I study how noise (natural and/or anthropogenic) affects the perception and use of vibrational cues and signals in arthropods. In my project I plan to use a laser-Doppler vibrometer to first quantify noise levels along highways or train tracks, but also along rivers, noisy streams or waterfalls. Then, based on field recordings we can compare noise transmission patterns on different species of plants, and parts of plants. This will be complemented with lab studies where I will look into which plant traits are important in the transmission of noise, signals and cues. Another aspect of my research focuses on the ecological interactions that are driven by these vibrational signals and cues (i.e. predator-prey interactions, mating, finding food or conspecifics). How are these ecological interactions affected by noise in light of the differences in transmission properties? Supervisors: Dr. Wouter Halfwerk
A growth in anthropogenic activities and infrastructure has led to increasing subterranean vibrat... more A growth in anthropogenic activities and infrastructure has led to increasing subterranean vibratory noise levels. Inland wind energy turbines, which are mostly located in agricultural fields, are a fast growing source of vibrational noise. Plants, which are rooted in the soil are constantly exposed to windmill-induced vibrations propagating through the ground. We have little understanding on how anthropogenic seismic vibrations affect plant development and how that in turn can affect plant-insect interactions. In this study we investigated the effect of windmill-like underground vibrational noise on plant development and on a plant-herbivore interaction. We experimentally exposed Pisum sativum plants from seed stage to seed production stage to high and low vibrational noise levels and monitored them daily. We recorded germination, flowering and fruiting time, as well as daily shoot-length growth. Moreover, we tested the direct and indirect effects of vibrational noise on herbivory ...
Is the warrant of arrest against Omar Al-Bashir acceptable and enforceable or is the intervention... more Is the warrant of arrest against Omar Al-Bashir acceptable and enforceable or is the intervention a case of "neocolonialism"? - A paper about the acceptable boundaries for the intervention of the International Criminal Court in a sovereign nation.
Wind, a major source of environmental noise, forces invertebrates that communicate with plant-bor... more Wind, a major source of environmental noise, forces invertebrates that communicate with plant-borne vibrations to adjust their signaling when communicating in windy conditions. However, the strategies that animals use to reduce the impact of wind noise on communication are not well studied. We investigated the effects of wind on the production of tremulatory signals in the neotropical katydid Copiphora brevirostris. First, we recorded katydid signaling activity and natural wind variation in the field. Additionally, we exposed katydid couples during their most active signaling time period to artificial wind of different levels, and we recorded the number of tremulations produced by the males. We found that wind levels are at their lowest between 2:00 and 5:00 in the morning, which coincides with peak signaling period for male katydids. Furthermore, we found that males produce significantly fewer tremulations when exposed to wind rather than acoustic noise or silence. Wind velocity si...
Wind, a major source of environmental noise, forces invertebrates that communicate with plant-bor... more Wind, a major source of environmental noise, forces invertebrates that communicate with plant-borne vibrations to adjust their signaling when communicating in windy conditions. However, the strategies that animals use to reduce the impact of wind noise on communication are not well studied. We investigated the effects of wind on the production of tremulatory signals in the neotropical katydid Copiphora brevirostris. First, we recorded katydid signaling activity and natural wind variation in the field. Additionally, we exposed katydid couples during their most active signaling time period to artificial wind of different levels, and we recorded the number of tremulations produced by the males. We found that wind levels are at their lowest between 2:00 and 5:00 in the morning, which coincides with peak signaling period for male katydids. Furthermore, we found that males produce significantly fewer tremulations when exposed to wind rather than acoustic noise or silence. Wind velocity si...
An introduced species' invasion success may be facilitated by the release of natural enemies, lik... more An introduced species' invasion success may be facilitated by the release of natural enemies, like parasites, which may provide an invader with a competitive advantage over native species (enemy release hypothesis). Lower parasite infection levels in introduced versus native populations have been well documented. However, any potential competitive advantage will depend on whether native competitors exhibit higher parasite loads than introduced hosts and whether native hosts suffer more (e.g., reduced reproduction or growth) from parasite infections than introduced hosts. In this study, we compared macroparasite richness, prevalence, and intensity in sympatric populations of one native and two introduced brachyuran crab hosts in the centre of their European range. While the native green crab Carcinus maenas (Linnaeus, 1758) hosted three parasite groups (acanthocephalans, microphallid trematodes, rhizocephalans), the two invasive crab species Hemigrapsus sanguineus (De Haan, 1835) and H. takanoi Asakura and Watanabe, 2005 were only infected with acanthocephalans. All acanthocephalans were molecularly identified (COI) as the native Profilicollis botulus (Van Cleave, 1916). Prevalence and intensities of P. botulus were generally lower in the introduced than in the native crabs. Metacercariae of microphallid trematodes were only found in the native C. maenas, with mean infection levels of 100–300 metacercariae per host, depending on geographical location. Likewise, the castrating rhizocephalan barnacle Sacculina carcini Thompson, 1836 was only found in C. maenas at a few locations with low prevalences (< 3%). This first study on infection levels in invasive Hemigrapsus species in Europe indicates that these invasive crabs indeed experience lower infection levels than their native competitor C. maenas. Future experiments are needed to investigate whether this difference in infection levels leads to a competitive advantage for the invasive crab species.
A growth in anthropogenic activities and infrastructure has led to increasing subterranean vibrat... more A growth in anthropogenic activities and infrastructure has led to increasing subterranean vibratory noise levels. Inland wind energy turbines, which are mostly located in agricultural fields, are a fast growing source of vibrational noise. Plants, which are rooted in the soil are constantly exposed to windmill-induced vibrations propagating through the ground. We have little understanding on how anthropogenic seismic vibrations affect plant development and how that in turn can affect plant-insect interactions. In this study we investigated the effect of windmill-like underground vibrational noise on plant development and on a plant-herbivore interaction. We experimentally exposed Pisum sativum plants from seed stage to seed production stage to high and low vibrational noise levels and monitored them daily. We recorded germination, flowering and fruiting time, as well as daily shoot-length growth. Moreover, we tested the direct and indirect effects of vibrational noise on herbivory ...
Is the warrant of arrest against Omar Al-Bashir acceptable and enforceable or is the intervention... more Is the warrant of arrest against Omar Al-Bashir acceptable and enforceable or is the intervention a case of "neocolonialism"? - A paper about the acceptable boundaries for the intervention of the International Criminal Court in a sovereign nation.
Wind, a major source of environmental noise, forces invertebrates that communicate with plant-bor... more Wind, a major source of environmental noise, forces invertebrates that communicate with plant-borne vibrations to adjust their signaling when communicating in windy conditions. However, the strategies that animals use to reduce the impact of wind noise on communication are not well studied. We investigated the effects of wind on the production of tremulatory signals in the neotropical katydid Copiphora brevirostris. First, we recorded katydid signaling activity and natural wind variation in the field. Additionally, we exposed katydid couples during their most active signaling time period to artificial wind of different levels, and we recorded the number of tremulations produced by the males. We found that wind levels are at their lowest between 2:00 and 5:00 in the morning, which coincides with peak signaling period for male katydids. Furthermore, we found that males produce significantly fewer tremulations when exposed to wind rather than acoustic noise or silence. Wind velocity si...
Wind, a major source of environmental noise, forces invertebrates that communicate with plant-bor... more Wind, a major source of environmental noise, forces invertebrates that communicate with plant-borne vibrations to adjust their signaling when communicating in windy conditions. However, the strategies that animals use to reduce the impact of wind noise on communication are not well studied. We investigated the effects of wind on the production of tremulatory signals in the neotropical katydid Copiphora brevirostris. First, we recorded katydid signaling activity and natural wind variation in the field. Additionally, we exposed katydid couples during their most active signaling time period to artificial wind of different levels, and we recorded the number of tremulations produced by the males. We found that wind levels are at their lowest between 2:00 and 5:00 in the morning, which coincides with peak signaling period for male katydids. Furthermore, we found that males produce significantly fewer tremulations when exposed to wind rather than acoustic noise or silence. Wind velocity si...
An introduced species' invasion success may be facilitated by the release of natural enemies, lik... more An introduced species' invasion success may be facilitated by the release of natural enemies, like parasites, which may provide an invader with a competitive advantage over native species (enemy release hypothesis). Lower parasite infection levels in introduced versus native populations have been well documented. However, any potential competitive advantage will depend on whether native competitors exhibit higher parasite loads than introduced hosts and whether native hosts suffer more (e.g., reduced reproduction or growth) from parasite infections than introduced hosts. In this study, we compared macroparasite richness, prevalence, and intensity in sympatric populations of one native and two introduced brachyuran crab hosts in the centre of their European range. While the native green crab Carcinus maenas (Linnaeus, 1758) hosted three parasite groups (acanthocephalans, microphallid trematodes, rhizocephalans), the two invasive crab species Hemigrapsus sanguineus (De Haan, 1835) and H. takanoi Asakura and Watanabe, 2005 were only infected with acanthocephalans. All acanthocephalans were molecularly identified (COI) as the native Profilicollis botulus (Van Cleave, 1916). Prevalence and intensities of P. botulus were generally lower in the introduced than in the native crabs. Metacercariae of microphallid trematodes were only found in the native C. maenas, with mean infection levels of 100–300 metacercariae per host, depending on geographical location. Likewise, the castrating rhizocephalan barnacle Sacculina carcini Thompson, 1836 was only found in C. maenas at a few locations with low prevalences (< 3%). This first study on infection levels in invasive Hemigrapsus species in Europe indicates that these invasive crabs indeed experience lower infection levels than their native competitor C. maenas. Future experiments are needed to investigate whether this difference in infection levels leads to a competitive advantage for the invasive crab species.
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