scholarly journals Spatial choice is biased by chemical cues from conspecifics in the speckeled worm eel Myrophis punctatus

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.


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.


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.


2018 ◽  
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 11cm higher in the presence of waterborne predators than control snails with no cue, while NC snails only climbed 5cm 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.


2011 ◽  
Vol 102 (3) ◽  
pp. 315-323 ◽  
Author(s):  
H.F. Groba ◽  
M.K. Castelo

AbstractThe robber flyMallophora ruficaudais one of the principal apicultural pests in the Pampas region of Argentina. As adults, the flies prey on honey bees and other insects; while, as larvae, they parasitize scarab beetle larvae. Females ofM. ruficaudalay eggs away from the host in tall grasses. After being dispersed by the wind, larvae drop to the ground, where they dig in search of their hosts. It is known that second instar larvae ofM. ruficaudaexhibit active host searching behaviour towards its preferred host, third instar larva ofCyclocephala signaticollis, using host-related chemical cues. Furthermore, previous works show that these chemical cues are produced in the posterior body half of hosts. However, the precise anatomical origin of these cues and whether they mediate any behaviour ofC. signaticollislarvae remains yet unknown. In order to determine the precise origin of the chemical cue, we carried out olfactometer assays with different stimuli of extracts of the posteriorC. signaticollisbody half. Additionally, we tested whetherC. signaticollisis attracted to any of the same extracts as in the previous experiments. We found that both second instar ofM. ruficaudaand third instar ofC. signaticollisare attracted to extracts of the fermentation chamber (proctodeum). This is the first report of attraction of conspecific larvae in scarab beetles. We discuss a possible case of system communication exploitation in an immature parasitoid-host system.


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.


Author(s):  
Borja Ruiz-Apilánez ◽  
Eloy Solís ◽  
Vicente Romero de Ávila ◽  
Carmen Alía ◽  
Irene García-Camacha ◽  
...  

Spatial distribution of economic activities in heritage cities: The case of the historic city of Toledo, Spain. Borja Ruiz-Apilánez¹, Eloy Solís¹, Vicente Romero de Ávila², Carmen Alía¹ ¹Universidad de Castilla-La Mancha, Escuela de Arquitectura. Avda. Carlos III, s/n ES-45071 Toledo ²Universidad de Castilla-La Mancha. Escuela de Ingenieros de Caminos. Avda. Camilo José Cela, s/n ES-19071 Ciudad Real E-mail: [email protected], [email protected], [email protected], [email protected] Keywords (3-5): Urban Economics, Space Syntax, Heritage Cities, Spain Conference topics and scale: Urban form and social use of spacePrevious studies have shown: (a) that Space Syntax theories and tools can be helpful to explain pedestrian flows and the spatial distribution of economic activities in cities and other human settlements (Chiaradia et al., 2009; Perdikogianni, 2003; Vaughan et al., 2013), and (b) that the economy of many heritage cities highly depends on tourism (Ashworth and Tunbridge, 2000; Kemperman et al., 2009). Assuming that, in this particular type of human settlements, heritage buildings such as the cathedral, the town hall, and other similar constructions operate as tourist attractors, this research investigates to what extent the location of these buildings, together with the two main syntactic properties of the elements of the street network—integration and choice—can describe the spatial distribution of economic activities in touristic heritage cities, using the UNESCO Heritage site of Toledo, Spain, as case study. In order to investigate this question, each segment of the street network has been characterized with four main values: (1) economic activity, (2) spatial integration, (3) spatial choice, and (4) heritage intensity. The first value, economic activity, represents the presence or absence of economic activity in the buildings that are accessible through each corresponding street segment. The second value, spatial integration, accounts for the integration values that each segment has at two different scales—the neighborhood and the whole city. The third value, spatial choice, considers the choice values that each segment has, again, at these two scales. The fourth value, heritage intensity, reflects the proximity of listed building to each individual street segment. Street audits were used to record the economic activities taking place in the ground floors and upper floors of the buildings within the historic city. Space Syntax analysis was used to determine the different integration and choice values for each street segment; and GIS tools were used to establish their heritage intensity. Afterwards, statistical analysis was employed to investigate the relationships among these four variables, showing how the distribution of economic activity in the street network of the historic city of Toledo can be well explained by the other three variables—spatial integration, spatial choice and heritage intensity.References Ashworth, G.J., Tunbridge, J.E. (2000) The Tourist-historic City: Retrospect and Prospect of Managing the Heritage City. Routledge. Chiaradia, A., Hillier, B., Schwander, C., Wedderburn, M. (2009) ‘Spatial Centrality , Economic Vitality / Viability. Compositional and Spatial Effects in Greater London’, in Proceedings of the 7th International Space Syntax Symposium. 1–19. Kemperman, A.D.A.M., Borgers, A.W.J., Timmermans, H.J.P. (2009) ‘Tourist shopping behavior in a historic downtown area’. Tourism Manaement. 30, 208–218. Perdikogianni, I. (2003) ‘Heraklion and Chania: A study of the evolution of their spatial and functional patterns’, in 4th International Space Syntax Symposium. London, p. 19.1-19.20. Vaughan, L., Dhanani, A., Griffiths, S. (2013) ‘Beyond the suburban high street cliché - A study of adaptation to change in London’s street network: 1880-2013’. Journal of Space  Syntax 4. 


2018 ◽  
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 11cm higher in the presence of waterborne predators than control snails with no cue, while NC snails only climbed 5cm 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.


2001 ◽  
Vol 52 (8) ◽  
pp. 1049 ◽  
Author(s):  
Dianne K. Berger ◽  
Mark J. Butler IV

Octopuses are notorious predators of crustaceans, yet knowledge of their interactions with lobsters is largely anecdotal. Whether by preying on juvenile lobsters or by competing with them for dens or bivalve prey, octopuses should influence the den selection and therefore spatial distribution of lobsters. Lobsters are chemosensitive, so if the interaction is strong, they may respond to chemical cues produced by octopuses and avoid dens or areas where octopuses dwell. In mesocosms, juvenile Caribbean spiny lobsters (Panulirus argus) avoided dens emanating octopus chemical signals. Field manipulations of artificial dens at several spatial scales (<0.1 m to 10 m) showed that the distribution of lobsters was significantly influenced by the proximity of octopuses. Lobsters were significantly less likely to inhabit dens within 2 m of an octopus den, but this strong negative effect disappeared when dens were 10 m apart.


Author(s):  
L. D. Jackel

Most production electron beam lithography systems can pattern minimum features a few tenths of a micron across. Linewidth in these systems is usually limited by the quality of the exposing beam and by electron scattering in the resist and substrate. By using a smaller spot along with exposure techniques that minimize scattering and its effects, laboratory e-beam lithography systems can now make features hundredths of a micron wide on standard substrate material. This talk will outline sane of these high- resolution e-beam lithography techniques.We first consider parameters of the exposure process that limit resolution in organic resists. For concreteness suppose that we have a “positive” resist in which exposing electrons break bonds in the resist molecules thus increasing the exposed resist's solubility in a developer. Ihe attainable resolution is obviously limited by the overall width of the exposing beam, but the spatial distribution of the beam intensity, the beam “profile” , also contributes to the resolution. Depending on the local electron dose, more or less resist bonds are broken resulting in slower or faster dissolution in the developer.


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