In the vast ocean, without walls and far from the floor, jellyfish can become drifting islands of activity. Creatures from far and wide will congregate on them to act out the ups and downs of life and death. Jellyfish have symbiotic relationships with living things of all sizes, from fish and shrimp that feed off them or off the pieces of food left between their tentacles, to single-celled photosynthesizing organisms that take shelter inside the cytoplasm of the jellyfish’s cells.
In this video, Trisha Towanda talks about one particular jellyfish, the fried egg jelly, and some of the other creatures that hang around it. There are moon jellies that the fried egg jelly eats. These moon jellies have little parasitic crustaceans on them called amphipods, which jump to the fried egg jelly while the moon jelly is being eaten. There are also crabs that ride around on the fried egg jelly, that are parasitic in their youth, but then grow to be helpful symbionts by eating off the little amphipods. This sort of coming of age story, where a symbiont’s relationship changes over its lifespan is an unusual one. Trisha put the pieces together by staring at them for hours and days and weeks when she was in Erik Thuessen’s lab at Evergreen State College.
Many thanks to Trisha Towanda, who is now stationed in the Seibel lab at the University of Rhode Island. This video was edited and animated by Sophia Tintori, with an original score by local pop hero Amil Byleckie. It is released under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 license. Here is the paper Trisha wrote about the story.
When collecting bugs out in the field, it can be easy to get more than one bargained for. Many flies, beetles, and other mobile beasties such as the harvestman shown above (Megalopsalis sp. from New Zealand) find themselves regular host to hitchhikers of arachnid origin: the five orangish globules nestled among the bases of this unfortunate individual’s limbs are parasitic mites hunkered down for the long haul.
Indeed, many tens of thousands of mite species spend their early lives attached to a host, slowly drawing nutrition from its internal fluids until they become large enough to drop off wherever their hosts have carried them, where they begin life as free-living adults. However, these parasitic freeloaders aren’t the only kind of tenants one will find on harvestmen; there are also diverse sorts of more benign bedfellows who climb aboard with no appreciable harm to their unwitting ride.
One group of these tag-alongs is the pseudoscorpions – distant relatives of true scorpions, living secretive lives in forest soil and tree bark – which many would doubtless find abjectly terrifying… if they ever got larger than a few millimeters. Below, you can see a pseudoscorpion hanging for dear life onto the leg of another Megalopsalis. There are reports of pseudoscorpions waiting eagerly around a flower for a bee pollinator to grab onto, or clustering around the pupal bores of flies just before the airborne adult emerges. The traditional interpretation of this behavior suggests that climbing aboard larger, more mobile animals is an adaptation meant to transport these tinier critters to a wider range of habitats. Others, however, have suggested that perhaps pseudoscorpions simply grab onto whatever passes by them in the hopes that they might be able to eat it.
Strangely enough, even pseudoscorpions can bear hitchhikers, as the parasitic mites on this neobisiid I collected during field work in Alabama attest (gray bugs next to the greenish dots). It’s hard not to be reminded of the poet Jonathan Swift’s famous verses:
“The vermin only teaze and pinch
Their foes superior by an inch.
So, naturalists observe, a flea
Has smaller fleas that on him prey,
And these have smaller still to bite ‘em,
And so proceed ad infinitum.”
First three photographs by Gonzalo Giribet. Last photograph by Christopher Laumer.
The leaves are starting to turn and the garden is getting thin as most fruits and vegetables are harvested. There are some fun surprises among the plants that remain, including this tobacco hornworm (Manduca sexta) above that was chewing on our tomatoes. It stayed in one spot, and over the course of two days more and more parasitoid wasp larvae, probably Cotesia congregata, emerged to spin their cocoons. When the mother wasp injected her eggs into the young caterpillar, she also injected a virus that had been multiplying in her ovaries. This virus continued to reproduce in its new host, castrating the caterpillar and preventing it from metamorphosing. This trick provides the the perfect feeding ground for the wasp babies.
Other organisms are also at their peak, and the woods are full of beautiful and delicious fungi. The specimen below is Laetiporus, also known as chicken of the woods because it is so common and quite eatable.
Photos by Casey Dunn. Thanks to Doug Morse, Alan Bergland, and Erika Edwards.
