News & Events
nGICE Research Highlights in Brief
One of the nGICE project’s aims was to perform integrated research projects between the three partners on the topic “Anthropogenic impact on insect chemical communication.” The participants chose to work with a wide palette of arthropod species, including bark beetles, mosquitoes, drosophilid flies, moths, ants, and ticks. In several projects the impact of increased levels of ozone and CO₂, and of augmented temperatures was investigated. In the experiments involving ozone, detrimental effects were observed, where chemical communication systems were severely compromised.
In Drosophila, odor-based sex identification was almost obliterated (Jiang et al., 2023 Nature Communication; 2024 Nature Communication) and in ants, colony-specific, hydrocarbon-dependent communication broke down, resulting in nestmate attacks (Jiang et al., PNAS 2026) Interestingly, all the effects observed were a result of the strong oxidizing effect of ozone, i.e., the effects were caused by the chemistry of the interactions. The effects on olfactory functions were, on the other hand, minor.
As an effect of elevated ambient CO₂ levels, the nGICE project demonstrated a direct impact on the development and survival of the dengue vector, Aedes aegypti, which had carry-over effects on adult foraging behavior and the expression of chemosensory genes in the peripheral olfactory system (Nalikkaramal et al., 2025a, Scientific Reports; Nalikkaramal et al., 2025b, Scientific Reports).
In addition, effects on host-plant choice by increasing atmospheric CO₂ were studied in the generalist moth Spodoptera littoralis. Olfactory cues are crucial for host selection, and we found that the volatile profile of preferred host plants changed with increasing CO₂. We also found effects on larval behavior, in which larval dispersal and migration increased. However, within a single generation, the moth adapted to the novel conditions and retained a similar behavioral pattern as under ambient CO₂. Host plant shifts may still occur over time, as we found host plant-specific variation in food quality with increasing CO2. The third environmental factor under investigation was temperature. In Drosophila, three different species, adapted to cold, temperate, or warm climates, respectively, were investigated regarding their temperature preferences and the impact of different temperature regimes on their olfactory-dependent behavior.
Dramatic effects were 3 observed, especially in the cold-adapted species when subjected to elevated temperatures (Baleba et al., Comm Biol 2023; Heliyon 2024). Beyond these studies of direct effects of human environmental emissions, nGICE projects studied more indirect effects and their mechanistic backgrounds, especially in insects of interest to human health (mosquitoes), human resource production (bark beetles), or as model organisms (drosophilid flies).
In the West Nile fever vector Culex pipiens, we found that its recent spread north within Europe as a consequence of climate change correlates with a shift from opportunistic to preferential host seeking, which likely increases the vectorial capacity of the northern mosquito populations (Menon et al., Parasites and Vectors, in revision). The nGICE project also allowed for an increased focus on the functional genomics of odorant receptors in mosquitoes. For Culex pipiens, we identified and functionally characterized an odorant receptor that detects host-specific odorants and likely is involved in regulating host preference among the two biotypes of this species (Menon et al., Parasites and Vectors, 2025; Menon et al., in prep.).
For both Aedes aegypti and the African malaria vector, Anopheles coluzzii, by combining structure-function analysis with gene editing and physiological and behavioral phenotyping, we confirmed the notion that salient odorant receptors regulate host preference (Haataja et al., in prep.). Using a similar approach, we demonstrated that single odorant receptor genes act as molecular switches to modulate nectar seeking in Aedes aegypti (Nalikkaramal et al., Nature Communication, in revision). In the disease-spreading yellow fever mosquito, a major highlight is the discovery of nootkatone as a novel repellent and the detailed characterization of its detection and central neural processing mechanisms (Triana et al., 2025. Current Biology).
In bark beetles, the nGICE project contributed, for example, significantly to the discovery that the fungal symbionts of the Eurasian spruce bark beetle metabolize the defense compounds of climate-stressed spruce trees to less toxic compounds, which serve as important olfactory cues for the beetles (Kandasamy et al., PLoS Biology 2023.). Additionally, two new pheromone receptors were identified in the bark beetle, providing novel insight into the ligand-binding mechanisms and evolutionary origins of such receptors, as well as pheromone-induced behavioral responses (Yuvaraj et al., 2024. BMC Biology; Biswas et al. 2024. Molecular Biology and Evolution).
In Drosophila melanogaster, the sequencing of museum specimens revealed genomic signatures that most likely reflect adaptations to human-induced environmental change in the Anthropocene (Shpak et al. 2023. PLoS Biology). In two other drosophilid species, exhibiting extreme adaptations to unorthodox ecological niches, we studied how this choice of habitat has affected the evolution of olfactory functions and physiological adaptations. D. busckii has evolved to feed on rotting vegetables, a diet toxic to many other drosophilids. Such a niche expansion has been possible by extreme adaptations both in the specificity of specific olfactory neurons and, even more important, through changes in cell respiration (Mahadevan et al 2025. Nature Comm) Similar evolutionary trends were observed in another fly species living on tree sap (Mahadevan et al 2024. iScience).
In conclusion, the scientific work within the nGICE Max Planck Center and the network it enabled resulted in significant scientific progress, which had not been possible without the interaction shaped through the Center. The results have been published in a number of scientific publications and doctoral theses and have been presented at international scientific conferences.