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153 records returned

A new use for synchrotron X-ray microtomography: three-dimensional biomechanical modeling of chelicerate mouthparts and calculation of theoretical bite forcesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We present the first report on the use of the non-invasive method of synchrotron X-ray microtomography to model the dynamics and theoretical bite forces of arthropod mouthparts. The nature of the data allowed us to include precise measurements of muscle areas and the spatial geometry of muscle origins and insertions into a biomechanical model of a morphological microstructure. We investigated the functional morphology of the chelicera in the oribatid mite Archegozetes longisetosus (Acari, Oribatida), a model organism for Chelicerata. The chelicera represents a first-class lever; the intrinsic muscular system consists of a ...
Source: Invertebrate Biology - October 30, 2009 Category: Biology Authors: Michael Heethoff, Roy A. Norton Source Type: journals

Morphological changes in the male accessory glands and testes in Vespula vulgaris (Hymenoptera, Vespidae) during sexual maturationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. The present study documents the pace of accessory gland and testes degeneration in the wasp Vespula vulgaris by means of a histological and metric approach, that has not been carried out for social wasps so far. To a certain extent, comparison is made with the degenerative processes of the mucus glands of the honeybee drone. In V. vulgaris, no generative tissue is left by the end of 9 d of age, and so degeneration is a fast process. The three different parts of the accessory glands (muscle layer, gland epithelium, and lumen) change with respect to age. The secretory cells of the epithelium reach their maximum act...
Source: Invertebrate Biology - October 29, 2009 Category: Biology Authors: Lien Moors, Eric Schoeters, Kristien Coudron, Johan Billen Source Type: journals

Can different species of medicinal leeches (Hirudo spp.) interbreed?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. Since the 18th century, the medicinal leech Hirudo medicinalis has been thought to comprise a single species with several different color morphs, but recently some of these color morphs have been assigned to separate species based on morphology, geographical distribution, and molecular sequence data. This research was aimed at testing the ability of three of these species, H. medicinalis, Hirudo verbana, and Hirudo orientalis, to interbreed. We found that in the laboratory, all three species were able to mate with each other and produce hybrid offspring. This suggests that the reproductive isolation is not strong...
Source: Invertebrate Biology - October 29, 2009 Category: Biology Authors: Laima Petrauskienė, Olga Utevska, Serge Utevsky Source Type: journals

A non-lethal method for estimation of gonad and pyloric caecum indices in sea starsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. Gonad and pyloric caecum indices are widely used indicators of reproductive effort and nutritional condition in asteroids. Current methods of quantification generally require sacrificing multiple animals and the resulting reduction in local sea star density could have an unintended impact on benthic communities. Using the intertidal sea star Pisaster ochraceus, we developed and tested a method for estimating organ indices through the non-lethal sampling of single arms. Indices estimated via dissections of single arms accurately predicted the values obtained by sacrificing whole animals. In laboratory and field tr...
Source: Invertebrate Biology - October 29, 2009 Category: Biology Authors: Eric Sanford, Megan E. Wood, Karina J. Nielsen Source Type: journals

Pycnogonid-cnidarian trophic interactions in the deep Monterey Submarine CanyonEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. Whale carcasses, sunken wood, and cold seeps provide organically enriched oases in the food-limited deep-sea benthos. At three such enriched habitats in Monterey Bay, CA, at a depth of nearly 3000 m, we observed pycnogonids (sea spiders) of at least two species, Colossendeis gigas and C. japonica, feeding on sea anemones that were commonly found there. Submersible remotely operated vehicles provided direct observations of feeding, as well as high definition video and photographic images. We recorded the co-occurrence of both pycnogonids and prey anemones during ten of 12 visits during 2002[ndash]2006. Anemones an...
Source: Invertebrate Biology - September 10, 2009 Category: Biology Authors: Caren E. Braby, Vicki B. Pearse, Bonnie A. Bain, Robert C. Vrijenhoek Source Type: journals

Bodyplan diversification in crinoid-associated myzostomes (Myzostomida, Protostomia)Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. When free-living organisms evolve into symbiotic organisms (parasites, commensals, or mutualists), their bodyplan is often dramatically modified as a consequence. The present work pertains to the study of this process in a group of marine obligate symbiotic worms, the Myzostomida. These are mainly ectocommensals and are only associated with echinoderms, mostly crinoids. Their usual textbook status as a class of the Annelida is generally accepted, although recent molecular phylogenetic studies have raised doubts on their relationships with other metazoans, and the question of their status remains open. Here, we re...
Source: Invertebrate Biology - September 3, 2009 Category: Biology Authors: Déborah Lanterbecq, Greg W. Rouse, Igor Eeckhaut Source Type: journals

Shiny spheres of placozoans (Trichoplax) function in anti-predator defenseEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. When individual placozoans, Trichoplax adhaerens, were fed to polyps of the hydroid Podocoryna carnea, the polyps became paralyzed in all 27 trials. In one instance the hydroid polyp died and in five instances a fragment of the placozoan survived. The time to recovery from paralysis varied with the relative size of the polyp and the placozoan. Placozoans were disassociated into separate cells and then reaggregated by centrifugation to produce pellets of tissue lacking the vesicles called shiny spheres, normally abundant in the upper epithelium. We fed pellets of two size classes to the hydroid polyps. When the pl...
Source: Invertebrate Biology - September 2, 2009 Category: Biology Authors: Alexis M. Jackson, Leo W. Buss Source Type: journals

Unusual modes of oogenesis and brooding in bivalves: the case of Gaimardia trapesina (Mollusca: Gaimardiidae)Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. I describe an unusual case of follicular oogenesis in a bivalve, Gaimardia trapesina, a common marine bivalve from the Magellan Region and adjacent Sub-Antarctic waters, whose members brood their developing larvae. The gonad in G. trapesina is an acinus organ that infiltrates the perivisceral connective tissue; the walls of the acini are formed by tall, slender cells with distal nuclei, supported by a thin conjunctive tissue layer. At the onset of vitellogenesis, each developing oocyte becomes surrounded by a one-cell-thick layer of follicle cells, which may originate from the wall of the acinus. The cells form a...
Source: Invertebrate Biology - September 1, 2009 Category: Biology Authors: Cristián Ituarte Source Type: journals

Effects of photoperiod on gluconeogenic activity and total lipid concentration in organs of crabs, Neohelice granulata, challenged by salinity changesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study assessed the effects of long (LD) or short (SD) days on the conversion of [14C]-glycerol to [14C]-glucose and total lipid concentration in organs of the crab Neohelice granulata challenged by a change in external salinity. In the 20[permil]-acclimated crabs, no difference was found in the concentration of total lipids in the muscle, hepatopancreas, gills, or hemolymph between crabs acclimated to SD or LD. In SD crabs, the total lipid levels in the anterior and posterior gills did not decrease during an osmotic challenge. Only in the posterior gills did the total lipid levels decrease during acclimation to the 34...
Source: Invertebrate Biology - September 1, 2009 Category: Biology Authors: Ana Lúcia Fernandes Chittó, Vanessa Schein, Rodrigo Etges, Luiz Carlos Kucharski, Roselis Silveira Martins Da Silva Source Type: journals

The watering pot shell Dianadema minima (Bivalvia, Anomalodesmata, Clavagellidae): re-description and an interpretation of adventitious crypt formationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. Two small cemented, cryptic, species of Dianadema (Bivalvia: Anomalodesmata: Clavagellidae) have been recorded from shallow waters of the Indian Ocean. These are Dianadema minima and Dianadema mascarensis. A study of their shells and adventitious crypt morphologies, however, suggests that the two species are conspecific, the former name taking precedence. This re-description of D. minima suggests that on settlement, the larva develops a juvenile shell that continues to grow until a length of [sim]9.0 mm is reached, when it secretes around itself a primary calcareous crypt and cements itself ventrally into a conca...
Source: Invertebrate Biology - September 1, 2009 Category: Biology Authors: Brian Morton Source Type: journals

Responses to low salinity by the sea star Pisaster ochraceus from high- and low-salinity populationsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study examined the effects of acute salinity changes on sea stars (Pisaster ochraceus) collected from a high-salinity site (Bamfield, BC) and a low-salinity site (Vancouver, BC). Sea stars from both sites were exposed to salinities ranging 15[ndash]30 psu. Following a 24-h exposure, the osmolality, sodium concentrations, and chloride concentrations in the perivisceral fluid all varied directly with salinity and were very close to the treatment salinities in both the Bamfield and Vancouver sea stars. The righting response (measured as an activity coefficient) was salinity dependent, with the lowest activity levels at a...
Source: Invertebrate Biology - September 1, 2009 Category: Biology Authors: Mirjam B.E. Held, Christopher D.G. Harley Source Type: journals

Juxtaligamental system of the disc and oral frame of the ophiuroid Amphipholis kochii (Echinodermata: Ophiuroidea) and its role in autotomyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. The ophiuroid Amphipholis kochii is able to detach its central disc from the underlying oral frame in response to external stimuli. In this article we supply new observations on the microanatomy and ultrastructure of the autotomy plane, and of the juxtaligamental system which is believed to bring about connective tissue changes that underpin the detachment process. We correct previous confusion over the innervation of juxtaligamental nodes involved in disc autotomy, provide evidence that juxtaligamental cells are a population of specialized nerve cells, and present observations on changes in the ultrastructure of...
Source: Invertebrate Biology - April 18, 2009 Category: Biology Authors: Natalia A. Charlina, Igor Yu. Dolmatov, Iain C. Wilkie Source Type: journals

Ectaquasperm-like parasperm in an internally fertilizing gastropodEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. Pomacea canaliculata is an internally fertilizing gastropod that produces, besides fertilizing sperm (=eusperm), a large number of unfertile sperm (=parasperm) that have no chromatin, are fusiform, and have three to five flagella. Here, we report that this snail also produces another type of parasperm, which results from a peculiar spermiogenesis including an anterior cytoplasmic migration. The mature oligopyrene parasperm has: (1) a rounded head including a partly lysed nucleus, (2) a conical mid-piece with eight large mitochondrial structures, and (3) a single flagellum ([sim]20 [mu]m). These characteristics, a...
Source: Invertebrate Biology - April 15, 2009 Category: Biology Authors: Beatriz C. Winik, Marta Catalán, Carlos Gamarra-Luques, Alfredo Castro-Vazquez Source Type: journals

Effect of seawater temperature on reproductive seasonality and fecundity of Pseudoplexaura porosa (Cnidaria: Octocorallia): latitudinal variation in Caribbean gorgonian reproductionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. The majority of tagged colonies of Pseudoplexaura porosa in Bermuda were reproductive over 2 months in the summer. They spawned 5[ndash]8 d after the full moon, with a peak on the sixth day, similar to colonies in Panama. The months of spawning were August and September in 1998, but July and August in 1999 and 2000. This temporal difference between the months of spawning corresponded to inter-annual variations in seawater temperature profiles. Initial gamete development each year occurred only when the daily mean seawater temperature during the month before spawning exceeded 27°C. There was a significant positiv...
Source: Invertebrate Biology - April 11, 2009 Category: Biology Authors: Samantha J. de Putron, John S. Ryland Source Type: journals

Sperm transfer, sperm storage, and sperm digestion in the hermaphroditic land snail Succinea putris (Gastropoda, Pulmonata)Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. Many hermaphroditic species are promiscuous, have a sperm digesting organ and an allosperm storage organ (i.e., spermatheca) with multiple compartments (i.e., spermathecal tubules) providing opportunities for sperm competition. The relative paternity of a sperm donor drives the evolution of mating behaviors that allow manipulation of the sperm receiver's reproductive behavior or physiology. We studied the relationship between sperm transfer, sperm storage, sperm digestion, and copulation duration in the hermaphroditic land snail Succinea putris, in which an active individual mates on top of a passive individual. ...
Source: Invertebrate Biology - March 31, 2009 Category: Biology Authors: Lobke Dillen, Kurt Jordaens, Thierry Backeljau Source Type: journals

Behavioral and morphological aspects of decorating in Oregonia gracilis (Brachyura: Majoidea)Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We describe these pappose setae and document the occurrence of similar setae in 36 other decorating majoids across seven families. In O. gracilis, the density of pappose and hooked setae independently covary with decoration amount, which is sexually dimorphic[mdash]juveniles and adult females decorate heavily, whereas adult males decorate sparsely. Adult males have reduced numbers of hooked and pappose setae, but the ontogenetic patterns for the two setal types are different, suggesting that they are quasi-independent characters. We experimentally ablated pappose setae to ask if they functionally contribute to decorating i...
Source: Invertebrate Biology - March 31, 2009 Category: Biology Authors: Sarah K. Berke, Sarah A. Woodin Source Type: journals

Digestive system of larval black flies (Diptera: Simuliidae): structure and phylogenyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. Larval gut characters of 45 species of black flies, representing 17 subgenera and 15 genera, were studied for their utility in taxon diagnosis and phylogenetic inference. Phase-contrast and scanning electron microscopy revealed a wealth of new characters in the esophageal armature of the foregut. Larval gut morphology, particularly characters of the esophageal armature, varied significantly among taxa, permitting generic diagnoses. A cladogram inferred from 13 gut characters supported a sister-group relationship between Parasimulium and the remaining simuliids, but did not show a strong phylogenetic signal for th...
Source: Invertebrate Biology - March 31, 2009 Category: Biology Authors: Sam-Kyu Kim, Peter H. Adler Source Type: journals

Life history and habitat requirements of the Oregon forestsnail, Allogona townsendiana (Mollusca, Gastropoda, Pulmonata, Polygyridae), in a British Columbia populationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. Population size, reproductive timing and habitats, seasonal behaviors, and juvenile activity were assessed in a British Columbia population of the endangered Oregon forestsnail, Allogona townsendiana, over a period of 4 years. Adult snail population size ranged from seven to 47 snails in four × 24-m2 sampling sites. The mating period peaked in March and April; adults aggregated in clusters of eight to 14 snails before mating. Pairs of snails were observed to mate for 225 min or more in close proximity to coarse woody debris and stinging nettle, Urtica dioica. Nesting peaked in April[ndash]May and resulted in a m...
Source: Invertebrate Biology - March 31, 2009 Category: Biology Authors: Karen M.M. Steensma, Patrick L. Lilley, Heather M. Zandberg Source Type: journals

Commensalism used by freshwater crayfish species to survive drying in seasonal habitatsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study indicates that members of G. insolitus are commensal upon larger crayfish species, using their burrows to survive the seasonal drying of their habitat. Conservation strategies for populations of G. insolitus will need to consider co-existing species of burrowing crayfish. (Source: Invertebrate Biology)
Source: Invertebrate Biology - March 31, 2009 Category: Biology Authors: Kerrylyn Johnston, Belinda J. Robson Source Type: journals

Allelic inheritance in naturally occurring parthenogenetic offspring of the gonochoric sea star Patiria miniataEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. In laboratory studies of fertilization using the gonochoric broadcast-spawning asterinid sea star Patiria miniata, we found many cases in which some mature eggs spawned by females formed cleavage-stage embryos and feeding bipinnaria larvae without fertilization by sperm. Segregation of maternal microsatellite alleles among the parthenogenetic offspring of known heterozygous females was consistent with several specific modes of asexual reproduction, including polar body suppression. Cryptic outcrossing by sperm contamination was ruled out by the failure to observe non-maternal alleles. The potential for asexual re...
Source: Invertebrate Biology - March 13, 2009 Category: Biology Authors: Jennifer Sunday, Lisa Raeburn, Heather Stewart, Michael W. Hart Source Type: journals

Assessment of rampant genitalic variation in the spider genus Homalonychus (Araneae, Homalonychidae)Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, geometric morphometric analysis employing landmark data is used to quantify both intra- and interspecific variation in this genus. The large amount of variation is condensed into two or three groups depending on the structures examined, and these groups correspond to either the two species or to previously established mitochondrial DNA clades within one of the species. The results also show that analyses of female structures do not separate the groups as readily as the analyses of the male structures. The large amount of variation present in some structures is not correlated with geography or population gene...
Source: Invertebrate Biology - March 11, 2009 Category: Biology Authors: Sarah C. Crews Source Type: journals

Polyfluorochrome marking slows growth only during the marking month in the green sea urchin Strongylocentrotus droebachiensisEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We present a new method of tagging using sequential fluorochrome markers, as well as a more precise method of quantifying growth. Such polyfluorochromes enable repeated markings that allow measurement of multiple growth points and unique identification of individuals or groups. We marked sea urchins, Strongylocentrotus droebachiensis, with four fluorochromes: alizarin complexone, calcein, calcein blue, and tetracycline. All fluorochromes marked both by injection and immersion. We examined the clarity of the mark produced with low, metabolically scaled doses, and higher doses similar to those that have been previously used....
Source: Invertebrate Biology - March 11, 2009 Category: Biology Authors: Olaf Ellers, Amy S. Johnson Source Type: journals

Hatching and earliest larval stages of the priapulid worm Priapulus caudatusEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. Here we describe the hatching and morphology of the earliest larval stages of the priapulid worm Priapulus caudatus for the first time. The hatching larva differs considerably from previously described larvae not only in its general body shape but also in its lack of a proper lorica including the typical lorica tubuli. Furthermore, no mouth opening or pharyngeal teeth have formed as yet, and the number and arrangement of scalids differ from that of later larvae. The hatching larva molts and emerges as the first lorica larva. This larva partially resembles earlier described lorica larvae, but there are a number of...
Source: Invertebrate Biology - March 11, 2009 Category: Biology Authors: Sofia A. Wennberg, Ralf Janssen, Graham E. Budd Source Type: journals

Comparing fecundity in parthenogenetic versus sexual populations of the freshwater snail Campeloma limum: is there a two-fold cost of sex?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. The predominance of sexuality in eukaryotes remains an evolutionary paradox, given the "two-fold cost of sex" of sex also known as the "cost of males." As it requires two sexual parents to reproduce and only one parthenogenetic parent, parthenogens should have twice the reproductive rate compared with their sexual counterparts and their genes should spread twice as fast, if all else is equal. Yet, parthenogenesis is relatively rare and considered an evolutionary dead-end, while sexuality is the dominant form of reproduction in multicellular eukaryotes. Many studies have explored short-term benefits of sex that co...
Source: Invertebrate Biology - January 30, 2009 Category: Biology Authors: Lisa T. Crummett, Marta L. Wayne Source Type: journals

Ascidian tunic cells: morphology and functional diversity of free cells outside the epidermisEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. Tunic cells are free cells distributed in the tunic, the integumentary matrix of tunicates. In ascidians, various types of tunic cells have been described both in solitary and in colonial species. Many of them are functionally specialized and are related to the protection of the animal, such as phagocytosis to prevent infection, acid storage to avoid predation, and pigmentation to protect against solar radiation. While some tunic cells are known to play a role in colonial allorecognition, bioluminescence, and algal symbiosis, the functional roles of many cell types still remain to be determined. The composition o...
Source: Invertebrate Biology - January 6, 2009 Category: Biology Authors: Euichi Hirose Source Type: journals

Internal and secreted bioluminescence of the marine polychaete Odontosyllis phosphorea (Syllidae)Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. The syllid polychaete Odontosyllis phosphorea produces brilliant displays of green bioluminescence during mating swarms. We studied freshly collected individuals of O. phosphorea in the laboratory to understand the characteristics of its luminescent system. Light emission appeared as an intense glow after stimulation with potassium chloride, and was associated with secreted mucus. The mucus was viscous, blue in color, and exhibited a long-lasting glow that was greatly intensified by addition of peroxidase or ammonium persulfate. The emission spectrum of mucus-associated bioluminescence was unimodal, with a maximu...
Source: Invertebrate Biology - January 5, 2009 Category: Biology Authors: Dimitri D. Deheyn, Michael I. Latz Source Type: journals

Discriminatory predation by three invertebrates on eastern oysters (Crassostrea virginica) compared with non-native Suminoe oysters (C. ariakensis)Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. Diminished populations of eastern oysters Crassostrea virginica in Chesapeake Bay have stimulated proposals to introduce Crassostrea ariakensis from Asia to restore oyster stocks. As part of a program evaluating possible ramifications of such an introduction, we studied how invertebrate predators responded to this non-native oyster. We compared predation activity under laboratory conditions by oyster drills (Urosalpinx cinerea; Eupleura caudata) that bore through an oyster's shell and by the seastar Asterias forbesi that pulls shell valves apart. These three predators preyed significantly (p (Source: Invertebrate Biology)
Source: Invertebrate Biology - January 5, 2009 Category: Biology Authors: Victor S. Kennedy, Kristi S. Shaw, Roger I.E. Newell Source Type: journals

Microsatellite inheritance and multiple paternity in the deep-sea octopus Graneledone boreopacifica (Mollusca: Cephalopoda)Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. Octopodids are a globally distributed group of marine molluscs. Despite this, our knowledge of their reproductive biology rests heavily on inference, as all phases of copulation, beginning with sperm transfer, occur within the mantle cavity. Male octopuses insert a spermatophore into the female's oviduct, which is predicted to release a sperm-filled sac that either bursts to release sperm for storage or to itself be stored in a gland in the middle of the oviduct. To test whether female octopuses use sperm from multiple males to fertilize their eggs, as may be predicted from anatomy and anecdotal accounts, we appl...
Source: Invertebrate Biology - January 5, 2009 Category: Biology Authors: Janet R. Voight, Kevin A. Feldheim Source Type: journals

Role of LSM34/SpSM50 proteins in endoskeletal spicule formation in sea urchin embryosEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. Sea urchin embryos form an endoskeletal spicule composed of calcium carbonate and occluded matrix proteins. The accumulation of the LSM34 spicule matrix protein in embryos of Lytechinus pictus (and its ortholog, SpSM50, in Strongylocentrotus purpuratus) has been inhibited using morpholino antisense oligonucleotides. The inhibition, using relatively high levels of antisense reagent, can result in the complete absence of spicules, and the complete loss of immunoreactive LSM34/SpSM50, as judged by immunostaining and Western blotting. Primary mesenchyme cells (PMCs) do form and express PMC-specific cell surface antig...
Source: Invertebrate Biology - October 1, 2008 Category: Biology Authors: Fred Wilt, Lindsay Croker, Christopher E. Killian, Kent McDonald Source Type: journals

Development of the female reproductive system in the freshwater crayfish Cherax quadricarinatus (Decapoda, Parastacidae)Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. The differentiation of the female reproductive system from a macroscopic and microscopic point of view was studied in Cherax quadricarinatus. For this characterization, 184 females were dissected and processed for the histological analysis. From the differentiation of the ovary up to its maturity, three ovarian morphotypes could be distinguished macroscopically: parallel strands without any contact between them, an H-shaped ovary, and a Y-shaped ovary. These morphotypes were compared within the Astacida. Four ovarian developmental stages were recognized based on ovary color, and the histological structure and rel...
Source: Invertebrate Biology - September 30, 2008 Category: Biology Authors: Fernanda J. Vazquez, Carolina Tropea, Laura S. López Greco Source Type: journals

Ultrastructural features of the trophonema and oogenesis in the starlet sea anemone, Nematostella vectensis (Edwardsiidae)Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. The starlet sea anemone, Nematostella vectensis Stephenson 1935, is a burrowing, estuarine species that has become a model organism for fundamental studies of cnidarian and metazoan development. During early oogenesis, oocytes appear in the basal region of the gastrodermis in the reproductive mesenteries and gradually bulge into the adjacent connective tissue space (mesoglea) where the majority of oocyte growth and vitellogenesis occurs. However, oocytes do not physically contact the cellular and amorphous matrix of the mesogleal compartment due to a thin, intervening basal lamina. Oocytes retain limited contact ...
Source: Invertebrate Biology - August 19, 2008 Category: Biology Authors: Kevin J. Eckelbarger, Cadet Hand, Kevin R. Uhlinger Source Type: journals

Magnetic resonance imaging of live freshwater mussels (Unionidae)Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We examined the soft tissues of live freshwater mussels, Eastern elliptio Elliptio complanata, via magnetic resonance imaging (MRI), acquiring data with a widely available human whole-body MRI system. Anatomical features depicted in the profile images included the foot, stomach, intestine, anterior and posterior adductor muscles, and pericardial cavity. Noteworthy observations on soft tissue morphology included a concentration of lipids at the most posterior aspect of the foot, the presence of hemolymph-filled fissures in the posterior adductor muscle, the presence of a relatively large hemolymph-filled sinus adjacent to t...
Source: Invertebrate Biology - August 13, 2008 Category: Biology Authors: F. Michael Holliman, Denise Davis, Arthur E. Bogan, Thomas J. Kwak, W. Gregory Cope, Jay F. Levine Source Type: journals

Central nervous system and sense organs, with special reference to photoreceptor-like sensory elements, in Polygordius appendiculatus (Annelida), an interstitial polychaete with uncertain phylogenetic affinitiesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. The phylogenetic position of Polygordius is still pending; relationships with either Opheliidae or with Saccocirrus are the most favored hypotheses. The present study of Polygordius appendiculatus was designed to look for morphological characters supporting either of these two hypotheses. The homology of the anterior appendages, and the structure of the central nervous system and nuchal organ all required clarification; we also examined whether photoreceptor-like sense organs exist in adults. From their innervation pattern, it is likely that the anterior appendages represent palps. They lack structures typical of...
Source: Invertebrate Biology - July 13, 2008 Category: Biology Authors: Verena Wilkens, Günter Purschke Source Type: journals

Characterization of the sexual pattern of Parastacus varicosus (Crustacea: Decapoda: Parastacidae)Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. Freshwater crayfishes of the genus Parastacus are intersex, i.e., show characteristics of both sexes in the same individual; also, intersexuality has been documented in hermaphroditic species. The aim of this study was to analyze the gonads of Parastacus varicosus, characterizing its sexual pattern. The animals were collected at Cova do Touro, Gravataí, Rio Grande do Sul, Brazil. Three sexual forms were identified: intersex females, intersex males, and transitional specimens showing an ovotestes gonad that could only be identified by means of histological analysis. All specimens had two pairs of gonopores and go...
Source: Invertebrate Biology - July 10, 2008 Category: Biology Authors: Daiana da Silva-Castiglioni, Laura López Greco, Guendalina Turcato Oliveira, Georgina Bond-Buckup Source Type: journals

Ultrastructure of the tegument of the cestode Paraechinophallus japonicus (Bothriocephalidea: Echinophallidae), a parasite of the bathypelagic fish Psenopsis anomalaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Invertebrate Biology, Volume 0, Issue 0, Page ???, OnlineEarly Articles. Abstract. The ultrastructure of the tegument in Paraechinophallus japonicus (Bothriocephalidea: Echinophallidae), a cestode parasite of the bathypelagic fish Psenopsis anomala, was studied using scanning and transmission electron microscopy. ... (Source: Invertebrate Biology)
Source: Invertebrate Biology - May 5, 2008 Category: Biology Tags: article Source Type: journals

Distribution of cells containing FMRFamide-related molecules in the embryonic development of Ophryotrocha labronica (Polychaeta: Dorvilleidae)Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Invertebrate Biology, Volume 0, Issue 0, Page ???, OnlineEarly Articles. Abstract. The timing and spatial distribution of cells containing FMRFamide-related molecules in the embryogenesis of the polychaete Ophryotrocha labronica were studied immunocytochemically. FMRFamide-like molecules emerge early during embryonic ... (Source: Invertebrate Biology)
Source: Invertebrate Biology - May 5, 2008 Category: Biology Tags: article Source Type: journals

Relationships between body size and sound-producing structures in crickets: do large males have large harps?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Invertebrate Biology, Volume 0, Issue 0, Page ???, OnlineEarly Articles. Abstract. Male crickets produce conspicuous acoustic signals to attract mates and deter potential rivals. These signals are created when a male cricket closes his wings rapidly and a file and scraper mechanism causes several areas of the wing to ... (Source: Invertebrate Biology)
Source: Invertebrate Biology - May 5, 2008 Category: Biology Tags: article Source Type: journals

Telotroch formation, survival, and attachment in the epibiotic peritrich Zoothamnium intermedium (Ciliophora, Oligohymenophorea)Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Invertebrate Biology, Volume 0, Issue 0, Page ???, OnlineEarly Articles. Abstract. Aspects of the life cycle of the peritrich ciliate Zoothamnium intermedium, an epibiont on calanoid copepods in the Chesapeake Bay, were investigated using host and epibiont cultures. Experiments were designed to characterize the formation, ... (Source: Invertebrate Biology)
Source: Invertebrate Biology - May 5, 2008 Category: Biology Tags: article Source Type: journals

Seasonal reproduction and sexual maturity in Odontocymbiola magellanica (Neogastropoda, Volutidae)Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Invertebrate Biology, Volume 0, Issue 0, Page ???, OnlineEarly Articles. Abstract. Members of Odontocymbiola magellanica (Volutidae, Odontocymbiolinae) inhabit Argentinean waters from 35°S to the Magallanes Strait. The reproductive biology of this potential fishery resource has not been studied before. Male individuals reach ... (Source: Invertebrate Biology)
Source: Invertebrate Biology - May 5, 2008 Category: Biology Tags: article Source Type: journals

Function of the flexible periostracal hairs in Trichotropis cancellata (Mollusca, Gastropoda)Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Invertebrate Biology, Volume 0, Issue 0, Page ???, OnlineEarly Articles. Abstract. The marine snail Trichotropis cancellata possesses hairy projections of periostracum (outer shell layer) whose function is unknown. Although rigid shell projections in molluscs have been studied extensively, the selective advantage of flexible ... (Source: Invertebrate Biology)
Source: Invertebrate Biology - May 5, 2008 Category: Biology Tags: article Source Type: journals

Secretory products of the haptoral reservoirs and peduncular glands in two species of Bravohollisia (Monogenea: Ancyrocephalidae)Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Invertebrate Biology, Volume 0, Issue 0, Page ???, OnlineEarly Articles. Abstract. Light and electron microscopy were used to characterize the structure of secretory cells and their products involved in attachment of two monogenean parasites of fish, in order to understand their role in the attachment process. In ... (Source: Invertebrate Biology)
Source: Invertebrate Biology - April 30, 2008 Category: Biology Tags: article Source Type: journals

Cotylea (Polycladida): a cladistic analysis of morphologyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Invertebrate Biology, Volume 0, Issue 0, Page ???, OnlineEarly Articles. Abstract. Polyclad flatworms are acoelomate bilaterians found in benthic communities worldwide, predominantly in marine environments. Current polyclad systematics is unstable, with two non-concordant classification schemes resulting in a poor ... (Source: Invertebrate Biology)
Source: Invertebrate Biology - April 29, 2008 Category: Biology Tags: article Source Type: journals

Reproductive behavior of intersexes of an intertidal amphipod Corophium volutatorEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Invertebrate Biology, Volume 0, Issue 0, Page ???, OnlineEarly Articles. Abstract. Intersexes are common in crustaceans. Typically, these intersexes are sterile or function as females, but prior evidence from laboratory experiments suggests that intersexes of a key species of gammaridean amphipod, Corophium volutator, might ... (Source: Invertebrate Biology)
Source: Invertebrate Biology - April 29, 2008 Category: Biology Tags: article Source Type: journals

Larval development of the featherstar Aporometra wilsoni (Echinodermata: Crinoidea)Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Invertebrate Biology, Volume 0, Issue 0, Page ???, OnlineEarly Articles. Abstract. Larval development of a small ovoviviparous comatulid crinoid, Aporometra wilsoni, was investigated using a population from South Australia. The genital pinnules of reproductive females each contain an ovary, within which are oocytes of ... (Source: Invertebrate Biology)
Source: Invertebrate Biology - April 29, 2008 Category: Biology Tags: article Source Type: journals

Parasitic mites influence fitness components of their host, the land snail Arianta arbustorumEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Invertebrate Biology, Volume 0, Issue 0, Page ???, OnlineEarly Articles. Abstract. Parasites can influence the population dynamics of their hosts by affecting life-history strategies and behavior. The hematophageous mite Riccardoella limacum lives in the lung cavity of terrestrial gastropods. We used correlational and ... (Source: Invertebrate Biology)
Source: Invertebrate Biology - April 29, 2008 Category: Biology Tags: article Source Type: journals

The parasitic polychaete known as Asetocalamyzas laonicola (Calamyzidae) is in fact the dwarf male of the spionid Scolelepis laonicola (comb. nov.)Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Invertebrate Biology, Volume 0, Issue 0, Page ???, OnlineEarly Articles. Abstract. The morphology of the obligately ectoparasitic polychaete Asetocalamyzas laonicola was studied by light and electron microscopy, and its taxonomic position was determined using molecular methods. The parasite has an extensive coelomic cavity, ... (Source: Invertebrate Biology)
Source: Invertebrate Biology - April 29, 2008 Category: Biology Tags: article Source Type: journals

Nutritional physiology and colony form in Podocoryna carnea (Cnidaria: Hydrozoa)Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Invertebrate Biology, Volume 0, Issue 0, Page ???, OnlineEarly Articles. Abstract. We compared growth rates and final morphological states of the athecate colonial hydroid Podocoryna carnea in two nutritional environments: one varying the quantity of food provided at a fixed interval and the second varying the time between ... (Source: Invertebrate Biology)
Source: Invertebrate Biology - April 29, 2008 Category: Biology Tags: article Source Type: journals

Differences in reproductive timing among sponges sharing habitat and thermal regimeEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Invertebrate Biology, Volume 0, Issue 0, Page ???, OnlineEarly Articles. Abstract. The reproductive cycles of four Mediterranean demosponges (Axinella damicornis, Corticium candelabrum, Raspaciona aculeata, and Chondrosia reniformis) were investigated during 2 consecutive years. Three of the species had annual gametogenic ... (Source: Invertebrate Biology)
Source: Invertebrate Biology - April 15, 2008 Category: Biology Tags: article Source Type: journals

Sexual dimorphism in the compound eye of the moth Operophtera brumata (Lepidoptera, Geometridae)Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This article examines the eyes of the moth Operophtera brumata, in which only the males have wings. Both sexes possess eyes of the superposition type, have facets with corneal nipples, and ... (Source: Invertebrate Biology)
Source: Invertebrate Biology - April 15, 2008 Category: Biology Tags: article Source Type: journals

Size-dependent sex allocation and sexual selection in Aplysia kurodai, a hermaphrodite with nonreciprocal matingEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Invertebrate Biology, Volume 0, Issue 0, Page ???, OnlineEarly Articles. Abstract. For simultaneous hermaphrodites, a male-to-female shift in sex allocation with growth, and weak sexual selection on the male function, is predicted by many theories, although empirical data for both predictions are insufficient for internally ... (Source: Invertebrate Biology)
Source: Invertebrate Biology - April 15, 2008 Category: Biology Tags: article Source Type: journals