scholarly journals Stream grazers determine their crawling direction on the basis of chemical and visual/tactile microalgal cues

Author(s):  
Izumi Katano ◽  
Hideyuki Doi

This study aimed to determine the association of herbivore behavior with cues from producers. We used stream grazer Glossosoma larvae and determined their crawling direction in relation to the chemical and visual cues from microalgae. The experimental treatments included control (no cue), particulate (chemical and visual/tactile cues), and dissolved (chemical cue) cues from microalgae. The experimental water samples were randomly placed into either arms of a Y-shaped channel, and the crawling direction of the grazers was determined. Although the grazers crawled toward the arm containing either particulate or dissolved cues, they preferred the arm with particulate cues. This suggested that grazers responded well when both visual/tactile (i.e., drifting algal cells) and chemical cues (algal smell) were present, and that visual/tactile cues were more important for foraging. In natural habitats, grazers detect cues from both producers and predators and use them to maximize fitness by avoiding predation and obtaining food.

2014 ◽  
Author(s):  
Izumi Katano ◽  
Hideyuki Doi

This study aimed to determine the association of herbivore behavior with cues from producers. We used stream grazer Glossosoma larvae and determined their crawling direction in relation to the chemical and visual cues from microalgae. The experimental treatments included control (no cue), particulate (chemical and visual/tactile cues), and dissolved (chemical cue) cues from microalgae. The experimental water samples were randomly placed into either arms of a Y-shaped channel, and the crawling direction of the grazers was determined. Although the grazers crawled toward the arm containing either particulate or dissolved cues, they preferred the arm with particulate cues. This suggested that grazers responded well when both visual/tactile (i.e., drifting algal cells) and chemical cues (algal smell) were present, and that visual/tactile cues were more important for foraging. In natural habitats, grazers detect cues from both producers and predators and use them to maximize fitness by avoiding predation and obtaining food.


Behaviour ◽  
2009 ◽  
Vol 146 (11) ◽  
pp. 1485-1498 ◽  
Author(s):  
Nancy Kohn ◽  
Robert Jaeger

AbstractThe use of multiple cues can enhance the detection, recognition, discrimination, and memorability of individuals by receivers. We conducted two experiments, using only males, to test whether territorial red-backed salamanders, Plethodon cinereus, could use only chemical or only visual cues to remember familiar conspecifics. In both experiments, focal males spent significantly more time threatening unfamiliar than familiar male intruders. They also chemoinvestigated the filter paper containing chemical cues of unfamiliar intruders more often than that of familiar intruders. These results suggest that red-backed salamanders can use both chemical and visual cues to recognize familiar individuals, allowing them to distinguish between less threatening neighbours and more threatening intruders in the heterogeneous forest floor habitat, where visual cues alone would not always be available.


2010 ◽  
Vol 8 (4) ◽  
pp. 899-902
Author(s):  
Rodrigo Egydio Barreto ◽  
Maria Fernanda Coelho Junqueira ◽  
Tan Tjui-Yeuw ◽  
Gilson Luiz Volpato

The speckeld worm eel Myrophis punctatus lives in high-densities assemblages, and usually digs through, or lies on the substrate. These behaviours could lead to chemical marks on the substrate and could modulate the spatial distribution in this species. We tested the hypothesis that the spatial choice of the speckled worm eel is modulated by the presence of conspecific odour on the substrate. Here, we showed that the speckled worm eel avoids the substrate area containing the conspecific odour, indicating that this chemical cue modulates the eel's spatial decision. The eels clearly detected the conspecific's odour. This perception might indicate the presence of conspecifics into the substrate. Since the eels avoided an area containing conspecific odour, we suggest this may be a response that avoids the consequences of invading a resident-animal's territory.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5744 ◽  
Author(s):  
John M. Carroll ◽  
Morgan B. Church ◽  
Christopher M. Finelli

The salt marsh periwinkle, Littorina irrorata, exhibits a spatial refuge from predation by climbing the stems of Spartina alterniflora in order to avoid benthic predators. Salt marsh periwinkles have a broad geographic distribution, and for many species, responses to predators also varies with biogeography. This study sought to determine if the geographical location of the home marsh influenced the response of periwinkles (climbing height) to blue crab predator cues both via air and water. Snails from Louisiana (LA) climbed higher in general than those from North Carolina (NC), regardless of chemical cue. However, LA snails climbed 11 cm higher in the presence of waterborne predators than control snails with no cue, while NC snails only climbed five cm higher in the same comparisons. Airborne chemical cue tended to have snails climbing at intermediate heights. These responses were significantly enhanced when both populations of snails were housed together. Periwinkle response to predator cues was stronger in LA than NC, and so it is possible that the behavioral response of these snails to predators varies with biogeography of the home marsh. Also interestingly, the results of this study also suggest that cue delivery is probably occurring via mechanisms other than water, and potentially via airborne cues. Therefore, salt marsh periwinkles likely respond to numerous cues that initiate behavioral responses, including airborne cues, and these responses may vary by home-marsh geography.


Author(s):  
Jonathan H. Cohen ◽  
Charles E. Epifanio

Early life history in marine benthic crustaceans often includes externally brooded eggs that hatch into free-swimming planktonic larvae. These larvae are relatively strong swimmers, and movement in the vertical plane provides a number of advantages, including modulation of horizontal transport and assurance of favorable predator–prey interactions. Swimming behavior in larval crustaceans is regulated by predictable external cues in the water column, primarily light, gravity, and hydrostatic pressure. Light-regulated behavior depends upon the optical physics of seawater and the physiology of light-detecting sensory structures in the larvae, which overall vary little with ontogeny. Swimming in response to light contributes to ecologically significant behaviors in planktonic crustacean larvae, including shadow responses, depth regulation, and diel vertical migration. Moreover, the photoresponses themselves, and in turn the evoked behaviors, change with the needs of larvae as development progresses. Regarding other sensory modalities, crustacean embryos and larvae respond to chemical cues using bimodal sensilla (chemosensory and mechanosensory) as contact receptors, and aesthetascs for detection of water-soluble cues. Processes and behaviors are stimulated by larval detection of chemical cues throughout ontogeny, including egg-hatching, avoidance of predators during free-swimming stages, and, ultimately, settlement and metamorphosis in juvenile habitats. The latter process can also involve tactile cues. The sensory-mediated behaviors described here for crustacean larvae have parallels in numerous arthropod and nonarthropod taxa. Emerging directions for future research on sensory aspects of behavior in crustacean larvae include multimodal sensory integration and behavioral responses to changing environmental stressors.


2020 ◽  
Author(s):  
Sandra Klintworth ◽  
Eric von Elert

Abstract In aquatic systems, organisms largely rely on chemical cues to perceive information about the presence of predators or prey. Daphnia recognize the presence of the predatory larvae of Chaoborus via a chemical cue, emitted by the larvae, a so-called kairomone. Upon recognition, neckteeth, an alteration of the carapace, are induced in Daphnia that reduce predation rates of Chaoborus. Neckteeth induction was often reported to entail costs. In a previous study, food quantity affected the level of neckteeth induction, with stronger neckteeth induction at low food concentrations and weak induction at high food concentrations. However, reducing neckteeth induction at high food quantities seems to be maladaptive and not in accordance with the concept that inducible defenses are associated with costs. Here, we hypothesized that weaker neckteeth induction at high food concentrations is caused by increased bacterial degradation of the kairomone. More specifically, we assume that higher algal food concentration is associated with higher bacterial abundances, which degrade the kairomone during the experiment. We tested our hypothesis by treating food algae with antibiotics before providing them as food to Daphnia. Antibiotics reduced bacterial abundances at high and low food concentrations. Reduced bacterial abundances at high food concentrations led to the same level of neckteeth induction as at low food concentrations. A linear regression revealed a significant correlation of neckteeth induction to bacterial abundances. We therefore conclude that differences in neckteeth induction at different food concentrations are not caused by the food quantity effects but by differences in bacterial degradation of the kairomone.


2019 ◽  
Vol 72 (11) ◽  
pp. 2705-2716 ◽  
Author(s):  
Supreet Saluja ◽  
Richard J Stevenson

Tactile cues are said to be potent elicitors of disgust and reliable markers of disease. Despite this, no previous study had explored what the full range of tactile properties are that cue disgust, nor how interpretation of these sensations influences disgust. To answer these questions, participants were asked to touch nine objects, selected to cover the range of tactile properties, and evaluate their sensory, affective, and risk-based characteristics (primarily how sick they thought the object would make them). Object contact was manipulated in four ways, with participants randomly allocated to corresponding groups—one that could see the objects (i.e., the control) and three that could not (i.e., the blind groups). To manipulate disease risk interpretation of the objects, labelling was used on the blind groups, with one receiving Disgust-Labels, one True-Labels and one no labels. Disgust was strongly associated with sticky and wet textures, and moderately with viscous, cold, and lumpy textures, suggesting adherence-to-skin may predict disgust. The participants in the disgust-labelled condition had the highest disgust ratings, and this was mediated by their increased sickness belief and fear of the objects. Object identification was poor when labels or visual cues were absent. Our findings suggest that tactile disgust may reflect a bottom-up sensory component—skin adhesion—moderated by judgements of disease-related threat.


2005 ◽  
Vol 62 (9) ◽  
pp. 1978-1984 ◽  
Author(s):  
Justin J Meager ◽  
Turid Solbakken ◽  
Anne C Utne-Palm ◽  
Tina Oen

We investigated the effects of turbidity on the foraging behaviour of juvenile Atlantic cod (Gadus morhua) on mysid prey (Praunus neglectus) in the laboratory. The influence of turbidity on vision and chemoreception was examined by measuring reactive distances and search times to visual, chemical, and visual–chemical prey cues over turbidity levels ranging from 0.4 to 17·m–1 (beam attenuation·m–1). We also compared foraging rates of juvenile cod on mysids in highly turbid water and clear water under well lit and totally dark conditions. Juvenile cod using chemical cues were able to locate mysids from significantly longer distances than when only visual cues were available. Turbidity did not affect reactive distance to chemical cues, and had only a weak negative effect on reactive distance to visual and visual–chemical cues. Search time was variable, but tended to increase with turbidity. Turbidity did not affect predation rates on free-ranging mysids, but predation rates were significantly lower in dark conditions than in well lit conditions. We suggest that juvenile cod use chemoreception in conjunction with vision (at close ranges) to locate prey in highly turbid water.


Behaviour ◽  
2013 ◽  
Vol 150 (12) ◽  
pp. 1467-1489 ◽  
Author(s):  
Arielle Duhaime-Ross ◽  
Geneviève Martel ◽  
Frédéric Laberge

Many animals use and react to multimodal signals — signals that occur in more than one sensory modality. This study focused on the respective roles of vision, chemoreception, and their possible interaction in determining agonistic responses of the red-backed salamander, Plethodon cinereus. The use of a computer display allowed separate or combined presentation of visual and chemical cues. A cue isolation experiment using adult male and juvenile salamanders showed that both visual and chemical cues from unfamiliar male conspecifics could increase aggressive displays. Submissive displays were only increased in juveniles, and specifically by the visual cue. The rate of chemoinvestigation of the substrate was increased only by chemical cues in adults, whereas both chemical and visual cues increased this behaviour in juveniles. Chemoinvestigation appears, thus, more dependent on sensory input in juvenile salamanders. A follow-up experiment comparing responses to visual cues of different animals (conspecific salamander, heterospecific salamander and earthworm) or an inanimate object (wood stick) showed that exploratory behaviour was higher in the presence of the inanimate object stimulus. The heterospecific salamander stimulus produced strong submissive and escape responses, while the conspecific salamander stimulus promoted aggressive displays. Finally, the earthworm stimulus increased both aggressive and submissive behaviours at intermediate levels when compared to salamander cues. These specific combinations of agonistic and exploratory responses to each stimulus suggest that salamanders could discriminate the cues visually. This study sheds some light on how information from different sensory modalities guides social behaviour at different life stages in a salamander.


2015 ◽  
Vol 66 (2) ◽  
pp. 127 ◽  
Author(s):  
Culum Brown ◽  
Jennifer Morgan

Macquarie perch, Macquaria austalasica, is an endangered species endemic to southern Australia whose distribution is highly fragmented and continues to decline. Key threatening processes include habitat destruction, dams and weirs, overfishing and interactions with introduced species. Here, we examined the responses of small and large Macquarie perch to two native predators and to the introduced redfin perch, Perca fluviatilis. Our results showed that Macquarie perch generally avoided large-bodied native predators but was attracted to small-bodied native predators. Responses to large and small redfin perch lay between these two extremes, suggesting that the Macquarie perch does treat these foreign fish as potential threats. Macquarie perch relied on both visual and chemical cues to identify predators, although its response tended to be stronger when exposed to visual cues. The results suggest that Macquarie perch has the capacity to recognise and respond to invasive species in a threat-sensitive manner, which has positive implications for the conservation management of the species.


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