In a world facing growing pressure on food systems, water resources, and biodiversity, some of the answers may come from an unexpected place: the armored bodies of tiny marine creatures.
For more than two decades, Prof. Amir Sagi of Ben-Gurion University of the Negev has been studying crustaceans as sophisticated biological systems that hold clues about growth, reproduction, and survival. Hidden beneath their shells are genetic mechanisms that could help farmers produce more sustainable food, protect ecosystems from invasive threats, and even fight diseases that affect hundreds of millions of people around the world.
“They are fascinating biological systems,” Sagi notes.
For him, crabs, shrimp, lobsters, and other crustaceans are not simply creatures of the sea. They are living laboratories, animals that have evolved remarkable solutions to some of nature’s most complicated challenges.
“I’m a marine biologist,” he says, describing the path that brought him to this field. After completing his postdoctoral research at Woods Hole in Cape Cod, with the University of Connecticut, Sagi initially considered building his academic career in the United States. He even received an offer from another American university. But after conversations with his family, he decided to explore the possibility of returning to Israel.
The opportunity came unexpectedly at an academic conference in the United States, where he met a researcher from Ben-Gurion University who told him that the Department of Life Sciences was searching for an invertebrate physiologist. “And the rest is history,” Sagi says.
Today, his laboratory at the university focuses on two central questions: how crustaceans build their bodies, and how their bodies determine who they become. The first area of research examines one of the most extraordinary processes in the animal kingdom – molting.
Unlike humans and other vertebrates, crustaceans do not grow by expanding an internal skeleton. Their skeleton exists outside their bodies, forming a protective shell that must be discarded as the animal grows. After shedding the old shell, the animal must quickly construct a new one and harden it before becoming vulnerable to predators.
“Imagine if we had to replace our entire skeleton within three days,” Sagi says. “That is essentially what they do.”
The process requires a complex interaction between genes, proteins, and physiological systems. Sagi and his team study how specific genes in the crustacean genome influence the construction of this external skeleton, and why they act the way they do – a field known as functional genomics.
New scientific possibilities
The goal is to gain a deeper understanding of the biology of crustaceans, but Sagi found that it may have practical applications as well. Perhaps the most significant discovery to emerge from Sagi’s laboratory came from a different question: What determines whether a crustacean becomes male or female?
The research began more than two decades ago, led by Dr. Rivka Manor, a researcher in life sciences at BGU, during her doctoral studies at the university. Her work revealed the existence of a hormone in decapod crustaceans that closely resembles insulin and plays a decisive role in determining sex.
“It turned out that this hormone is responsible for the masculinity of the crustacean,” Sagi explains. “If the hormone is present, the crustacean is male. If it does not, the crustacean becomes female.”
The discovery opened a new scientific possibility: controlling the sex of crustacean populations through a biological switch. “From the moment we discovered it, we could determine what the sex of every crustacean would be using an on/off mechanism,” Sagi says.
While the discovery is scientifically significant in animal biology, in the world of aquaculture, it represents a major technological breakthrough. As demand for seafood increases and natural fisheries face growing pressure, farming aquatic species has become increasingly important. “In aquaculture, as in any animal husbandry, males and females have different advantages, depending on the environment. A male can fulfill certain agricultural goals, while a female can serve other needs,” Sagi says.
The technology developed by Sagi’s team makes it possible to create single-sex populations, a tool that can allow farmers to grow populations specifically suited to their needs.
The research has already moved beyond the laboratory. In Vietnam and Thailand, former students from Sagi’s group and others using the biotechnologies developed at BGU have established companies producing millions of monosex crustacean larvae for aquaculture.
Environmental benefits
In addition to farming, Sagi found that a surprising application of the research lies in environmental protection. Some crustaceans are powerful predators of snails, including snail species that serve as hosts for parasites responsible for schistosomiasis, also known as bilharzia – a disease that affects millions of people, particularly in regions where communities depend on freshwater sources.
“The parasite enters through the skin from snails that live in the water,” Sagi explains. “Children are especially vulnerable because of their exposure to these environments.”
His team is investigating whether crustaceans can be used as biological control agents to reduce populations of disease-carrying snails.
But introducing a predator into a new ecosystem comes with a significant danger: the solution itself could become an ecological problem. A species that reproduces uncontrollably can become invasive and damage the environment it was meant to protect. This is where Sagi’s earlier discovery becomes crucial.
By creating populations made up of only one sex, researchers may be able to use crustaceans’ natural abilities without allowing them to establish permanent populations in the wild. “We use our knowledge to create populations that are single-sex and will not reproduce in nature,” he says.
A project currently underway in Kenya is examining whether this approach can provide a safe and sustainable method for controlling disease-carrying snails and rice field pests. For Sagi, this is the future of environmental science: not fighting nature, but learning how to work with it.
“The interesting thing is that the same knowledge that allows us to understand reproduction can also help us solve ecological problems,” he says.
Science without borders
While Sagi’s research focuses on creatures that live beneath the surface of the water, he has also recently been confronting another question: how Israeli science is perceived around the world. During a recent academic journey through South America, including Brazil and Argentina, Sagi said he arrived unsure of what reception he would receive.
Instead, he encountered something he had not expected – a strong desire for scientific collaboration. “I was surprised,” he says. “I didn’t know what to expect.”
At the universities he visited, administrators and researchers went out of their way to welcome and host him. In one remote location in the Amazon, researchers traveled long distances to attend his lecture. “It was moving,” he recalls.
For Sagi, the experience revealed a more nuanced and hopeful picture of Israeli academia’s place in the world, one that exists alongside discussions of academic boycotts and strained international relationships.
“There is a lot of talk about rejection, about papers being refused, or conferences where Israelis are not invited,” he says. “But there are also many people who understand that Israeli academia is a strong and independent constant, unaffected by politics. [There are] people who want to preserve and deepen connections with Israeli researchers based on their research excellence.”
Case in point: In 2024, Sagi was awarded by a committee in Malaysia (a country that does not have diplomatic relations with Israel) the ACEEU Asia-Pacific Lifetime Achievement Award. The desire for collaboration, he believes, is especially important in fields such as environmental biotechnology, where the challenges are global by definition.
“Climate change, food security, invasive species, and infectious diseases do not stop at national borders. The scientific efforts needed to address them must not either.”
This article was written in cooperation with Ben-Gurion University of the Negev.
The Environment and Climate Change portal is produced in cooperation with the Goldman Sonnenfeldt School of Sustainability and Climate Change at Ben-Gurion University of the Negev. The Jerusalem Post maintains all editorial decisions related to the content.
