Evidence against a (2)n synchronous increase of spermatogonia to produce spermatocytes in drosophila hydei

The numbers of primary spermatocytes within cysts as well as numbers of postmeiotic spermatids in bundles in Drosophila hydei were determined. Within the contents of a single testis the cysts of primary spermatocytes are found to contain 5–11 germ cells. Furthermore, the number of spermatocytes per cyst is age-dependent, in that pupae have a mean of 8.1 cells whereas fertile adult males have a mean of 7.1 cells. Counts of spermatids in section of testes add further support to the view that the primary spermatocytes, from which the spermatids originated, were not formed in a strict geometric progression.     

Quadriflagellar primary spermatocytes in the cotton leafworm,Spodoptera littoralis (Boisd.) (Noctuidae,Lepidoptera)

Summary The surface morphology of primary spermatocytes from testicular cysts of the last instar larvae of Spodoptera littoralis was examined by scanning electron microscopy (SEM). At this stage, each primary spermatocyte possesses four developing flagella, directed towards the lumen of the cyst. The identical length of flagella in all primary spermatocytes from a single cyst indicates that the initiation and rate of flagellar growth are synchronized. Some asynchrony can, however, be observed in the translocation of flagella to secondary spermatocytes during the first meiotic division.     

Reproductive Aspects of a Tropical Population of the Fiddler Crab Uca annulipes (H. Milne Edwards, 1837) (Brachyura: Ocypodidae) at Costa Do Sol Mangrove, Maputo Bay, southern Mozambique

Uca annulipes(H. Milne Edwards) is the dominant fiddler crab inhabiting mangrove forests in East Africa. However, several aspects concerning its reproduction are poorly known. Such information is necessary for a better understanding of several biological aspects occurring in this species. The aim of this study was to assess the reproductive biology of Uca annulipes as well as some factors determining its breeding season. Samplings were undertaken from January to December 2002 at Costa do Sol, a tropical mangrove forest around Maputo Bay, southern Mozambique. Crabs were randomly sampled, measured for carapace width (CW) and checked for the presence of eggs on female pleopods. Like most tropical brachyurans, Uca annulipes follows a continuous reproduction throughout the year with peaks of spawning during summer season and low frequency of egg-bearing females during winter. The frequency of ovigerous females was correlated with the air temperature (r ²= 0.652, p < 0.05) and rainfall (r ²= 0.897, p < 0.001), with the last parameter being the most important factor regulating the reproductive activity of this crab.     

Meiosis in DROSOPHILA MELANOGASTER. III. the Effect of Orientation Disruptor (ord) on Gonial Mitotic and the Meiotic Divisions in Males

Orientation disruptor (ord), a meiotic mutant that is recombination defective in females and disjunction defective in males and females, has been analyzed using serial section electron and light microscopy. From analysis of primary spermatocytes we have confirmed that ord males are defective in some aspect of the mechanism(s) that holds sister chromatids together during meiosis. In addition, we have determined that ord causes high frequencies of nondisjunction during spermatogonial mitotic divisions, as well as during the meiotic divisions. Mitotic nondisjunction involves the large autosomes more frequently than the sex chromosomes or chromosome 4 and results in high frequencies of primary spermatocytes that are either monosomic or trisomic for chromosome 2 or 3. Abnormalities in spermatocyte cyst formation are also observed in males homozygous for ord. These abnormalities include loss of regulation of meiotic synchrony and the number of gonial cell divisions.     

Microstructural Reconstruction for the Testicular Cysts of Wolf Spider Using 3D Volume Rendering Technique

In insects, the alignment of neighboring spermatid in the late stages is nearly perfect, so that a transverse section of a cyst containing late spermatids transects all the spermatids at approximately the same level. However, the testicular cysts of spiders are spherical, most cysts are arranged in order of increasing maturity from the periphery to the center of the testis. For this reason, it is difficult to observe the whole spermatids within a single microscopic slide and count them. Therefore, we demonstrate microstructural reconstruction technique enabling to count exact number of sperm cells per cyst with aid of 3D volume rendering. For image processing and reconstruction, serially sectioned histologic specimens were scanned with microscopy and 3D images were reconstructed using Amira 5.3.2 software from the image stacks of the germ cells and surrounding testicular cysts subsequentially. With the information gathered by 3D reconstruction, it has finally been counted that exactly 32 (2⁵) cells of the secondary spermatocytes per cyst. This means that most cysts in P. laura contain exactly 64 (2⁶) spermatids or spermatozoa, which presumably arose from four synchronous mitotic and two meiotic divisions. In addition, the number of divisions occurring in a cyst appears to be constant for this spider because it has been known that the number of spermatids per cyst is characteristic for each species.     

Temperature-dependent functional response of Euborellia annulipes (Dermaptera: Anisolabididae) preying on Plutella xylostella (Lepidoptera: Plutellidae) larvae

Temperature mediates trophic interactions, including relationships between insect pests and predators, and functional response studies are often used to determine the suitability of predators as biocontrol agents. We investigated the effects of temperature on the functional response of Euborellia annulipes (Lucas) (Dermaptera: Anisolabididae) preying on Plutella xylostella (L.) (Lepidoptera: Plutellidae) larvae. Predation rate, type of functional response, attack rate (a'), handling time (T_h), and maximum predation rate (T/T_h) of the predator were estimated using seven prey densities and three thermal conditions. The functional response of E. annulipes to P. xylostella was temperature-dependent, type III under the lower temperatur (18°C and 25 °C) , and type II at 32 °C. We observed increasing values of a’ in 25 °C and 32 °C, decreasing values of Th and highest T/T_h as the thermal condition increased. Our findings suggest that E. annulipes could be effective to control P. xylostella under different thermal conditions, however its predation behavior changes according to temperature variation.     

Gastropod shells: A potentially limiting resource for hermit crabs

The availability of gastropod shells to hermit crabs in the Newport River Estuary, Beaufort, N.C. has been assessed by determining the numbers of usuable shells occurring in characteristic subtidal habitats and by measuring shell size adequacy. The proportion of useable shells occupied by hermit crabs ranged from 58–99 % and many of the shells not used by hermit crabs were judged unavailable because they were occupied by sipunculids or only uncovered by the dredge. The shell adequacy index (shell size occupied/shell size preferred) was significantly below 1.0 for the largest species (Pagurus pollicaris Say) in the one location where sufficient numbers were collected and for the next largest species (P. longicarpus Say) in three of the four locations where it was collected. The shell size adequacy index for the smallest species (P. annulipes Stimpson) did not differ significantly from 1.0 in either of the two locations in which it was found. These observations suggest that the availability of gastropod shells plays a significant rôle in limiting the abundance of at least the larger hermit crabs.     

Sperm cell number per bundle in Gnorimus nobilis L. (Coleoptera,Scarabaeidae)

An attempt was made to determine the number of spermatozoa per bundle in a scarabaeoid species Gnorimus nobilis both through the analysis of the premeiotic cytology of germ line cells and by counting the spermatids within a spermiocyst at the beginning of the process of spermiogenesis. The obtained results, taken together, indicate that definitive spermatogonia go through a series of 6 synchronous mitotic divisions before entering meiosis as primary spermatocytes, which in turn produce 256 (2⁸) spermatozoa per bundle after completion of meiosis and spermiogenesis. The obtained data are compared with similar ones for other beetle species belonging to the family Scarabaeidae and the suborder Coleoptera-Polyphaga, respectively. Also, some phylogenetic implications of these data are briefly discussed.     

Fate in Model Ecosystems of Microbial Species of Potential Use in Genetic Engineering

Three Oscillatoria strains and one Anabaena species were isolated from three different water supply systems in California that experienced earthy-musty taste and odor problems in their drinking water. Unialgal cultures, free of actinomycetes, were purged using the Grob closed-loop stripping analysis method, and the resulting methylene chloride extracts were analyzed on a gas chromatograph/mass spectrometer. Geosmin was produced by Oscillatoria simplicissima and Anabaena scheremetievi, and 2-methylisoborneol was produced by O. curviceps and O. tenuis. These compounds are the two major causes of earthy-musty tastes and odors in water. In three instances, the major odorant found in culture was previously identified in the water or sediment sample from which the respective organism was isolated. O. curviceps was implicated in a taste and odor episode involving 2-methylisoborneol in a major reservoir. Geosmin and 2-methylisoborneol were easily detected with culture samples of only 4 to 25 ml.     

F-Actin and Tubulin During Spermatogenesis in Gamasid Mites (Acari: Parasitina)

Abstract F-actin and tubulin behaviour was investigated using fluorescence probes and electron microscopy in the course of spermatogenesis in two gamasid mites, Porrhostaspis lunulata Müller (Parasitidae) and Pergamasus truatellus Athias-Henriot (Pergamasidae). In spermatogonia and primary spermatocytes of both species, the proteins were localized mainly in the intercellular bridges and, in lesser quantities, in the cytoplasm. Overall, actin was present along the plasma-lemmal contact sites of the gonial cells. At the beginning of spermatid elongation, actin could be detected in two regions: in perinuclear cytoplasm and under the plasmalemma. Subplasmalemmal actin, visible as threads running along acrosome-adhering protrusions of the nuclear envelope, is supposedly located within the electron-dense material filling the subacrosomal gap. Tubulin was found on both sides of each actin thread; its location was consistent with two sets of microtubules adhering to the inner acrosomal membrane. Their involvement in acrosome shaping is suggested. As spermatid elongation terminated, the previous pattern of proteins disappeared. In Pergamasus, however, actin emerged briefly near the centrifugal ends of spermatids (granular bodies zone). In spermatocyte-containing cysts, actin and tubulin fluorescence (more pronounced in Porrhostaspis) was associated with intercellular junctions between the cyst cells. In both species, diffuse actin fluorescence was also detected in the cytoplasm of cyst cells assembling elongated spermatids; the reaction was intensified at the end of the elongation process, when the cytoplasm of cyst cells aggregated around the centripetal ends of spermatids.     

Late spermatocytes from immature rat testis isolation,electron microscopy,lectin agglutinability and capacity for glycoprotein and sulfogalactoglycerolipid biosynthesis

A method is described for preparing late spermatocytes form immature rat testes which yields about 2 · 10⁵ cells per testis a purity of 70–80% and a viability of over 90%. The spermatocytes are highly agglutinable by both concanavalin A and wheat germ agglutinin but no major difference in lectin-mediated agglutinability was observed between late spermatocytes, early spermatids and spermatozoa. Isolated spermatocytes were capable of incorporating [¹⁴C]glucosmine into glycoprotein at a linear rate for about 50 min at 30°C and contained a glycoprotein N-acetylglucosaminyltransferase (8.6 nmol/mg protein per h) and a glycoprotein fucosyltransferase (4.5 nmol/mg protein per h) previously described in partially purified adult mouse testicular germinal cells. A Golgi-rich fraction was prepared from isolated spermatocytes wchich was enriched 15-fold in the N-acetylglucosaminyltransferase, 19-fold in the fucosyltransferase and 3-fold in a galactosyltransferase. These studies showed that late spermatocytes were higly active in glycoprotein synthesis. Studies on the incorporation of [³⁵S]sulfate into sulfogalactoglycerolipid indicated that late spermatocytes were not the primary site of synthesis of this lipid although late spermatocytes were shown to be highly enriched in sulfogalactoglycerolipid (5 times the level in whole rat testis). Further, [³⁵S]sulfogalactoglycerolipid took 5 weeks to migrate from its site of synthesis to the epididymis. These studies suggest that sulfogalactoglycerolipid is sulfated at a spermatocyte cell stage prior to the late (pachytene and diplotene) seprmatocyte stage.     

Redescription of Three Ektaphelenchus Species (Nematoda: Aphelenchina)

Three Ektaphelenchus species with unusual spicules are redescribed. Ektaphelenchus obtusus and E. riograndensis are redescribed from newly discovered material in the collection of the USDA Forest Service RMRS. Lectotype slides are designated for both species. Ektaphelenchus obtusus is characterized by a set-off head, lips of unequal size, double rows of oocytes and spermatocytes, and a hooked spicule terminus. Ektaphelenchus riograndensis is distinguished by a rounded head with six equal lips, and spicules with a large, rounded apex, and recurved terminus. A bursa and gubernaculum are absent in both species. Ektaphelenchus scolyti is redescribed from type material deposited in the collection of Rothamsted Experimental Station. It is characterized by a well set-off head, double rows of oocytes and spermatocytes, and spicules with a hooked terminus. A bursa and gubernaculum are absent.     

Chromosomal segregational mechanisms in ant-lions (Myrmeleontidae,Neuroptera)

In a single male specimen of Myrmeleon mexicanum Banks the sex chromosomes, normally X and Y, were replaced by what appeared to be X¹X² and Y. These segregated as expected on that interpretation in only half of the spermatocytes — in the other half, one X and the Y segregated from the other X. This atypical segregation is explicable on the assumption that one of the supposed Xs is a supernumerary, not a sex chromosome, and the diploid complement of the male comprises six pairs of autosomes plus a supernumerary and the X and Y sex chromosomes. The orientation of the X chromosomes at first metaphase was variable: kinetochoric activity may be localized midway the length of the chromosome, as in gonial mitosis, or terminally. Comparative study of three congeneric species, seven of Brachynemurus, one of Psammoleon, and one of Vella showed normal segregation in all, and no evidence for secondary kinetochoric activity. In nine of the species studied one pair of autosomes was unconjoined at first metaphase in 0.3%–1.2% of primary spermatocytes. These autosomes segregated precociously with the sex chromosomes in the central unit of the spindle. In one exceptional male of Brachynemurus hubbardi Currie all first meiotic metaphases showed this behavior, and a compound X¹X²/Y¹Y² system was thus simulated. Bivalent formation replaced distance segregation of sex chromosomes in 0.4%–3.2% of the spermatocytes in seven of the thirteen species studied. These sex-bivalents frequently displayed partial or complete failure in congression.     

The Disphragis notabilis (Schaus) species-group in Costa Rica (Lepidoptera,Notodontidae)

The four described taxa in the Disphragis notabilis (Schaus) species-group are reviewed, including the types and their dissected genitalia. Disphragis hemicera (Schaus), stat. rev., is elevated to species rank, D. normula (Dognin) is retained as a synonym of D. notabilis, D. sobolis Miller is confirmed as distinct from D. hemicera, and D. bifurcata sp. n., is newly described. Both D. hemicera and D. bifurcata occur in Costa Rica. The known ranges of the other species are outlined. Defining characters of each species are presented and a key to species is provided. Unusual variation in the genitalia is noted.     

Predation potential of the earwig Euborellia annulipes on fruit fly larvae and trophic interactions with the parasitoid Diachasmimorpha longicaudata

The earwig Euborellia annulipes (Lucas) (Dermaptera: Anisolabididae), a generalist predator, has been observed in fruits infested with fruit fly larvae, which are frequently parasitized by parasitoid wasps. Neither the capacity of earwigs to predate on fruit flies nor intraguild interactions between earwigs and fruit fly parasitoids have been investigated. Here, we studied in laboratory conditions the predation on the fruit fly Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) by the earwig E. annulipes, and whether parasitism of fruit fly larvae by the parasitoid wasp Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae) influences predation by the earwig. We evaluated the predation capacity, functional response and prey preference of E. annulipes for parasitized and non-parasitized fruit fly larvae in choice and no-choice tests. We found that earwigs prey on second- and third-instar larvae and pupae of C. capitata and consumed larger numbers of second-instar larvae, followed by third-instar larvae and pupae. Females prey on larger numbers of fruit flies than did males, regardless of the prey developmental stage, but both sexes exhibited a type II functional response. Interestingly, males killed but did not consume fruit fly larvae more than did females. In no-choice tests, earwig females consumed equal numbers of parasitized and non-parasitized fruit fly larvae. However, in choice tests, the females avoided feeding on parasitized larvae. Subsequent tests with hexane-washed parasitized and non-parasitized larvae showed that putative chemical markings left on fruit flies by parasitoids did not drive the earwig preference towards non-parasitized larvae. These findings suggest that E. annulipes is a potential biological control agent for C. capitata, and that, because the earwig avoids consuming larvae parasitized by D. longicaudata, a combination of the two natural enemies could have an additive effect on pest mortality.     

Revision of the Neotropical bark mantis genus Liturgusa Saussure, 1869 (Insecta,Mantodea, Liturgusini)

The praying mantis genus Liturgusa Saussure, 1869 occurs only in Central and South America and represents the most diverse genus of Neotropical Liturgusini (Ehrmann 2002). The genus includes bark dwelling species, which live entirely on the trunks and branches of trees and run extremely fast. All species included within the genus Liturgusa are comprehensively revised with a distribution stretching from central Mexico, the island of Dominica to the southeastern regions of Brazil and southern Bolivia. All known species are redescribed to meet the standards of the new treatment of the genus (11 species). Three new genera are described including Fuga gen. n., Velox gen. n., and Corticomantis gen. n. for species previously included in Liturgusa as well as Hagiomantis. Liturgusa mesopoda Westwood, 1889 is moved to within the previously described genus Hagiomantis Audinet Serville, 1838. A total of 19 species are newly described within Liturgusa, Fuga, and Velox including L. algorei sp. n., L. bororum sp. n., L. cameroni sp. n., L. cura sp. n., L. dominica sp. n., L. fossetti sp. n., L. kirtlandi sp. n., L. krattorum sp. n., L. manausensis sp. n., L. maroni sp. n., L. milleri sp. n., L. neblina sp. n., L. purus sp. n., L. stiewei sp. n., L. tessae sp. n., L. trinidadensis sp. n., L. zoae sp. n., F. grimaldii sp. n., and V. wielandi sp. n. Four species names are synonymized: Liturgusa peruviana Giglio-Tos, 1914, syn. n. = Liturgusa nubeculosa Gerstaecker, 1889 and Hagiomantis parva Piza, 1966, syn. n., Liturgusa sinvalnetoi Piza, 1982, syn. n., and Liturgusa parva Giglio-Tos, 1914, syn. n. = Mantis annulipes Audinet Serville, 1838. Lectotypes are designated for the following two species: Liturgusa maya Saussure & Zehntner, 1894 and Fuga annulipes (Audinet Serville, 1838). A male neotype is designated for Liturgusa guyanensis La Greca, 1939. Males for eight species are described for the first time including Liturgusa cayennensis Saussure, 1869, Liturgusa lichenalis Gerstaecker, 1889, Liturgusa guyanensis La Greca, 1939, Liturgusa maya Saussure & Zehntner, 1894, Liturgusa nubeculosa Gerstaecker, 1889, Fuga annulipes (Audinet Serville, 1838), Corticomantis atricoxata (Beier, 1931), and Hagiomantis mesopoda (Westwood, 1889). The female of Fuga fluminensis (Piza, 1965) is described for the first time. Complete bibliographic histories are provided for previously described species. The spelling confusion surrounding Liturgusa/Liturgousa is resolved. Full habitus images for males and females are provided for nearly all species. Habitus and label images of type specimens are provided when possible. Diagnostic illustrations of the head and pronotum for males and females are provided for all species when possible. Illustrations of male genital structures are provided for all species for which males are known. Measurement data, including ranges and averages, are provided for males and females of all species. Combined male and female genus and species level dichotomous keys are provided with a Spanish translation. A complete table of all examined specimens lists label data, museum codes, repositories, and other specimen specific information. A KML file with all georeferenced locality records is downloadable from mantodearesearch.com for viewing in Google Earth. Natural history information is provided for species observed by the author.     

Chromosome numbers in antlions (Myrmeleontidae) and owlflies (Ascalaphidae) (Insecta,Neuroptera)

A short review of main cytogenetic features of insects belonging to the sister neuropteran families Myrmeleontidae (antlions) and Ascalaphidae (owlflies) is presented, with a particular focus on their chromosome numbers and sex chromosome systems. Diploid male chromosome numbers are listed for 37 species, 21 genera from 9 subfamilies of the antlions as well as for seven species and five genera of the owlfly subfamily Ascalaphinae. The list includes data on five species whose karyotypes were studied in the present work. It is shown here that antlions and owlflies share a simple sex chromosome system XY/XX; a similar range of chromosome numbers, 2n = 14-26 and 2n = 18-22 respectively; and a peculiar distant pairing of sex chromosomes in male meiosis. Usually the karyotype is particularly stable within a genus but there are some exceptions in both families (in the genera Palpares and Libelloides respectively). The Myrmeleontidae and Ascalaphidae differ in their modal chromosome numbers. Most antlions exhibit 2n = 14 and 16, and Palparinae are the only subfamily characterized by higher numbers, 2n = 22, 24, and 26. The higher numbers, 2n = 20 and 22, are also found in owlflies. Since the Palparinae represent a basal phylogenetic lineage of the Myrmeleontidae, it is hypothesized that higher chromosome numbers are ancestral for antlions and were inherited from the common ancestor of Myrmeleontidae + Ascalaphidae. They were preserved in the Palparinae (Myrmeleontidae), but changed via chromosomal fusions toward lower numbers in other subfamilies.     

Polymorphisme biochimique chez le faisan commun (Phasianus colchicus)

Egg white proteins, hemoglobin, serum proteins and enzymes from Phasianus colchicus have been examined by starch gel electrophoresis. All three genetic parameters, mean proportion of loci polymorphic per population (P), mean numbers of alleles per locus (A), and mean proportion of loci heterozygous per individual (H), are given. Comparison were made between the proteins of the related species Coturnix coturnix japonica, and the variation of pheasant proteins is discussed in connexion with the genetic structure of the population studied.     

Postembryonic development of the cervicothoracic skeleton of Euborellia annulipes (Lucas) (Dermaptera: Labiduridae)

The nymphal and adult cervicothoracic skeleton of Euborellia annulipes (Lucas) is described and discussed.