Can microalgae boost insect immunity?
Updated: 4 days ago
By Christina Adamaki-Sotiraki, PhD candidate, Laboratory of Entomology and Agricultural Zoology, University of Thessaly
When we talk about insect nutrition, we usually ask how fast insects grow or how much protein they produce. During my Short-Term Scientific Mission (STSM), I wanted to ask something different: can what larvae eat boost their immune response against bacteria?
I’m a PhD candidate at the University of Thessaly (Greece), under the supervision of Prof. Christos Athanassiou. My research focuses on optimising the mass rearing of edible insects.
With the support of COST Action CA23127 (GIN-TONIC), I spent five weeks, from 31 August to 9 October 2025, at the Department of Biotechnology and Life Sciences, University of Insubria (Varese, Italy). There I worked with Prof. Gianluca Tettamanti and Dr. Daniele Bruno.
Why immunity matters for insect farming
The Black Soldier Fly (Hermetia illucens) is one of the most important insect species when it comes to circular bioeconomy. Its larvae turn organic by-products into protein for feed and many more ingredients. As production scales up, keeping millions of larvae healthy becomes a real challenge. Diet is one of the simplest tools farmers have, so we asked whether functional ingredients could strengthen the larvae’s natural defences.
Our candidate was a widely available microalga: Chlorella vulgaris.
So, I mixed larval diets with microalga and compared them with a standard control diet. During rearing, I tracked growth, development time and survival.
Then came the immune test. I collected haemolymph from larvae. I then checked how well it stopped two model bacteria from growing: Micrococcus luteus (Gram-positive) and Escherichia coli (Gram-negative).
What we found
Microalgae can affect the larvae’s innate immunity, but the effect depends on the type of bacteria. For the insect sector, this points to functional feeds that support animal health, not just growth.
The work didn’t stay in the lab. In June 2026, I presented our results at the Insects to Feed the World (IFW) conference in Turin, Italy. The talk was titled “Green Shields for Hermetia illucens: Boosting the defense mechanisms of Black Soldier Fly via microalgae supplementation.” It was a great chance to discuss the findings with the international insect community and get feedback ahead of publication.
What’s next
Beyond the data, the STSM built a lasting bridge between the University of Thessaly and the University of Insubria. We are already planning researcher exchanges, follow-up STSMs and joint project proposals.
A note for future applicants!
If you’re an early-career researcher wondering whether an STSM is worth it, my answer is yes!
Five weeks in a new lab gave me new techniques, a new research direction, a conference talk and collaborators I’ll keep working with. That is a lot to get from one short mission.
This STSM was funded by COST Action CA23127 – Group on Insect Nutrition (GIN-TONIC), supported by COST (European Cooperation in Science and Technology).
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