Showing papers in "International journal of invertebrate reproduction in 1981"
TL;DR: It is reasoned that the delay response is elicited by an inhibitory factor released continually from Diplosoma, which is reversible, non-pathological, and species specific.
Abstract: In nature, the marine bryozoan, Bugula pacifica, is consistently the ‘loser’ when competing for space with the compound ascidian, Diplosoma macdonaldi. We provide laboratory evidence to show that Bugula larvae will delay settling in either ‘Diplosoma-conditioned water’ or an alcohol Diplosoma extract. It is reasoned that the delay response is elicited by an inhibitory factor released continually from Diplosoma. This response is reversible, non-pathological, and species specific. The possible ecological significance of larval avoidance behavior in this and other communities is discussed.
102 citations
TL;DR: It is demonstrated that injection of ecdy- sterone induces de novo synthesis and release of vitellogenin in both sexes of Sarcophaga bullata and the dose-response curve was linear on a semi- logarithmic scale.
Abstract: Using Polyacrylamide gel electrophoresis, cycloheximide, incorporation of 3H-labelled amino acids and immunological methods, we have demonstrated that injection of ecdy- sterone induces de novo synthesis and release of vitellogenin in both sexes of Sarcophaga bullata. Vitellogenin concentrations were measured by the Mancini-radial immunodiffusion technique. In males a dose as low as 1 ng always makes vitellogenin appear in the haemolymph but very reproducible results are only obtained when doses varying from 10 to 250 ng were injected. In this range, the dose-response curve was linear on a semi- logarithmic scale. In females, vitellogenin concentration remained low until a few hours after liver feeding and thereafter it rose sharply and reached its maximum about 24 h after the protein meal. 100 μg 6-hydroxydopamine HCl, injected before liver feeding in 4-day-old females, inhibited vitellogenin synthesis and yolk deposition, probably by interfering with the release of a brain hormone. This inhibitory effec...
83 citations
TL;DR: The energy metabolism of the LD animals had been clearly affected as was apparent from the metabolic drain to the female reproductive activity and a change in calcium metabolism, which reflects changes in energy metabolism.
Abstract: At a Long Day photoperiod (LD = 16 h light, 8 h dark) egg laying of snails kept under laboratory breeding conditions started 2 weeks earlier than in animals kept at Medium Day (MD = 12 h light, 12 h dark) or Short Day (SD = 8 h light, 16 h dark) photoperiods. At the end of the experimental period of 24 weeks the total number of egg masses produced by the LD animals had been 6 and 10 times higher than that of the MD and the SD animals, respectively, while the mean size (number of eggs) of the egg masses of the LD snails was only 30 and 10% larger. The high ovipository activity of the LD animals was reflected in the proportional wet weights of the female accessory sex organs, which tended to be larger. The energy metabolism of the LD animals had been clearly affected as was apparent from the metabolic drain to the female reproductive activity and a change in calcium metabolism, which reflects changes in energy metabolism. Growth of the LD snails, measured as the increase in body wet weight and in shell heig...
76 citations
TL;DR: The hemolymph titres of ecdysteroids in both mated and virgin females peak 5 days after a blood meal, and injection of Ecdysterone into ovariectomized females results in the release of ovulation hormone in the mated, but not the virgin, female.
Abstract: The hemolymph titres of ecdysteroids in both mated and virgin females peak 5 days after a blood meal. Ovariectomy prevents both the peak in ecdysteroids and the release of a myotropic ovulation hormone from the neurosecretory cells of the brain. Injection of ecdysterone into ovariectomized females results in the release of ovulation hormone in the mated, but not the virgin, female.
55 citations
TL;DR: Ecdysteroid levels in Leptinotarsa decemlineata were measured by radioimmunoassay (RIA), using an antiserum with a 10 times higher affinity for ecdysterone than for ecdysone and polyethylene glycol as a means for separating free from bound hormone.
Abstract: Ecdysteroid levels in Leptinotarsa decemlineata were measured by radioimmunoassay (RIA), using an antiserum with a 10 times higher affinity for ecdysterone than for ecdysone and polyethylene glycol as a means for separating free from bound hormone. In reproducing males, raised under long day conditions (LD: 16 h photophase, 25°C) there was a peak of 54 ng/g at day 3–4, declining thereafter to very low values. In LD-females, 50 ng/g was found at day 2 (just before the onset of vitellogenesis), decreasing to 20 ng/g at day 5 (start of oviposition) and increasing again thereafter to 95 ng/g at day 14. In prediapausing animals, raised under short day conditions (SD: 10 h photophase, 25°C) the level was practically the same in both sexes and it was significantly higher than in reproducing animals. In both sexes a peak of about 96 ng/g was found from day 2 to 4, thereafter the level dropped quickly. During diapause the level increased slowly and in 9 month diapausing adults it was about 75 ng/g. This is the fir...
52 citations
TL;DR: Lower limits of egg sizes for Ascoglossa with lecithotrophic and capsular development were substantially lower than limits reported for other opisthobranchs, probably because of the use of albumen as nutrient reserves in species with extended development.
Abstract: Data on egg size, capsule size, development type, and the presence and nature of albumen are summarized for 32 species of Ascoglossa, including new data on 23 species from Florida and the Caribbean. Lower limits of egg sizes for Ascoglossa with lecithotrophic and capsular development were substantially lower than limits reported for other opisthobranchs, probably because of the use of albumen as nutrient reserves in species with extended development. Capsule size is a more accurate predictor of development type than egg size. The use of albumen as a nutrient resource is associated with a relatively high plasticity of development.
45 citations
TL;DR: It is concluded that an apyrene spermatogenesis inducing factor (ASIF) becomes active on the fourth day of the 5th instar larva in addition to the already existing macromolecular factor.
Abstract: Lepidopteran spermatogenesis is dichotomous, producing eupyrene (nucleated) and apyrene (anucleated) spermatozoa. The eupyrene precedes the apyrene spermatogenesis. The timing of the switchover from eupyrene to apyrene spermatogenesis was determined by cultivating testes of accurately aged codling moth larvae in a medium containing mammalian serum but neither hemolymph nor insect hormones. In cultures, eupyrene spermatogenesis occurred in testes dissected from either 4th or 5th instar larvae, probably due to macromolecular factor-like activity of the serum of the medium. But apyrene spermatogenesis occurred only in testes explanted during or after the fourth day of the 5th instar larva. It is concluded that: (1) An apyrene spermatogenesis inducing factor (ASIF) becomes active on the fourth day of the 5th instar larva in addition to the already existing macromolecular factor. (2) Primary spermatocytes can develop into either eupyrene or apyrene spermatozoa. (3) The apyrene spermatogenesis commitment and pu...
43 citations
TL;DR: All the species of Rhinotermitidae and Termitidae studied by us show a similar spheroidal sperm model, devoid of acrosome, flagellum and manchette at spermatid stage, and are made up of only a round nucleus, two mitochondria and a centriole; this widely distributed model seems to be the more evolved in the order.
Abstract: In this paper, the ultrastructure of the spermatozoon of Zootermopsis nevadensis (Isoptera, Hodotermitidae) and of some Rhinotermitidae and Termitidae is described. Zootermopsis sperm is rod like, aflagellate, immotile, and without an acrosome; it is composed of a filiform nucleus encircled by a monolayered microtubular manchette, and a few mitochondria. This spermatozoon was previously thought to be flagellate, and therefore the most primitive in Isoptera: our present study suggests a new phylogenetical position for Hodotermitidae. All the species of Rhinotermitidae and Termitidae studied by us show a similar spheroidal sperm model, devoid of acrosome, flagellum and manchette at spermatid stage, and are made up of only a round nucleus, two mitochondria and a centriole. This widely distributed model seems to be the more evolved in the order. The nature of sperm evolution in the Isoptera is considered.
40 citations
TL;DR: Some properties of gonad-inhibiting hormone from the eyestalks of male Cancer magister have been examined with normal and eyestalkless female Crangon crangon as test animals.
Abstract: Some properties of gonad-inhibiting hormone (GIH) from the eyestalks of male Cancer magister have been examined with normal and eyestalkless female Crangon crangon as test animals. GIH is neither sex- nor species-specific, is thermostable and is dialyzable through cellophane membranes. It has a molecular weight of about 2000.
33 citations
TL;DR: The results suggest that sperm motility very probably does not contribute to spermathecal filling in Aedes aegypti, Simulium decorum, and Plecia nearctica, and that fluid absorbtion is the more likely mechanism.
Abstract: A recently completed study of sperm transfer and spermathecal filling in Culicoides melleus (Ceratopogonidae) provided evidence that the spermathecae create an incoming current by fluid absorption. This current, rather than sperm motility, was thought to accomplish transfer of spermatozoa from spermatophore to spermathecae. This review discusses the approach used to assess the role of sperm motility, as applied critically to available observations in other lower Diptera. Aedes aegypti (Culicidae), Simulium decorum (Simuliidae) and Plecia nearctica (Bibionidae) are considered. The results suggest that sperm motility very probably does not contribute to spermathecal filling in these species, and that fluid absorbtion is the more likely mechanism. Certain physical properties of the female reproductive systems are discussed in the light of this conclusion.
31 citations
TL;DR: Isolated abdomens were also capable of oocyte maturation when treated with excess amounts of JH alone, and JH I was the most effective followed by JH II and then JH III; however, the same amount of 20-hydroxyecdysone injected into isolated abdomens obtained shortly after adult emergence had no discernible effect on vitellogenesis.
Abstract: Aedes atropalpus is an autogenous mosquito characterized by a first gonadotropic cycle which results in approximately 200 mature oocytes without a bloodmeal. Ovarian development is completely inhibited if these animals are decapitated or ligated between the thorax and abdomen shortly after adult emergence. Injection of 4.8 ng of 20-hydro- xyecdysone into decapitated females 12 h after eclosion restores ovarian development in all females so treated. However, the same amount of 20-hydroxyecdysone injected into isolated abdomens obtained shortly after adult emergence had no discernible effect on vitellogenesis. In contrast, all abdomens which received 0.5 ng of topically applied JH I followed by the injection of 4.8 ng 20-hydroxyecdysone produced mature oocytes. Isolated abdomens were also capable of oocyte maturation when treated with excess amounts of JH alone; JH I was the most effective followed by JH II and then JH III. Polyacrylamide gel electrophoretic analysis of vitellin extracted from the ovaries o...
TL;DR: The results suggest that a direct or indirect stimulation by the neuroendocrine system is normally required for TARG protein synthesis.
Abstract: Surgical removal of the corpus allatum or neurosecretory cells of the brain results in a marked reduction in protein accumulation in the transparent accessory reproductive gland (TARG) of the male. Topical application of C18 juvenile hormone stimulates a dose-dependent accumulation of protein in allatectomized males. These results suggest that a direct or indirect stimulation by the neuroendocrine system is normally required for TARG protein synthesis.
TL;DR: An annual reproductive periodicity of Tripneustes gratilla in northern Taiwan is revealed by both the Gonad development stages and the gonad index.
Abstract: An annual reproductive periodicity of Tripneustes gratilla in northern Taiwan is revealed by both the gonad development stages and the gonad index. The gonads of T. gratilla recovered from spawning in February—March, propagated gametocytes in April—June, came to prematurity in July—August, and matured in September—November. Spawning occurred in October—December. The breeding pattern of T. gratilla over a broad geographical area appears to be related to seasonal changes of sea temperatures.
TL;DR: A comparative spermatological survey of ascothoracid crustaceans is presented, finding that several species of Dendrogaster have flagellate sperm with short heads and midpieces; their sperm may be secondarily shortened, and therefore less generalized than previously thought.
Abstract: A comparative spermatological survey of ascothoracid crustaceans is presented. They have the most generalized sperm morphology known in Crustacea. Several species of Dendrogaster have flagellate sperm with short heads and midpieces; their sperm may be secondarily shortened, and therefore less generalized than previously thought. The flagellate spermatids of Petrarca okadai and Ulophysema oeresundense have cup-shaped acrosomes, elongate nuclei and midpieces, and sheaths of microtubular organelles. Seminal receptacles in female Gorgonolaureus sp. are lined with a chitinous cuticle and contain flagellate sperm. The anterior basal body in sperm of the subclasses Cirripedia s.s., Mystacocarida, and Branchiura may be interpreted as a synapomorphy linking them within the class Maxillopoda, and Ascothoracida should be recognized as a subclass distinct from Cirripedia.
TL;DR: Flies with mature follicles in the first gonotrophic cycle could have the second and third cycle JH-activated, and when these flies were allatectomized, 3 cycles of eggs would be produced and oviposited, but the 4th gonotroph cycle would not develop past previtello-genesis.
Abstract: Ovarian follicles at stage 3 were ‘activated’ by juvenile hormone (JH), and follicles at stage 4 required eggs development neurosecretory hormone (EDNH) to initiate vitellogenesis. Removal of the corpus allatum (CA) from flies with stage-2 follicles Or removal of the ring gland (RG) from flies with stage-4 follicles stopped ovarian maturation at stage 4. Flies with mature follicles in the first gonotrophic cycle could have the second and third cycle JH-activated. When these flies were allatectomized, 3 cycles of eggs would be produced and oviposited, but the 4th gonotrophic cycle would not develop past previtello-genesis.
TL;DR: Ultrastructural studies of egg envelopes in four species of harvestmen have shown that a spongy vitelline envelope secreted by the oocytes appears on the oocyte surface at the beginning of viteLLogenesis, and the involvement of follicle cells in metabolic exchanges with the Oocyte is suggested.
Abstract: Ultrastructural studies of egg envelopes in four species of harvestmen have shown that a spongy vitelline envelope secreted by the oocyte appears on the oocyte surface at the beginning of vitellogenesis. As the oocytes grow, characteristic changes in the thickness and structure of the vitelline envelope can be observed. The homogeneous vitelline envelopes of eggs located inside the uterus are coated with a layer of loose, foamy material. The vitelline envelopes of laid eggs are covered only with mucus which binds the eggs together. The involvement of follicle cells in metabolic exchanges with the oocyte is suggested.
TL;DR: Exposure of Ephestia cautella eggs to anoxic conditions retards the development of the embryo, causing a marked delay in hatching, and phosphate treatment results in little or no hatch delay in survivability.
Abstract: Exposure of Ephestia cautella eggs to anoxic conditions retards the development of the embryo, causing a marked delay in hatching. Phosphine treatment results in little or no hatch delay in survivi...
TL;DR: An increase in temperature to 25 or 30°C during embryonic development and the first stages of post-embryonic development in the temperature-sensitive thelygenic offspring of Orchestia gammarellus, brings about a higher male ratio in the broods, that is to say weakens or cancels the action of the feminising factor.
Abstract: An increase in temperature to 25 or 30°C during embryonic development and the first stages of post-embryonic development in the temperature-sensitive thelygenic offspring of Orchestia gammarellus, brings about a higher male ratio in the broods, that is to say weakens or cancels the action of the feminising factor. The effect appears much earlier at 30 than at 25°C. At 30°C, the results achieved partly depend on the stage of embryonic development during which the heat treatment is applied. The more sensitive stages correspond to gastrulation and the formation of germ layers. The sensitivity to the increased temperature depends on the sexual genotype of the individuals: the 2AYY are more sensitive than the XY animals.
TL;DR: The results clearly suggest that the OT is not involved in the endocrine control of cellular differentiation, growth and synthetic activity of the female accessory sex organs.
Abstract: The small lateral lobes (LL) are paired ganglia connected with the lateral side of the cerebral ganglia. Extirpation and implantation experiments demonstrate that (neuroendocrine) centres in the LL decrease body growth and increae the production of eggs and egg capsules. Castration is followed by an acceleration of body growth and a reduction of egg capsule production. Since reimplanted ovotestes (OT) degenerated rapidly, it could not be established whether this effect is hormonal or neuronal. The results clearly suggest that the OT is not involved in the endocrine control of cellular differentiation, growth and synthetic activity of the female accessory sex organs. The ways in which LL and OT may control the antagonistic processes of body growth and reproduction are discussed.
TL;DR: The spermatophore of the cave-spider Telema tenella is elaborated in the vas deferens and has the shape of a long inverted gutter with two rows of digitations and spermatozoa piled up inside.
Abstract: The spermatophore of the cave-spider Telema tenella is elaborated in the vas deferens. It has the shape of a long inverted gutter with two rows of digitations and spermatozoa piled up inside. The spermatozoon possesses a 9 + 3 axoneme, retracted in the cytoplasm to form from 4 to 4.5 peripheral whorls; the elongated nucleus and its acrosomal rod make 1.5 whorl. The spermatozoa keep the main part of their cytoplasm. The spermatophore is inserted in the male palp, then transferred to the female during coition. With the exception of this family, all other male Araneae transfer free spermatozoa during coition.
TL;DR: Individuals from a population of the intertidal sea anemone Actinia fragacea (Tugwell) were collected at approximately monthly intervals over an 18 month period, and large numbers of small cells were seen in the endoderm of the female gonads, lying close to the mesoglea.
Abstract: Individuals from a population of the intertidal sea anemone Actinia fragacea (Tugwell) were collected at approximately monthly intervals over an 18 month period. Samples of gonad were removed from each anemone and examined by light and electron microscopy. During late spring and early summer, large numbers of small cells were seen in the endoderm of the female gonads, lying close to the mesoglea. For convenience, these cells were classified into three types. Type I cells are 6–9 μm in diameter, with relatively very large nuclei, which may contain synaptinemal complexes, and scant cytoplasm containing few organelles. Type II cells are larger, reaching 15 μ m in diameter, with more abundant cytoplasm containing more organelles and inclusions. The nucleus is more dense, but may also contain synaptinemal complexes. Type III cells are less common. They are similar in size to Type II cells, but their nuclei contain irregular dense chromatin masses, and the nuclear envelope is incomplete or absent. The possible ...
TL;DR: Preliminary ultra-structural observations on vitellogenic oocytes show that the Golgi apparatus is responsible for the production of cortical granules, but the origin of the yolk granules is not known.
Abstract: Development of the oocytes of Harmothoe imbricata (L.) occurs whilst they remain attached to the segmental blood vessels of the fertile segments, each oocyte surrounded by the cytoplasm of follicle cells. During the early stages of oogenesis, only protogonia and ‘tangled-knot’ stage premeiotic oocytes are readily recognisable. Preliminary ultra-structural observations on vitellogenic oocytes show that the Golgi apparatus is responsible for the production of cortical granules, but the origin of the yolk granules is not known. Large whorls of endoplasmic reticulum and regions of presumed transfer of material from the nucleus to the cytoplasm are seen at various stages during oogenesis. Mature oocytes, in metaphase I of meiosis, are collected into the nephridia after a brief coelomic phase, and are soon spawned.
TL;DR: It is suddenly after 10 h of regeneration that DNA is synthesized as shown by the variations of the rate of DNA labelling, as planarian cells are totally impervious to exogenous thymidine.
Abstract: For the first time, a study of DNA synthesis during planarian regeneration is presented. DNA content per animal was measured at different times after sectioning. It reached a first maximum at 18 h after sectioning, then diminished slowly until day 7. This DNA content was further compared to RNA and protein contents. It is suddenly after 10 h of regeneration that DNA is synthesized as shown by the variations of the rate of DNA labelling. As planarian cells are totally impervious to exogenous thymidine, 32P was used to establish these variations. Cells showing DNA polymerase activity were then detected in situ by a histoenzymological method; they were localized in a crown just behind the blastema. Measurements of the pool of adenylic nucleotides showed that ATP and ADP concentrations increased immediately after sectioning until 18 h, then they decreased until day 7. After a transitory diminution following sectioning, AMP concentration rose slightly up to 48 h and then decreased. The effect of the changes of...
TL;DR: The spermatheca of Melanoplus sanguinipes consists of a preapical and an apical diverticulum, and a long, thin ductus seminalis, and Histologically, the three components are identical.
Abstract: The spermatheca of Melanoplus sanguinipes consists of a preapical and an apical diverticulum, and a long, thin ductus seminalis. Histologically, the three components are identical. The wall of the spermatheca includes a basement membrane, secretory and epithelial cells, and a cuticular intima. Small, discrete bundles of muscle occur outside the basement membrane. In each secretory cell is a large central cavity which connects with a cuticular channel (efferent ductule) running through the epithelial cell to the spermathecal lumen. During sexual maturation, light- and dark-staining vesicles accumulate in the secretory cells and discharge their contents into the central cavity. Simultaneously, glycogen accumulates in the epithelial cells. Allatectomy of newly emerged females renders the secretory cells unable to produce material, an effect which can be reversed by topical application of synthetic juvenile hormone. The secretion contains protein and acidic mucopolysaccharide. After insemination the quantitie...
TL;DR: Observations on the effect of an aggregation pheromone of Dermestes maculatus indicate the production and liberation with faeces of two different compounds of a primer type.
Abstract: Observations on the effect of an aggregation pheromone of Dermestes maculatus indicate the production and liberation with faeces of two different compounds of a primer type. One is produced by larvae themselves and accelerates growth, the other is produced by adults and inhibits larval development. Both larval and adult pheromones synchronize larval ecdyses.
TL;DR: Margarites vorticiferus is the largest member of the genus found at Attu and the only member known to brood its young and the umbilicus is significantly larger in female specimens than in male specimens.
Abstract: Specimens of Margarites vorticiferus Dall collected at Attu Island, Alaska, during July 1979, were found brooding eggs and young in the umbilicus. The number of developing young in each brood ranged between 471 and 3264. Each brood contained several developmental stages including uncleaved eggs, unhatched embryos, hatched pro-toconch-bearing juveniles and two distinct juvenile size classes. The umbilicus of M. vorticiferus is significantly (t-test; P < 0.001) larger in female specimens than in male specimens. Margarites vorticiferus is the largest member of the genus found at Attu and the only member known to brood its young.
TL;DR: The hypothesis for the neotenic derivation of the Maxillopoda (Copepoda, Cirripedia and Ascothoracica, Mystacocarida, and Branchiura) from a eumalacostracan form is examined, and is found wanting.
Abstract: A description of the sperm of an Antarctic Dendrogaster species, an ascothoracican parasite of starfish, based on light microscopy and scanning and transmission electron microscopy, is presented. The sperm heads are 6–7 μm, long, with a laterally-placed acrosomal vesicle at the tip. The midpiece is as long as the head, and tapers to a flagellum 45–50 μm long. The basal body of the axoneme is embedded in the posterior part of the nucleus, and the axoneme has the usual ring of nine microtubule bundles, though interior bundles were indistinguishable. Present knowledge of other ascothoracican sperm is reviewed, and the present sperm are shown to be the most primitive yet discovered in Crustacea. The hypothesis for the neotenic derivation of the Maxillopoda (Copepoda, Cirripedia and Ascothoracica, Mystacocarida, and Branchiura) from a eumalacostracan form is examined in light of this new information, and is found wanting. Furthermore, it is suggested that similarities among the spermatozoa of several maxillopo...
TL;DR: The fine structure of the spermatozoon of Tetranychus urticae is described during passage from the testis to the site of insemination in the ovary and can be observed in the lumen of the receptaculum seminis of the female.
Abstract: The fine structure of the spermatozoon of Tetranychus urticae is described during passage from the testis to the site of insemination in the ovary. The male sex cells differentiate from a cytoplasmic mass which is characterised by nuclei bearing tubule-like structures. Infoldings appear in peripheral membrane of the germ cells at the beginning of spermiogenesis, chromatin condenses, and the nuclear membrane is reduced. The spermatozoon is surrounded by a double membrane: the inner one is the sperm membrane and the outer one is of somatic origin. The sperm reach the glanular region of the testis where they are transformed into amoeboid cell and are next collected in the seminal vesicle. After copulation, the sperm can be observed in the lumen of the receptaculum seminis of the female from which they soon enter the epithelial cells. Still surrounded by a double membrane, the sperm, which are now packed in clusters, develop microtubules immediately beneath the inner membrane and enlarge by decondensation of ...