ELLIOTT ET AL.: THE CAVE FAUNA OF CALIFORNIA 
33 
Collembolans are primitive arthropods similar to insects except that they lack wings, they have 
internal mouth parts, and most have no tracheae. 
Collembolans, usually less than 6 mm long, are soil and cave detritivores, free-living organ¬ 
isms that prefer moist conditions. They frequently are found near bacteria and fungi growing on 
biofilms, roots, wood, detritus, and feces. They provide the base of cave food chains, and are often 
consumed by micropredators such as rhagidiid mites, tiny spiders, harvestmen, and pseudoscorpi¬ 
ons. 
California caves have 43 verified, and up to 58 potential species of collembolans to date, sum¬ 
marized in Table 5. The various orders and families are distributed across most California cave 
regions. The largest group, the Family Entomobryidae with up to 18 species, has one described, 
probable troglobite, Sinella tecta, from five caves in Calaveras County, Sierra Nevada North 
(a related species is in Fig. 67). The Onychiuridae have two undescribed, probable troglobites from 
Clay Cave, Napa County, Bay Area/Delta Region, and three caves in Siskiyou County: Lava Flows 
North. Several undescribed, undetermined collembolans from three regions appear to be troglo- 
bitic. 
Few collembolans in California caves are troglobites, and many are common epigean species 
or troglophiles. The Tomoceridae are an important family with 14 species in most regions, and are 
noticeable as larger, gray to pale springtails ( Tomocerus , Figs. 68 and 101). Hypogastruridae (Order 
Poduromorpha) are another important family with 5 species (Fig. 69). So far the Isotomidae seem 
to be limited to Lava Flows North, the Neanuridae to Sierra Nevada North, and the Katiannidae to 
Sierra Nevada South, but their true ranges probably are much larger. The round-shaped Order 
Symphypleona, Family Arrhopalitidae (3 potential species), are found in Lava Flows North and 
Sierra Nevada South caves. Both Oncopuridae and Arrhopalitidae contain troglobitic species in 
other parts of the United States, but are not known as such in California. 
It is apparent that we are just beginning to understand collembolans in Calfomia caves. Prob¬ 
ably many new species will be found, and studies will be needed to delineate their roles in the cave 
ecosystems. 
Diplurans (Class Diplura) 
Campodeids (Order Rhabdura) 
Campodeids (Fig. 70) are small, eyeless, white creatures with two long, filamentous cerci 
(tails). California has a remarkable dipluran fauna with about 8% of global richness (Graening et 
al. 2014). Members of the family Campodeidae are abundant as troglobites and troglophiles in 
caves throughout much of the world. One described species, Campodea ( Campodea ) californien- 
sis, has been recorded from a few California caves. The only troglobites or likely troglobites are 
several undescribed species of the genus Haplocampa, which are the dominant taxon in volcanic 
caves of western North America (Graening et al. 2014). 
Japygids (Order Dicellurata) 
Japygids (Fig. 71) range up to 50 mm in length, but most are much smaller. They are all eye¬ 
less and the body is light-colored and have heavily sclerotized unsegmented cerci, shaped much 
like that of the earwigs (Dermaptera), which are not closely related. They are usually found in soil 
and leaf litter and under rocks. Most japygids from California caves remain undetermined or unde¬ 
scribed. The only species identified is Occasjapyx kofoidi (family Japygidae), known only from 
two caves in Shasta County. It is possible that it is a troglobite. The only definitely troglobitic 
japygid in the U.S.A. is Mixojapyx reddelli from Texas. 
