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Teresa Stephanie Tay Bin Qi Gan Siew Chen Serina Lee Chin Sing Lim Koh Siang Tan Serena Lay-Ming Teo 《Invertebrate reproduction & development.》2013,57(4):248-256
ABSTRACTThe South American charru mussel, Mytella strigata, was recently recorded in Singapore waters, possibly introduced into Southeast Asia through shipping. The mussels have rapidly spread across estuarine coastal mudflats. Adult mussels were collected, spawned in aquaria and larvae were successfully cultured to the juvenile stage in the laboratory. The larval morphology and development of M. strigata is described in this paper. D-shaped veligers were produced within 20 h of fertilization and were approximately 75 µm in shell length. These larvae were capable of settlement two weeks post fertilization. Given an adequate amount of food, they were able to grow up to 1 mm in shell length within 30 days. The larval shell of M. strigata possesses anterodorsal G2 hinge teeth as distinct wavy ledges, with a pitted resilial ridge clearly evident in the juvenile shell. 相似文献
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We are developing techniques to restore coral populations by enhancing larval supply using “artificial spawning hotspots” that aggregate conspecific adult corals. However, no data were available regarding how natural larval supply from wild coral populations is influenced by fertilization rate and how this is in turn affected by local population density and genetic diversity. Therefore, we assessed population density and genetic diversity of a wild, arborescent coral, Acropora yongei, and compared these parameters with those of an artificially established A. yongei population in the field. The population density of wild arborescent corals was only 0.27% of that in the artificial population, even in a high‐coverage area. Genetic diversity was also low in the wild population compared with the artificial population, and approximately 10% of all wild colonies were clones. Based on these results, the larval supply in the artificial population was estimated to be at least 1,400 times higher than that in wild A. yongei populations for the same area of adult population. 相似文献
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The free-swimming early larval stages of Argulus foliaceus (Linneaus) (Branchiura) are studied using digital video, light microscopy, and SEM. We analyze and document the mode of swimming in the hatching stage of A. foliaceus and the subsequent juvenile stages with fully developed thoracopods. We present new observations and an analysis of the functional morphology of a cleaning behavior in the first stage. This stage swims very efficiently using the large exopods of the second antennae in concert with the mandibular palp (naupliar limbs), while the subsequent stages use the now developed thoracopods for propulsion. This posterior shift in propulsion is similar to--but independent from--what is seen in other crustaceans. The hatching stage has previously been referred as a "metanauplius" but as the first and second maxillae are developed and active, and buds of all four thoracopods are present, it is too advanced to be included in the naupliar phase. The hooks of the first antennae and the distal hooks of the maxillae are demonstrated to function not only as attachment organs (to the host), but also to play a significant role in the cleaning of the naupliar swimming appendages. A digital video-based analysis of the swimming mode is provided. The larval swimming pattern is generally similar to that of other crustaceans such as Branchiopoda and Cirripedia, but autapomorphies of the Branchiura include the following: 1) While actively swimming, the naupliar appendages are almost straight during the recovery stroke and 2) they have a relatively small deflection during movement ( approximately 25 degrees or approximately 35 degrees for mandible and second antenna respectively), 3) the larval mandible has a uniramous palp which is the retained exopod. The morphological implications of the transition from the possibly nonfeeding pelagic, or free-swimming, first larval stage to the feeding, parasitic second stage are discussed and compared with other crustaceans. 相似文献
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James E. Milstead 《Journal of invertebrate pathology》1980,35(3):260-264
At 28.5°C, oral dosages of the invasive juveniles of Heterorhabditis bacteriophora and intrahemocoelic injections of its associated bacterium, Xenorhabdus luminescens, resulted in a decrease in larval feeding rate, larval wet weight, and frass production in its host, the seventh-instar larvae of Schizura concinna. 相似文献
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Uric acid and urea added to non-crowded cultures of D. Melanogaster are able to reproduce the larval stop (cessation in development) detected in highly competitive situations. The quantitative analysis of media as well as of larvae and pupae reveals the presence of both compounds as natural waste products of nitrogen metabolism in Drosophila. The nature of their effect is discussed in terms of larval intoxication as a mechanism which may account for the effects usually observed in crowded cultures: development delay, lower survival and also larval stop (which can only be detected by interrupting the competitive process by an overfeeding technique). 相似文献
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A comparative study was undertaken of southwestern corn borers (Diatraea grandiosella) collected from south central Mexico (19°N latitude) and southeast Missouri (37°N latitude). All the life stages of the Mexican insects were found to be larger or heavier, or both, than were those of the Missouri insects. Mexican larvae grew at a higher rate and attained a significantly heavier body weight than did Missouri larvae. Although both Mexican and Missouri larvae underwent ecdyses during diapause, Mexican larvae ecdysed more frequently than did the Missouri larvae at 23°C light:dark 12 h:12 h. Larvae that ecdysed most frequently did not necessarily spend longer in diapause. Electrophoresis of the fat body and haemolymph proteins of Mexican and Missouri larvae revealed similar patterns. The fat body of diapausing Mexican larvae contained substantial amounts of a diapause-associated protein which has been characterized previously from the fat body of Missouri Larvae. Double immunodiffusion confirmed that the diapause-associated protein of the Mexican larvae was identical to that present in the Missouri larvae. Smaller amounts of this protein appear to be present in the fat body of diapausing Mexican larvae than are present in that of diapausing Missouri larvae. 相似文献
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This study documents the rearing of two pygmy angelfish species, Centropyge fisheri and Centropyge resplendens, and the early life history and reproduction of their hybrid offspring. A C. fisheri female, collected from Hawaii, and a C. resplendens male, captive‐bred from parental stock collected from Ascension Island, were maintained at the hatchery facility for 7 months. Continuous spawning was achieved at a photoperiod cycle of 14L:10D and a water temperature of 26·5° C, range ±1° C. Over the 110 day period, the C. fisheri female spawned 102 times, 57% of which resulted in embryos (fertilized eggs). The mean ±s.d. fecundity per spawn was 730 ± 459 eggs (range 52–1967). Fertility (% eggs that developed into embryos) of all eggs that were preserved was 22·4 ± 25·6%. A total of 235 hybrid juveniles were raised through metamorphosis with an average larval survival of 16·4%. Eight F1 hybrid juveniles isolated for further study began to display signs of reproductive behaviour c. 300 days post‐hatch (dph). Spawn resulting in non‐fertile eggs were first obtained 319 dph, and fertilized eggs developing into embryos were obtained after 411 dph from at least two female individuals. While no attempt was made at rearing the F2 larvae, embryo and larval development were normal up to 8 dph. Reproduction and development observed for all hybrid generations in this study were normal, similar to other Centropyge species and indicates a very close phylogenetic relationship between what are currently considered distinct species, e.g. C. fisheri and C. resplendens. 相似文献
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In the silkworm, Bombyx mori, apolysis of the spiracle is the first visible sign of the initiation of a larval moult. After spiracular apolysis, the characteristic sequence of new spiracle formation can be recognized easily through the cuticle around the old spiracle. This sequence, called the spiracle index, was used as the basis for a precise developmental chronology of the larval moulting period. At certain spiracle-index stages, histological changes in the larval ventral abdominal integument were also examined. By allatectomy and abdominal ligations, the critical periods for the secretion of juvenile hormone and ecdysone respectively were found to be at the initiation of spiracular apolysis and at the time when general apolysis was complete. The haemolymph-ecdysteroid level as measured by radioimmunoassay was about 30–50 ng/ml during the first 2 days of the 4th instar, 60–70 ng/ml at the time of initiation of spiracular apolysis, and 200 ng/ml at the time of completion of apolysis of the general body surface. The maximal level of the hormone was about 290 ng/ml at the mid-moulting period. The relationship between the ecdysteroid titre and morphological events occurring during the larval moult was discussed. 相似文献
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Abstract. Antibodies against the echinoderm-specific neuropeptide S1 and against 5HT were used to examine the fate of the larval nervous system during metamorphosis in the ophiuroid Ophiactis resiliens . In contrast to most echinoderms, the onset of peptidergic and serotonergic expression was delayed to the advanced ophiopluteus stage, in particular for 5HT. In advanced ophioplutei, peptidergic immunoreactivity was located in simple fibres associated with the ciliated bands, a stomach nerve ring, and cells along the antero-lateral arms. 5HT immunoreactivity was concentrated in 2 oral ganglia in the adoral projections, located at the posterior rim of the mouth. Clusters of 5HT-positive cells were also found along the antero-lateral arms. The ophiopluteus lacked a serotonergic (or peptidergic) anterior ganglion. In echinoids, holothuroids, and crinoids, anterior ganglia are thought to have a sensory role in settlement and metamorphosis. Given that ophioplutei metamorphose in the plankton and that larval structures degenerate before settlement, the absence of apical ganglia correlates with the lack of a functional role for larval structures in substrate selection and settlement. Although most of the larval nervous system degenerated during metamorphosis, the adoral projections and associated oral ganglia appeared to be incorporated into the juvenile mouth, suggesting a potential role for larval neurons in contributing to oral neuronal structures in the adult. S1-positive neurons and fibres in the rudiment developed de novo and in parallel with development of the epineural canal. This structure gives rise to the primordia of the adult circumoral nerve ring and radial nerves, indicating that differentiation of the adult nervous system begins in the early stages of metamorphosis. 相似文献
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The objectives of the present study were to determine if spatial differences existed between zooplankton, larval yellow perch Perca flavescens and bluegill Lepomis macrochirus (<13 mm total length, L(T)) in Pelican Lake (332 ha), NE, U.S.A. It was hypothesized that wind could act as a transport mechanism for larval fishes in this shallow lake, because strong winds are common at this geographic location. Potential spatial differences were explored, relating to zooplankton densities, size structure and densities of larval P. flavescens and L. macrochirus. Density differences (east v. west side of the lake) were detected for small- (two occasions), medium- (two occasions) and large-sized (one occasion) L. macrochirus larvae. No density differences were detected for small P. flavescens larvae; however, densities of medium- and large-sized P. flavescens were each higher on the west side of the lake on two occasions. There was no evidence that larval P. flavescens and L. macrochirus distributions were related to wind because they were not associated with large wind events. Likewise, large wind event days did not result in any detectable spatial differences of larval P. flavescens and L. macrochirus densities. There appeared to be no spatial mismatch between larval densities and associated prey in the years examined. Thus, wind was not apparently an influential mechanism for zooplankton and larval P. flavescens and L. macrochirus transport within Pelican Lake, and spatial differences in density may instead be related to vegetation and habitat complexities or spawning locations within this shallow lake. 相似文献
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This study describes the anatomical and developmental aspects of muscular development from the early embryo to competent larval stage in the gastropod Ilyanassa obsoleta. Staining of F‐actin revealed differential spatial and temporal patterns of several muscles. In particular, two major muscles, the larval retractor and pedal retractor muscles originate independently and display distinct developmental patterns similar to observations in other gastropod species. Additionally, together with the larval retractor muscle, the accessory larval muscle developed in the embryo at the trochophore stage. Therefore, both these muscles develop prior to ontogenetic torsion. The pedal retractor muscle marked the most abundant growth in the mid veliger stage. Also during the middle stage, the metapodial retractor muscle and opercular retractor muscle grew concurrently with development of the foot. We show evidence that juvenile muscles, such as the buccal mass muscle and siphon muscle develop initially during the late veliger stage. Collectively, these findings substantiate that larval myogenesis involves a complex sequence of events that appear evolutionary conserved within the gastropods, and set the stage for future studies using this model species to address issues concerning the evolution and eventual fates of larval musculature in molluscs. J. Morphol., 2009. © 2009 Wiley‐Liss, Inc. 相似文献
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Yuichi Mochizuki 《Invertebrate reproduction & development.》2017,61(3):189-199
Postembryonic developmental stages of an endoparasitic pycnogonid, Ammothella biunguiculata in Izu Peninsula, Japan are described. Eleven stages were identified beginning with a protonymphon larva attached to the male oviger. We found endoparasitic individuals in the host actinian from the second to tenth instar, and forms in the ninth stage to adult were found free-living. This indicates a transition from being endoparasitic to free-living during the ninth to tenth instar stages. The first instar protonymphon attached to the adult male oviger has a gland duct on the anterior margin of each chelifore scape which completely disappears with the second instar. The disappearance of the chelifore gland duct coincides with the beginning of an endoparasitic stage in the development of this species. Although the larval morphology and the postembryonic development of pycnogonids have been summarized by several authors, the present study concludes that much remains to be learnt. 相似文献
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Jose A. Cuesta Guillermo Guerao Christoph D. Schubart Klaus Anger 《Acta zoologica》2011,92(3):225-240
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Chitin synthesis in third-instar Lucilia cuprina larvae cultured at 23 °C was investigated using in vivo and in vitro systems, the latter with whole and with homogenized integuments. Synthesis was at a maximum between 24 and 48h after ecdysis from the second instar. Chitin was deposited in layers, and labeled GlcNAc was rapidly cleared from the hemolymph. In in vitro homogenate systems, the rapid conversion of UDP-([14C]GlcN)Ac to ([14C]GlcN)Ac and its 1-phosphate derivative contributed to the low incorporation of this precursor into chitin. The extent of the conversion was reduced by the addition of KCN or phenylthiourea. In in vivo and in vitro tissue systems the level of incorporation of ([14C]ClcN)Ac was higher than that of UDP-([14C]GlcN)Ac. However, in in vitro homogenate systems there was no difference unless UTP was added when the level of incorporation of only ([14C]GlcN)Ac was increased (by a factor of 9). Incorporation of UDP-([14C]GlcN)Ac, but not that of ([14C]GlcN)Ac, was decreased when larvae were deprived of food. Soluble oligosaccharides were detected in in vitro homogenate systems. They were formed during chitin synthesis and may represent newly initiated chitin chains. A reappraisal of current ideas on chitin synthesis in insects is needed. 相似文献
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Toxicity of gallic acid to melon fruit fly,Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae)
Ruchi Sharma 《Archives Of Phytopathology And Plant Protection》2013,46(17):2043-2050
Melon fruit fly, Bactrocera cucurbitae (Coquillett) is an important pest of cucurbits and other vegetable crops. It is not only a serious pest of cucurbit crops but sometimes also attacks non-host plants. In an endeavour to explore secondary metabolites as important and safe means of pest management, we investigated the effects of gallic acid, a phenolic compound, on the growth and development of melon fruit fly, B. cucurbitae. Larval survival and emergence were severely affected by gallic acid treatment. Both decreased in a concentration dependent manner with increase in concentration. Gallic acid-treated larvae took longer duration to pupate and reach the adult stage as compared to control larvae. Inhibitory effects of gallic acid were also observed on larval weight, pupal weight, mean relative growth rate and food assimilated which decreased with treatment. The ability of gallic acid to disrupt the development of B. cucurbitae suggests that the phenolic compound might have caused oxidative stress in the body of the insect. 相似文献
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Léopold Ghinter Christophe Anderson Dominique Robert Gesche Winkler Louis Bernatchez Céline Audet 《Journal of fish biology》2023,102(3):712-717
Knowledge of the larval ecology of winter-spawning fish from the Estuary and Gulf of St. Lawrence, Canada, remains scarce due to the seasonal ice cover that prevents ichthyoplankton sampling using conventional methods. Two winter-spawning species, Atlantic halibut (AH, Hippoglossus hippoglossus) and Greenland halibut (GH, Reinhardtius hippoglossoides), support the most important groundfish fisheries of this area. In March 2020, the authors captured 10 halibut larvae ranging in size from 5 to 14 mm during an opportunistic survey in the GSL onboard an icebreaking vessel. Of these, eight were AH and two GH. Judging by their very small size, the larvae were only a few days old, suggesting that the spawning grounds are close to the capture sites. This effort constitutes a first step in validating the putative spawning areas for these two important GSL stocks. This knowledge is important for the conservation and sustainable management of these fisheries. 相似文献
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D. H. Williamson † G. P. Jones S. R. Thorrold ‡ A. J. Frisch § 《Journal of fish biology》2009,74(4):891-905
This study examined the toxicological and physiological responses of a commercially important coral-reef grouper, Plectropomus leopardus (Serranidae), to injection of enriched stable-isotope barium chloride (BaCl2 ) solution. Thirty adult P. leopardus were subject to one of two 138 BaCl2 injection treatment groups (corresponding to dosage rates of 2 and 4 mg 138 Ba kg−1 body mass), and a control group in which fish were injected with 0·9% sodium chloride (NaCl) solution. Fish from each group were sampled at post-injection intervals of 48 h and 1, 3, 5 and 8 weeks, at which time blood and tissue samples were removed from each fish. Residual concentrations of Ba and 138 Ba:137 Ba ratios were measured in muscle, gonad, liver and bone tissues of each experimental fish. Elevated Ba concentrations were detected in all treatment fish tissue samples within 48 h post injection. Residual Ba concentrations decreased throughout the remainder of the 8 week experimental period in all tissues except bone. The BaCl2 injection had no significant effects on measured whole blood variables or on the plasma concentrations of steroid hormones. Enriched Ba stable isotopes can therefore be used at low dosages to mark larvae of commercially important marine fishes, without adverse effects on the health of the fishes or on humans who may consume them. 相似文献