Rising carbon dioxide level disrupts insects' ability to choose optimal egg-laying sites
Moths rely on carbon dioxide emissions from host plants to identify optimal egg-laying sites. As atmospheric CO₂ levels rise, this natural signal becomes confused, leading the moths to make maladaptive choices that threaten the survival of their offspri
The sensory mechanisms underlying CO2-induced oviposition behavior in Helicoverpa armigera
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Schematic representation of the sensory mechanisms underlying CO2-induced oviposition behavior in Helicoverpa armigera. Abbreviations: LPO, labial pit organ; LPOG, labial pit organ glomerulus; CB, central body; Ca, calyx of the mushroom body; LH, lateral horn; AN, antennal nerve.
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Credit: ©Science China Press
Climate change is rapidly reshaping ecosystems across the globe, and new research has identified a previously unrecognized consequence: disrupted insect reproductive behavior. A recent study published in National Science Review reveals that rising atmospheric carbon dioxide (CO2) levels are interfering with how agricultural pests choose egg-laying sites—posing significant risks to biodiversity, food security, and pest management strategies.
Insects, despite their adaptability, are especially sensitive to shifts in environmental conditions. As global temperatures rise and atmospheric composition changes, their behavior is changing in ways that ripple through ecosystems. CO2, the primary greenhouse gas driving global warming, has increased from 278 ppm in 1750 to approximately 420 ppm in 2023. Emerging evidence shows that elevated CO2 levels—alongside pollutants such as ozone and nitrogen oxides—are disrupting insects' ability to detect chemical cues essential for reproduction and survival. Until now, the underlying mechanisms remained poorly understood.
Now, an international collaborative study by scientists from the Chinese Academy of Agricultural Sciences, the Norwegian University of Science and Technology, and the Max Planck Institute has provided key insights. Focusing on Helicoverpa armigera—the cotton bollworm, a major global crop pest—the team discovered that females normally use plant-emitted CO2 to locate suitable egg-laying sites, particularly favoring younger leaves that emit higher CO2 gradients. These sites are critical for larval survival and development. However, under elevated atmospheric CO2 concentrations, this behavior is significantly disrupted. The study found that moths’ CO2-sensing ability is impaired, causing them to lay eggs in less suitable locations. “This disruption is akin to confusing a key olfactory cue from a GPS system,” said Prof. Guirong Wang, lead author of the study. “Without accurate CO2 signals, the insects struggle to find ideal egg-laying sites, which could affect pest population dynamics and agricultural damage.”
https://www.eurekalert.org/news-releases/1094098
