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Circadian rhythms are known for locomotory and reproductive behaviours, and the functioning of sensory organs, nervous structures, metabolism and developmental processes. The mechanisms and cellular bases of control are mainly inferred from circadian phenomenologies, ablation experiments and pharmacological approaches. Cellular systems for regulation(More)
Reduction of tympanal hearing organs is repeatedly found amongst insects and is associated with weakened selection for hearing. There is also an associated wing reduction, since flight is no longer required to evade bats. Wing reduction may also affect sound production. Here, the auditory system in four silent grasshopper species belonging to the Podismini(More)
In Tettigoniidae (Orthoptera: Ensifera), hearing organs are essential in mate detection. Male tettigoniids usually produce calling songs by tegminal stridulation, whereas females approach the males phonotactically. This unidirectional communication system is the most common one among tettigoniids. In several tettigoniid lineages, females have evolved(More)
We report identification of a beta-type pigment-dispersing hormone (PDH) identical in two water flea species, Daphnia magna and Daphnia pulex. It has been identified by cloning of precursors, chromatographic isolation from tissue extracts followed by immunoassays and de novo-mass spectrometric sequencing. The peptide is restricted to a complex system of(More)
Unisexual reproduction is a widespread phenomenon in invertebrates and lower vertebrates. If a former sexual reproducing species becomes parthenogenetic, we expect traits that were subject to sexual selection to diminish. The bushcricket Poecilimon intermedius is one of the few insect species with obligate but diploid parthenogenetic reproduction. We(More)
Audition in insects is of polyphyletic origin. Tympanal ears derived from proprioceptive or vibratory receptor organs, but many questions of the evolution of insect auditory systems are still open. Despite the rather typical bauplan of the insect body, e.g., with a fixed number of segments, tympanal ears evolved at very different places, but only ensiferans(More)
Comparative studies of the organization of nervous systems and sensory organs can reveal their evolution and specific adaptations. In the forelegs of some Ensifera (including crickets and tettigoniids), tympanal hearing organs are located in close proximity to the mechanosensitive subgenual organ (SGO). In the present study, the SGO complex in the(More)
Insect ears evolved many times independently. As a consequence, a striking diversity exists in the location, construction and behavioural implementation of ears. In this review, we first summarise what is known about the evolutionary origin of ears and the presumed precursor organs in the various insect groups. Thereafter, we focus on selective forces for(More)
The subgenual chordotonal organ complex in insects is modified in ensiferan taxa like Gryllidae and Tettigoniidae into hearing organs with specific sets of auditory receptors. Here, this sensory organ complex is documented in the nonhearing splay-footed cricket Comicus calcaris. The tibial chordotonal organ consists of three parts: the subgenual organ, the(More)
We investigated the neuroanatomy and physiology of the complex tibial organ of an atympanate ensiferan, the Gryllacridid Ametrus tibialis. This represents the first analysis of internal mechanoceptors in Gryllacridids. The complex tibial organ is tripartite consisting of a subgenual organ, intermediate organ and a homologue organ to the crista acustica of(More)