasites from the lepidopterous larvae that feed onAmaranthus hybridus are also reported as parasites ofS. frugiperda, a serious pest of corn. Therefore these larvae onA. hybridus may be a source of the parasites found attackingS. frugiperda.     

The relationship between host destruction and parasite reproductive potential inMuscidifurax raptor,M. zaraptor,andSpalangia endius [Chalcidoidea: Pteromalidae]

Highly significant correlations existed between parasite reproduction and host destruction statistics calculated for 3 hymenopterous parasites of muscoid flies,Muscidifurax raptor Girault & Sanders,M. zaraptor Kogan & Legner, andSpalangia endius Walker, ovipositing under varied environmentally controlled conditions. A consideration of an individual parasite's host destructive capacity is important in order to correctly evaluate the direct impact of periodic inundative releases in the field. In this study mortality resulting from host-feeding, probing and aborted parasitism averaged ca. 37, 28, and 31% forS. endius, M. raptor andM. zaraptor, respectively. The observation of such highly significant correlations with reproductive potential indicates a means for more accurate evaluation of field performance (hosts destroyed both reproductively and incidentally) in 3 useful species.     

The parasitoid complex [Hym.: Ichneumonoidea] ofToxoptera aurantii [Hom.: Aphidoidea] in the Mediterranean area

The parasitoid complex of the Black Citrus Aphid,Toxoptera aurantii (B.d.F.) in the Mediterranean area has been complemented on the basis of samples collected in South Italy and Lebanon. To the complex presently belong 10 Ichneumonoid species of the generaAphidius Nees,Diaeretiella Staryý,Ephedrus Haliday,Lipolexis Förster,Lysiphlebus Förster,Praon Haliday andTrioxys Haliday. Of these,Aphidius colemani Viereck, in spite of its wide distribution in the Mediterranean region, seems to be restricted to Near East (Israel and Lebanon) asT. aurantii parasitoid. The nearctic speicesLysiphlebus testaceipes (Cresson) is localized in Spain, South France, Corsica, Central and South Italy, including Sicily. In Italy, this endoparasitoid has heavily interfered with the local dominant congeneric speciesLysiphlebus confusus Tremblay & Eady andLysiphlebus fabarum (Marshall). The possible associative relationships betweenLysiphlebus testaceipes andL. fabarum have been examined in the samples collected in South Italy. The results of the examination suggest that the 2 species are negatively associated with each other, i.e. the abundance of 1 of the 2 species makes it more likely that the other will decrease in numbers. Moreover, the data concerning the relative abundance of both species in the same area indicate that a shift may have occurred in favour ofL. testaceipes between 1977 and 1978. The nearctic parasitoid seems to be able to displace the 2 congeneric species by a competitive biological mechanism which is still in course of investigation.     

Parasitism ofPhthorimaea operculella [Lep.: Gelechiidae] larvae in Queensland

Parasitism ofPhthorimaea operculella (Zeller) larvae on potato foliage was examined intensively in the Lockyer Valley, south-eastern Queensland from 1975–78 and extensively from other hosts and areas of Queensland. The % parasitism in the Lockyer Valley exceeded 50% in 29 of the 36 collections. The parasite species were dominated by the introducedCopidosoma desantisi Annecke & Mynhardt (Encyrtidae) andOrgilus lepidus Muesebeck (Braconidae) which together accounted for 92.6% of parasite numbers recorded. In more northern areas of Queensland, the dominant parasite species found was the introducedApanteles subandinus Blanchard (Braconidae). Other hymenopterous parasites found wereMicrochelonus curvimaculatus Cameron (Braconidae), Elasmus funereus Riek (Elasmidae) andTemelucha minuta (Morley) (Ichneumonidae).     

Steinernema scapterisci n. sp. (Rhabditida: Steinernematidae)

Steinernema scapterisci n. sp., isolated in Uruguay from the mole cricket Scapteriscus vicinus, can be distinguished from other members in the genus by the presence of prominent cheilorhabdions, an elliptically shaped structure associated with the excretory duct, and a double-flapped epitygma in the first-generation female. The spicules of the male are pointed, tapering smoothly to a small terminus, and the shaft (calomus) is long, bearing a sheath. The gubernaculum has a long, upward-bent anterior part. The ratio of head to excretory pore divided by tail length of the third-stage juvenile is greater for S. scapterisci n. sp. than for S. carpocapsae. Steinernema scapterisci n. sp. did not hybridize with S. carpocapsae strain Breton. In laboratory tests, S. scapterisci n. sp. killed 10% or less of non-orthopteran insects, including the wax moth larva, a universal host for other species of Steinernema.     

New fig insects [Hym.: Chalcidoidea] from India: Three torymids parasitic on agaonids

Two new species of fig wasps (Sycoscapter punctatus Abdurahiman & Joseph andSycobiella amplissima Abdurahiman & Joseph) parasitic onManiella delhiensis Abdurahiman & Joseph fromFicus amplissima Smith, and the female of a known species (Philotrypesis anguliceps Westwood) parasitic onBlastophaga quadraticeps Mayr fromFicus religiosa L. are described.     

Notes on the taxonomy and nomenclature ofAphidius species [Hym.: aphidiidae] parasitic on the pea aphid in North America

A brief discussion is given on the taxonomy, nomenclature, distribution, and hosts of severalAphidius species attacking the pea aphid,Acyrthosiphon pisum (Harris), in North America.Aphidius pisivorus Smith,A. smithi S. & S. R., andA. ervi Hal. are considered distinct species attacking the pea aphid;A. nigripes Ashm. is shown not to be a parasite of the pea aphid;A. pulcher Baker is placed in synonymy withA. nigripes. Distinguishing characters for each species are illustrated.     

Life history ofSmicronyx guineanus andSm. Umbrinus (Col.: Curculionidae) onStriga hermonthica (Scrophulariaceae)

The life history ofSmicronyx guineanus andSm. umbrinus, weevils attackingStriga hermonthica, was studied in Burkina Faso, West Africa. Field experiments were conducted in 1992 and 1993 at Kaya, in fields of sorghum (Sorghum bicolor (L.) Moench and pearl millet (Pennisetum americanum (L.) K. Schum. (syn.P. typhoides (Burm.) Stapf &; Hubb). The weevils are univoltine; the adults emerge in late August, mate and eggs are laid in the ovary ofStriga inflorescence. Larval feeding in the ovary causes galling and prevents seed production. The main damage toStriga seed capsule is caused by the larvae of at least twoSmicronyx species. Last-instar larvae drop to the soil and bury themselves to a depth of 1–15 cm, pupate and enter into dormancy. Most pupae are found in the upper 5–10 cm of the soil. The pupal period lasts from late October to late July. In May, we found 75.6% of pupae against 24.4% of adults in dormancy.     

Biological and ecological studies of the parasitoidChelonus inanitus [Hym.: Braconidae] in Israel

Only one species ofChelonus Panzer,Chelonus inanitus (L.), was found to be widespread in all areas of Israel. The parasitoid was particularly widespread in alfalfa fields but also was present in cotton, sugar beet, artichoke and corn. Spodoptera littoralis (Boisd) andS. exigua (Hbn.) were the main hosts ofC. inanitus although it might develop in other Lepidoptera species. A study of its population showed that adults were present in the spring, summer and autumn but not during the winter. In most cases the population density of the parasitoid appeared to be related to that of the hosts. Parasitism and sex ratio ofC. inanitus in alfalfa fields were studied. The number of males (average of 75%) was higher than that of the females. Percentage of parasitism in larvae ofS. littoralis andS. exigua reached up to 39.8% and 13.5% respectively. The parasitism values in eggs ofS. littoralis were up to 71%.     

Host specificity ofTyta luctuosa [Lep.: Noctuidae], an insect associated withConvolvulus arvensis [Convolvulaceae]

As part of a program to find biological control agents forConvolvulus arvensis L.,Tyta luctuosa (Denis & Schiffermüller), a defoliator, has been tested for host specificity in the laboratory and in field cages. While several host plants from different families are recorded in the literature, there was feeding only on members of theConvolvulaceae. There was complete development only on species ofConvolvulus andCalystegia.