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Silvia Dorn - One of the best experts on this subject based on the ideXlab platform.
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Perception of achromatic cues during Host Location of a pupal parasitoid
Entomologia Experimentalis Et Applicata, 2020Co-Authors: Sabine Fischer, Felix L Wackers, Jorg Samietz, Silvia DornAbstract:Visual cues employed by parasitic Hymenoptera havedifferent behavioral relevance during the Location of theHost microhabitat from a distance and Host Location afterlanding. During the approach flight of bees and wasps,achromatic contrast is perceived first, followed by chro-matic (color) contrast (Giurfa et al., 1996). The distancefrom which a target, e.g., the Host habitat, can be visuallydetected is determined by the size of the target area that pro-duces achromatic contrast with the background (Ne’eman& Kevan, 2001). Chromatic information is used over arelatively short range (Giurfa & Lehrer, 2001; Ne’eman K Pfannenstielet al., 1992; Smith et al., 1993; Potting et al., 1997). Despitethe importance of visual cues in Host finding of hymen-opteran parasitoids, there are only three electrophysiologicalstudies addressing their spectral sensitivity (Peitsch et al.,1992; Mellor et al., 1997; Brown et al., 1998) and twobehavioral studies on color vision, i.e., the sensation ofchromatic contrast independent of intensity contrast(Wardle, 1990; Messing & Jang, 1992). While informationon chromatic vision is scarce, the role of achromatic cuesin parasitoid Host Location is largely unknown.For species that parasitize the pupae of endophytic Hosts,i.e., Hosts concealed within plant tissue, olfactory cues arenot readily available as the pupae do not feed, do not pro-duce feces, and pupation often occurs away from the larvalfeeding sites. Instead, these parasitoid species can use vibra-tional sounding and plant-derived visual cues for Host loca-tion. Plant tissue damaged by Host infestation can desiccateor discolor and serve as an achromatic Host Location cue forparasitoids such as
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Terpene-mediated parasitoid Host Location behavior on transgenic and classically bred apple genotypes.
Journal of Agricultural and Food Chemistry, 2009Co-Authors: Ute Vogler, Anja S. Rott, Cesare Gessler, Silvia DornAbstract:Terpene-mediated interactions between transgenic or classically bred apple genotypes and associated insects were investigated. Apple genotypes were either resistant or susceptible to Venturia inaequalis that causes apple scab. They were subjected to infestation by Phyllonorycter leafminers and/or inoculation with V. inaequalis. Apple leaf extracts were analyzed by gas chromatography-mass spectrometry to quantify squalene, a triterpene known to mediate Host Location by Pholetesor parasitoids that are specialized on leafminers. Squalene contents in leafminer-infested leaves differed between the transgenic apple scab resistant line and a classically bred cultivar sharing the same resistance gene. This resistant cultivar showed an increase in squalene contents from healthy to leafminer-infested leaves. This was not the case in the transgenic resistant line. However, there was also no increase in the susceptible isogenic cultivar. Behavioral bioassays with parasitoid females also reflected these findings. Hence, alterations in leaf chemistry and corresponding responses of the parasitoid are apparent among classically bred cultivars, rather than in the genetically modified resistant line.
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Body temperature of the parasitic wasp Pimpla turionellae (Hymenoptera) during Host Location by vibrational sounding
Physiological Entomology, 2008Co-Authors: Stefan Kroder, Anton Stabentheiner, Jorg Samietz, Silvia DornAbstract:The pupal parasitoid Pimpla turionellae (L.) uses self-produced vibrations transmitted on the plant substrate, so-called vibrational sounding, to locate immobile concealed pupal Hosts. The wasps are able to use vibrational sounding reliably over a broad range of ambient temperatures and even show an increased signal frequency and intensity at low temperatures. The present study investigates how control of body temperature in the wasps by endothermic mechanisms may facilitate Host Location under changing thermal environments. Insect body temperature is measured with real-time IR thermography on plant-stem models at temperature treatments of 10, 18, 26 and 30 °C, whereas behaviour is recorded with respect to vibrational Host Location. The results reveal a low-level endothermy that likely interferes with vibrational sound production because it occurs only in nonsearching females. At the lowest temperature of 10 °C, the thoracic temperature is 1.15 °C warmer than the ambient surface temperature whereas, at the high temperatures of 26 and 30 ° C, the wasps cool down their thorax by 0.29 and 0.47 °C, respectively, and their head by 0.45 and 0.61 °C below ambient surface temperature. By contrast, regardless of ambient temperature, searching females always have a slightly elevated body temperature of at most 0.30 °C above the ambient surface temperature. Behavioural observations indicate that searching females interrupt Host Location more frequently at suboptimal temperatures, presumably due to the requirements of thermoregulation. It is assumed that both mechanisms, producing vibrations for Host Location and low-level endothermy, are located in the thorax. Endothermy by thoracic muscle work probably disturbs signal structure of vibrational sounding, so the processes cannot be used at the same time.
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Body temperature of the parasitic wasp Pimpla turionellae (Hymenoptera) during Host Location by vibrational sounding
Physiological Entomology, 2008Co-Authors: Stefan Kroder, J??rg Samietz, Anton Stabentheiner, Silvia DornAbstract:The pupal parasitoid Pimpla turionellae (L.) uses self-produced vibrations transmitted on the plant substrate, so-called vibrational sounding, to locate immobile concealed pupal Hosts. The wasps are able to use vibrational sounding reliably over a broad range of ambient temperatures and even show an increased signal frequency and intensity at low temperatures. The present study investigates how control of body temperature in the wasps by endothermic mechanisms may facilitate Host Location under changing thermal environments. Insect body temperature is measured with real-time IR thermography on plant-stem models at temperature treatments of 10, 18, 26 and 30 °C, whereas behaviour is recorded with respect to vibrational Host Location. The results reveal a low-level endothermy that likely interferes with vibrational sound production because it occurs only in nonsearching females. At the lowest temperature of 10 °C, the thoracic temperature is 1.15 °C warmer than the ambient surface temperature whereas, at the high temperatures of 26 and 30 ° C, the wasps cool down their thorax by 0.29 and 0.47 °C, respectively, and their head by 0.45 and 0.61 °C below ambient surface temperature. By contrast, regardless of ambient temperature, searching females always have a slightly elevated body temperature of at most 0.30 °C above the ambient surface temperature. Behavioural observations indicate that searching females interrupt Host Location more frequently at suboptimal temperatures, presumably due to the requirements of thermoregulation. It is assumed that both mechanisms, producing vibrations for Host Location and low-level endothermy, are located in the thorax. Endothermy by thoracic muscle work probably disturbs signal structure of vibrational sounding, so the processes cannot be used at the same time. © 2007 The Authors.
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Temperature affects interaction of visual and vibrational cues in parasitoid Host Location.
Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology, 2006Co-Authors: Stefan Kroder, Jorg Samietz, Silvia DornAbstract:Parasitoid Host Location in nature is facilitated by simultaneously using different information sources. How multisensory orientation on the same spatial scale is influenced by environmental conditions is however poorly understood. Here we test whether changes in reliability of cues can cause parasitoids to alter multisensory orientation and to switch to cues that are more reliable under extreme temperatures. In the ichneumonid wasp Pimpla turionellae, multisensory use of thermally insensitive vision and thermally sensitive mechanosensory Host Location by vibrational sounding (echoLocation on solid substrate) was investigated with choice experiments on plant-stem models under optimum temperature (18°C), at high- (28°C) and low-temperature limits (8°C) of vibrational sounding. Temperature affected relative importance of vibrational sounding whereas visual orientation did not vary. At 18°C, parasitoids used visual and vibrational cues with comparable relative importance. At 8 and 28°C, the role of vibrational sounding in multisensory orientation was significantly reduced in line with decreased reliability. Wasps nearly exclusively chose visual cues at 8°C. The parasitoids switch between cues and sensory systems depending on temperature. As overall precision of ovipositor insertions was not affected by temperature, the parasitoids fully compensate the loss of one cue provided another reliable cue is available on the same spatial scale.
Jorg Samietz - One of the best experts on this subject based on the ideXlab platform.
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Perception of achromatic cues during Host Location of a pupal parasitoid
Entomologia Experimentalis Et Applicata, 2020Co-Authors: Sabine Fischer, Felix L Wackers, Jorg Samietz, Silvia DornAbstract:Visual cues employed by parasitic Hymenoptera havedifferent behavioral relevance during the Location of theHost microhabitat from a distance and Host Location afterlanding. During the approach flight of bees and wasps,achromatic contrast is perceived first, followed by chro-matic (color) contrast (Giurfa et al., 1996). The distancefrom which a target, e.g., the Host habitat, can be visuallydetected is determined by the size of the target area that pro-duces achromatic contrast with the background (Ne’eman& Kevan, 2001). Chromatic information is used over arelatively short range (Giurfa & Lehrer, 2001; Ne’eman K Pfannenstielet al., 1992; Smith et al., 1993; Potting et al., 1997). Despitethe importance of visual cues in Host finding of hymen-opteran parasitoids, there are only three electrophysiologicalstudies addressing their spectral sensitivity (Peitsch et al.,1992; Mellor et al., 1997; Brown et al., 1998) and twobehavioral studies on color vision, i.e., the sensation ofchromatic contrast independent of intensity contrast(Wardle, 1990; Messing & Jang, 1992). While informationon chromatic vision is scarce, the role of achromatic cuesin parasitoid Host Location is largely unknown.For species that parasitize the pupae of endophytic Hosts,i.e., Hosts concealed within plant tissue, olfactory cues arenot readily available as the pupae do not feed, do not pro-duce feces, and pupation often occurs away from the larvalfeeding sites. Instead, these parasitoid species can use vibra-tional sounding and plant-derived visual cues for Host loca-tion. Plant tissue damaged by Host infestation can desiccateor discolor and serve as an achromatic Host Location cue forparasitoids such as
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Body temperature of the parasitic wasp Pimpla turionellae (Hymenoptera) during Host Location by vibrational sounding
Physiological Entomology, 2008Co-Authors: Stefan Kroder, Anton Stabentheiner, Jorg Samietz, Silvia DornAbstract:The pupal parasitoid Pimpla turionellae (L.) uses self-produced vibrations transmitted on the plant substrate, so-called vibrational sounding, to locate immobile concealed pupal Hosts. The wasps are able to use vibrational sounding reliably over a broad range of ambient temperatures and even show an increased signal frequency and intensity at low temperatures. The present study investigates how control of body temperature in the wasps by endothermic mechanisms may facilitate Host Location under changing thermal environments. Insect body temperature is measured with real-time IR thermography on plant-stem models at temperature treatments of 10, 18, 26 and 30 °C, whereas behaviour is recorded with respect to vibrational Host Location. The results reveal a low-level endothermy that likely interferes with vibrational sound production because it occurs only in nonsearching females. At the lowest temperature of 10 °C, the thoracic temperature is 1.15 °C warmer than the ambient surface temperature whereas, at the high temperatures of 26 and 30 ° C, the wasps cool down their thorax by 0.29 and 0.47 °C, respectively, and their head by 0.45 and 0.61 °C below ambient surface temperature. By contrast, regardless of ambient temperature, searching females always have a slightly elevated body temperature of at most 0.30 °C above the ambient surface temperature. Behavioural observations indicate that searching females interrupt Host Location more frequently at suboptimal temperatures, presumably due to the requirements of thermoregulation. It is assumed that both mechanisms, producing vibrations for Host Location and low-level endothermy, are located in the thorax. Endothermy by thoracic muscle work probably disturbs signal structure of vibrational sounding, so the processes cannot be used at the same time.
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Temperature affects interaction of visual and vibrational cues in parasitoid Host Location.
Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology, 2006Co-Authors: Stefan Kroder, Jorg Samietz, Silvia DornAbstract:Parasitoid Host Location in nature is facilitated by simultaneously using different information sources. How multisensory orientation on the same spatial scale is influenced by environmental conditions is however poorly understood. Here we test whether changes in reliability of cues can cause parasitoids to alter multisensory orientation and to switch to cues that are more reliable under extreme temperatures. In the ichneumonid wasp Pimpla turionellae, multisensory use of thermally insensitive vision and thermally sensitive mechanosensory Host Location by vibrational sounding (echoLocation on solid substrate) was investigated with choice experiments on plant-stem models under optimum temperature (18°C), at high- (28°C) and low-temperature limits (8°C) of vibrational sounding. Temperature affected relative importance of vibrational sounding whereas visual orientation did not vary. At 18°C, parasitoids used visual and vibrational cues with comparable relative importance. At 8 and 28°C, the role of vibrational sounding in multisensory orientation was significantly reduced in line with decreased reliability. Wasps nearly exclusively chose visual cues at 8°C. The parasitoids switch between cues and sensory systems depending on temperature. As overall precision of ovipositor insertions was not affected by temperature, the parasitoids fully compensate the loss of one cue provided another reliable cue is available on the same spatial scale.
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Effect of ambient temperature on mechanosensory Host Location in two parasitic wasps of different climatic origin
Physiological Entomology, 2006Co-Authors: Stefan Kroder, Jorg Samietz, Silvia DornAbstract:Several parasitic wasps of the Pimplinae (Ichneumonidae) use self-produced vibrations transmitted through plant substrate to locate their concealed immobile Hosts (lepidopteran pupae) by reflected signals. This mechanosensory mechanism of Host Location, called vibrational sounding, depends on the physical characteristics of the plant substrate and the wasp’s body and is postulated to depend on ambient temperature. Adaptations of two parasitoid species to thermal conditions of their habitats and the influence of temperature on the trophic interaction during Host Location are investigated in the tropical Xanthopimpla stemmator (Thunberg) and compared with the temperate Pimpla turionellae (L.). Plant-stem models with hidden Host mimics are offered to individual wasps under defined temperature treatments and scored for the number and Location of ovipositor insertions. Significant effects of temperature are found on Host-Location activity and its success. The tropical species possesses an optimum temperature range for vibrational sounding between 26 and 32 °C, whereas the performance decreases both at low and high temperatures. The temperate species reveals substantial differences with respect to performance at the same thermal conditions. With increasing temperature, P. turionellae shows a reduced response to the Host mimic, reduced numbers of ovipositor insertions, and decreased precision of mechanosensory Host Location. In the tropical X. stemmator, the female wasps are able to locate their Host with high precision over a broad range of ambient temperatures, which suggests endothermic thermoregulation during vibrational sounding. Environmental physiology may therefore play a key role in adaptation of the Host Location mechanism to climatic conditions of the species’ origin.
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Ambient temperature affects mechanosensory Host Location in a parasitic wasp
Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology, 2005Co-Authors: Jorg Samietz, Stefan Kroder, D. Schneider, Silvia DornAbstract:Certain parasitic wasps (Ichneumonidae, Pimplinae) use self-produced vibrations transmitted on plant substrate to locate their immobile concealed Hosts (i.e. lepidopteran pupae). This mechanosensory mechanism, called the vibrational sounding, depends both on physical cues of the environment and physical activity of the parasitoid and is postulated to depend on ambient temperature. We analysed the influences of temperature on vibrational sounding by choice experiments using plant-stem models with hidden Host mimics in the temperate species Pimpla turionellae. The results show a significant effect of temperature on Host-Location activity and on the success of this process. Outside an optimum range, the performance of the wasps decreased both at low and high temperatures. Below 10°C and beyond 24°C, the wasps displayed (1) substantial reduction in responsiveness, i.e. proportion of females showing ovipositor insertions, (2) reduction of quantitative activity with ovipositor insertions in the individuals, and (3) reduced precision of mechanosensory Host Location. Nevertheless, female wasps were able to locate their Host over a surprisingly broad range of ambient temperatures which indicates that the wasps are able to compensate for temperature effects on vibrational sounding.
Bruce E. Hibbard - One of the best experts on this subject based on the ideXlab platform.
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Tolerance of Western Corn Rootworm Larvae (Coleoptera: Chrysomelidae) to 6-Methoxy-2-benzoxazolinone, a Corn Semiochemical for Larval Host Location
Journal of Economic Entomology, 1994Co-Authors: E. M. Abou-fakhr, Bruce E. Hibbard, Louis B. BjostadAbstract:6-Methoxy-2-benzoxazolinone (MBOA) and 2,4-dihydroxy-7-methoxy-l,4-benzoxazin-3-one (DIMBOA), its natural precursor, are toxic to many insect species. We studied the possible toxicity of MBOA, a Host-Location semiochemical for western corn rootworm larvae, to larvae of this species. DIMBOA previously was shown by other workers to be toxic to frst-instar western corn rootworm, Diabrotica virgifera virgifera LeConte. Using methods that previously showed DIMBOA to be toxic, we found that MBOA had no toxic effects on larvae of the western corn rootworm. The tolerance of western corn rootworm larvae to MBOA is consistent with the putative role of this benzoxazolinone as a semiochemical for the species.
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6-Methoxy-2-benzoxazolinone: A semiochemical for Host Location by western corn rootworm larvae
Journal of Chemical Ecology, 1992Co-Authors: Louis B. Bjostad, Bruce E. HibbardAbstract:A bioassay-driven sequential fractionation scheme was used to isolate all portions of a crude dichloromethane corn seedling extract behaviorally active to larvae of the western corn rootworm, Diabrotica virgifera virgifera LeConte. 6-Methoxy-2-benzoxazolinone (MBOA) was identified as one of the most important components of an attractive crude corn extract. MBOA was found on or in the intact root tissues by injecting an extract of undamaged roots onto an HPLC immediately after extraction. MBOA was demonstrated to be volatile and functions as a semiochemical in conjunction with carbon dioxide in Host Location by western corn rootworm larvae, which are oligophagous on the roots of maize and several other species of grasses. Because MBOA occurs almost exclusively in maize and other grasses, it offers a simple way for the larvae to distinguish possible Hosts from non-Hosts. MBOA has previously been reported as a chemical defense against other insect species. This is the first report in grasses of a secondary compound that is toxic or a deterrent to nonadapted insect herbivores but that is used as a semiochemical in Host Location by a specialist insect species.
Louis B. Bjostad - One of the best experts on this subject based on the ideXlab platform.
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Tolerance of Western Corn Rootworm Larvae (Coleoptera: Chrysomelidae) to 6-Methoxy-2-benzoxazolinone, a Corn Semiochemical for Larval Host Location
Journal of Economic Entomology, 1994Co-Authors: E. M. Abou-fakhr, Bruce E. Hibbard, Louis B. BjostadAbstract:6-Methoxy-2-benzoxazolinone (MBOA) and 2,4-dihydroxy-7-methoxy-l,4-benzoxazin-3-one (DIMBOA), its natural precursor, are toxic to many insect species. We studied the possible toxicity of MBOA, a Host-Location semiochemical for western corn rootworm larvae, to larvae of this species. DIMBOA previously was shown by other workers to be toxic to frst-instar western corn rootworm, Diabrotica virgifera virgifera LeConte. Using methods that previously showed DIMBOA to be toxic, we found that MBOA had no toxic effects on larvae of the western corn rootworm. The tolerance of western corn rootworm larvae to MBOA is consistent with the putative role of this benzoxazolinone as a semiochemical for the species.
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6-Methoxy-2-benzoxazolinone: A semiochemical for Host Location by western corn rootworm larvae
Journal of Chemical Ecology, 1992Co-Authors: Louis B. Bjostad, Bruce E. HibbardAbstract:A bioassay-driven sequential fractionation scheme was used to isolate all portions of a crude dichloromethane corn seedling extract behaviorally active to larvae of the western corn rootworm, Diabrotica virgifera virgifera LeConte. 6-Methoxy-2-benzoxazolinone (MBOA) was identified as one of the most important components of an attractive crude corn extract. MBOA was found on or in the intact root tissues by injecting an extract of undamaged roots onto an HPLC immediately after extraction. MBOA was demonstrated to be volatile and functions as a semiochemical in conjunction with carbon dioxide in Host Location by western corn rootworm larvae, which are oligophagous on the roots of maize and several other species of grasses. Because MBOA occurs almost exclusively in maize and other grasses, it offers a simple way for the larvae to distinguish possible Hosts from non-Hosts. MBOA has previously been reported as a chemical defense against other insect species. This is the first report in grasses of a secondary compound that is toxic or a deterrent to nonadapted insect herbivores but that is used as a semiochemical in Host Location by a specialist insect species.
Donald L J Quicke - One of the best experts on this subject based on the ideXlab platform.
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the adaptive significance of Host Location by vibrational sounding in parasitoid wasps
Proceedings of The Royal Society B: Biological Sciences, 2000Co-Authors: Gavin R Broad, Donald L J QuickeAbstract:Vibrational sounding, which is a form of echoLocation, is a means of Host Location by some parasitoid wasps. The wasp taps the substrate (wood, stem or soil) and detects the position of a potential Host through the returning 'echoes'. The deployment of vibrational sounding is inferred through the form of the subgenual organ in the female tibia in combination with the presence of modifications to the female antenna used for tapping the substrate. Vibrational sounding and its associated modifications were found in two families. The use of vibrational sounding by parasitoid wasps was positively correlated with the depth of the Host in the substrate relative to the size of the parasitoid. There were also significant correlations between the use of vibrational sounding and parasitism of immobile and concealed Hosts and between vibrational sounding and idiobiosis. The data suggested that vibrational sounding evolved under a variety of ecological conditions, being employed in the Location of wood-boring, stem-boring, soil-dwelling and cocooned Hosts and stem-nesting aculeates, often in situations in which the Host does not produce vibrations itself.