Favoritos de hmheinz

I managed to catch the moment where two Juniperus virginiana pollen grains' intines expanded and ruptured their exines. I think the first probably helped trigger the second. Check out this paper for more on the mechanism at work here.
Measurements
Unruptured exines
23–27×21–25 μm; Q=1.01–1.15
Images
All slides in water
1: External intines hydrating and expanding to rupture exines
2: Intact pollen grains
3: Ruptured pollen grains
4: Habit

More phages from the deep water of this tea-stained lake. The first shot is of a bacterium captured at the moment of rupture by tailed phages. It looks like they made a pretty efficient transfer of bacterium to phage biomass. The burst size of 10 (if none were lost) is in line with other observations from nutrient-poor lakes. Next is a close-up of a tailless phage. The capsomeres are clearly evident, suggesting that this one is a single-stranded DNA virus of the Microviridae (I'm just guessing here). Number three has a long, non-contractile tail. That makes it a siphovirus. Four appears to have a contractile tail that will allow it to inject its DNA hypodermic-style. Nice head. Then two attached phages. Many bacterial cells seemed to have attached phages - hard to explain. Finally, an interesting community of viruses, tailed and tailless, on what might be a conjugation tube that is used to transfer DNA between bacterial cells. Conjugation is a handy way to pass on genes to confer immunity to phages. But it comes with a tradeoff - phages attach to the tube to inject their own nucleic acids. I like the curious structure of the lengthened icosahedra (?) of some of the phages.

Truly no idea what these brown things are. They were growing underneath a board. Weird tree roots? Weird fungus? Insect casings? (Not animal scat; these were growing out of the ground under a board, and there was no space for an animal.) Help....

Attached a photo circling the items in question.

Attached another photo showing a side view (poked it with a stick).

Comparing to photos online, I wonder if it's some sort of insect casing, as it looks like the structure is assembled from little bits.

Jan 20, 2024 update: We were able to collect samples of these casings and send them to the UW Madison Dept. of Entomology Insect Diagnostic Lab, where they were able to dissect them.

Quoting from the email we received: "I dissected several of the cases and was able to determine that they are indeed from insects (the inside of the cases were lined in silk). Furthermore, I was able to narrow it down to some sort of caterpillar (Order Lepidoptera). Inside of the cases, I was able to find shriveled remains of the larval exuvia (shed exoskeleton); the structure of the head capsule remnants and arrangement of the eyes were consistent with caterpillars. While fresh caterpillars can be identified using taxonomic keys, the shed exoskeleton was shriveled up and missing some of the head capsule, so I haven't been able to narrow down a caterpillar family at this point. I did some digging into potential leads (bagworms, "prominent" caterpillars, etc.) but have not been able to find a consistent match yet. I've found a note in the literature that members of several different families can go to the ground to pupate and can incorporate pieces of plant materials into their cocoon."

I'm updating this observation to Lepidoptera for now. We will look for new examples of these casings throughout the year in the hopes we can gather more information.