Snail Mucus Proteins Essential for Pest Reproduction Trails

Greg Howard
24th May, 2025

Snail Mucus Proteins Essential for Pest Reproduction Trails

Immunolocalization confirms that AChE-like proteins are synthesized within the mucous gland secretory cells (a–d) and actively secreted into the trail mucus of the reproductive white Italian snail (Theba pisana) (e–g), supporting the study's hypothesis that these proteins act as an external bio-scavenging defense against pesticides.

Image adapted from: Lutschini et al. / CC BY (Source)

Key Findings

  • In Tasmania, Australia, scientists discovered that invasive snails Theba pisana produce special proteins in their mucus during reproduction
  • These proteins help the snails resist common pesticides by neutralizing them before they can harm the snails' nerves
  • This understanding can lead to better strategies for controlling these pests and protecting crops
Invasive land snails like Theba pisana pose significant threats to agriculture and ecosystems worldwide. As global populations grow, ensuring food security becomes increasingly challenging, especially with pests that damage crops and spread rapidly. Traditional methods to control these pests often rely on pesticides containing organophosphates, chemicals designed to kill a broad range of insects and pests. However, the effectiveness of these pesticides is diminishing as pests develop resistance, making it crucial to understand the underlying mechanisms of this resistance. A recent study conducted by researchers at the University of the Sunshine Coast explored how Theba pisana might be developing resistance to organophosphate pesticides[1]. The study focused on an enzyme called acetylcholinesterase (AChE), which is essential for nerve function in many organisms, including snails. AChE breaks down acetylcholine, a neurotransmitter, ensuring that nerve signals are properly regulated. Organophosphates target AChE, inhibiting its function and leading to the paralysis and death of pests. However, mutations in the AChE gene can lead to changes in the enzyme, making it less susceptible to inhibition by these pesticides and thereby conferring resistance. The researchers conducted a detailed analysis of the AChE-like genes in Theba pisana. They discovered an expanded family of these genes, which grouped into three distinct clades when examined phylogenetically. Notably, one of these clades included AChE genes typically found in vertebrates, suggesting a unique evolutionary adaptation in these snails. Most of the AChE-like genes were highly expressed in the snail’s mucous glands during the reproductive stage. This finding indicates that these enzymes might play a role beyond nerve function, particularly in reproduction. To further understand the role of AChE-like proteins, the team performed proteomic analysis of the snail’s trail mucus during the reproductive stage. They identified four AChE-like proteins as major components of the mucus. Immunolocalization techniques revealed that these proteins were abundant in the mucous gland secretory cells and distributed throughout the trail mucus during the reproductive stage. Interestingly, these proteins were largely absent from the mucus during non-reproductive periods, suggesting that their production is linked to the snail’s reproductive activities and increased mobility after periods of dormancy. This study builds on previous research that has examined the impact of pesticides on Theba pisana. For instance, earlier studies have investigated the acute toxicity and biochemical responses of these snails to abamectin, a widely used biocide[2], as well as the effects of sublethal concentrations of pesticides like abamectin and thiamethoxam on various physiological and immunological parameters of Theba pisana[3]. These studies highlighted how pesticides can disrupt energy reserves, enzyme activities, and immune functions in snails, underscoring the importance of understanding resistance mechanisms to develop more effective control strategies. Additionally, previous genetic studies on Theba pisana in California revealed significant differences in populations from different regions, suggesting multiple introduction events and potential genetic variability[4]. This genetic diversity might contribute to the species' ability to adapt and develop resistance to pesticides in various environments. The findings from the University of the Sunshine Coast study provide valuable insights into how Theba pisana may be mitigating the effects of organophosphate pesticides. By producing AChE-like proteins in their mucus, these snails could be neutralizing the pesticides before they reach their target sites in the nervous system. This bio-scavenging mechanism would render the pesticides less effective, allowing the snails to survive and reproduce despite pesticide exposure. The abundance of these proteins during the reproductive stage aligns with the snails' need for increased mobility and activity, periods during which they are more likely to encounter pesticides in their environment. Understanding this resistance mechanism is crucial for developing new strategies to manage invasive snail populations. If snails can effectively neutralize pesticides through their mucus, alternative methods or more targeted pesticides may be necessary to control their spread. Moreover, the identification of specific AChE-like proteins involved in resistance could lead to the development of diagnostic tools to monitor resistance levels in snail populations, allowing for more informed pest management decisions. Overall, this study advances our knowledge of pesticide resistance in invasive land snails by revealing a novel mechanism involving AChE-like proteins in mucus. It highlights the importance of molecular and proteomic approaches in uncovering the strategies pests use to survive chemical control measures. By building on previous research and providing a deeper understanding of Theba pisana's biology, this work paves the way for more effective and sustainable management practices to protect agriculture and natural ecosystems from invasive pests.

BiochemEcologyAnimal Science

References

Main Study

1) Acetylcholinesterase-like proteins are a major component of reproductive trail mucus in the invasive pest land snail, Theba pisana

Published 21st May, 2025

https://doi.org/10.1371/journal.pone.0323380

Related Studies

2) Insights into the ecotoxicological perturbations induced by the biocide Abamectin in the white snail, Theba pisana.

https://doi.org/10.1080/03601234.2022.2044708

3) Use of multiple endpoints to investigate the ecotoxicological effects of abamectin and thiamethoxam on Theba pisana snails.

https://doi.org/10.1016/j.ecoenv.2018.10.027

4) Multiple Introductions of the Pestiferous Land Snail Theba pisana (Müller, 1774) (Gastropoda: Helicidae) in Southern California.

https://doi.org/10.3390/insects12080662


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