The activity of saccharolytic enzymes in Collembola is associated with species affinity for caves

Abstract

Abstract:The activity of enzymes associated with digestion can reflect food availability and feeding preferences of invertebrates in a particular habitat. Caves are mostly nutrient-poor habitats lacking primary production. In the present study the enzymatic activity of cellulases, trehalases and chitinases was measured in eight collembolan species differently associated with the cave environment: the troglobionts (obligate cave species) Pseudacherontides spelaeus and Protaphorura janosik; the eutroglophiles Ceratophysella denticulata, Folsomia candida and Heteromurus nitidus; the subtroglophiles Hypogastrura aequepilosa and Orthonychiurus rectopapillatus; and the trogloxene (not associated with caves) Megaphorura arctica.Qualitative enzymatic patterns and quantitative differences in species activity were considered in terms of the taxonomic, feeding and ecological classifications of Collembola. Activity of the tested enzymes was confirmed in all species. Cellulolytic and chitinolytic activity seemed to play a crucial role for the discrimination of guilds within all categories. An increasing trend of chitinolytic activity was observed in Collembola associated with the subterranean environment and deeper soil layers, while cellulolytic activity decreased towards more adapted cave forms. Variability in enzymatic activity in cave-dwelling species indicated food specialization across sub-and eutroglophiles and troglobionts, respectively. The results of this study point out that enzymatic activity varies between groups of the cave fauna with different degrees of association to subterranean habitats (cave guilds).

Multidimensional trophic niche revealed by complementary approaches: Gut content, digestive enzymes, fatty acids and stable isotopes in Collembola

“…For the fifteen trophic niche parameters derived from the four methods ( Data on digestive enzyme activity were added with 0.02 μg product mg -1 h -1 (the minimum positive value observed) for all values and then log 10 -transformed. We normalised data of chitinase activity separately for Berg et al (2004) and Parimuchová et al (2018) by subtracting mean and dividing by standard deviation to account for the differences in chemical protocols.…”

“…( 2004 ) and Parimuchová et al. ( 2018 ) by subtracting mean and dividing by standard deviation to account for the differences in chemical protocols. Proportional data (gut content and FA) were logit‐transformed, with 0 and 1 proportions adjusted to 0.025 and 0.975, respectively, using the logit function in the car package.…”

“…Digestive enzymes, such as cellulase, chitinase and trehalase, represent the ability of an animal to decompose corresponding types of organic compounds, and provide a way to assess which ingested materials may be digested (Nielsen, 1962 ; Parimuchová et al., 2018 ; Siepel & de Ruiter‐Dijkman, 1993 ). Cellulose is a major component of cell walls of green plants and algae; cellulase activity suggests herbivory, algivory or litter grazing of soil animals.…”

“…Fungal spores and hyphae in the gut indicate fungivory, while coarse plant detritus, roots and shoots suggest herbivory and litter grazing, and amorphous material such as fine detritus may imply feeding on soil organic matter and faecal pellets. However, visual gut content analysis only presents a snapshot of the ingested items, overestimates poorly digestible particles and provides limited information in case of feeding on fluids. Digestive enzymes, such as cellulase, chitinase and trehalase, represent the ability of an animal to decompose corresponding types of organic compounds, and provide a way to assess which ingested materials may be digested (Nielsen, 1962; Parimuchová et al., 2018; Siepel & de Ruiter‐Dijkman, 1993). Cellulose is a major component of cell walls of green plants and algae; cellulase activity suggests herbivory, algivory or litter grazing of soil animals.…”

A synthesis on troglobitic springtails in Europe

“…Troglobitic collembolans apparently rarely feed on decaying wood but commonly on the hyphae of polypores and other wood‐rot fungi (Christiansen, 1964). Some species are strict guanobionts Pseudacherontides spelaeus (Ionesco, 1922), while others ( Protaphorura janosik Weiner, 1900) occurs in a wider spectrum of cave microhabitats, including cave sediment and rotten wood (Parimuchová et al, 2018). Therefore, further studies have to be conducted for a better understanding of how competition between cave‐dwelling Collembola influences the large‐scale distribution.…”