Scum Starblight
Scum Starblights are distinct from Starblights as a genus group for their ability to live outside wetlands, though it still requires abundant moisture. In addition to rivers and swamps, they live in slow-moving streams and puddles. They spread when torrential rain causes streams to flood or creates rivulets along the ground, or when raindrops hitting the ground launches spores or sporelings from puddles. Though descended from a curly-stemmed species of Starblight with three spore clusters in the pathogenic form, Scum Starblights have five spore clusters, which grow as in tight balloon-like arrangements.
Though their cell walls are black, their photosynthetic pigments are green. When they die, the cell walls rapidly change color. Rarely, their concentrations in an area can grow so high as to stain patches of the sides of streams black from all the Scum Starblights, but within hours. Within hours, the scum changes to dark green and eventually to a light, desaturated green. Occasionally this transformation occurs in small ponds, creating ponds filled with color-changing “pond scum”.
Disease Aspects and Life Cycle
Much as in its ancestor, Scum Starblights reproduce through spores, which float about in water. The spores grow into floating sporelings and feed on decaying matter, supplementing it with sunlight. Sporelings detect hosts through chemicals they release into the water, and seek them out. Once a host has been found, the sporeling uses its claw-like apparatuses and proboscis to cling to the host and dig into its body. It then transforms into a non-photosynthetic stage and feeds on the host’s cells, causing a form of Starblight. The pathogenic form reproduces through clusters of spores when attached to a host.
Hosts get black patches on their bodies and often lean over due to damage. At time of evolution, the disease is eventually fatal to all its hosts, although very large hosts can take a long time to die, and suddenly getting exposed to strong sunlight delays progression of the disease. Given its ancestor group lived in wetlands, such as Niyo Swamp, those Asterplent descendants that are long-term swamp-dwelling species are more resistant to Scum Starblight. Given Asterplents' easy colonization of nearby habitats and the rainforest's proximity to Niyo Swamp, the Scum Starblight's arrival gives an advantage to originally swamp-dwelling Asterplent-descendant species, and penalizes colonization of the rainforest from originally savanna-dwelling species.
Scum Starblight outbreaks coincide with flooding of the Niyo Tropical River. Since clay drains slowly, it often co-occurs in the same places as Wright Clayrot and can make outbreaks worse. However, unlike Wright Clayrot, it is more abundant where there is a lot of organic matter, for its sporelings are dependent on decomposing things. Scum Starblights and Wright Clayrots form an interesting dynamic where outbreaks of Wright Clayrots create conspicuous gaps in the forest floor in some areas, potentially allowing for colonization by nearby savanna-originating Asterplent-descendants, only for Scum Starblights to become long-term diseases in those same populations, ultimately encouraging colonization by closer, better-adapted populations.
Young, mobile Asterplents are not typically immersed in wet soil as the adults are, so Scum Starblights only sporadically infect them. As Tombstone Asterplents root themselves atop corpses, they expose less of their main bodies to wet soil, making disease progression slower. Palmcaps very rarely get Scum Starblight infections, as they spend so much of their lives on top of trees.
Should mobile hosts get back up into the sky, it can carry the pathogen to other habitats. However, the Scum Starblight’s dependence on consistently warm, wet conditions and low tolerance for intense, prolonged ultraviolet light exposure limits what habitats it can spread to, as it cannot enter a dormant state to wait for better conditions. It simply bakes off if would-be hosts are in the savanna during the dry season for too long, and bakes off even faster should they pass through deserts. While adapted to warm temperatures, Scum Starblight dies very fast from outright hot ones: they die very fast when temperatures exceed 42.7 degrees Celsius (109 degrees Fahrenheit).