Tag Archives: nocturnal

Nocturnal Spiders Employ Captured Fireflies as Luminous Lures to Entice Prey

Posted on by
Reply

Sheet Web Spider Psechrus Clavis is known to utilize the coloration and web of its own body as visual cues to effectively capture and consume insects. Interestingly, it doesn’t immediately eat the male fireflies, referred to as Daifan Lampaloid; instead, these spiders retain them on the web, allowing the fireflies to continue emitting bioluminescent signals for up to an hour. This observation has raised intriguing questions among a research team from Tunghai University, the University of New South Wales, the Sydney Institute of Technology, and the National Museum of Natural Sciences in Taiwan.

Sheet web spider with fireflies caught in the web. Image credit: Tunghai University Spider.

Researcher I-Min TSO and colleagues at Tunghai University documented Psechrus Clavis retaining fireflies on the web while these insects continued to emit bioluminescent light for up to an hour.

They noted that the spiders periodically check for the captured fireflies.

Fascinated by this peculiar behavior, the researchers designed an experiment to see if it serves as a hunting strategy.

The experiment involved placing firefly-like LEDs on the actual sheet spider web, using other webs as controls.

The results indicated that the web with LEDs attracted three times as many prey compared to the control web.

This figure increased to ten times more prey when actual fireflies were visible.

The findings affirm that the presence of captured fireflies enhances the spider’s hunting success.

Researchers also discovered that the majority of captured fireflies are male and likely mistaken for potential mates.

“Our findings underscore the previously unrecognized interaction where Firefly Signals, intended for sexual communication, also benefit spiders,” remarked Dr. TSO.

“This study provides new insights into how sit-and-wait predators can adapt to attract prey, revealing the intricate complexities of predator-prey interactions.”

“This behavior may have evolved in sheet web spiders as a way to avoid the energy costs associated with producing their own bioluminescence, similar to anglerfish.”

“Instead, spiders can leverage the allure of their prey’s glow to attract their own targets.”

Video recordings taken during the experiments show sheet web spiders employing various tactics when interacting with different prey species.

The spider swiftly consumes a moth caught in the web but takes its time with the trapped fireflies.

“The varying treatment of prey suggests that spiders may use specific cues to differentiate between prey species and adjust their responses accordingly,” explained Dr. TSO.

“We hypothesize that the bioluminescent signals of fireflies help spiders to fine-tune their handling behavior towards different types of prey.”

This study was published in Journal of Animal Ecology.

____

Ho Yin Yip et al. Visual seduction through bioluminescence of prey seduces waiting predators. Journal of Animal Ecology Published online on August 27th, 2025. doi:10.1111/1365-2656.70102

Source: www.sci.news

Alpine ibex are becoming more nocturnal as the climate warms up

Posted on by
Reply

Ibex can be at risk from wolves if they move around at night

robert andrighetto

Alpine ibex have become increasingly nocturnal to escape rising daytime temperatures, despite the increased risk of encountering predators.

Animals living in cold regions are expected to be greatly affected by rising global temperatures due to climate change. Alpine Ibex (capra ibex), usually seen grazing during the day in the European Alps, is one such animal.

To see what the impact was, Stefano Grignorio Researchers from the University of Ferrara in Italy tracked 47 individuals in Italy's Gran Paradiso National Park or Swiss National Park from May to October between 2006 and 2019. The animals were fitted with collars equipped with movement sensors.

Researchers found that warmer daytime temperatures made ibex more active at night. Grignolio said the discovery was surprising because doing so increases the chances of encountering wolves, one of their main natural enemies.

“Global warming seems to be driving their behavior changes dramatically,” he says. “Predation is just a variable.”

The ibex, a climate-sensitive animal, has probably shifted to a more nocturnal schedule to avoid the heat. Warmer daytime temperatures mean your body needs to expend more energy to cool itself compared to the energy needed to stay warm at night, Grignolio says.

However, while this response may help ibex cope with warmer climates, it may not be a viable long-term solution for ibex. “[They] may not be able to meet their demands [dietary] If they become too nocturnal or have increased predation, their requirements will not be met.” Niels Martin Schmidt At Aarhus University, Denmark.

“This study successfully quantifies some of the more subtle and often overlooked responses to climate change,” Schimdt says.

topic:

Source: www.newscientist.com