Role of larval release pheromones and peptide mimics in abdominal pumping and swimming behavior of ovigerous blue crabs, Callinectes sapidus (original) (raw)
Related papers
Larval release behaviors in the blue crab Callinectes sapidus: role of chemical cues
Journal of Experimental Marine Biology and Ecology, 2002
Egg hatching by brachyuran crabs is often precisely timed relative to environmental cycles and may be controlled by the female, the developing embryos, or both. The current conceptual model for larval release in subtidal brachyuran crabs is that the exact time of release is controlled by the developing embryos. At the time of hatching, the eggs release pheromones that induce stereotypic larval release behaviors in ovigerous females consisting of rapid abdominal pumping. This behavior breaks open the eggs and results in synchronized hatching. To test this model, we examined the role of pheromone substances released by developing and hatching eggs in initiating this pumping behavior in ovigerous blue crabs Callinectes sapidus. Pumping behavior was used as a bioassay to determine if pumping activity changes with the developmental state of the eggs and to test the response of ovigerous crabs to (1) substances released by hatching eggs (hatch water), (2) substances present in homogenized eggs containing early-and late-stage embryos (homogenized egg water), and (3) substances released by developing eggs containing early-and late-stage embryos (egg conditioned water). Pumping activity associated with egg maintenance increased with embryo development. Pumping activity increased with increasing concentration of hatch water and the threshold concentrations for females possessing early-and late-stage eggs were similar. Water containing homogenized eggs also evoked larval release behaviors and response thresholds were the same for females exposed to early-and late-stage egg treatments. Egg conditioned water prepared from eggs containing late-stage embryos was more potent than water prepared from eggs with earlystage embryos. Collectively, these results support the model that larval release in C. sapidus is controlled by pheromones released from hatching eggs and indicate that (1) the responsiveness of ovigerous C. sapidus to the pheromones is relatively independent of the stage of embryo development, (2) homogenates of both early-and late-stage eggs contain similar pheromone
Larval Release Rhythms and Larval Behavior of Palinurid Lobsters: A Comparative Study
2000
This dissertation investigated larval release and larval behavior of the Caribbean spiny lobster Panulirus argus and the spotted spiny lobster P. guttatus. These species were examined under laboratory conditions to determine the phase relationship between larval release and natural environmental cycles. P. argus displayed a nocturnal tidal rhythm, while P. guttatus displayed a circadian rhythm in larval release. P. argus releases larvae near the time of nocturnal high slack water, while P. guttatus released larvae near the time of sunrise.
Chemical Mediation of Larval Release Behaviors in the Crab Neopanope sayi
The Biological Bulletin, 1991
Control of egg hatching was investigated in ovigerous females of the crab Neopanope sayi. Larval release is a brief event, generally lasting less than 15 min, during which females perform stereotypic behaviors involving vigorous abdomen pumping. Substances released by hatching eggs (pumping factors) of N. sayi, Rhithropanopeus harrisii, and Uca pugilator, but not Sesarma cinereum, evoked these stereotypic behaviors (pumping response) in ovigerous N. sayi. Spontaneous pumping and responsiveness to pumping factors varied with the age of the embryos. These results indicate that the eggs release pheromones around the time of hatching, which supports the general model for egg-hatching control described for R. harrisii (Forward and Lohmann, 1983). The chemistry of N. sayi pumping factors was investigated, and the pumping response was used as a bioassay in this study. Pumping factors adsorbed to Amberlite XAD-7 resin and could be eluted from it with methanol. Size fractionation by cascade pressure dialysis showed that the active molecules were < 1000 daltons. Acid hydrolysis followed by reverse-phase HPLC amino acid analysis showed that the biologically active fraction contained peptides. Cysteine, glycine, methionine, and isoleucine were the four most common amino acids in these peptides. The responsiveness of N. sayi to hatch water from R. harrisii, the general similarity of adsorptive characteristics of hatch waters from the two species toward XAD-7 resin, and the amino acid compositional analysis suggest that the pumping factors from both species are similar. This supports the hypothesis that N. sayi pumping factors are also small peptides, as was suggested for those of R. harrisii (Rittschof et al., 1985, 1989).
Control of larval release in the Caribbean spiny lobster, Panulirus argus: role of chemical cues
Marine Biology, 2007
The current model for larval release in subtidal crustaceans suggests that hatching time is controlled by the embryos, which release a pheromone that stimulates the parent female to undergo behaviors that synchronize larval release. Alternatively, hatching could be controlled by the females. Ovigerous spiny lobsters Panulirus argus (Latreille) exhibit stereotypic behaviors during larval release, including rapid abdominal extensions and pleopod-pumping activity. Ovigerous P. argus were collected from coral reefs in the Florida Keys, USA during the summers of 2005 and 2006. Pleopod-pumping activity was quantiWed to determine if a female's pumping activity correlates with the developmental state of the embryos. The role of pheromones released by developing and hatching embryos in controlling pumping behaviors was tested by measuring the pumping response of ovigerous lobsters to (1) hatch water, (2) homogenized embryo water, (3) embryo-conditioned water (unhatched late-stage embryos soaked for 20 h), and (4) water containing homogenized post-hatch embryo cases. Bioassays were conducted under constant conditions (dim-red light) in the laboratory at random times during the day to control for any possible rhythm in pumping activity. Spontaneous pleopod-pumping activity increased signiWcantly with increasing embryo development. Upon exposure to hatch water, ovigerous lobsters with late-stage embryos displayed increased pleopod pumping with increased treatment concentration. Water individually conditioned with homogenized late-stage embryos, intact late-stage embryos, and homogenized post-hatch embryo cases all induced larval release behaviors in females with late-stage embryos. Ovigerous females with early-stage embryos did not respond to water conditioned with homogenized early-or late-stage embryos. These results suggest that active substances are released by embryos at the time of hatching and induce the stereotypical pumping behaviors of the female that synchronizes larval release. The results support the model that larval release in subtidal crustaceans is controlled by pheromones released from hatching embryos.
Journal of Chemical Ecology, 1990
Studies of crab egg hatching and larval release behavior in the crab, Rhithropanopeus harrisii, generated a model describing the process. In the model, carboxyl terminal arginine peptides serve as pheromones that synchronize larval release. In response to the peptides, the female performs stereotypic larval release behavior and casts larvae into the water column. The peptides originate from trypsin-like enzymatic activity as part of the egghatching process. Hatching can be simulated experimentally by incubating ovigerous crabs in either bovine or porcine trypsin. The female performs the larval release behavior. Eggs detach from the female, and immobile larvae hatch prematurely. Preincubation of trypsin with trypsin inhibitors eliminates these effects. Approximately nanomolar concentrations of five different polypeptide trypsin inhibitors evoke the female's larval release behavior. Because both peptides and trypsin inhibitors evoke larval release behavior and because trypsin inhibitors bind to both the peptide receptor and the enzyme with high affinity, the receptor binding site and trypsin catalytic site must be very similar. A relationship between the binding site of a peptide receptor and the catalytic site of trypsin is postulated. The difference may be substitution by a basic amino acid for the catalytic site serine. Molecular graphics modeling indicates that all necessary conditions for receptor binding can be met by substitution with lysine for the active site serine in the trypsin catalytic site. This substitution eliminates catalytic activity, maintains the binding affinity for trypsin inhibitors, and increases binding strength for peptides.
Journal of experimental zoology. Part A, Comparative experimental biology, 2006
Hatching of embryos in the estuarine crab Sesarma haematocheir is highly synchronized with nocturnal high tide and completes within 1 hr among all embryos incubated by the female. This highly synchronized hatching is induced by a "Hatching-Program Inducing Factor (HPIF)" released from the female. To further define the cues involved in synchronized hatching, experiments were designed to characterize this factor and to determine possible sites of release and temporal release patterns using strategies involving isolation of egg masses, perfusion, and ablation experiments on fully developed embryos that had not yet entered the hatching program. Embryo transplantations indicate that not only HPIF may be released from the branchial chamber, but that it is extraordinarily unstable, and loses activity within 15 min, which frustrates further attempts at characterization. Nevertheless, with regard to temporal release patterns, it was established that HPIF activity was detected durin...
The Journal of experimental biology, 2014
Female blue crabs (Callinectes sapidus) in their pubertal moult stage release unidentified sex pheromone molecules in their urine, causing males to respond with courtship behaviours including a display called courtship stationary paddling and a form of precopulatory guarding called cradle carry. We hypothesized that pheromones are mixtures of molecules and are more concentrated in urine of pubertal premoult females compared with other moulting stages and thus that these molecules are biomarkers (i.e. metabolites that can be used as an indicator of some biological state or condition) of pubertal premoult females. We tested this hypothesis by combining bioassay-guided fractionation and biomarker targeting. To evaluate the molecular mass of the putative pheromone by bioassay-guided fractionation, we separated urine from pubertal premoult females and intermoult males by ultrafiltration into three molecular mass fractions. The <500 Da fraction and the 500-1000 Da fraction but not the >1000 Da fraction of female urine induced male courtship stationary paddling, but none of the fractions of male urine did. Thus, female urine contains molecules of <1000 Da that stimulate courtship behaviours in males. Biomarker targeting using nuclear magnetic resonance (NMR) spectral analysis of the 500-1000 Da fraction of urine from premoult and postmoult males and females revealed a premoult biomarker. Purification, nuclear magnetic resonance, mass spectrometry and high pressure liquid chromatography analysis of this premoult biomarker identified it as N-acetylglucosamino-1,5-lactone (NAGL) and showed that it is more abundant in urine of premoult females and males than in urine of either postmoult or juvenile females and males. NAGL has not been reported before as a natural product or as a molecule of the chitin metabolic pathway. Physiological and behavioural experiments demonstrated that blue crabs can detect NAGL through their olfactory pathway. Thus, we hypothesize that NAGL is a component of the sex pheromone and that it acts in conjunction with other yet unidentified components.
Pheromones inhibit the hatching of diapausing Anostraca (Crustacea: Branchiopoda
Hatching of resting eggs of Streptocephalus torvicornis (Waga, 1942) and Branchipus schaefferi Fischer, 1834, two sympatric fairy shrimps, was tested using medium in which these two species and Chirocephalus diaphanus (Prévost, 1803) had been raised. The medium of adults inhibited the hatching of conspecific nauplii, even when diluted by 50% using distilled water. Streptocephalus torvicornis resting eggs hatch in the medium of C. diaphanus but not in the medium of B. schaefferi. Resting eggs of B. schaefferi hatched in low numbers in S. torvicornis medium, and in high numbers in that of C. diaphanus.
LOBSTERS: A COMPARATIVE STUDY by
2007
This dissertation investigated larval release and larval behavior of the Caribbean spiny lobster Panulirus argus and the spotted spiny lobster P. guttatus. These species were examined under laboratory conditions to determine the phase relationship between larval release and natural environmental cycles. P. argus displayed a nocturnal tidal rhythm, while P. guttatus displayed a circadian rhythm in larval release. P. argus releases larvae near the time of nocturnal high slack water, while P. guttatus released larvae near the time of sunrise. The role of 'pumping pheromones' in controlling larval release behaviors was tested by measuring the pumping response of ovigerous P. argus to (1) hatch water, (2) homogenized-embryo water, (3) embryo-conditioned water, and (4) water containing homogenized-egg cases. Lobsters with late-stage embryos displayed increased pleopod pumping with increased concentration of hatch water. Water individually conditioned with homogenized late-stage embryos, intact late-stage embryos, and homogenized eggcases induced pumping activity in females with late-stage embryos, indicating the presence of a chemical cue. I quantified pumping responses upon exposure to synthetic peptides to determine if they mimicked pheromones that induce larval release behaviors. Pumping behavior was evoked by oligopeptides with a basic amino acid at the carboxy-terminus, v preceded by several neutral amino acids. Carboxyl-terminal arginine peptides serve as pheromone mimics. I investigated whether these peptides originate from the action of trypsin-like enzymes by conducting a bioassay measuring pumping activity of ovigerous P. argus subjected to increasing concentrations of trypsin, trypsin inhibitor, and a combination of the two. Pumping activity increased with increasing concentrations of trypsin and trypsin inhibitor, while behaviors ceased when ovigerous females were subjected to a complex of the two. Pheromones are generated by trypsin-like enzymes assisting in the degradation of the egg membranes at the time of hatching. Vertical swimming behaviors of stage-I phyllosoma larvae of P. argus and P. guttatus were observed under laboratory conditions. P. argus larvae displayed a pattern of twilight vertical migration, while P. guttatus larvae displayed nocturnal diel vertical migration (DVM). Rhythms persisted for 5-6 cycles under constant conditions, indicating that an endogenous rhythm in activity plays a proximate role in DVM for both species. vi Dedication This work is dedicated to the memories of my father, Charles A. Ziegler II, my sister Christine J. Ziegler, my aunt Susan F. Holl, and my best friends Loretta D. Abel