Deep-sea spiders breed methane bacteria in their bodies

Scientists have discovered a special feeding strategy for sea spiders living near underwater methane leakage: They grow bacteria on their exoskeletons and then harvest them for food.

The discovery, published in the Proceedings of the National Academy of Sciences, reveals how these octopus animals thrive in one of the most extreme environments on Earth.

Three new spider species in this genus Sericosura Found in methane leakage from California to Alaska, each hosting hosts a community of various methane and methanol consuming bacteria on its outer surface. The tissue carbon isotope values ​​shown by the spider averaged -45‰, providing clear evidence of methane assimilation.

Bacterial buffet on exoskeleton

Using advanced microscopy techniques, the researchers observed that bacteria formed “evenly spaced volcanic-like aggregations” throughout the spider body, surrounded by protective layers of biopolymers. Many of these bacterial clusters seem to be destroyed, with the remaining cellular footprints, active grazing of spiders.

“We recommend that these sea spiders breed and feed on methyl and methyl nutritious bacteria,” the team said in their study. The arrangement is similar to underwater agriculture, where spiders maintain bacterial crops on their bodies before consumption.

What makes this relationship particularly compelling is the diversity of bacterial partners. Spiders have three different microbial families at the same time: methyl nucleic acid, methyl cycadae and methyl eosinophila. No other animal species supports these three methane-processed bacteria.

Generation of bacterial inheritance

This study reveals unexpected changes in reproduction. Male sea spiders carry egg sacs that contain the same egg sacs as bacterial communities on adult surfaces, suggesting that these microbial partners are transferred from parents to offspring. This vertical transmission can explain how spiders maintain their bacterial farms across generations.

During the study period, the researchers found that 50% of the collected specimens were contemplative males, higher than the typical height of the spider family. Rich available bacterial foods may enhance reproductive success.

Methane to spider tissue for five days

To confirm this relationship, the scientists conducted a feeding experiment using carbon 13 labeled methane and methanol. Within five days, both compounds’ carbon appeared in spider digestive tissue, demonstrating that methane-derived nutrients are actively incorporated into animals.

The bacterial community showed faster absorption, with some cells reaching 12 times the natural carbon 13 abundance. Even the sticky polymer matrix around bacteria is rich in labeled carbon, suggesting that microorganisms share resources between resources.

Hidden ecosystem connections

This discovery extends our understanding of methane, which is often considered to be merely greenhouse gases as the basis of the deep-sea food network. Spiders join a group of animals that use methane as their energy source, although their farming methods seem unique.

Perhaps most interestingly, the study found evidence of metabolic cooperation within the bacterial community itself. Methylribobiotic bacteria produce methanol when they consume methane and then feed other bacterial families in layers of energy transfer, thus maximizing the nutritional choices of spiders.

These findings highlight unknowns about deep-sea ecosystems. These spider-bacterial partnerships were found in Del Mar methane seepage, a relatively small subsea area with well-studied waters next to Southern California, but they possess completely novel biological relationships.

As lead author Bianca Dal Bó points out: “This work helps us better understand biodiversity on Earth, which is crucial.” Research shows that even in the most remote environments of the planet, life can find innovative ways to thrive through unexpected partnerships.

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