Guenzel, Y. | bioRxiv Science

bioRxiv2023

Synergistic olfactory processing for social plasticity in desert locusts

1Desert locust plagues threaten the food security of millions. Central to their formation is crowding-induced social plasticity from solitarious to gregarious phenotypes. We investigated the impact of population density changes on locusts foraging choices and their neurobiology by examining how relevant food and social odors are coded in the antennal lobe. Our analysis shows that gregarious locusts are highly attentive to social cues during foraging, with olfaction playing an essential role. Using calcium imaging, we show that corresponding odors are encoded by projection neurons, revealing a stable combinatorial response map. Transient dynamics in the glomeruli converge into temporally evolving response motifs in the somata that differ between gregarious and solitarious insects. The dynamics of response motifs facilitate a crowding-dependent synergy between olfactory processing of food-related and social odors. Our study demonstrates the effectiveness of calcium imaging for locust olfaction, suggesting a crowding-induced adaptation to enhance food detection in swarms. 2 TeaserIn dense swarms, desert locusts optimize foraging efficiency by exhibiting an enhanced olfactory response to food odors.

neuroscience↗

bioRxiv2022

Information integration for nutritional decision-making in desert locusts

1Swarms of the migratory desert locust can extend over several hundred square kilometres, and starvation compels this ancient pest to devour everything in its path. Theory suggests that gregarious behaviour benefits foraging efficiency over a wide range of spatial food distributions. However, despite the importance of identifying the processes by which swarms locate and select feeding sites to predict their progression, the role of social cohesion during foraging remains elusive. We investigated the evidence accumulation and information integration processes that underlie locusts nutritional decision-making by employing a Bayesian formalism on high-resolution tracking data from foraging locusts. We tested individual gregarious animals and groups of different sizes in a 2-choice behavioural assay in which food patch qualities were either different or similar. We then predicted the decisions of individual locusts based on personally acquired and socially derived evidence by disentangling the relative contributions of each information class. Our study suggests that locusts balance incongruent evidence but reinforce congruent ones, resulting in more confident assessments when evidence aligns. We provide new insights into the interplay between personal experience and social context in locust foraging decisions which constitute a powerful empirical system to study local individual decisions and their consequent collective dynamics.

animal behavior and cognition↗