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In an attempt to find tardigrades in the abundant lichen growing on my untreated deck, I instead grew out from the lichens soaking in water lots of Colpoda. Soon larger carnivorous Colpodidae, Bresslaua, appeared and began feasting on their smaller Colpoda cousins. I found a few reproductive cysts containing four daughter cells and was able to capture the emergence of the cells from the cyst.

From: https://en.wikipedia.org/wiki/Colpoda

Colpoda are distinctly reniform (kidney-shaped) and are strongly convex on one side, concave on the other. The concave side often looks like a bite was taken out of it. Although they are not as well known as the paramecium, they are often the first protozoa to appear in hay infusions, especially when the sample does not come from an existing mature source of standing water.

Colpoda are often found in moist soil and because of their ability to readily enter protective cysts will quite frequently be found in desiccated samples of soil and vegetation[3] as well as in temporary natural pools such as tree holes.[4] They have also been found in the intestines of various animals, and can be cultured from their droppings.[5]

Colpoda cucullus has been found inhabiting the surface of plants and seems to dominate the microfauna there. Several species of Colpoda have been found in the pitcher plant Sarracenia purpurea, despite the presence of protease digestive enzymes in the liquid.[6]

Colpoda also tend to be found in abundance where increased levels of bacteria offer an enriched food source. In commercial chicken houses, for example, they seemed to be ubiquitous but the species found vary widely from one location to the next, suggesting that these populations represent local soil and aquatic populations which migrated into the new habitat.[7]

In addition to inhabiting a wide variety of microclimates, Colpoda can be found almost everywhere around the world where there is standing water or moist soil, even where these conditions are only ephemeral. Colpoda brasiliensis for example was discovered in Brazilian floodplains in 2003.[8] Colpoda irregularis has been found in the high desert region of Southwest Idaho. Colpoda aspera has been found in the Antarctic. Colpoda are also found in the arctic where warmer temperatures and longer summers lead to greater density and species diversity.[9]

Not only is the genus widespread, there are also several species that have nearly global distribution, and, indeed, it has been suggested this may be true of all species, a fact that could be borne out by better investigation.[10] Though Colpoda are not normally found in the marine environment, there are many ways they can travel from one continent to another. For example, cysts can become lodged in the plumage of migratory birds, becoming dislodged hundreds or even thousands of miles away. Also, because cysts are so small and light, they can be swept by air currents into the upper atmosphere, and then come down on another continent.[11]

Colpoda normally divide in cysts, from which two to eight individuals emerge, four being the most common number. This produces genetically identical individuals. The rate at which such reproduction occurs and how it is affected by various environmental conditions has been the subject of a great deal of scientific research.[12]

On rare occasions, Colpoda have been observed to divide into 4 individuals without producing a cyst wall. It has been suggested that cystless reproduction was the normal mode of reproduction for Colpoda under optimum conditions and that the formation of cysts was a reaction to adverse environmental conditions. However, the knowledge gained by many years of culturing Colpoda in hay infusions has shown that this mode of reproduction remains rare despite what would seem to be ideal environmental conditions.[13]

As in other ciliates, division in Colpoda may be preceded by a sexual phenomenon known as conjugation. This involves two Colpoda joining at the oral groove and exchanging DNA. Following conjugation, the Colpoda divides, redistributing the DNA of the two original cells to produce numerous genetically distinct offspring.[14][15][16]