In a surprising reversal of fortune, Israeli researchers have found a certain group of beetle larvae that feed on frogs.

As Ed Yong reports in his Discover blog:

During its lifetime, a frog will snap up thousands of insects with its sticky, extendable tongue. But if it tries to eat an Epomis beetle, it’s more likely to become a meal than to get one.

The larvae have shown 100% success in their ability to lure the frogs into becoming a meal. In fact, these beetles eat nothing else in the larval stage. Here are the gruesome details.

According to the researchers, Epomis larvae combine a sit-and-wait strategy with unique movements of their antennae and mouthparts to draw the attention of an amphibian (frogs and toads were used in the study). Thinking it has spotted potential prey, the amphibian comes closer and the larva increases the intensity of these enticing motions.

When the amphibian attacks, the larva manages to avoid the predator’s tongue and uses its unique double-hooked mouthparts to attach itself to the amphibian’s body and initiate feeding, which can include both sucking of bodily fluids and chewing body tissues, usually killing the much larger amphibian.

“It seems that instead of serving as food items for amphibians, Epomis larvae have evolved to specifically take advantage of amphibians as a food source,” says researcher Gil Wizen.

These findings extend the perspective of co-evolution in the arms race between predator and prey and suggest that counterattack defense behavior has evolved into predator-prey role reversal.

The research is published in the online journal PLoS ONE. Images and video of the beetle and the frightening attack can be found at Wired and Discover.

Image: Gil Wizen/AFTAU

Villy Christensen of the University of British Columbia (UBC) said, “Yes, there will be fish left, but it will be a very different ocean from the ones your parents and grandparents knew and even different from now.”

The biggest difference? Large, predatory fish will be gone.

In fact, over the last one hundred years, the population of these large, top-of-the-food-web fish has declined by two-thirds, half of that decline occurring only in the last 40 years. And that population continues to decline.

There will be many small fish left, but not necessarily the ones we eat.

He and his colleague, Reg Watson, also from UBC, are working with scientists, governments and NGOs to build a global database of fishing efforts to truly understand what’s going on in the world’s oceans.

Seventy-six million tons of fish are consumed each year, and Watson found that we are fishing harder for the same or less result. It’s possible that we’ve hit “peak fish,” according to Watson. Jacqueline Alder of the UN Environment Program in Kenya is working with the UBC group, looking at their models in terms of marine biodiversity and sustainability. She urged that we must reduce fishing efforts immediately to allow fish stocks to rebuild.

In addition, there was much discussion around the non-sustainability of using fish for feedstock in aquaculture and agriculture– fish we are not directly eating. The science and technology have to get better to use plant-based feedstock for fish farms.

Christensen stressed this is a large view of what’s going on in the entire ocean ecosystem, not just one area or species.

For more focused, local information, read our recent article on banning shark finning, and the San Francisco Chronicle had a devastating article last week stating that some of the fish in the Delta may be too far gone to save from extinction.

Image: Mila Zinkova/Wikimedia