[Morphoecological Aspects of Preimaginal Stages of Development of the Parasitic Wasp Minotetrastichus frontalis (Nees, 1834) (Insecta, Hymenoptera, Eulophidae)].

This work is devoted to studying the morphology and biology of preimaginal stages of development of the parasitic wasp Minotetrastichus frontalis. The morphological characteristics of eggs and larvae, the features of interaction of the parasitic wasp with the host (Phyllonorycter issikii), and other biological characteristics were determined. For the species identification of the studied specimens of insects, we performed molecular genetic analysis using a nuclear 28S RNA gene fragment as a molecular marker. The result showed a strong genetic polymorphism of the populations of the studied species for the selected marker.

A survey of the effectiveness of non-cell autonomous RNAi throughout development in the sawfly, Athalia rosae (Hymenoptera).

RNA interference (RNAi) is a powerful and convenient tool not only for functional analysis of specific genes, but also for large-scale screening of gene function in insects; however, reports on its efficiency throughout development in a single species are limited. We demonstrate here that non-cell autonomous RNAi by injection of double-stranded RNA (dsRNA) knocks down targeting genes in most developmental stages in the sawfly, Athalia rosae. Injection of dsRNA targeting the green fluorescence protein (gfp) gene into eggs of a transgenic strain carrying the constitutively expressing gfp gene resulted in the absence of GFP fluorescence during embryogenesis, while a portion of the gfp dsRNA-injected embryos began exhibiting GFP fluorescence at late embryogenesis. When gfp dsRNA was injected into parental female pupae, the RNAi effect was carried over to all embryos of the next generation and the effect lasted until mid-larval stages. Parental injection of dsRNA was more efficient than embryonic injection in terms of penetrance of the effect and the survival rate. After injection of gfp dsRNA into last instar larvae, the RNAi effect was sustained during prepupal and pupal stages and in adults. The gfp gene transcript markedly decreased in these knockdown phenotypes. It was revealed by employing fluorescence-labeled dsRNA that injected dsRNA was taken up in internal organs. Knockdown of an endogenous gene, Distal-less (Dll), resulted in typical phenotypes represented by the lack and malformation of Dll-expressing organs, such as distal parts of the appendages and wing edges without showing off-target effects. In contrast, RNAi by dsRNA injection seems to be hardly effective in mid- to late-larval stages.

Armazenamento de Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) em baixas temperaturas / Cold storage of Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae)

Avaliou-se o efeito do armazenamento em baixa temperatura de pupas de Trichogramma pretiosum, em ovos de Sitotroga cerealella, sobre a emergência e a viabilidade reprodutiva do parasitoide. Os testes foram conduzidos em câmara climática a 5, 8 e 10° C, 70% UR, escotofase constante, com 10 tratamentos (testemunha, 4, 6, 8, 10, 12, 14, 16, 18 e 20 dias de armazenamento) e 10 repetições. Foram distribuídos 1.000 ovos contendo pupas em tubos de ensaio (10 x 3 cm), 100 foram mantidos a 25º C, 70% UR e 14 horas de fotofase (testemunha) e os demais armazenados. Após cada período de armazenamento, 100 ovos foram transferidos para 25º C e avaliados quanto à emergência e funções reprodutivas. A emergência de T. pretiosum não foi influenciada pelo período de armazenamento nas três temperaturas (Tukey P ≤ 0,05) e as menores taxas de emergência foram de 85,6%, 84,5% e 77,6%, respectivamente para os parasitoides armazenados a 5, 8 e 10° C. Não houve perda da viabilidade reprodutiva dos parasitoides provenientes da estocagem nas temperaturas avaliadas, pois todas as fêmeas acasaladas produziram indivíduos de ambos os sexos. Estes resultados auxi-liarão no planejamento da criação massal, embalagem e transporte de T. pretiosum do laboratório para o local de liberação.

The objective of this work was to evaluate the effect of storage at low temperature of Trichogramma pretiosum pupae in eggs of Sitotroga cerealella on the emergence and reproduction rates of the parasitoid. The trials were conducted in a climatic chamber at 5, 8 and 10º C, 70% R.H., constant scotophase, with 10 treatments: 4, 6, 8, 10, 12, 14, 16, 18, 20 days of storage and a control not kept in storage, all in 10 replicates. A total of 1,000 eggs containing pupae were distributed in glass tubes (10 x 3 cm), 100 of which were kept at 25° C, 70% RH and 14 h photophase (control), while the remaining ones were stored. After each storage period 100 eggs were transferred to 25º C and the emergence and reproductive capacity were observed. The T. pretiosum emergence rate was not affected by the storage time at 3 temperatures (Tukey P ≤ 0.05) and the lowest emergence rates were 85.6%, 84.5% and 77.6%, respectively for parasitoid storage at 5, 8 and 10º C. The reproductive capacity of T. pretiosum was not affected after the exposure periods in the temperatures evaluated. This result will aid in the planning of mass production, package and transport of T. pretiosum to the place of release.

Characterization of abdominal appendages in the sawfly, Athalia rosae (Hymenoptera), by morphological and gene expression analyses.

Larvae of the sawfly, Athalia rosae, have remarkable abdominal prolegs. We analyzed the morphogenesis of appendages and the expression of decapentaplegic and Distal-less genes during embryonic development to characterize the origin of prolegs. Proleg primordia in abdominal segments A1-A9 appeared shortly after the inner lobes (endites) of gnathal appendages were formed. These were located on the ventral plates, medioventral to the appendages of the other segments in light of serial homology. Nothing was seen where the main axis of the appendage should develop in abdominal segments. The primordia in A1 and A9 disappeared before larval hatching. Anal prolegs appeared separate from cerci, the main axes of appendages, which were formed temporarily in A11. The expression of decapentaplegic, which reflects the primary determination of appendages, was detected in the lateral juxtaposition with the prolegs. Distal-less was expressed in the main axes of appendages, protruding endites and the cerci, but not in prolegs and anal prolegs or the gnathal endites which do not protrude. These findings suggest a possibility that the abdominal and anal prolegs of A. rosae are outgrowths of ventral plates which derived from coxopodal elements, but not main axes of appendages.

An overview of proximate factors affecting the nesting behavior of solitary wasps and bees (Hymenoptera: Aculeata) in preexisting cavities in wood

Guilds of Aculeate solitary wasps and bees that nest in preexisting cavities in wood are important components of terrestrial ecosystems because they engage in several ecological interactions (e.g. predation and pollination) with other species of plants and animals. Spatial and temporal variations in richness and abundance of solitary wasps and bees can be related to changes in environmental structure and in the diversity of other groups of organisms. The nesting period of these Aculeata is their most critical life cycle stage. Females of solitary wasp and bee species invest relatively more time constructing and provisioning their nests than do females of social species. Differently from species that nest in the soil or construct exposed nests, the main factors affecting the reproductive success of solitary species nesting in preexisting wood holes are still unknown. Our objective is to provide an overview of the role of proximate causes of nesting failure or success among solitary wasps and bees (Aculeata), for designing effective conservation and management strategies for these Hymenoptera.

Espécies de vespas e abelhas solitárias que nidificam em cavidades pré-existentes no lenho de plantas integram uma guilda de nidificação e são importantes componentes da maioria dos ecossistemas terrestres. Isso se deve, em parte, ao grande número de interações (e.g. predação e polinização) que mantêm com outras espécies de organismos. Variações espaciais e temporais em sua abundância e riqueza podem estar correlacionadas a alterações na estrutura do ambiente. Uma fase crítica no ciclo de vida de vespas e abelhas solitárias é o período de nidificação. As fêmeas dessas espécies investem a maior parte de seu tempo de vida em construir e aprovisionar seus ninhos. Ao contrário do que ocorre para espécies que nidificam no solo ou fazem seus ninhos expostos, até o momento não houve tentativa alguma de discutir o conjunto de fatores que influenciam o sucesso de nidificação das espécies que nidificam em cavidades pré-existentes no lenho de plantas. Este artigo revê aspectos que afetam a nidificação desses Aculeata, com ênfase em fatores proximais, tais como a disponibilidade e características de cavidades no lenho. Compreender como esses fatores agem sobre a sobrevivência e o sucesso reprodutivo é de grande importância para a conservação e manejo dessas espécies.

Registro de Aphaereta laeviuscula (Spinola) (Hymenoptera: Braconidae) e Nasonia vitripennis (Walker) (Hymenoptera: Pteromalidae) como parasitóide de Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae), no estado do Rio de Janeiro / Register of Aphaereta laeviuscula (Spinola) (Hymenoptera: Braconidae) and Nasonia vitripennis (Walker) (Hymenoptera: Pteromalidae) as parasitoids of Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae), in the State of Rio de Janeiro, Brazil

As capturas ocorreram entre janeiro e dezembro de 2004 em área urbana de Nova Iguaçu; área rural de Seropédica e em área florestal na Reserva Biológica do Tinguá, Nova Iguaçu, RJ. Foram usadas 1.528 larvas de C. hominivorax como iscas, 505 na área urbana, 556 na rural e 467 na florestal. Foram calculados os índices de Sinantropia, Coeficiente de Constância, o risco (Odds Ratio) de parasitismo entre as áreas, prevalência e intensidade parasitária. O percentual de emergência foi de 46,6 por cento. A espécie A. laeviuscula foi capturada apenas em ambiente rural, seus índices foram: sinantropia = +50, c. constância = 25 por cento, prevalência = 0,72 por cento e intensidade parasitária = 44,5. N. vitripennis foi capturada nas áreas rural e urbana e os índices foram: sinantropia = +98, constância = 58,3 por cento, Odds Ratio = IC95 por cento = 0,025 < µ > 0,27, P < 0,05, prevalência = 3,2 por cento e intensidade parasitária = 7,35. O risco de parasitismo por N. vitripennis em áreas urbanas é alto. Registra-se a ocorrência de A. laeviuscula como parasito de C. hominivorax no estado do Rio de Janeiro.

The captures occurred between January and December of 2004 in urban area in the city of Nova Iguaçu, the rural area of the city of Seropédica and in a forest area in the Biological Reserve of the Tinguá, Nova Iguaçu State of Rio de Janeiro. The total of 1,528 larvae of Cochliomyia hominivorax (Coquerel) were used as bait, 505 in the urban area, 556 in rural and the 467 in the forest one. The indices of Synantropic, Coefficient of Constancy, the risk (Odds Ratio) of parasitism between the areas was calculated, prevalence and parasitic intensity. The percentage of emergence was of 46.6 percent. Aphaereta laeviuscula (Spinola) was captured only in rural environment; its indices were: Synantropic I. = +50, c. constancy = 25 percent, prevalence = 0.72 percent and I. parasitic = 44.5; already Nasonia vitripennis (Walker) was captured in the areas rural and urban and the indices had been: synanthropy = +98, constancy = 58.3 percent, Odds Ratio = IC95 percent = 0,025 < µ > 0.27, P < 0,05, prevalence = 3.2 percent and parasitic intensity = 7.35. The risk of parasitism for N. vitripennis in urban areas is high. The occurrence of A. laeviuscula as parasitic of C. hominivorax is registered in the State of Rio de Janeiro.

Cephalotes clypeatus Fabricius (Hymenoptera: Formicidae): hábitos de nidificação e ocorrência em carcaça animal / Cephalotes clypeatus Fabricius (Hymenoptera: Formicidae): nesting habits and occurrence in animal carcass

A posição ecológica dos himenópteros da família Formicidae em carcaças animais varia de predador, ao alimentar-se de ovos, larvas e pupas de alguns insetos, a necrófago, quando se alimentam de exudatos ou dos tecidos em decomposição. As formigas estão presentes em cadáveres humanos sujeitos a análises forenses e podem inclusive ser úteis na determinação do intervalo post-mortem (IPM). Cephalotes clypeatus Fabricius é exclusivamente arborícola, e ocorre apenas no continente americano. Durante experimento realizado em dezembro de 2003 no campus da Universidade Estadual de Campinas, uma carcaça de camundongo (Mus musculus, linhagem Swiss) de 35,9 g foi exposta em aparato adequado para coleta de exemplares de formigas adultas. A carcaça se decompôs totalmente em quatro dias. Foram coletados 82 exemplares adultos de C. clypeatus, nos dois primeiros dias de exposição. Os indivíduos de C. clypeatus foram observados alimentando-se dos exudatos, tecidos da carcaça e de larvas de dípteros que se encontravam na carcaça. O himenóptero em questão nidificou em galhos ocos de Senna multijuga (Rich.) H.S. Irwin & Barneby (Caesalpinaceae), que se localizava a 1 m do aparato que continha a carcaça. Estudos quanto à biologia desse Cephalotini são necessários, para que se possa ter noção exata do papel da espécie na utilização dos recursos de carcaças animais, e, portanto, no processo de sucessão entomológica. Trata-se do primeiro registro de C. clypeatus em carcaças animais.

The ecological position of the family Formicidae in animal carcasses varies from predator, when feeding on eggs, larvae and pupae of some insects to necrophagous, when the ants feed on exudates or decomposing tissues. Ants are present in human corpses subject to forensic analyses and can also be used in estimation of the post-mortem interval (PMI). Cephalotes clypeatus Fabricius is exclusively arboricolous and occurs only in the American continent. During a field study conducted in the Campus of the Universidade Estadual de Campinas, in December 2003, a laboratory mouse carcass weighing 35,9 g was placed in an iron-mesh cage, which was adequate to collect adult ants. The carcass decomposed in four days. The total of 82 specimens of C. clypeatus was collected, in the first two days of exposure. They were observed feeding on exudates, tissues of the carcass, and on Diptera larvae occurring in the carcass. This species was observed nesting in hollow branches of Senna multijuga (Rich.) H.S. Irwin & Barneby (Caesalpinaceae), which was found one-meter far from the cage. Further investigation on the biology of this Cephalotini must be performed, in order to understand the role of this species in the utilization of animal carcasses, and in the entomological succession process as well. This is the first report of C. clypeatus in animal carcasses.

Compatible invasion of a phylogenetically distant host embryo by a hymenopteran parasitoid embryo.

Embryonic invasion into the tissue of genetically different organisms has been known only in mother-embryo interactions of viviparous organisms. Hence, embryonic invasions have been thought to occur only within the same or closely related species. For endoparasitic Hymenoptera, which are oviposited in their host egg but complete their development in the later stages, entry into the host embryo is essential. To date, the entry of these parasitoids is known to be accomplished by either egg deposition directly into the embryo or by the newly hatched larva boring into the embryo. However, Copidosoma floridanum is a polyembryonic parasitoid whose development is characterized by a prolonged embryonic stage, and which lacks a larval form during its host embryogenesis. We have analyzed the behavior and fate of C. floridanum embryos co-cultured with their host embryo in vitro. Here, we show that the morula-stage embryo of C. floridanum actively invades the host embryo. Histological analyses have demonstrated that C. floridanum embryonic invasion is associated with adherent junction to host cells rather than causing an obvious wound on the host cells. These findings provide a novel case of embryonic invasion into a phylogenetically distant host embryo, ensuring cellular compatibility with host tissues.

Isolation of white gene orthologue of the sawfly, Athalia rosae (Hymenoptera) and its functional analysis using RNA interference.

We isolated and characterized the white gene orthologue of the sawfly, Athalia rosae (Hymenoptera). The A. rosae white (Ar white) cDNA cloned was 2058-bp long encoding 685 amino acids in a single open reading frame (ORF). Comparison of the cDNA sequence with the genomic DNA sequence revealed that the ORF was derived from 11 exons. Ar white was a single copy gene as evidenced by genomic Southern blotting and its cytological localization on the metaphase chromosomes. The deduced amino acid sequence aligned well with known insect white orthologous gene products sharing conserved regions such as the ATP-binding motif and the six transmembrane-spanning segments. Expression of Ar white was detected at embryonic and pupal stages by Northern blotting. In situ hybridization detected the embryonic expression in a pair of the lateral tips of protocephalic placodes from where optic organs are formed. Ar white function was examined using double-stranded RNA (dsRNA)-mediated interference. The synthesized dsRNA targeting Ar white transcripts caused a decrease in the level of the original mRNAs, and resulted in the white phenocopy in the embryonic eye pigmentation when microinjected into eggs from wild-type females. The effects occurred in a dose-dependent manner.

Ocorrência, morfologia e ultra-estrutura da glândula de Dufour de Scaptotrigona postica Latreille (Hymenoptera: Apidae) / Dufour gland occurence, morphology and ultrastructure in Scaptogrigona postica Latreille (Hymenoptera: Apidae)

A glândula de Dufour é uma glândula acessória do aparelho reprodutivo feminino das abelhas. Nas abelhas neotropicais sem ferrão, tem sido pouca estudada sob todos os aspectos: morfológico, ontogenético e bioquímico. Na tentativa de colaborar com o conhecimento dessa glândula em abelhas sem ferrão, foi realizado um estudo da sua ocorrência, morfologia e desenvolvimento em Scaptotrigona postica Latreille. Os resultados mostraram que ela se encontra ausente nas operárias, como ocorre em muitas outras espécies desse grupo. Nas rainhas, as células glandulares parecem mais ativas nas virgens, possuindo uma desenvolvida rede de retículo endoplasmático liso tubular, grânulos de secreção e polirribossomos dispersos no citoplasma, além de apresentarem núcleos maiores do que os das células glandulares das fisogástricas. Nas rainhas fisogástricas há dois tipos de células glandulares, ambas aparentemente inativas sinteticamente. As glândulas das rainhas fisogástricas são claramente capazes de captar substâncias da hemolinfa, provavelmente lipídios, que não penetram nas células, mas passam pelos espaços intercelulares e, através da cutícula, chegam diretamente à luz da glândula. A bem desenvolvida dupla camada de lâmina basal ao redor da glândula pode atuar no processo de captação de substâncias da hemolinfa. A secreção, e conseqüentemente sua função, pode ser diferente nas duas classes de rainhas.

The Dufour gland is an accessory gland of the bee reproductive female apparatus. In neotropical stingless bees, this gland has been poorly investigated, concerning to developmental, morphological or biochemical characteristics. In order to collaborate with the knowledge of the Dufour gland in stingless bees, a study of its occurrence, morphology and development was performed in Scapatotrigona postica Latreille. The results showed that this gland is absent in workers, although it occurs in workers of many stingless bee species. The glandular cells seem to be very active in virgin queens, presenting a well developed tubular network of smooth endoplasmic reticulum, secretion granules and some polyribosomes in the glandular cell cytoplasm, besides larger nuclei than in physogastric queens. In physogastric queen glands there are two types of cells, both of them apparently not synthetically active. Nevertheless, the physogastric queen glands are clearly able to absorb substances from the haemolymph, probably lipids that do not cross the cells, but pass through the intercellular cell spaces and cuticle, and are released directly to the gland lumen. The very developed double-layered gland basal lamina may actuate in the process of substances uptaking. The secretion, and consequently its function, can be different in these two queen types.

Host regulation and the embryonic development of the endoparasitoid Toxoneuron nigriceps (Hymenoptera: Braconidae).

Insect endoparasitoids modulate the host physiology through the injection of maternal-derived substances into the host, inducing physiological and hormonal changes in the host's internal environment to benefit parasitoid development. These changes are direct to control host development and regulate nutrient availability to the developing parasitoid, and they are synchronized with parasitoid development. Eggs of some of these parasitoids have low yolk content and require nutrients from the host hemolymph to initiate and complete embryogenesis. We report changes in the amino acid composition and protein profile of the host hemolymph of the endoparasitoid Toxoneuron nigriceps, and improved the in vitro culture of pre-germ band stage eggs. The protein profile of parasitized larvae was similar to controls throughout the embryonic development, but total amino acid concentration decreased in the first 2 h after parasitization, significantly increasing in the following hours up to 8 h. Amino acid levels were higher in parasitized larvae from 16 to 28 h after parasitization. Comparison of single amino acids indicated amino acids involved in energy metabolism (Krebs cycle) followed a trend during parasitoid embryogenesis, and their changes were correlated with embryonic development. Improvement in the in vitro development of 6 h-old eggs of T. nigriceps was obtained by adding factors released by the host fat body to the artificial medium, while a cell lysate stimulated embryogenesis and allowed the full development of newly laid eggs in vitro.

Development and morphology of teratocytes in Encarsia berlesei and Encarsia citrina: first record for Chalcidoidea.

In several species of hymenopteran parasitoids of the superfamilies of Ichneumonoidea and Platygastroidea, the membrane enveloping the parasitoid embryo dissociates at hatching into a number of cells, called teratocytes, which autonomously develop in the host haemolymph. In this work we report for Encarsia berlesei and Encarsia citrina (Hymenoptera: Chalcidoidea), the dissociation of the extraembryonic membrane into cells whose morphological and embryological features correspond to those of teratocytes. In E. berlesei the membrane dissociated at hatching into 4-9 larger cells (100 microm diameter) and about 10 smaller cells (60 microm), which scarcely doubled their size during maturation. In E. citrina the membrane dissociated into five large cells (250 microm) which did not grow appreciably. Ultrastructural investigation of the dissociated cells in E. berlesei revealed that their surface was covered by microvilli, whose density and length increased from the egg stage to the 12 h following hatching. During the same period, rough endoplasmic reticulum evolved from a parallel profile to that of the cisternal type, while abundant vesicles represented the dominant cytological feature. The ploidy level of these cells ranged between 8c and 140c at hatching, but increased to 40c-350c at maturation. These findings provide the first clear evidences for the presence of teratocytes in the superfamily Chalcidoidea.

Short, long, and beyond: molecular and embryological approaches to insect segmentation.

Over the past dozen years, studies comparing the expression of orthologues of the Drosophila segmentation genes among various insects have served to broaden our view of the ways in which insects make segments. The molecular data suggest that, although the overall genetic mechanisms of segmentation during embryogenesis have been conserved, the details of this process vary both within and between various insect orders. Here we summarize comparative gene expression data relevant to segmentation with an emphasis on understanding the extent of molecular patterning prior to gastrulation. These results are discussed in embryological context with an eye toward understanding the evolution of segmentation within insects.

Participation of testicular spermatids in development upon intracytoplasmic injection into eggs of the sawfly, Athalia rosae (Insecta, hymenoptera).

Fertilization by intracytoplasmic injection of mature sperm into mature eggs has previously been achieved in the sawfly, Athalia rosae (Insecta, Hymenoptera). In the present study, we examined the potential of spermatids, premature male gametes, for participating in development. When round spermatids and elongating spermatids from pupal testes were injected into the anterior end of mature eggs, about 5% of the total injected eggs developed into chimeric embryos (independent participation in development of the egg and spermatid nuclei). Some of them developed further, hatched, and pupated, with 1-2% of the total injected eggs becoming haploid chimeric male adults in which both the egg-derived and injected spermatid-derived nuclei contributed to the germline. No fertilized embryos were obtained by these injections. Elongated spermatids (immature sperm) from newly eclosed adult male testes upon injection did produce fertilized embryos that developed into normal diploid females (about 7% of the total injected). These results indicate that insect spermatids (round and elongating) have the potential to participate in development, but only independently of the egg nucleus. J. Exp. Zool. 286:181-192, 2000.

Evidence for a genomic imprinting sex determination mechanism in Nasonia vitripennis (Hymenoptera; Chalcidoidea).

Five different models have been proposed for the sex determination mechanism of Chalcidoidea (Hymenoptera). Except for the most recently proposed model (genomic imprinting sex determination; GISD), each of these models has required complicating additions to explain observed phenomena. This report provides the first experimental test of the GISD model while simultaneously examining the four previously proposed models of sex determination. This test utilizes the parasitic wasp Nasonia vitripennis, crossing polyploid females with males harboring the paternal sex ratio chromosome (PSR). The results of this study support the GISD model as the mechanism of sex determination in Chalcidoidea. Specifically, crosses demonstrate that sex determination is independent of embryonic heterozygosity, ploidy, and gametic syngamy but is directly correlated with the embryonic presence of correctly imprinted chromosomes of paternal origin. These crossing experiments also provide information about the poorly characterized mechanisms of PSR, a supernumerary chromosome that induces paternal autosome loss in early embryos. The results demonstrate that the poor transmission of PSR through females is not a result of the ploidy of the host but of an alternative sex-dependent process. Crossing data reveal that PSR consistently induces the loss of the entire paternal complement that it accompanies, regardless of whether this complement is haploid or diploid.

Embryonic development of an endoparasitoid, Microplitis croceipes (Hymenoptera: Braconidae) in cell line-conditioned media.

Embryos of the parasitoid Microplitis croceipes develop from pregerm band stage to first larval instar in cell culture medium conditioned by a cell line (IPLB-LdFB) derived from fat body from an atypical host Lymantria dispar. However, the percentage of eggs that develop normally to the first larval instar stage is significantly less than for those maintained in IPL-52B medium conditioned with host fat body tissue. Therefore, we examined the capacity of five insect cell lines to promote growth and development of pregerm band eggs in five media, IPL-52B, TC-199, TC-100, Grace's, and ExCell 400. The developmental response of M. croceipes was dependent both on the cell line and the cell culture medium used. TC-100, TC-199, and Grace's media promoted development to the germ band stage without the need for conditioning with host tissue. IPL-52B supported development to the germ band stage when a defined lipid concentrate was added. In IPL-52B medium, the IPLB-LdFB cell line promoted a significantly higher number of eggs developing to germ band relative to the other cell lines; however, none of the cell line-conditioned IPL-52B medium significantly stimulated egg hatch relative to the control medium. None of the cell line-conditioned Grace's media had a significant effect on eggs attaining germ band stage compared with the Grace's control medium. However, Grace's medium conditioned with the IAL-TND1 and IPLB-LdFB cell lines promoted development beyond germ band, resulting in a significantly higher percentage of hatching eggs than the Grace's control medium.(ABSTRACT TRUNCATED AT 250 WORDS)

A morphogenetic fate map constructed from Habrobracon juglandis gynandromorphs.

A morphogenetic fate map is presented for the parasitic wasp, Habrobracon juglandis. Twenty adult cuticular structures of 1211 haploid-diploid gynandromorphs were placed on the fate map using the sturtoid calculation. The overall shape and organization of the Habrobracon fate map are similar to those of the Drosophila fate mape, both of which approximate the shape of an insect embryo but show structures arranged in a manner resembling the adult body plan. Independent samples of gynandromorphs yield similar maps.

Increased production of genetic mosaics in Habrobracon juglandis by cold shock of newly oviposited eggs.

Eggs from an ebony stock exposed to 5-5 degrees C prior to syngamy exhibited increased production of genetic mosaics in comparison with untreated eggs from the same females. No increase in mosaic production occurred for cold-shocked cleavage-stage embryos from the ebony stock or from pre-cleavage cold-shocked eggs from a wild-type stock. Heat shock of pre-syngamy eggs also failed to increase the production of genetic mosaics. These findings are consistent with predictions based on the post-cleavage fertilization theory of mosaic origin in Habrobracon or with a hypothesis of differential mortality.

Mitochondrial and other ultrastructural changes in the developing Habrobracon embryo.

Cells of the wasp, Habrobracon juglandis, were studied by electron microscopy with the view to comparing ultrastructural changes, especially those found in mitochondria, that occur during the first two-thirds of the 29 h embryonic period. In 1- to 2-h embryos (the earliest studied) mitochondria are distributed principally in the periplasm and typically are arranged in clumps with their long axes parallel to each other. Based on a study of profiles occurring in thin sections, most appear to be elongate with poorly developed cristae, have dense matrices and are longer than those of later stages. At 3-4 h of age, in incipient blastoderm cells, the mitochondria are distributed throughout the cytoplasm with 40% located lateral to the nuclei and 42% concentrated in a subnuclear position. Most (81%) exhibit spherical profiles, with well-developed cristae and less dense matrices than those found at earlier ages. In fully formed blastodermal cells (7-8 h), mitochondria are similar morphologically except that a lower percentage (53%) are spherical; almost half (48%) have migrated to a supra-nuclear location. In early gastrula cells (11-12 h) no significant variations from the blastoderm condition were apparent. Mitochondria in the oldest cells studied (18-19 h) show somewhat greater structural complexity and variability. The number per cell section is drastically reduced compared to earlier ages, but this, at least in part, is related to a reduction in cell size. Changes observed in other cellular constituents are also described. Comparisons are made with similar variations reported in other developing organisms and their possible significance is discussed.