Interesting fact: Hungry spiders lose their eyesight

A groundbreaking study led by biologists at the University of Cincinnati has found that undernourished jumping spiders lose light-sensitive cells crucial for their vision. The research could shed light on the role nutrition plays in common age-related vision problems, such as macular degeneration.

Elke Buschbeck, a professor in the UC College of Arts and Sciences, and her co-authors focused on the photoreceptors in the eyes of bold jumping spiders, tiny eight-legged predators native to North America. These minuscule hunters are known for their exceptional vision, which they rely on to stalk their prey.

The research team stumbled upon their discovery while examining the eyes of wild-caught bold jumping spiders using a custom-made ophthalmoscope, designed to capture images of insect and spider retinas. 

They discovered dark spots on some of the spiders’ photoreceptors, indicating degeneration during their life or development. “You could tell just by looking at them that some of the photoreceptors had died,” Buschbeck said.

To determine whether the photoreceptors were actually degenerating or merely being bleached by the experimental method, UC doctoral student Shubham Rathore turned to electron microscopy. This confirmed that the cells were indeed dying, making jumping spiders an intriguing model for studying retinal and neuronal health.

How the study was done

To investigate whether poor nutrition was the cause of photoreceptor loss, UC graduates Miranda Brafford and John Goté conducted an experiment with two groups of captive spiders. One group was fed a normal, unrestricted diet, while the other received only half portions.

The underfed spiders lost more photoreceptors, especially in the retina’s densest part. Buschbeck likened this region to the macula in human eyes, which processes visual information directly in front of us.

According to Buschbeck, photoreceptors are energetically costly and difficult to maintain. “If you deprive them of nutrition, the system fails,” she explained. In the United States, macular degeneration, which has no known cure, affects approximately 20 million people and is the leading cause of age-related vision loss. 

Buschbeck noted that there is evidence linking macular degeneration in humans to metabolic processes and difficulties with energy delivery.

Rathore and Buschbeck plan to further explore whether degeneration begins in the support tissues surrounding photoreceptors and identify specific nutrients that promote good visual health. 

However, Annette Stowasser, the study’s senior author and an assistant professor in UC’s College of Arts and Sciences, warned against drawing direct comparisons between vision deficits in spiders and humans. She emphasized the need for carefully designed studies to identify the exact nutrients involved, as these may depend on environmental factors and other variables.

Nevertheless, Stowasser acknowledged that the observed effects of nutrient deprivation underscore the importance of closely examining the impact of nutrients on vision. 

Nathan Morehouse, co-author and director of UC’s Institute for Research in Sensing, expressed excitement about the potential for breakthroughs in macular degeneration treatments inspired by jumping spiders. “Sometimes answers to challenging problems can come from unexpected places,” he said.

This study, published in the journal Vision Research, was supported by grants from the National Science Foundation.

More about spiders

Spiders are a diverse and fascinating group of arachnids with over 48,000 known species found across the world. They exhibit a wide variety of behaviors, adaptations, and ecological roles. Here are some interesting facts and characteristics about spiders:

Anatomy

Spiders typically have two main body segments (the cephalothorax and the abdomen), eight legs, and multiple eyes. Most spiders possess eight eyes, but some species may have fewer or none at all. The arrangement and number of eyes can help identify different spider families.

Silk production

Spiders are famous for their ability to produce silk, a strong and flexible protein fiber. They use silk for various purposes, such as spinning webs to catch prey, creating egg sacs, building shelter, and even as a safety line while moving around.

Venom

Most spiders are venomous, using their venom to immobilize or kill their prey. However, only a small number of species are dangerous to humans, such as the black widow, the brown recluse, and some funnel-web spiders.

Hunting strategies

Spiders employ diverse hunting strategies. While many build intricate webs to catch prey, others actively hunt, like jumping spiders, which stalk and pounce on their prey, or wolf spiders, which chase down their targets.

Reproduction

Spiders exhibit unique mating behaviors. In some cases, the male performs complex courtship displays to attract and avoid being eaten by the female. After mating, the female lays her eggs in a protective silk sac, and in some species, the female guards the eggs until they hatch.

Diversity

Spiders come in various shapes, sizes, and colors, and can be found in almost every terrestrial habitat, including deserts, forests, grasslands, and even urban environments.

Molting

As they grow, spiders undergo a process called molting, during which they shed their exoskeleton to make room for a larger one. Young spiders may molt several times before reaching adulthood.

Benefits to humans

Spiders play a vital role in controlling insect populations, as they are natural predators of many pests. Additionally, their venom and silk have been the subject of extensive research, leading to potential applications in medicine, biotechnology, and materials science.

Overall, spiders are a diverse and ecologically significant group of arachnids that exhibit a wide range of fascinating behaviors and adaptations.

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