The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Jacobus Vijverberg - One of the best experts on this subject based on the ideXlab platform.
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The effects of food and temperature regimes on life-history responses to fish Kairomones in Daphnia hyalina × galeata*
Hydrobiologia, 2020Co-Authors: Arve Doksaeter, Jacobus VijverbergAbstract:Life-history responses to two concentrations of fish released info-chemicals at two temperature and food regimes were investigated for one clone of Daphnia hyalina × galeata. The presence of fish Kairomones had a negative impact on size at maturity, carbon allocation to individual eggs and size of neonates in all treatments. Food concentration and temperature had positive effects on size of adult stages, independent of kairomone treatment. However, kairomone treatment were not found to interact with food or temperature. Age at maturity was positively influenced by increased temperature and food concentrations, whereas no direct kairomone effects were detected for this trait. Clutch size was not directly influenced by kairomone treatment, whereas both food concentration and temperature had strong, positive effects.
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the effects of food and temperature regimes on life history responses to fish Kairomones in daphnia hyalina galeata
Hydrobiologia, 2001Co-Authors: Arve Doksaeter, Jacobus VijverbergAbstract:Life-history responses to two concentrations of fish released info-chemicals at two temperature and food regimes were investigated for one clone of Daphnia hyalina × galeata. The presence of fish Kairomones had a negative impact on size at maturity, carbon allocation to individual eggs and size of neonates in all treatments. Food concentration and temperature had positive effects on size of adult stages, independent of kairomone treatment. However, kairomone treatment were not found to interact with food or temperature. Age at maturity was positively influenced by increased temperature and food concentrations, whereas no direct kairomone effects were detected for this trait. Clutch size was not directly influenced by kairomone treatment, whereas both food concentration and temperature had strong, positive effects.
H Stibor - One of the best experts on this subject based on the ideXlab platform.
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Predator-mediated life history shifts in Daphnia: enrichment and preliminary chemical characterisation of a kairomone exuded by fish
Archiv Fur Hydrobiologie, 2006Co-Authors: E Von Elert, H StiborAbstract:Daphnia responds to chemical cues released by fish with adaptive changes in life history traits, e. g. a reduction in size at first reproduction (SFR). We used effects on SFR of a clone of Daphnia magna to characterise the chemical nature of the kairomone released by Leuciscus idus. The kairomone was of low lipophilicity and was enriched from incubation water by C 18 -solid phase extraction. The chemical cue was an anion at neutral pH and was reversibly inactivated by acetylation. Ester bonds, olefinic bonds or glucuronic acid can be excluded as essential for the biological activity. The effects on SFR increased with increasing concentrations of enriched kairomone. HPLC yielded only two adjacent active fractions that differed in retention times from those obtained for the diel vertical migration inducing Kairomones released by other cyprinid fish species.
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the role of yolk protein dynamics and predator Kairomones for the life history of daphnia magna
Ecology, 2002Co-Authors: H StiborAbstract:Resource allocation for reproduction of daphniids is strongly determined by the production of yolk protein. It is the main process channeling material into the reproductive pool of the animals. My investigations of yolk protein dynamics provided evidence that Daphnia are able to exhibit flexible brood reduction behavior and that individuals do not use all of the produced yolk protein for reproduction. The animals show parental optimism, meaning that they start to produce more material for offspring than they actually release. Yolk protein dynamics were influenced by predator-released Kairomones. Fish Kairomones influenced the beginning of yolk production resulting in a shorter time until first reproduction. In addition, daphniids exposed to fish Kairomones used more of the produced yolk protein for reproduction than did control animals. The fish kairomone did not influence the rate of yolk production. In contrast, Chaoborus Kairomones influenced the rate of yolk production, but did not change either the beginning of yolk production or the proportion of yolk that was used for egg production. The yolk protein dynamics of daphniids and their ability to exhibit flexible brood reduction behavior can help to explain kairomone-induced life history modifications of daphniids in numerous life history experiments.
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constraints on the plasticity of daphnia magna influenced by fish Kairomones
Functional Ecology, 2000Co-Authors: H Stibor, Muller D NavarraAbstract:1. Daphnia magna reproduced at a smaller size (body mass) when exposed to fish-kairomone than D. magna growing up without this cue. 2. The total egg mass for first reproduction was the same in both groups, but the proportion of clutch mass to total body mass was about 11% higher in daphniids exposed to fish-kairomone. This difference was about the same for low and high food concentrations (0·5 or 1·5 mgC l−1). 3. Although egg mass was the same, triglyceride (TAG) content of the egg material was significantly lower when daphniids were exposed to fish-Kairomones for both food concentrations. 4. The TAG content of the clutch was lowered to the extent that the TAG proportion in the clutch in relation to the somatic mass of the animal was the same for animals treated with fish-kairomone and controls (5% of body mass at first reproduction). 5. The lower TAG content per clutch resulted in a lower quality of the individual egg in daphniids exposed to fish-kairomone. The resulting higher susceptibility to starvation under low food conditions is a substantial cost of the plastic response to fish-Kairomones. 6. This cost may set a limit on the plastic response in resource allocation of Daphnia magna exposed to fish-Kairomones. However, daphniids living in a system with fish predation are more likely to be eaten by fish than to starve to death.
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Constraints on the plasticity of Daphnia magna influenced by fish‐Kairomones
Functional Ecology, 2000Co-Authors: H Stibor, D. Müller NavarraAbstract:1. Daphnia magna reproduced at a smaller size (body mass) when exposed to fish-kairomone than D. magna growing up without this cue. 2. The total egg mass for first reproduction was the same in both groups, but the proportion of clutch mass to total body mass was about 11% higher in daphniids exposed to fish-kairomone. This difference was about the same for low and high food concentrations (0·5 or 1·5 mgC l−1). 3. Although egg mass was the same, triglyceride (TAG) content of the egg material was significantly lower when daphniids were exposed to fish-Kairomones for both food concentrations. 4. The TAG content of the clutch was lowered to the extent that the TAG proportion in the clutch in relation to the somatic mass of the animal was the same for animals treated with fish-kairomone and controls (5% of body mass at first reproduction). 5. The lower TAG content per clutch resulted in a lower quality of the individual egg in daphniids exposed to fish-kairomone. The resulting higher susceptibility to starvation under low food conditions is a substantial cost of the plastic response to fish-Kairomones. 6. This cost may set a limit on the plastic response in resource allocation of Daphnia magna exposed to fish-Kairomones. However, daphniids living in a system with fish predation are more likely to be eaten by fish than to starve to death.
Sandra Lass - One of the best experts on this subject based on the ideXlab platform.
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hatching with the enemy daphnia diapausing eggs hatch in the presence of fish Kairomones
Chemoecology, 2005Co-Authors: Sandra Lass, Justyna Wolinska, Piet SpaakAbstract:Infochemicals are known to play a key role in mediating predator-prey interactions, both in aquatic and terrestrial communities. However, state-dependent variation may exist in how effectively individuals can use this information, depending on genotype, life stage and experience. For our study, we used the predator-prey model system fish-waterflea Daphnia magna Straus (Cladocera, Daphniidae). Adult Daphnia use fish-derived infochemicals, so-called Kairomones, as indicators of predation risk, and exhibit a spectrum of morphological, behavioural and life-history responses to the presence of fish Kairomones. Here, we investigate whether diapausing eggs, an embryonic resting stage in the life cycle of D. magna, also use fish Kairomones and tune their hatching to the risk of fish predation, as reported for diapausing stages of dinoflagellates. In two laboratory experiments, we studied hatching proportion and time until hatching of D. magna diapausing eggs in the absence and presence of fish Kairomones. D. magna families differed significantly in their response to the presence of fish Kairomones; some families reduced hatching proportion, whereas others increased it. Our results imply genotype-dependent differences in the hatching reactions to fish Kairomones as observed for other traits in adult Daphnia.
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facing multiple enemies parasitised hosts respond to predator Kairomones
Oecologia, 2002Co-Authors: Sandra Lass, Kerstin BittnerAbstract:During their lifetime most organisms are exposed to various enemies influencing their victims in multiple direct and indirect ways. Most studies concentrate on the effects of one enemy at a time, thereby not taking into account that in nature organisms are often simultaneously exposed to more than one enemy. We conducted a life-history experiment to investigate the simultaneous effects of predators (fish, Leuciscus idus) and parasites (microparasite, Caullerya mesnili) on their victim (Daphniagaleata). D. galeata were exposed to predator Kairomones, parasites or both. D. galeata are able to sense the presence of fish predators via chemical cues (= Kairomones). Both fish predator Kairomones and microparasite infections influence the life history of Daphnia. Some of the effects of fish predator Kairomones are directly opposed to microparasite effects; fecundity, for example, is increased in the presence of fish Kairomones and decreased in Daphnia parasitised with C. mesnili. We investigated the influence of both threats on age at maturity, body size at different adult instars, fecundity and survival of one D. galeata clone. In the presence of fish Kairomones, all D. galeata matured significantly earlier and increased the number of eggs in the second brood significantly. Parasitised D. galeata matured significantly earlier than non-parasitised ones in the absence and presence of fish Kairomones. An infection with the microparasite C. mesnili led to significantly lower clutch sizes at the second adult instar, to significantly smaller body sizes from adult instar three onwards and to significantly reduced survival. No significant interaction effect between the responses to fish presence and to parasite infection was found for any of the investigated life-history traits. The lack of interaction effects between the exposure to predator Kairomones and parasite infection was most likely due to the different timing of the effects. Fish Kairomones affected D. galeata early in its life history whereas C. mesnili increased in its effects over time. Our results show that parasitised D. galeata are able to exhibit life-history responses to fish predator presence early in their lives. Thus, D. galeata parasitised with C. mesnili have a similar chance as non-parasitised D. galeata to escape from fish predation via life-history changes. Since older parasitised D. galeata are smaller, they may have an even better chance to escape visual predators under actual predation.
Jeanmarie Delpuech - One of the best experts on this subject based on the ideXlab platform.
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increase of the behavioral response to Kairomones by the parasitoid wasp leptopilina heterotoma surviving insecticides
Archives of Environmental Contamination and Toxicology, 2005Co-Authors: Jeanmarie Delpuech, C Bardon, M BouletreauAbstract:Hymenopterous parasitoids are key species involved in the regulation of insect populations. Kairomone perception is an important step leading to host parasitization. The massive use of insecticides induces environmental pollution that can interact with the reproduction of parasitoids. In this work, we have determined the sublethal effects of two insecticides, an organophosphorus (chlorpyrifos) and a pyrethroid (deltamethrin), on the arrestment, by host Kairomones, of female parasitoids surviving an LD 20 for 24 h. The behavior of the parasitoids has been recorded with a video-computerized system. The analysis of the behaviors in control conditions versus exposed to an LD 20 have shown that both insecticides significantly increased the arrestment of parasitoids by Kairomones. This increase was not followed up by a modification of the kinetics of the behavior. In both control and exposed conditions, parasitoids regularly increased their residence time on the kairomone patch indicating that no saturation to Kairomones had occurred. In a field situation where hosts could be scarce, this increase in arrestment could be advantageous for parasitoids by increasing their host finding.
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modification by the insecticide chlorpyrifos of the behavioral response to Kairomones of a parasitoid wasp leptopilina boulardi
Archives of Environmental Contamination and Toxicology, 2001Co-Authors: N Komeza, M Bouletreau, Pierre Fouillet, Jeanmarie DelpuechAbstract:Parasitoids are key species involved in the regulation of natural populations. Host parasitization is realized via some important steps in which kairomone perception is essential. Due to the wide use of insecticides and their contribution to environmental pollution, the determination of their sublethal effects on behaviors involved in the reproduction of parasitoids becomes a necessity. In this work, we analyzed the effects of a lethal dose 20% of chlorpyrifos, an organophosphorus insecticide, on the behavior of L. boulardi toward the kairomone of its host. The insecticide significantly modified the kinetics of the residence time of parasitoids on a patch marked by Kairomones. Females exposed to the insecticide were less efficient in finding the kairomone patch than control females, and they tended to stay on that patch, whereas control females rapidly left it. These effects are discussed considering the mode of action of the insecticide. Because search time allocation of host is an important component for parasitism efficiency, this modification of behavior could interfere with the reproduction capacity of parasitoids. Therefore, in a context of environmental pollution, the repercussions of such sublethal effects on the population biology of insects need to be considered.
Ran Li - One of the best experts on this subject based on the ideXlab platform.
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differential attraction of parasitoids in relation to specificity of Kairomones from herbivores and their by products
Insect Science, 2008Co-Authors: Sumera Afsheen, Xia Wang, Ran LiAbstract:Infochemicals are used by foraging parasitoids in the host selection process from habitat preference until host recognition. Kairomones from the herbivore host plays a vital role in the attraction of parasitoids, particularly in the micro-habitat. Parasitoids are specifically attracted to their respective herbivore species even when different herbivores are present on the same plant. Chemicals emitted from different stages of host (eggs, larvae, pupae, adult), host by-products (e.g., frass, exuviae, mandibular gland secretions, defense secretions etc.), or intra-specific infochemicals (pheromones) can be main signals for the parasitoids. Parasitoids can differentiate between host and non-host, between different hosts and host stages by perceiving specific volatile and contact Kairomones from the host itself, host along with its by-product, by-products alone or intra-specific infochemicals; of which frass (by-product) and intra-specific infochemicals are the most reported ones. Adult and larval parasitoids have been reported to be attracted to Kairomones of their target stage or byproduct of their host. Pupal parasitoids have been found to utilize Kairomones from the preceding host stage while egg parasitoids are known to exploit a variety of host infochemicals, for example, either from eggs themselves or other non-target host stages, especially adults and adult-related by-products. The kairomonal chemicals identified so far include various groups, but mainly hydrocarbons. A high degree of host specificity and host acceptance is important for the parasitoids as any mistake may result in the loss of fitness.
