I’ve never seen this before: a few hundred riffle beetles, Elmidae, all gathered behind a boulder in Rio Java. The larva are common, and I’d rarely see individual adults—here, in the thin film of water cascading over the boulder, were hundreds.
I don’t know what this fly is or does, and it’s maggot must be phenomenally large (flies, like many other insects with complete or holometabolous metamorphosis, don’t “grow” as adult—little flies aren’t babies, they’re likely just different species). On top of it’s size, there were pseudoscorpians hitching a ride on its legs (phoretic dispersal), so when it landed on our current, they began to climb down and investigate their surroundings!
I’ve seen some phoretically dispersed mites on dung beetles (an Instagram post I can’t link) and tabanid flies before too.
A few years ago, a NAPIRE student of mine, Jerry, investigated predation risk of crabs in and away from leaf litter. He found substantial predation in the assay, and, this year, Zane is picking up the idea again (more to come).
The crabs are fairly abundant in the streams, but their densities can vary greatly, and, overall, the density is lower in the larger reaches of Rio Java (greater discharge) and those crabs that we do find in the river have a larger carapace width—big crabs in the big river. Perhaps predation is driving this pattern! And look, here’s a pile of dead crabs, partially eaten, probably by a mammal adjacent to a small backwater pool within the river.
A trap-jaw ant (Odontomachus bauri) potential queen dispersing with the help of some wings!
Some wasps working away with couple of videos. I’m still getting used to this camera, and I like the video feature, particularly with the macro-lens.
Trap-jaw ants (Odontomachus bauri) patrol a bed of moss and detritus on a tree trunk, jaws wide open. Disruptions to hairs on the inner side of their jaw trigger an explosively fast and powerful closure—check out the size of their head, which houses the muscles responsible for clamping their mandibles inward.
The closure is so powerful that the ant itself is sometimes launched off of the ground. In fact, they use the launch to escape predators.
Don’t worry, they’re unable to hurt humans.
There are all kinds of cool things about this Chrysomelidae tortoise beetle (Hemisphaerota cyanaea) on the internet, including:
- Their capacity to stick to leaves. These bizarre little, herbivorous beetles stick themselves to Saw Palmetto leaves with the help of thousands of setae (hairs) soaked in excreted oil when disturbed by a potential predator.
- Their larvae build nests from feces.
And look closely… there are POLLEN grains all over the little beetles. Can you imagine having hundreds of sticky bouncy-ball-size pollen grains attached to your body and eyes!? The micro-world of biology is fascinating.
Trechalea extensa with an egg sack!