Cave map Organisims Karsts Moiliili

Life inside the caves


According to Frank Howarth, stresses in a cave environment include, “perpetual darkness and humidity, lack of important environmental cues, complex mazelike living space, stressful or even lethal gas mixtures, patchy food resources, barren rocky substrates, wet and slippery vertical surfaces, and occasional flooding.” (1993: S65). Despite these barriers, there are still organisms present inside the Moiliili Water Cave. Some recent cave exploration observed blind catfish and blind spiders, while blind mullet and blind gambusia were located in nearby ponds (Lao: pers comm.). Lao thinks that the underground fish first came from a surface source, and then adapted to the dark environment (Watanabe 1996). Other organisms present include freshwater golby, small snails, and a millipede (pers observation).

 

Cave Video

   

The main factor attributed to the adaptation of cave species is stress. Stress is defined by Frank Howarth (1993: S65) as: “an environmental parameter that causes a potentially injurious change in a biological system,” and causes: “an increase in mutation and recombination rates as well as other changes in the genome.” Cave adapted species usually share such features as “reduced or absent eyes and bodily pigments, elongate appendages and body form, flightlessness or otherwise reduced dispersal powers, and often more numerous and enlarged sensory structures.” (Howarth 1993: S66). Mutation rate increases by the distressing of the genome of small founder populations by the selection pressures in the cave. This causes the adapted population to emerge quicker than under less stressful conditions (Howarth 1993).

The primary food resources in caves include organic substances that are brought inside by water and gravity. As William Halliday (pers. comm.) observed, the fish inside the (Moiliili) cave were eating something that dripped from a dribble of water. He also noted that “biota is concentrated near the entrance. Large and small roots are present, with mycelia present on some” (Halliday 1994).

Other food resources include, plant roots and accidentals. Plant roots (fig. 4) tunnel deep into the earth in search of water. In some caves, food energy may be derived from the chemoautotrophic bacteria found with such roots (Howarth 1993). Accidentals are organisms that enter into or fall into caves accidentally. These organisms are not suited for cave life and become food for other organisms (Howarth 1993).