Chronobiologic view of molt and longevity of Folsomia candida (Collembola) at different ambient temperatures

A reanalysis of data published earlier indicates that the springtail, Folsomia candida, kept in continuous darkness, lengthens its intermolt interval (stadia) with age. At an environmental temperature of 21 degrees or 26 degrees C, the early stadia show an about-half-weekly or circasemiseptan interval and later stadia an about-weekly or circaseptan intermolt interval. At 15 degrees C, early stadia are about circaseptan, lengthening to nearly circadiseptan with aging. Our own studies of Folsomia candida at 23 degrees C show that the incidence of molting in 24 springtails observed at 3-hr intervals for 17 days is characterized by a prominent circadian rhythmicity and an infradian periodicity with a period of about 3 days. Both components are statistically highly significant (P = 0.001) when assessed concomitantly by least-squares rhythmometry.