The Function of Chemo- and Mechanoreceptors in Lobster (Homarus Americanus) Feeding Behaviour

1982 ◽  
Vol 98 (1) ◽  
pp. 317-327
Author(s):  
CHARLES D. DERBY ◽  
JELLE ATEMA
Keyword(s):  
Mytilus Edulis ◽  
Feeding Behaviour ◽  
Homarus Americanus ◽  
Feeding Performance ◽  
Functional Roles ◽  
Before And After

The behaviour of lobsters preying on live mussels (Mytilus edulis) was observed before and after chemosensory or chemosensory-mechanosensory deafferentation of different sensory appendages. Deafferentation of the antennules, leg tips, or maxillipeds (but not the carapace or proximal leg segments) interfered with feeding performance by causing an increase in the time necessary to crush a mussel after search initiation. In addition, deafferentation of the leg tips or the maxillipeds caused a decline in number of mussels crushed but for different reasons: leg-treated lobsters walked over the mussels without picking them up, whereas maxilliped-treated lobsters grasped the mussels as usual but either did not crush or did not eat them as readily as did normal lobsters. Deafferentation of leg chemoreceptors resulted in the same behavioural deficiencies as deafferentation of leg chemo-and mechanoreceptors, demonstrating that it is the leg chemoreceptors that are essential in releasing this grasping response. Chemoreceptors on different appendages of lobsters therefore fulfill different functional roles in their feeding behaviour.

scholarly journals Divergent Response to the SSRI Citalopram in Male and Female Three-Spine Sticklebacks (Gasterosteus aculeatus)

2020 ◽  
Vol 79 (4) ◽  
pp. 478-487
Author(s):  
Martin Kellner ◽  
K. Håkan Olsén
Keyword(s):  
Surface Waters ◽  
Aggressive Behaviour ◽  
Feeding Behaviour ◽  
Selective Serotonin Reuptake Inhibitors ◽  
Gasterosteus Aculeatus ◽  
Male And Female ◽  
Behavioural Effects ◽  
Before And After ◽  
Over Time ◽  
Divergent Response

AbstractSelective serotonin reuptake inhibitors (SSRIs) are psychotropic pharmaceuticals used as antidepressants. SSRIs are commonly found in surface waters in populated areas across the globe. They exert their effect by blocking the serotonin re-uptake transporter in the presynaptic nerve ending. The present study examined whether behavioural effects to exposure to SSRI citalopram depend on personality and sex in the stickleback (Gasterosteus aculeatus). Three aspects of stickleback behaviour are examined: feeding behaviour, aggression, and boldness. We exposed sticklebacks to 350–380 ng/l citalopram for 3 weeks. Feeding and aggressive behaviour were recorded before and after exposure, whereas scototaxis behaviour was tested after exposure. The results show treatment effects in feeding and aggressive behaviour. Feeding is suppressed only in the male group (χ2 = 20.4, P < 0.001) but not in the females (χ2 = 0.91, P = 0.339). Aggressive behaviour was significantly affected by treatment (χ2 = 161.9, P < 0.001), sex (χ2 = 86.3, P < 0.001), and baseline value (χ2 = 58.8, P < 0.001). Aggressiveness was suppressed by citalopram treatment. In addition, the fish showed no change in aggression and feeding behaviour over time regardless of sex and treatment, which indicate personality traits. Only females are affected by treatment in the scototaxis test. The exposed females spent significantly (χ2 = 5.02, P = 0.050) less time in the white zone than the female controls.

How does changing the feeding bin affect cows’ behaviour?

2019 ◽  
Vol 86 (1) ◽  
pp. 43-47
Author(s):  
Maria Soonberg ◽  
Tanel Kaart ◽  
David Richard Arney
Keyword(s):  
Feeding Behaviour ◽  
Index Number ◽  
Dry Period ◽  
Health Records ◽  
Activity Monitors ◽  
Before And After ◽  
Group Change ◽  
The Right ◽  
Over Time ◽  
Improve Health

AbstractIn a system in which cows are grouped and given differential access to feeding bins with different rations, and where these groups change over time, it is important to find out how a change in the ration (and hence feeding bin) affects the cow's feeding behaviour. Monitoring the locomotion of cows can be used to predict oestrus and improve health (lameness diagnosis), but activity monitors can also be used to estimate both activity and numbers of feeding visits by cows. Ice tag activity monitors were attached to the right hind legs of ten cows. Walking, standing, lying data and health records were used to record changes before and after a change in each cow's feeding bin. Results comparing activity before and after feeding bin change revealed significant increases in motion index, number of steps taken per minute and number of lying bouts per minute (all P < 0.001). Comparing the behaviours of cows subsequently followed during the dry period showed significant differences in motion indices and number of steps taken per minute (P < 0.001) in the dry period. The results indicate that cows are affected by feeding bin change and group change, which can lead to an increase in behaviour associated with the stress response, especially in heifers.

Preferences and amount of food eaten by the prawn Penaeus esculentus over moult cycle

1992 ◽  
Vol 43 (4) ◽  
pp. 727 ◽  
Author(s):  
BJ Hill ◽  
TJ Wassenberg
Keyword(s):  
Regression Analysis ◽  
Feeding Behaviour ◽  
Carapace Length ◽  
Linear Regression Analysis ◽  
Moult Cycle ◽  
Natural Diet ◽  
Stepwise Linear Regression Analysis ◽  
Stepwise Linear Regression ◽  
Daily Food ◽  
Before And After

Analysis of the natural diet of prawns over the moult cycle shows a preference for molluscan tissue at all stages, with an apparent greater preference in the stage immediately following the moult dropping in the intermoult stages and then increasing again before the next moult. A laboratory study was carried out to provide more information on feeding behaviour over the moult cycle. Adults of Penaeus esculentus (carapace length 25 to 30 mm, weight 15.5 to 25.2 g) held at 32 to 35 and 23 to 25°C did not feed on the night of ecdysis. On the following nights, feeding increased to peak at 2.7 g of penaeid tissue per day in moult Stage C. For the rest of the moult cycle, feeding was fairly steady at about 1.23 g of penaeid tissue per day but dropped sharply two nights before ecdysis. The prawns increased in weight by 0.7 to 6.1 g (mean 3.5 g) over a moult cycle. A stepwise linear-regression analysis showed that, within the range tested, the increase in weight was not a function of prawn weight, duration of moult cycle (range 14 to 34 days), or daily food consumption (0.95 to 2.33 g). They ate more crustacean tissue (Metapenaeus bennettae) than bivalve tissue (Perna canaliculatus) over the entire moult cycle, except for the night before and after ecdysis, when they ate bivalve tissue almost exclusively.

Modeling shell disease in American lobster (Homarus americanus) as individual-based health trajectories

2014 ◽  
Vol 71 (6) ◽  
pp. 808-813 ◽  
Author(s):  
Michael F. Tlusty ◽  
Anita Kim ◽  
Kathleen M. Castro
Keyword(s):  
Conceptual Understanding ◽  
Gulf Of Maine ◽  
Homarus Americanus ◽  
Molt Cycle ◽  
Health Trajectories ◽  
Human Parasite ◽  
Before And After ◽  
Shell Disease ◽  
Lobster Fishery ◽  
Important Disease

The emergence of epizootic shell disease in American lobsters (Homarus americanus) has presented many new challenges to understanding the interface between disease and the management of the lobster fishery. While a variety of the potentially causative and correlative factors for shell disease have been explored, a clear etiological agent remains elusive. The recency of this disease and the lack of identifiable causal agents have hindered the development of conceptual models that can yield testable predictions. Here, a model originally developed for human–parasite interactions was applied to lobster shell disease as a means to unify the broad experimental and field observations. The model is a graphical means to understand the onset and severity of shell disease and is a function of the length of the molt cycle and the rate of the decrease of health both before and after lesion formation as a function of bacterial abundance and pathogenicity. The model also accounts for shell hardening and passive and active portals of entry for the bacteria. The timing for a conceptual understanding of the epidemiology of shell disease is critical because its prevalence is increasing in key fishing areas. Ideally, such a model will help researchers create hypothesis-driven predictive experiments from which we can further our understanding of an important disease to a critical member of the Gulf of Maine ecosystem.

Determinants of Postmolt Size in the American Lobster (Homarus americanus). II. Folding of Premolt Cuticle

1994 ◽  
Vol 51 (8) ◽  
pp. 1774-1779 ◽  
Author(s):  
Jin-Hua Cheng ◽  
Ernest S. Chang
Keyword(s):  
Homarus Americanus ◽  
Size Increase ◽  
American Lobster ◽  
Eyestalk Ablation ◽  
Before And After ◽  
Rearing Condition

The effects of eyestalk ablation, regeneration, and rearing condition on the size of new cuticles before and after expansion were studied in juvenile Homarus americanus. Both eyestalk-ablated and intact lobster grew larger in large spaces than in small spaces. In contrast, regeneration reduced molt increment. Despite large differences in molt increment (percentage of size increase during a molt) among experimental groups, the percentage of postmolt size increase that could be accounted for by unfolding of the new cuticle was large and constant in each group. In addition, transferring freshly molted lobster to dilute seawater did not produce any further size increase but instead caused cuticle breakage in some animals. We conclude that molt increment in lobster is determined by regulating the size of the cuticle before ecdysis. The size of the postmolt cuticle is primarily a result of unfolding of the new, previously folded cuticle.

scholarly journals Trachymyrmex septentrionalis ant microbiome assembly is unique to individual colonies and castes.

2021 ◽  
Author(s):  
Emily A Green ◽  
Jonathan L Klassen
Keyword(s):  
Developmental Differences ◽  
Functional Roles ◽  
Northern Mexico ◽  
Insect Colonies ◽  
Before And After ◽  
Eastern Usa ◽  
Rearing Condition ◽  
Fungus Growing Ants ◽  
Conserved Core ◽  
Microbiome Assembly

Within social insect colonies, microbiomes often differ between castes due to their different functional roles, and between colony locations. Trachymyrmex septentrionalis fungus-growing ants form colonies throughout the eastern USA and Northern Mexico that include workers, female and male alates (unmated reproductive castes), larvae, and pupae. How T. septentrionalis microbiomes vary across this geographic range and between castes is unknown. Our sampling of individual ants from colonies across the Eastern USA revealed a conserved core T. septentrionalis worker ant microbiome, and that worker ant microbiomes are more conserved within colonies than between them. A deeper sampling of individual ants from two colonies that included all available castes (pupae, larvae, workers, female and male alates), from both before and after adaptation to controlled laboratory conditions, revealed that ant microbiomes from each colony, caste, and rearing condition were typically conserved within but not between each sampling category. Tenericute bacterial symbionts were especially abundant in these ant microbiomes and varied widely in abundance between sampling categories. This study demonstrates how individual insect colonies primarily drive the composition of their microbiomes, and that these microbiomes are further modified by developmental differences between insect castes and the different environmental conditions experienced by each colony.

Chemosensitivity of Walking Legs of the Lobster Homarus Americanus: Neurophysiological Response Spectrum and Thresholds

1982 ◽  
Vol 98 (1) ◽  
pp. 303-315
Author(s):  
CHARLES D. DERBY ◽  
JELLE ATEMA
Keyword(s):  
Amino Acids ◽  
Mytilus Edulis ◽  
Ammonium Chloride ◽  
Response Spectrum ◽  
Extracellular Recording ◽  
Homarus Americanus ◽  
Taste Receptors ◽  
Live Prey ◽  
Recording Techniques

Responses of chemoreceptors in the walking legs of the lobster Homarus americanus to 35 individual compounds and 3 mixtures (prey odours and extracts) were studied using extracellular recording techniques. Compared against a standard mussel (Mytilus edulis) extract, these receptors were most sensitive to the amino acids L-glutamate, hydroxy-L-proline, L-aspartate, L-arginine, glycine, taurine, and L-alanine, as well as such other compounds as ammonium chloride, betaine, and the tripeptide glutathione. Most of these excitants are among those compounds most prevalent in the prey of lobsters. Some proteins and odours from live prey were also effective stimuli. In general, carbohydrates, alcohols, nucleosides, and nucleotides were only slightly excitatory. The lowest thresholds for 10 compounds ranged from 3.5×10−6 to 3.5×10−14 M; these thresholds are lower than previously reported for crustacean taste receptors.

Feeding and condition shifts after encountering a pathogen

Behaviour ◽  
2021 ◽  
pp. 1-24
Author(s):  
Alicia Reyes-Ramírez ◽  
Maya Rocha-Ortega ◽  
Alex Córdoba-Aguilar
Keyword(s):  
Body Condition ◽  
Feeding Behaviour ◽  
Adult Stage ◽  
The Body ◽  
Infection Status ◽  
Metarhizium Robertsii ◽  
Before And After ◽  
Males And Females ◽  
Protein Rich ◽  
The Impact

Abstract Feeding behaviour is a dynamic process, especially if an individual is dealing with an infection. Here, we used Tenebrio molitor beetles to evaluate the effects of changes in diet macronutrients (protein:carbohydrate) on: (i) feeding behaviour before and after infection (using the entomopathogenic fungus Metarhizium robertsii) in males; and (ii) body condition, measured as the amount of proteins, carbohydrates, and lipids in the body, in males and females. Given that females also depend on the nutrients from the spermatophore, we also addressed the impact on female condition of using spermatophores from males whose diets differed in macronutrients whether they were confronting an infection. We found that males with different diets and regardless of their infection status, and females with different diets, all consumed less of the protein-rich diet but more of the carbohydrate-rich diet. In addition, infection in males produced anorexia. The infection resulted in males and the females they mated with, with fewer body proteins and lipids. This suggests that unlike studies in other insects, T. molitor does not consume large amounts of protein during the adult stage, even during an infection. Females’ condition depended strongly on that of their mates, improving even when paired with infected males. This implies that females may be using the nutrients that the males transfer during mating for maintenance.

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