The Experts below are selected from a list of 180 Experts worldwide ranked by ideXlab platform
Wilhelm Barthlott - One of the best experts on this subject based on the ideXlab platform.
-
a new bioinspired method for pressure and flow sensing based on the underwater air retaining surface of the backswimmer Notonecta
Beilstein Journal of Nanotechnology, 2018Co-Authors: Matthias Mail, Adrian Klein, Horst Bleckmann, Anke Schmitz, Torsten Scherer, Peter T Ruhr, Goran Lovric, Robin Frohlingsdorf, Stanislav N Gorb, Wilhelm BarthlottAbstract:In technical systems, static pressure and pressure changes are usually measured with piezoelectric materials or solid membranes. In this paper, we suggest a new biomimetic principle based on thin air layers that can be used to measure underwater pressure changes. Submerged backswimmers (Notonecta sp.) are well known for their ability to retain air layers on the surface of their forewings (hemelytra). While analyzing the hemelytra of Notonecta, we found that the air layer on the hemelytra, in combination with various types of mechanosensitive hairs (clubs and pins), most likely serve a sensory function. We suggest that this predatory aquatic insect can detect pressure changes and water movements by sensing volume changes of the air layer under water. In the present study, we used a variety of microscopy techniques to investigate the fine structure of the hemelytra. Furthermore, we provide a biomimetic proof of principle to validate our hypothesis. The suggested sensory principle has never been documented before and is not only of interest for sensory biologists but can also be used for the development of highly sensitive underwater acoustic or seismographic sensory systems.
-
superhydrophobic surfaces of the water bug Notonecta glauca a model for friction reduction and air retention
Beilstein Journal of Nanotechnology, 2011Co-Authors: Petra Ditschekuru, Erik S Schneider, Janerik Melskotte, Martin Brede, Alfred Leder, Wilhelm BarthlottAbstract:Superhydrophobic surfaces of plants and animals are of great interest for biomimetic applications. Whereas the self-cleaning properties of superhydrophobic surfaces have been extensively investigated, their ability to retain an air film while submerged under water has not, in the past, received much attention. Nevertheless, air retaining surfaces are of great economic and ecological interest because an air film can reduce friction of solid bodies sliding through the water. This opens perspectives for biomimetic applications such as low friction fluid transport or friction reduction on ship hulls. For such applications the durability of the air film is most important. While the air film on most superhydrophobic surfaces usually lasts no longer than a few days, a few semi-aquatic plants and insects are able to hold an air film over a longer time period. Currently, we found high air film persistence under hydrostatic conditions for the elytra of the backswimmer Notonecta glauca which we therefore have chosen for further investigations. In this study, we compare the micro- and nanostructure of selected body parts (sternites, upper side of elytra, underside of elytra) in reference to their air retaining properties. Our investigations demonstrate outstanding air film persistence of the upper side of the elytra of Notonecta glauca under hydrostatic and hydrodynamic conditions. This hierarchically structured surface was able to hold a complete air film under hydrostatic conditions for longer than 130 days while on other body parts with simple structures the air film showed gaps (underside of elytra) or even vanished completely after a few days (sternites). Moreover, the upper side of the elytra was able to keep an air film up to flow velocities of 5 m/s. Obviously the complex surface structure with tiny dense microtrichia and two types of larger specially shaped setae is relevant for this outstanding ability. Besides high air film persistence, the observation of a considerable fluid velocity directly at the air–water interface indicates the ability to reduce friction significantly. The combination of these two abilities makes these hierarchically structured surfaces extremely interesting as a biomimetic model for low friction fluid transport or drag reduction on ship hulls.
Ross A Black - One of the best experts on this subject based on the ideXlab platform.
-
predator induced phenotypic plasticity in daphnia pulex life history and morphological responses to Notonecta and chaoborus
Limnology and Oceanography, 1993Co-Authors: Ross A BlackAbstract:Results from a laboratory life-table study show Daphnia pulex has a unique set of rapidly induced responses to waterborne chemicals from each of two predator species. Additionally, Daphnia exhibits a unique set of induced responses when simultaneously exposed to both predators. Daphnids possessed neck teeth and experienced delayed maturity when exposed to waterborne chemicals released from larvae of the phantom midge Chaoborus americanus. Possessing the Chaoborus-induced phenotypic plasticity was not associated with a lower population growth rate relative to that in the control treatment. When exposed to waterborne chemicals released from the backswimmer Notonecta undulata, D. pulex exhibited an unexpected assemblage of responses. The Notonecta-induced phenotypic plasticity included rapid juvenile growth to a large size at first reproduction, little growth beyond maturity, and high reproductive output. Simultaneous exposure to chemical cues from Notonecta and Chaoborus resulted in a life history and morphologies that agreed with predicted life history and morphological responses of Daphnia that had been simultaneously exposed to largeand small-size selective predators. Predators are an important evolutionary force shaping the life histories, morphologies, and behaviors of their prey. Several aquatic taxa possess phenotypically plastic life histories and morphologies that may be induced by the presence of specific predators (Have1 1987; Dodson 19893; Harvell 1990). Predator-induced phenotypic plasticities can be viewed as being particularly adaptive because any disadvantage incurred by having a predator-resistant form is borne only when the predator is present. Among zooplankton, several species exhibit seasonal variation in morphologies to which the term cyclomorphosis has been applied (Hutchinson 1967; Black and Slobodkin 1987). Dodson (1974a) suggested zooplankton change shape as an adaptive strategy to foil the efforts of specific size-selective predators. An abundance of recent evidence supports his hypothI Present address: Water Resources Laboratory, University of Louisville, Louisville, Kentucky 40292. Acknowledgments I thank Stanley I. Dodson, John E. Havel, Nina Hemphill, and an anonymous reviewer for comments on the interpretation of the results presented and on the preparation of this manuscript. Daniel D. Wiegmann provided statistical advice. I received financial support through a Henry Freeman Vilas Graduate Fellowship from the University of Wisconsin-Madison Graduate School and an NSF grant (BSR 88-05805) to S. I. Dodson. esis. Several of the morphological changes seen in common cyclomorphic species of zooplankton can be induced by waterborne chemicals released from invertebrate predators (see Havel 1987; Stemberger and Gilbert 1987). Also, several predators are each capable of inducing a different morphological response in a prey species (Dodson 1989a). In practically every reported case of predator-induced morphological shifts, possession of the induced morphology is coupled with shifts in life history traits (for Daphnia, Black and Dodson 1990; Riessen and Sprules 1990; for rotifers, Stemberger 1988; for Bryozoa, Harvell 1986). When life history traits of the induced form result in lower fitness relative to the uninduced form, in the absence of the predator, investigators have interpreted the life history shifts as the cost of the induced morphology (Stemberger 1988; Walls and Matti 1989; Black and Dodson 1990; Riessen and Sprules 1990). In this study, life-table experiments were used to collect survivorship, fecundity, and morphological data from Daphnia pulex individuals that were exposed to chemical cues from two invertebrate predators, the backswimmer Notonecta undulata (Insecta, Hemiptera) and larvae of the phantom midge Chaoborus americanus (Insecta, Diptera). Both are common predators of Daphnia and often co-occur (Dodson and Have1 1988), although
Shannon J. Mccauley - One of the best experts on this subject based on the ideXlab platform.
-
Co-occurring Notonecta (Hemiptera: Heteroptera: Notonectidae) Species Differ in Their Behavioral Response to Cues of Belostoma (Hemiptera: Heteroptera: Belostomatidae) Predation Risk
Annals of The Entomological Society of America, 2019Co-Authors: Ilia Maria C. Ferzoco, Celina B. Baines, Shannon J. MccauleyAbstract:Abstract Predators affect prey through direct consumption as well as by inducing prey to defensively alter their phenotypes, including behavioral phenotypes, to maximize survival under predation risk. Closely related sympatric prey species with shared natural enemies may resolve behavioral trade-offs under predation risk differently. In a laboratory experiment, we investigated two co-occurring semiaquatic backswimmer congeners, which exhibit differences in their degree of habitat specialization across a gradient of habitat permanence. Notonecta irrorata Uhler primarily occur in ephemeral ponds, whereas Notonecta undulata Say are habitat generalists that are commonly found in both permanent and ephemeral ponds. We tested whether the two species differed in antipredator responses to both visual and chemical cues of a shared predator, the giant water bug, in a fully factorial design. The generalist species, N. undulata, exhibited reductions in activity in the presence of predator chemical cues only, whereas the specialist species, N. irrorata, remained consistently active across predator cue treatments. Our work shows that there are species-specific differences in how prey assess or respond to predation risk. The varying propensities of these backswimmer congeners to behaviorally respond to a shared predator, and differences in their behavior when exposed to different predation risk cues may be linked to underlying divergence in their life-history strategies.
-
Sex-biased dispersal is independent of sex ratio in a semiaquatic insect
Behavioral Ecology and Sociobiology, 2017Co-Authors: Celina B. Baines, Ilia Maria Ferzoco, Shannon J. MccauleyAbstract:Dispersal influences a variety of ecological and evolutionary dynamics including metapopulation persistence and local adaptation. Sex-biased dispersal evolves when the costs and benefits associated with dispersal differ between the sexes. These costs and benefits may be fixed, resulting in a consistent pattern of sex-biased dispersal within species whereby one sex always disperses more and/or further than the other. Alternatively, the costs and benefits may vary depending on the intensity of competition experienced by the two sexes. In this case, the direction of the sex bias may be plastic and depend on the sex ratio of the population. In the current study, we asked whether a semiaquatic, flight capable insect ( Notonecta undulata ) exhibits sex-biased dispersal and whether the strength of intrasexual competition experienced by males and females determines the direction of the sex bias. We conducted a mesocosm experiment in which we manipulated the population sex ratio and measured the probability of dispersal for males and females. We found that while both sexes dispersed, male dispersal rates were higher, and this pattern was independent of sex ratio. This suggests that fixed sex-specific dispersal costs and/or benefits are likely to be more important determinants of sex-biased dispersal in notonectids than population sex ratio. Significance statement Dispersal is the process by which individuals move through space and cause gene flow and therefore is a major factor determining the distribution of individuals, populations, species, and alleles—a topic which is one of the core themes in ecology. Dispersers commonly differ from non-dispersers in a variety of phenotypes, including sex. Sex-biased dispersal may have important implications for the populations that send out and receive dispersers, because males and females have different impacts on populations. We explored whether sex-specific dispersal behavior in an insect ( Notonecta undulata ) changes depending on how intensely individuals have to compete for resources (e.g., food, mates) with individuals of the same sex. We found that males dispersed more, and this was true regardless of which sex experienced stronger intrasexual competition. This suggests that males experience lower costs and/or greater benefits from dispersing than do females.
-
Notonecta exhibit threat sensitive predator induced dispersal
Biology Letters, 2010Co-Authors: Shannon J. Mccauley, Locke RoweAbstract:Dispersal is a central process determining community structure in heterogeneous landscapes, and species interactions within habitats may be a major determinant of dispersal. Although the effects of species interactions on dispersal within habitats have been well studied, how species interactions affect the movement of individuals between habitats in a landscape has received less attention. We conducted two experiments to assess the extent to which predation risk affects dispersal from an aquatic habitat by a flight-capable semi-aquatic insect (Notonecta undulata). Exposure to non-lethal (caged) fish fed conspecifics increased dispersal rates in N. undulata. Moreover, dispersal rate was positively correlated with the level of risk imposed by the fish; the greater the number of notonectids consumed by the caged fish, the greater the dispersal rate from the habitat. These results suggest that risk within a habitat can affect dispersal among habitats in a landscape and thus affect community structure on a much greater scale than the direct effect of predation itself.
Nils Kautsky - One of the best experts on this subject based on the ideXlab platform.
-
trophic interactions in rockpool food webs regulation of zooplankton and phytoplankton by Notonecta and daphnia
Freshwater Biology, 1998Co-Authors: Marie Arnér, Sanna Koivisto, Jon Norberg, Nils KautskyAbstract:We studied trophic interactions in experimental rockpools with three different food web structures: phytoplankton and small-bodied zooplankton; phytoplankton, small-bodied zooplankton and Daphnia; and phytoplankton, small-bodied zooplankton, Daphnia and Notonecta. Nutrients, primary productivity, chlorophyll a and zooplankton species composition and biomass were measured over eight weeks. 2. Daphnia had a negative impact on other zooplankton and reduced the phytoplankton biomass and primary productivity. In the absence of Daphnia, small-bodied zooplankton species were abundant, in particular cyclopoid copepods. Concentrations of dissolved nutrients were lower and the standing crop of primary producers was higher when Daphnia was absent. 3. The presence of the invertebrate predator Notonecta produced a top-down effect which was similar to that reported for planktivorous fish, i.e. a selective reduction of daphnids followed by an increase of small-bodied zooplankton species and phytoplankton biomass. 4. The study showed that consumer regulation of Daphnia by Notonecta and of algae by Daphnia are important, but also demonstrated that trophic level biomasses were controlled by a combination of predation and resource limitation.
-
Does cadmium pollution change trophic interactions in rockpool food webs
Environmental Toxicology and Chemistry, 1997Co-Authors: Sanna Koivisto, Marie Arnér, Nils KautskyAbstract:The authors studied the regulation of phytoplankton and zooplankton biomass in rockpool food webs under chronic cadmium pollution. Experimental food webs with two and three trophic levels were composed of phytoplankton, small-bodied zooplankton (Chydorus sphaericus, Cyclops sp., and rotifers), Daphnia magna, and Notonecta sp., a zooplanktivorous predator. Every food web received a control and cadmium treatment allowing a separate study of cadmium and predation effects. After a 3-week stabilization period, cadmium and Notonecta were added and changes in primary productivity, chlorophyll, zooplankton species composition, and biomass were followed during 8 weeks. The results showed that phytoplankton and Daphnia were consumer regulated in both control and cadmium treatments, although resource availability ultimately determined the biomass at each trophic level. Daphnia was the only zooplankton species that reduced phytoplankton and also the only species that was eliminated by Notonecta predation. Notonecta had an indirect positive impact on phytoplankton biomass that increased after the extinction of Daphnia. Cadmium significantly reduced phytoplankton and Daphnia but did not change the trophic interactions between them, i.e., Daphnia and chlorophyll were significantly negatively correlated both in the control and cadmium treatments. Cadmium did not affect the relationship between Daphnia and Notonecta.
Leon Blaustein - One of the best experts on this subject based on the ideXlab platform.
-
oviposition habitat selection by anopheles gambiae in response to chemical cues by Notonecta maculata
Journal of Vector Ecology, 2011Co-Authors: Alon Warburg, Joel E. Cohen, Alon Silberbush, Roy Faiman, Alex Shtern, Shai Markman, Leon BlausteinAbstract:ABSTRACT: A number of mosquito species avoid predator-inhabited oviposition sites by detecting predator-released kairomones. In the laboratory, we found that when offered de-ionized water and de-ionized water conditioned with Notonecta maculata, gravid Anopheles gambiae females preferentially oviposited into the former. We then conducted further experiments using two chemical components found in Notonecta-conditioned water, chemically pure n-tricosane and/or n-heneicosane, that was previously shown to repel oviposition by Culiseta longiareolata. These hydrocarbons failed to deter oviposition by An. gambiae females. Thus, different mosquito species may rely on distinct chemical cues to avoid predators. Identification and chemical characterization of such kairomones could facilitate innovative, environmentally sound mosquito control.
-
Mosquito females quantify risk of predation to their progeny when selecting an oviposition site
Functional Ecology, 2011Co-Authors: Alon Silberbush, Leon BlausteinAbstract:Summary 1. Numerous studies demonstrate that given the dichotomous choice of predator-free habitats vs. habitats containing predators, prey choose predator-free habitats when foraging for food or ovipositing. However, predation risk is rarely dichotomous in nature, and very few studies have assessed whether prey can quantify predation risk when selecting habitats. 2. It was shown previously that gravid females of the mosquito Culiseta longiareolata, when simultaneously offered pools with multiple choices of densities of the predator Notonecta maculata, oviposited more in the zero-predator density pools but oviposited less frequently and similarly across all other densities. This flat oviposition response across various Notonecta densities was in contrast to a decrease in mosquito immature survival with increasing Notonecta density. Here, we reconsider this question with the same species but with a different experimental design; rather than experimentally assessing multiple predator densities simultaneously, we offered only pairwise choices on any given night. Specifically, we offered ovipositing Culiseta females all pairwise combinations from no, low and high predation risk (0, 1 and 4 Notonecta per pool). 3. Overall oviposition was lower when mosquitoes could only choose pools containing Notonecta (1 or 4). In all pairwise comparisons, more females chose pools of lesser predation risk. Thus, gravid females of this species, and probably many other species, can quantify predation risk, and not only assess presence or absence of predation risk, when choosing oviposition sites. 4. This is the first demonstration that an ovipositing female of any species can quantify risk of predation. We suggest, based on statistical and behavioural factors, that pairwise comparisons, and not simultaneous multiple-choice experiments, are the experimental design of choice to adequately test this ability.
-
Effects of predator density and duration of predator occupancy on crustacean abundance and diversity in experimental pools
Hydrobiologia, 2010Co-Authors: Avi Eitam, Leon BlausteinAbstract:Keystone predators, by reducing the abundance of competitively superior prey, may have indirect positive effects on weak competitors, possibly increasing their abundance or preventing local competitive exclusion. By analogy to the Intermediate Disturbance Hypothesis, we would expect species diversity to peak at intermediate predator densities. In a replicated artificial pool experiment, we examined the relationships between density of the backswimmer Notonecta maculata (0, 1, 2, and 4 per 30 l pool) and invertebrate taxon diversity over an 11-week period of predator occupancy. Diversity reached high levels at high predator density sooner than at intermediate density. At the end of the experiment, taxon diversity was greatest at densities of 2 and 4 Notonecta per pool. While the overall predator density–diversity curve was in line with the intermediate disturbance hypothesis, the reduction in diversity from intermediate to high predator density was not statistically significant. Density of the preferred prey Daphniamagna decreased with Notonecta density, while densities of the smaller cladocerans Moinabrachiata and Ceriodaphnia spp. increased. Suppression of Daphnia at high Notonecta densities may partially explain the increase in Moina and Ceriodaphnia densities. However, most of the relationship between Notonecta and the smaller cladocerans appears to be independent of Daphnia, suggesting complex interactions within the community. Our results suggest that keystone predation plays a strong role in structuring this community. Although diversity did not decrease significantly at the highest predator density as predicted, such a decrease may be more likely for pools with longer durations of predator occupancy or with higher predator densities.
-
chemical detection of the predator Notonecta irrorata by ovipositing culex mosquitoes
Journal of Vector Ecology, 2005Co-Authors: Leon Blaustein, Jonathan Blaustein, Jonathan M ChaseAbstract:We tested the oviposition response of Culex mosquitoes to the predator Notonecta irrorata in an outdoor artificial pool experiment employing equal numbers of control and predator pools. There was a strong oviposition avoidance by Culex of Notonecta pools; 83% of egg rafts were found in control pools during the period in which Notonecta were present. After removing Notonecta, mosquitoes continued to avoid ovipositing in the former Notonecta pools for two additional days suggesting a predator-released kairomone as the cue used by the mosquitoes to detect the presence of this predator.
-
oviposition habitat selection by mosquitoes in response to predator Notonecta maculata density
Physiological Entomology, 2004Co-Authors: Avi Eitam, Leon BlausteinAbstract:. Some species of mosquitoes can detect the presence of predatory notonectid bugs and avoid oviposition in predator pools. The oviposition response of two mosquito species, Culiseta longiareolata Macquart and Culex laticinctus Edwards (Diptera: Culicidae), to a range of densities of the predator, Notonecta maculata Fabricius (Heteroptera: Notonectidae), was tested here. Densities of 0, 1, 2 or 4 Notonecta were established in 30-L artificial pools. Both mosquito species oviposited less in predator pools, but the response was unrelated to predator density, whereas vulnerability of Culiseta immatures to predation was density-dependent. Thus, although mosquitoes can detect Notonecta at any density within the range tested, they may be unable to discriminate among predator densities. The avoidance of predator pools by Culiseta, as well as its vulnerability to predation, occurred to a lesser degree than in earlier studies. This may have been due to the mitigating effects of components of the biotic community.
