This is a real oddity and clearly an early penetrator
of the land sea boundary. Its ability to
take down essentially any insect it gets close to is impressive.
It is also a timely reminder of just how huge the
global insect biomass truly is. It
readily outweighs any other non - plant live forms altogether.
It also suggests an insect control strategy that
should be better explored. Why not do
way more banding of plants or simply spray on sticky droplets that remain
naturally hydrated. I think we actually
know enough to do this.
New Glue-Spitting Velvet Worm Found in
Vietnam
The ancient animals,
which spit an immobilizing material onto prey, hadn't been spotted before
because they spend most of their lives hidden in soil to keep their permeable
skin moist
Small bugs of the rain forest have many things to worry
about, assuming they are capable of anxiety. But surely some of their more
feared predators are velvet worms, a group of ancient animals that spit an immobilizing, gluelike
material onto prey before injecting them with saliva and chomping down.
It turns out the velvet worm family is more diverse than
thought: A new species has been found in the jungles of Vietnam. Unlike related velvet worms, this species
has uniquely shaped hairs covering its body. It reaches a length of 2.5 inches
(6 centimeters), said Ivo de Sena Oliveira, a researcher at the University of
Leipzig, Germany, who along with colleagues describes the species in
Zoologischer Anzeiger (A Journal of Comparative Zoology).
The paper and related work by Oliveira suggest thousands
of unknown species of these creatures are waiting to be found throughout the
world's tropical rain forests, he said. Research by Oliveira in the Amazon rain forest alone suggests there may be one new species
of velvet worm about every 15 miles (25 kilometers), he told LiveScience.
Little-known glue-spitter
The animals are
extremely difficult to find and little known, because they spend most of life
hidden in moist areas in the soil, in rotting logs or under rocks, due in part
to the fact that their permeable skin allows them to quickly dry out, Oliveira
said. In some areas, "if you're not there at the right moment of the year,
during the rainy season, you won't find them," he added. The rainy season
is the one time of year this Vietnamese species exits the soil, he said.
Unlike arthropods (a huge group of animals that includes ants
and spiders), velvet worms lack hard exoskeletons. Instead their bodies are
fluid-filled, covered in a thin skin and kept rigid by pressurized liquid. This
hydrostatic pressure allows them to walk, albeit very slowly, on fluid-filled,
stubby legs that lack joints.
Slimed
Their slowness
works to their advantage. To hunt, they sneak up on other insects or
invertebrates. And that's when the sliming begins — velvet worms like the
newfound species hunt by spraying a "net of glue" onto their prey
from two appendages on their backs, Oliveira said. This nasty material consists
of a mix of proteins that impedes movement. "The more the prey moves, the
more it gets entangled," he said.
Oftentimes the
velvet worms will eat any excess "glue," which is energetically
costly to make. Although the animals have been shown to take down prey larger
then themselves, they often choose smaller creatures, likely to ensure they
don't waste their precious bodily fluids, Oliveira said.
Fossils show that velvet worms haven't changed much since
they diverged from their relatives (such as the ancestors of arthropods and waterbears) about 540 million years ago, Oliveira said.
Studies of velvet worms could help shed light on the evolution of arthropods, he added.
There are two families of velvet worm, one spread around
the tropics, and another found in Australia and New Zealand. Members of the former
group generally tend to be loners. But the other family may be more social. One
2006 study found that members of the species Euperipatoides
rowelli can hunt in groups of up to 15, and that the dominant
female eats first.
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