Odontomachus haematodus with parasite. Armenia, Belize.
I can’t imagine what an insect infected with a mermithid nematode must feel. In Belize last week we encountered several parasitized trap-jaw ants, each stumbling about with a belly twice the heft of that in a healthy ant. Scaled to human size, a mermithid would be at least as intrusive as an anaconda coiled among the intestines.
Young worms infect ant larvae via contaminated soil in the brood nest. Adult ants who developed with a parasite sapping their nutrients eclose in a recognizably stunted fashion: a swollen, worm-hosting abdomen and a curiously shrunken head. I was surprised on photographing the victims that the trap-jaw could still snap shut audibly and convincingly.
How affected are mermithized ants? Compare an infected individual to a healthy one (albeit of a different species):
Top: a mermithid-carrying Odontomachus haematodus ant with distorted abdomen and shrunken head; bottom: a healthy Odontomachus clarus worker showing typical proportions for an uninfected ant.
When mature, worms break free from their hosts. The process kills the poor ant, but it frees the nematode to mate and lay eggs.
Still. One more reason I’m glad not to be an insect.
Canon MP-E 65mm 1-5x macro lens on a Canon EOS 7D
ISO 200, f/13, 1/100 sec
diffused overhead twin flash
What were those red globes stuck to the buggy fuzzball?
They were parasitic mites- probably Erythraeidae- feeding on a planthopper nymph in the family Flatidae.
Five points to Ted MacRae for nabbing the bug family first, and five more to Chris Borkent for the mites. I *think*, but am not sure, that the bug is Metcalfa as guessed by Dave H, Dave W. and Monika- so I’ll award a point each there as well. The legs of the mite are visible in the photo above.
You may remember Wesley Fleming, the glass artist I blogged about last year. It seems he’s accomplished a remarkable new piece: a leafcutter ant infected with a parasitic Cordyceps fungus. As far as I know this is the first Cordyceps ever created from glass.
If you’d like to see it in person, this and some of Fleming’s other pieces will be on display at the Racine Art Museum this summer.
What is Cordyceps, you ask? Watch:
I did not expect everyone to nearly instantaneously solve yesterday’s termite ball mystery. I’m either going to have to post more difficult challenges (from now on, nothing will be in focus!) or attract a slower class of reader.
Cuckoo fungus grows in a termite nest.
As you surmised, those little orange balls are an egg-mimicking fungus. It is related to free-living soil fungi, but this one has adopted a novel growth form that is similar in diameter, texture, and surface chemistry to the eggs of Reticulitermes termites. These hardened sclerotia are carried about the termite nest as if they were the termite’s own offspring, earning them the title “Cuckoo fungus”. Since termites are blind there is no advantage to the fungus in visually looking like an egg, though, so we sighted creatures can tell the difference at a glance.
For more about the Cuckoo fungus, check out the publications of Kenji Matsuura. Matsuura first identified the balls as a fungus ten years ago, as a graduate student, and has been working on them ever since.
Termites can't tell the difference between their own eggs (white) and the fungal sclerotia (orange).
From National Geographic’s In the Womb:
Here’s a sharper version: Continue reading →
We often think of ants as paragons of hard work, but a surprising number of species get by through mooching off the labor of others. Trachymyrmex fungus growers, the larger spiny ants pictured above, do things the old-fashioned way. They dig their own nests, send workers out to gather food, and meticulously cultivate the fungus garden that serves as the primary food source for the colony.
Then, along comes the slim, sneaky Megalomyrmex symmetochus. These little parasites hollow out a cozy little nest within the Trachymyrmex garden and spend their time leisurely consuming the brood of their oblivious hosts. An easy life, for an ant.
photo details: Canon MP-E 65mm 1-5x macro lens on a Canon 20D
f/13, 1/250 sec, ISO 100
flash diffused through tracing paper
levels adjusted in Photoshop
(Thanks to Rachelle Adams for letting me photograph her lab colonies)
Here’s a story about a parasitic nematode that turns black ants into ripe red berries. What’s this about?
The parasite needs to get its eggs from an infected ant to healthy ants. Apparently it hasn’t been successful the old-fashioned way, just broadcasting its eggs about the environment. Instead, these little worms have figured out a far more effective egg delivery vehicle: birds.
Ants of the genus Cephalotes often feed from bird droppings (for instance, see here). If a parasitic egg can get itself into a bird’s digestive system, it’ll wind up in a juicy fecal pellet where it may be inadvertently picked up by hungry ants.
The manner in which the nematode reaches a bird is particularly clever: parasites of reproductive age make the infected ant look like bird food. The rounded end of the ants’ abdomen (the gaster) turns from black to red, and infected ants raise their gasters high in the air where they appear like ripe berries. Bird eats ant, bird poops out parasite eggs, ants eat egg-laden poop, ants begin to resemble bird food, and the cycle continues.