A unique set of cells pumps water in the kidneys to help extract moisture from the air.
Introduction
The red flour beetle (Tribolium castaneum) is a common pest in storages that feeds on stored grains, flour, cereals, pasta, biscuits, beans, and nuts. It is an extremely resilient creature, capable of surviving in harsh and dry environments thanks to its unique ability to extract fluids not only from grains and other food sources but also from the air. The beetle opens its rear when the humidity is relatively high, absorbing moisture through this opening and converting it into liquid used to hydrate the rest of its body.
Absorption Mechanism
Scientists have been aware of this capability for over a century, but biologists have finally begun to understand the underlying molecular mechanisms according to a research paper published in March in the Proceedings of the National Academies of Science. This study will contribute to future research on how to intervene in this hydration process to keep red flour beetle populations under control, as they are significantly resistant to pesticides. They can also tolerate higher levels of radiation than cockroaches.
Importance of Research
There are about 400,000 known species of beetles roaming the planet, although scientists believe there are over a million species. Each year, up to 20 percent of the world’s grain storage is contaminated by red flour beetles, grain weevils, Colorado potato beetles, and confused flour beetles, particularly in developing countries. Red flour beetles are a common model for scientific research in the fields of development and functional genomics. The entire genome was sequenced in 2008, and the beetle shares between 10,000 and 15,000 genes with the fruit fly (Drosophila), another model organism for genetic research. However, the life cycle of the beetle more closely resembles that of other insects.
Absorption Process
The rectums of most mammals and insects absorb any remaining nutrients and water from waste products in the body before defecation. However, the rectum of the red flour beetle is a model of super efficiency in this regard. The beetle can generate very high salt concentrations in its kidneys, allowing it to extract all the water from its feces and recycle that moisture back into its body.
Molecular Mechanism
Halberg and his team took scanning electron microscope images of the rectal structure of the beetle. They also collected tissue samples and extracted RNA from lab-bred red flour beetles, then used a new resource called BeetleAtlas to analyze gene expression, searching for any relevant genes.
Future Applications
The next step is to build on these new insights to understand how to intervene in the beetle’s unique hydration process at the molecular level, possibly by designing molecules that can do so. These molecules could be integrated into more environmentally friendly pesticides that target red flour beetles and similar pests without harming beneficial insects such as bees.
Conclusion
Halberg said, “Now we understand exactly which genes, cells, and molecules are involved when the beetle absorbs water through its rectum. This means we suddenly have a grip on how to disrupt these very effective processes by developing pesticides that target this function and thus kill the beetle.” He added, “There are twenty times more biomass of insects on Earth than that of humans. They play key roles in most food webs and have a significant impact on all ecosystems and human health. Therefore, we need to better understand them.”
Source: Ars Technica
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