The role of tenebrionid beetles on litter fragmentation processes and soil biogeochemical cycles in arid Patagonia

CHELI, G. H.; BOSCO, T.; SARAVÍ, H.; CARRERA, A.; MARTÍNEZ, F. J.; FLORES, G. E.

Praga

Simposio; 5th International Tenebrionoidea Symposium; 2018

Tenebrionid beetles are among the most abundant and diverse insects of arid environments.They are considered mostly detritivores and given their multiple physiological and behavioraladaptations, they might play an important role on biogeochemical cycles in theseenvironments. However, in South America, there are few or no studies that has directlyquantified or demonstrated this role. South America endemic species of the Nycteliini tribe(subfamily Pimelinae) are specially adapted to arid and semi-arid environments. Within thistribe, the genus Nyctelia dominates the fauna of Tenebrionidae in Patagonian steppes, beingNyctelia dorsata (Fairmaire) one of the main components of the epigean insect community ofnortheast of Patagonia. Due to their apterous condition N. dorsata distribution is restrictedand It is frequently observed feeding on litter. The objective of this work was to evaluate thedetritivore role of N. dorsata and its effect on soil N cycle throughout microcosmsexperiment. Collected Tenebrionids were fasted for 7 days before the experiment starts.Microcosms were subjected for 26 days to the following treatments: Soil with no litter (S);Soil + litter of one of the most important plant species on its diet (Lycium chilense) (SL) andSoil + litter (Lycium chilense) + N. dorsata (SLN). At the end of the experiment, litter massloss and total soil N concentration were analyzed by GLM. Litter mass loss was significantlyhigher at SLN than at SL. Total soil N was higher at SLC than at SL and S while we found nodifferences between S and SL. We concluded that in Patagonian arid environments N. dorsataplays a key role in biological fragmentation processes of plant residues and soilbiogeochemical cycles. Moreover, this role is particularly important in dry season, when soilmicrobial activity is reduced due to the harsh environmental conditions.