The Role of Chemical Senses in Predation, Risk Assessment, and Social Behavior of Spiny Lobsters

Chemical senses play a critical role in predator-prey and social interactions of many animals. Predators often evoke adaptive escape responses by prey, one of which is the release of chemicals that induce adaptive avoidance behaviors from both predators and conspecifics. I explore the use of chemicals in predator-prey and social interactions, using a crustacean model system, the spiny lobster. As predators, spiny lobsters are opportunistic, polyphagous feeders, and they rely heavily on their chemical senses during feeding. Some of their potential prey deter attacks through chemical defenses that act through the spiny lobsters’ chemical senses. An example of this is sea hares, Aplysia californica, which secrete an ink when vigorously attacked by sympatric spiny lobsters, Panulirus interruptus. I show that that this ink defends sea hares from spiny lobsters through several mechanisms that include phagomimicry, sensory disruption, and deterrence, and that the ink’s efficacy is enhanced by its naturally high acidity. As prey, spiny lobsters rely heavily on their chemical senses to assess risk from predators. One way to assess risk of predation is through ‘alarm cues’, which are injury-related chemicals. I show that injured Caribbean spiny lobsters, Panulirus argus, release alarm cues in their hemolymph, and that nearby conspecifics detect these cues using olfaction. Hemolymph from conspecifics induces primarily alarm behavior in the form of retreat, sheltering, and suppression of appetitive responses. In contrast, hemolymph from heterospecifics, depending on phylogenetic relatedness, induces either mixed alarm and appetitive behaviors or primarily appetitive behaviors. Spiny lobsters also use chemical cues to assess risk during social interactions with conspecific. I show that spiny lobsters use urine-borne chemical signals and agonistic behaviors to communicate social status and that these chemical signals are detected exclusively by the olfactory pathway. Dominant animals increase urine release during social interactions, whereas subordinates do not. Experimental prevention of urine release during interactions causes an increase in agonism, but this increase is abolished when urine of dominants is reintroduced. My findings lay the foundation for neuroethological studies of risk-assessment systems mediated by intraspecific chemical cues

An animal model of differential genetic risk for methamphetamine intake

The question of whether genetic factors contribute to risk for methamphetamine (MA) use and dependence has not been intensively investigated. Compared to human populations, genetic animal models offer the advantages of control over genetic family history and drug exposure. Using selective breeding, we created lines of mice that differ in genetic risk for voluntary MA intake and identified the chromosomal addresses of contributory genes. A quantitative trait locus was identified on chromosome 10 that accounts for more than 50% of the genetic variance in MA intake in the selected mouse lines. In addition, behavioral and physiological screening identified differences corresponding with risk for MA intake that have generated hypotheses that are testable in humans. Heightened sensitivity to aversive and certain physiological effects of MA, such as MA-induced reduction in body temperature, are hallmarks of mice bred for low MA intake. Furthermore, unlike MA-avoiding mice, MA-preferring mice are sensitive to rewarding and reinforcing MA effects, and to MA-induced increases in brain extracellular dopamine levels. Gene expression analyses implicate the importance of a network enriched in transcription factor genes, some of which regulate the mu opioid receptor gene, Oprm1, in risk for MA use. Neuroimmune factors appear to play a role in differential response to MA between the mice bred for high and low intake. In addition, chromosome 10 candidate gene studies provide strong support for a trace amine-associated receptor 1 gene, Taar1, polymorphism in risk for MA intake. MA is a trace amine-associated receptor 1 (TAAR1) agonist, and a non-functional Taar1 allele segregates with high MA consumption. Thus, reduced TAAR1 function has the potential to increase risk for MA use. Overall, existing findings support the MA drinking lines as a powerful model for identifying genetic factors involved in determining risk for harmful MA use. Future directions include the development of a binge model of MA intake, examining the effect of withdrawal from chronic MA on MA intake, and studying potential Taar1 gene × gene and gene × environment interactions. These and other studies are intended to improve our genetic model with regard to its translational value to human addiction

Spiny lobsters detect conspecific blood-borne alarm cues exclusively through olfactory sensilla

When attacked by predators, diverse animals actively or passively release molecules that evoke alarm and related anti-predatory behavior by nearby conspecifics. The actively released molecules are alarm pheromones, whereas the passively released molecules are alarm cues. For example, many insects have alarm-signaling systems that involve active release of alarm pheromones from specialized glands and detection of these signals using specific sensors. Many crustaceans passively release alarm cues, but the nature of the cues,sensors and responses is poorly characterized. Here we show in laboratory and field experiments that injured Caribbean spiny lobsters, Panulirus argus, passively release alarm cues via blood (hemolymph) that induce alarm responses in the form of avoidance and suppression of feeding. These cues are detected exclusively through specific olfactory chemosensors,the aesthetasc sensilla. The alarm cues for Caribbean spiny lobsters are not unique to the species but do show some phylogenetic specificity: P. argus responds primarily with alarm behavior to conspecific blood, but with mixed alarm and appetitive behaviors to blood from the congener Panulirus interruptus, or with appetitive behaviors to blood from the blue crab Callinectes sapidus. This study lays the foundation for future neuroethological studies of alarm cue systems in this and other decapod crustaceans

Spiny lobsters use urine-borne olfactory signaling and physical aggressive behaviors to influence social status of conspecifics

Decapod crustaceans, like many other animals, engage in agonistic behaviors that enhance their ability to compete for resources with conspecifics. These agonistic behaviors include the release of chemical signals as well as physical aggressive and submissive behaviors. In this study, we report that Caribbean spiny lobsters, Panulirus argus, use both urine-borne chemical signaling and physical aggressive behaviors during interactions with conspecifics, and that these agonistic behaviors can influence the behavior and eventual social status of the interactants. Spiny lobsters that engaged primarily in physical aggressive behaviors became dominant, whereas spiny lobsters that received these physical aggressive behaviors responded with avoidance behaviors and became subordinates. Dominant animals frequently released urine during social interactions, more than when they were not in contact with subordinates and more than when they were not paired with another animal. Subordinates released urine significantly less often than dominants,and no more than when not paired. Preventing release of urine by catheterizing the animals resulted in an increase in the number and duration of physical interactions, and this increase was primarily driven by dominants initiating interactions through physical aggressive behaviors. Introducing urine from one of the catheterized animals into an aquarium reduced physical aggressive behavior by dominant animals to normal levels. Urine-borne signals alone were capable of inducing avoidance behaviors from solitary spiny lobsters in both laboratory and field conditions. We conclude that urine serves as a chemical signal that communicates social status to the interactants. Ablation experiments showed that that these urine signals are detected primarily by aesthetasc sensilla of the olfactory pathway

ANTISPERM ANTIBODY AND MALE INFERTILITY

Introduction: Antisperm antibody (ASA) in men cause autoimmune disease, respectively, immune infertility. DNA fragmentation is the separation or breaking of DNA strands in pieces. DNA fragmentation testing is a type of male fertility test that measures the percentage of damaged DNA in a sperm sample. Aim: The purpose of this study was to detect the presence of ASA and their incidence in male infertility with unknown etiology, as well as to evaluate the correlation between ASA and the percentage of sperm DNA fragmentation. Methods: The study included 61 men with unknown infertility and 39 males control. Evaluation of the presence of antisperm antibody in the semen resulted in a direct mixed anti globulin (MAR) reaction and sperm DNA fragmentation with the Halosperm Halotech DNA, Madrid, Spain, test based on SCD technique, based on DNA-denatured. Results: In the MAR test, 21.68 % of infertile men with unknown etiology were positive for ASA. Only one case was found in fertile male with positive ASA. Results of the DNA fragmentation index (DFI %) did not have a positive correlation with the ASA presence percentage in patients with positive test MAR. Conclusions: Results show that antisperm antibody (ASA) are involved in decreased fertility in vivo conditions in patients with positive test MAR. DNA Fragmentation Index Results (% DFI %) did not show genetic damage to the spermatozoa in these cases with immune infertility. Key words: Antisperm antibody, male infertility, Sperm DNA fragmentation (DFI), MAR test

Microstructure Based Modeling of Dual Phase 600 Steel

The purpose of this study was to examine the microstructure of DP600 steel using both experimental and finite element modeling methods. The microstructure is generated using 2D modeling and 3D synthetic modeling processes. The goal was to demonstrate the significance and procedures of each step taken until the final modeling component was completed

Chemosensory neurons in the mouthparts of the spiny lobsters <em>Panulirus argus</em> and <em>Panulirus interruptus</em> (Crustacea: Decapoda)

We studied electrophysiological properties of single chemosensory neurons in the mouthparts of the spiny lobsters Panulirus argus and Panulirus interruptus to complement our growing understanding of the behavioral roles of mouthparts of decapod crustaceans. Food mixtures and 13 single compounds were used to characterize the response specificity, sensitivity, and time course of individual neurons in the endopods of maxilliped 2 and 3. Additional chemoreceptors were found in the mandibular palp and basis of maxilliped 1 but they were not characterized. Neurons were broadly tuned, with the five most potent single compounds being ammonium, adenosine-5' -monophosphate, taurine, glutamate, and aspartate. Cluster analysis indicated that the neurons constitute a heterogeneous population that could be placed into seven groups linked according to their most excitatory compound. These neurons in the mouthparts had concentration-dependent responses, with thresholds between 10(-7) and 10(-4) M and without saturation even at 10(-3) or 10(-2) M. They also quickly adapted when exposed to their best compounds at 10(-4) and 10(-3) M. A comparison of the response properties of these neurons in the mouthparts with those of chemosensory neurons in other crustacean appendages shows that neurons in the mouthparts have relatively broad tuning biased toward detecting and resolving high concentrations. Based on these comparisons, we suggest a functional distinction among the chemosensors on the different appendages: long distance detection by the antennae, precise location and collection by the pereiopods, and detailed assessment of quality by the mouthparts