There’s no such thing as a one-night stand with anglerfish.
Marine biologists have just discovered that these toothy, deep-sea creatures possess an unprecedented immune adaptation that allows their bodies to conjoin during an indefinitely-long mating process, called “sexual parasitism,” according to a study published Thursday in the journal Science
Anglerfish are an extreme example of sexual dimorphism, in which the female anglers dwarf males in every way. In fact — and not unlike some human societies — the only function men seem to serve is reproductive. Otherwise, they just take, take, take …
According to oceanic researchers, the insignificant male anglerfish will latch on to the substantial female and integrate itself — flesh, blood and all — in a form of “anatomical joining.” At this point, the fused male partners become completely reliant on the female for food and safety.
For the dominant mate and mother, it’s like she has two types of children. Go figure.
Scientists say the seemingly imbalanced power structure evolved to cope with the vast blackness of the deep sea, which makes it unfathomably difficult for single anglerfish to find a date, forcing them to settle for any dude who wants to glom on — up to eight of them at once.
However, it’s more than the average host-parasite relationship, scientists more recently revealed, as this sexual fusion process has prompted female anglerfish to develop a unique immune system that accepts the foreign tissue of male anglerfish as its own. In other vertebrate species, they pointed out, this physiological commingling would trigger an immune response — much like our own bodies do during transplantation. It’s the reason why transplant patients take immunosuppressive drugs, so their bodies won’t “reject” the new organ or limb.
“These findings hinted at the possibility that the immune system of anglerfishes was very unusual among the tens of thousands of vertebrate species,” said Jeremy Swann, whose new study is a collaboration between researchers at Max Planck Institute of Immunobiology and Epigenetics in Freiburg, Germany, and the University of Washington, Seattle.
The genetic processes behind their unique mating ritual has eluded scientists since a pair were first discovered stuck together, caught dead in a net in Icelandic waters a century ago. In fact, it was only two years ago that humans witnessed the live act.
By analyzing the genomes of several anglerfish species, researchers found that conjoined anglers lacked the mapping for major histocompatibility (MHC) antigens, a component of cells that send a signal to the immune system when an intruder, such as foreign tissue or other pathogen, enters the body. This rendered their T cells, the immune system’s army of white blood cells, apparently impotent.
“Apart from this unusual constellation of MHC genes, we discovered that the function of killer T cells, which normally actively eliminate infected cells or attack foreign tissues during the organ rejection process, was also severely blunted if not lost entirely,” said Swann, whose research also indicated that some species also lacked the genetic coding for antibodies, another immune defense.
It’s a surprising finding to many scientists, who previously assumed the conventional immune system is a function vital to the survival of vertebrates.
The women of the world, however, may be less shocked by the female angler’s tenacity. After all, we’ve been adapting to men and persevering for millennia.