Biology subjects

Wolff, G. H.

Publications and source records attributed to Wolff, G. H..

4 recordsLinked to original sources

bioRxiv2026

Low-frequency sounds elicit escape climb in free-flying Aedes aegypti mosquitos

Mosquitoes use their sensitive hearing in a well-described courtship and mating behavior, but their ability to discriminate other stimuli relevant to their survival and reproduction via this sensory channel remains underexplored. Here, we characterize a rapid climb response in free-flying mosquitoes elicited by loud low-frequency sounds (tested at 180Hz and 300Hz) but not by tones of equivalent acoustic loudness reflecting conspecific female (450Hz) and male (700Hz) wingbeat frequencies. Presentation of the same sounds in tethered flight elicited modulation of both wingstroke amplitude and frequency components similar in magnitude to those observed in response to a looming visual stimulus. These tones are spectrally consistent with recorded audio of a dragonfly takeoff, playback of which is sufficient to release the behavior. Taken together, these data are consistent with the hypothesis that mosquitoes use their hearing to detect the acoustic signature of aerial predators such as dragonflies.

animal behavior and cognition↗

bioRxiv2019

Mushroom Body Homology and Divergence across Pancrustacea

Descriptions of crustacean brains have mainly focused on three highly derived lineages: the reptantian infraorders represented by spiny lobsters, lobsters, and crayfish. Those descriptions advocate the view that dome- or cap-like neuropils, referred to as "hemiellipsoid bodies," are the ground pattern organization of centers that are comparable to insect mushroom bodies in processing olfactory information. Here we challenge the doctrine that hemiellipsoid bodies are a derived trait of crustaceans, whereas mushroom bodies are a derived trait of hexapods. We demonstrate that mushroom bodies typify lineages that arose before Reptantia and exist in Reptantia. We show that evolved variations of the mushroom body ground pattern are, in some lineages, defined by extreme diminution or loss and, in others, by the incorporation of mushroom body circuits into lobeless centers. Such transformations are ascribed to modifications of the columnar organization of mushroom body lobes that, as shown in Drosophila and other hexapods, contain networks essential for learning and memory. We propose that lobed mushroom bodies distinguish crustaceans that negotiate the multidimensionality of complex ecologies, where continuous updating of multistimulus valence and memory is paramount.

neuroscience↗

bioRxiv2019

Neuromodulation and Differential Learning Across Mosquito Species

Mosquitoes can learn to change their host-feeding behaviors, such as shifting activity times to avoid bednets or switching from biting animals to biting humans, leading to the transfer of zoonotic diseases. Dopamine is critical for insect learning, but its role in the antennal lobe remains unclear, and it is unknown whether different mosquito species learn the same odor cues. We assayed aversive olfactory learning and dopaminergic brain innervation in four mosquito species with different host preferences and report here that they differentially learn odors salient to their preferred host and innervation patterns vary across species. Using genetically-encoded GCaMP6s Aedes aegypti, we mapped odor-evoked antennal lobe activity and report that glomeruli tuned to \"learnable\" odors have significantly higher dopaminergic innervation. Changes in dopamine expression in the antennal lobes of diverse invertebrate species may be an evolutionary mechanism to adapt olfactory learning circuitry without changing brain structure and for mosquitoes an ability to adapt to other hosts when their preferred are no longer present.

neuroscience↗

bioRxiv2019

Geosmin attracts Aedes aegypti mosquitoes to oviposition sites

Geosmin is one of the most recognizable and common microbial smells on the planet. Some insects, like mosquitoes, require microbial-rich environments for their progeny, whereas for other insects such microbes may prove dangerous. In the vinegar fly Drosophila melanogaster, geosmin is decoded in a remarkably precise fashion and induces aversion, presumably signaling the presence of harmful microbes. We have here investigated the effect of geosmin on the behavior of the yellow fever mosquito Aedes aegypti. In contrast to flies, geosmin is not aversive in mosquitoes but stimulates egg-laying site selection. Female mosquitoes could associate geosmin with microbes, including cyanobacteria consumed by larvae, who also find geosmin - as well as geosmin producing cyanobacteria - attractive. Using in vivo multiphoton imaging from mosquitoes with pan-neural expression of the calcium reporter GCaMP6s, we show that Ae. aegypti code geosmin in a similar fashion to flies, i.e. with extreme sensitivity and with a high degree of selectivity. We further demonstrate that geosmin can be used as bait under field conditions, and finally we show that geosmin, which is both expensive and difficult to obtain, can be substituted by beetroot peel extract, providing a cheap and viable mean of mosquito control and surveillance in developing countries.

neuroscience↗