Biology subjects

Arntsen, C.

Publications and source records attributed to Arntsen, C..

3 recordsLinked to original sources

bioRxiv2026

Food perception alone stimulates oviposition through serotonin signaling in Drosophila

Reproduction is strongly shaped by nutrient availability, but whether sensory information about food can regulate reproductive output before nutrients are consumed remains unclear. Here, using Drosophila melanogaster, we show that sensory perception of dietary yeast, a protein-rich food source widely used to stimulate fecundity in the fruit fly, is sufficient to rapidly promote egg laying. Specifically, we found that yeast odor exposure increased the rate of oviposition and the number of eggs laid within hours, independent of yeast intake, and that this response was mediated by olfactory signaling through the odorant receptor co-receptor Orco. We further identified serotonin receptor 2A (5-HT2A), but not 5-HT2B, as necessary for yeast odor-induced egg laying. We then asked whether yeast odor also elicits broader life-history changes and whether its reproductive and longevity effects depend on a shared mechanism. Consistent with previous observations, yeast odor also shortened lifespan. However, this lifespan effect was independent of 5-HT2A signaling, indicating that the reproductive and longevity responses to food perception are separable. Finally, our brain connectomic analyses revealed that yeast-responsive olfactory neurons preferentially influence oviposition descending neurons (OviDNs) compared with other olfactory neurons. OviDNs further connect with endocrine-related circuitry in the corpora allata (CA), and, most interestingly, the interneurons linking OviDNs to CA neurons are enriched for serotonergic and dopaminergic modulation. Taken together, our observations indicate that nutrient acquisition is not a prerequisite for animals to adjust their reproduction to the nutritional environment. Sensory information predicting food availability itself can elicit changes in neural state, likely through olfactory-reproductive circuits, that acutely alter reproductive physiology.

physiology↗

bioRxiv2026

Insulin receptor signaling in gustatory cells suppresses sugar taste sensitivity and feeding in Drosophila

Dynamic sensory processing helps animals adjust behaviors in response to changing environments and internal states. Hunger is a salient internal cue that can directly modify chemosensory signaling to promote homeostatic behavior. In Drosophila melanogaster, hunger enhances the sensitivity of sweet gustatory receptor neurons (GRNs) to encourage feeding, and here we investigated candidate hunger/satiety hormone receptors to identify mechanisms of metabolic regulation in primary taste cells. The conserved insulin receptor (InR) is expressed in sweet GRNs, and targeted InR knockdown and inactivation within these cells elevated sucrose sensitivity, increased sucrose consumption, and altered feeding behavior under sated conditions. Additionally, sweet cellular responses to sucrose were reciprocally affected by inactive and overactive InR signaling. These findings reveal that InR signaling can modulate sweet sensitivity at the level of primary taste cells, suppressing feeding by reducing taste responsiveness under specific metabolic conditions.

neuroscience↗

bioRxiv2025

Artificial sweeteners differentially activate sweet and bitter gustatory neurons in Drosophila

Artificial sweeteners are highly sweet, non-nutritive compounds that have become increasingly popular over recent decades despite research suggesting that their consumption has unintended consequences. Specifically, there is evidence suggesting that some of these chemicals interact with bitter taste receptors, implying that sweeteners likely generate complex chemosensory signals. Here, we report the basic sensory characteristics of sweeteners in Drosophila, a common model system used to study the impacts of diet, and find that all noncaloric sweeteners inhibited appetitive feeding responses at higher concentrations. At a cellular level, we found that sucralose and rebaudioside A co-activated sweet and bitter gustatory receptor neurons (GRNs), two populations that reciprocally impact feeding behavior, while aspartame only activated bitter cells. We assessed the behavioral impacts of sweet and bitter co-activation and found that low concentrations of sucralose signal appetitive feeding while high concentrations signal feeding aversion. Finally, silencing bitter GRNs reduced the aversive signal elicited by high concentrations of sucralose and significantly increased sucralose feeding behaviors. Together, we conclude that artificial sweeteners generate a gustatory signal that is more complex than "sweetness" alone, and this bitter co-activation has behaviorally relevant effects on feeding that may help flies flexibly respond to these unique compounds.

neuroscience↗