Sawflies, belonging to the suborder Symphyta within the order Hymenoptera, have long intrigued entomologists for their evolutionary lineage, unique larval behaviours, and impact on agriculture and forestry. Recent scientific advancements have brought sawflies into sharper focus. This article highlights some of the most significant studies from the past 18 months, spanning genetics, pest control, behaviour, and climate change resilience.
Read further to know more about sawflies and the interesting investigations about them.
How Sawfly Alters Plant Defence and What are the Population Genomic Advances?
A compelling ecological 2023 study showed that the act of laying eggs (oviposition) by Nematus oligospilus on weeping willow (Salix babylonica) induces plant defences before any larval feeding begins. These defences include increased jasmonic acid levels and changes in volatile organic compounds. Larvae feeding on these preconditioned plants grew more slowly and entered pupation much later than usual, demonstrating how subtle insect–plant interactions can significantly influence development and survival.
In another breakthrough for molecular entomology, researchers developed 56 novel genome-wide microsatellite markers for Acantholyda posticalis, a web-spinning sawfly affecting pine forests in China. These markers vary in their polymorphic information content (PIC), offering a valuable tool for population genetic analysis. Notably, some markers cross-amplified in related species (Cephalcia), broadening their application across Pamphiliidae. This development is expected to inform strategies for pest management, conservation genetics, and the evolutionary study of sawflies.
Pest Management and Climate Forecasting
In northwestern Mexico, scientists identified a new pine-infesting sawfly from the genus Zadiprion. Using species distribution models, they projected that this pest is likely to remain within its current habitat over the next 50 years, despite ongoing climate change. These findings underscore the need for long-term monitoring, as even non-expanding pest populations can maintain significant ecological and economic impacts.
Sustainable Control of Sawflies in Berry Crops
In Ukrainian blackcurrant plantations, Pristiphora rufipes has emerged as a destructive pest. Researchers compared various biocontrol methods, including Bacillus thuringiensis (Bt), entomopathogenic fungi (Beauveria bassiana, Metarhizium anisopliae), and combinations with pheromone traps. The integrated approach led to an 85% reduction in larvae and notable decreases in adult populations and foliage damage. While Bt was also effective independently, its combination with fungal agents showed the highest efficacy, especially in moist conditions. Drought, however, limited fungal performance, highlighting the role of environmental conditions in biological control success.
Why Sampling Techniques Play Key Role
Over 25 years, a comparative study in Slovakia and Hungary examined the effectiveness of sweep nets versus Malaise traps in sampling sawfly populations. Both methods had specific biases: sweep nets under-sampled Allantinae, while Malaise traps underrepresented Argidae and other subfamilies. For accurate biodiversity assessments and ecological monitoring, researchers recommend using both tools in tandem.
Takeaway
From evolutionary insights buried in Miocene fossils to modern biotechnological tools, sawfly research is undergoing a quiet but significant transformation. These insects are no longer just forest or crop pests, they are windows into cooperation, climate resilience, and co-evolution with plants. With tools for genetic analysis, improved sampling methods, and integrated pest control strategies, researchers and growers are better equipped than ever to understand and manage these complex and fascinating insects.
References
- https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.70500
- https://peerj.com/articles/7220
- https://link.springer.com/article/10.1007/s11756-024-01651-3
- https://link.springer.com/article/10.1007/s00040-024-01012-y
- https://www.jyu.fi/en/news/research-on-pine-sawflies-sheds-light-on-the-evolution-of-cooperation
- https://www.frontiersin.org/articles/10.3389/fevo.2023.1084063/full
Photo Credit: Shutterstock/HHelene
