Acoustic communication is prominent in adult anuran amphibians, in reproductive, territorial and ... more Acoustic communication is prominent in adult anuran amphibians, in reproductive, territorial and defensive contexts. In contrast, reports on vocalizations of juvenile anurans are rare and anecdotal, and their function unstudied. We here provide conclusive evidence for vocalizations in juvenile spadefoot toads (Pelobates fuscus) in very early terrestrial stages. While the aquatic tadpoles did not emit sounds, first vocalizations of metamorphs were heard as early as in stages 42-43, and calls were regularly emitted from stage 44 on, often from specimens still bearing extensive tail stubs. Three main types of calls could be distinguished, of which one consists of a series of short notes, one of a typically single longer and pulsed note, and one of a single tonal note. In experimental setups, the number of calls per froglet increased with density of individuals and after feeding, while on the contrary calls were not elicited by playback. The function of these juvenile calls remains uncl...
Since 1996 the "Workgroup Odonata in North Rhine-Westphalia" ("AK Libellen NRW") has built up a d... more Since 1996 the "Workgroup Odonata in North Rhine-Westphalia" ("AK Libellen NRW") has built up a data base including about 150.000 data sets concerning the occurrence of dragonfl ies in North Rhine-Westphalia (NRW). Th is data confi rms an increase and spread of some thermophilous dragonfl y species in NRW, and the eff ects of climate change evidenced by an increasing average temperature, are considered to be important reasons for this process.
In the city of Münster rain storage ponds have been constructed since 1980 to temporarily store p... more In the city of Münster rain storage ponds have been constructed since 1980 to temporarily store peak flow discharge and large amounts of surface effluents. A dragonfly inventory of all rain storage ponds identified 27 species (61 % of a total of 44 species occurring in the city area of Münster), with 22 classified as (potentially) permanent settlers and five species as guests. Beside species frequently occurring at all types of water habitats of the city area a number of specialized species could be found. The earlier comprise Cercion lindenii, Erythromma najas (Red-eyed damselfly), Ischnura pumilio (scare blue-tailed damselfly) and Aeshna grandis (brown aeshna), more specialised species are Lestes dryas (scare emerald damselfly), Somatochlora metallica (brilliant emerald) and Orthetrum brunneum (southern European skimmer). The colonization depends on the one hand on light conditions and vegetation structure of the ponds, on the other side on the spatial relationship to other import...
In the city of Münster rain storage ponds have been constructed since 1980 to temporarily store p... more In the city of Münster rain storage ponds have been constructed since 1980 to temporarily store peak flow discharge and large amounts of surface effluents. A dragonfly inventory of all rain storage ponds identified 27 species (61 % of a total of 44 species occurring in the city area of Münster), with 22 classified as (potentially) permanent settlers and five species as guests. Beside species frequently occurring at all types of water habitats of the city area a number of specialized species could be found. The earlier comprise Cercion lindenii, Erythromma najas (Red-eyed damselfly), Ischnura pumilio (scare blue-tailed damselfly) and Aeshna grandis (brown aeshna), more specialised species are Lestes dryas (scare emerald damselfly), Somatochlora metallica (brilliant emerald) and Orthetrum brunneum (southern European skimmer). The colonization depends on the one hand on light conditions and vegetation structure of the ponds, on the other side on the spatial relationship to other import...
Acoustic communication is prominent in adult anuran amphibians, in reproductive, territorial and ... more Acoustic communication is prominent in adult anuran amphibians, in reproductive, territorial and defensive contexts. In contrast, reports on vocalizations of juvenile anurans are rare and anecdotal, and their function unstudied. We here provide conclusive evidence for vocalizations in juvenile spadefoot toads (Pelobates fuscus) in very early terrestrial stages. While the aquatic tadpoles did not emit sounds, first vocalizations of metamorphs were heard as early as in stages 42-43, and calls were regularly emitted from stage 44 on, often from specimens still bearing extensive tail stubs. Three main types of calls could be distinguished, of which one consists of a series of short notes, one of a typically single longer and pulsed note, and one of a single tonal note. In experimental setups, the number of calls per froglet increased with density of individuals and after feeding, while on the contrary calls were not elicited by playback. The function of these juvenile calls remains uncl...
Since 1996 the "Workgroup Odonata in North Rhine-Westphalia" ("AK Libellen NRW") has built up a d... more Since 1996 the "Workgroup Odonata in North Rhine-Westphalia" ("AK Libellen NRW") has built up a data base including about 150.000 data sets concerning the occurrence of dragonfl ies in North Rhine-Westphalia (NRW). Th is data confi rms an increase and spread of some thermophilous dragonfl y species in NRW, and the eff ects of climate change evidenced by an increasing average temperature, are considered to be important reasons for this process.
In the city of Münster rain storage ponds have been constructed since 1980 to temporarily store p... more In the city of Münster rain storage ponds have been constructed since 1980 to temporarily store peak flow discharge and large amounts of surface effluents. A dragonfly inventory of all rain storage ponds identified 27 species (61 % of a total of 44 species occurring in the city area of Münster), with 22 classified as (potentially) permanent settlers and five species as guests. Beside species frequently occurring at all types of water habitats of the city area a number of specialized species could be found. The earlier comprise Cercion lindenii, Erythromma najas (Red-eyed damselfly), Ischnura pumilio (scare blue-tailed damselfly) and Aeshna grandis (brown aeshna), more specialised species are Lestes dryas (scare emerald damselfly), Somatochlora metallica (brilliant emerald) and Orthetrum brunneum (southern European skimmer). The colonization depends on the one hand on light conditions and vegetation structure of the ponds, on the other side on the spatial relationship to other import...
In the city of Münster rain storage ponds have been constructed since 1980 to temporarily store p... more In the city of Münster rain storage ponds have been constructed since 1980 to temporarily store peak flow discharge and large amounts of surface effluents. A dragonfly inventory of all rain storage ponds identified 27 species (61 % of a total of 44 species occurring in the city area of Münster), with 22 classified as (potentially) permanent settlers and five species as guests. Beside species frequently occurring at all types of water habitats of the city area a number of specialized species could be found. The earlier comprise Cercion lindenii, Erythromma najas (Red-eyed damselfly), Ischnura pumilio (scare blue-tailed damselfly) and Aeshna grandis (brown aeshna), more specialised species are Lestes dryas (scare emerald damselfly), Somatochlora metallica (brilliant emerald) and Orthetrum brunneum (southern European skimmer). The colonization depends on the one hand on light conditions and vegetation structure of the ponds, on the other side on the spatial relationship to other import...
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