Life history strategies and production of caddisflies in a perennial headwater stream in Patagonia

Abstract

Synchrony, one of the main traits of population life histories, refers to the degree to which individuals complete a certain stage of the life cycle at the same time. It can be governed by temperature, variations in temperature, photoperiodic cues, detritus inputs, or discharge regimes. We investigated life cycles and secondary production of five caddisfly species in a second order stream in the Patagonian Mountains. In addition, we analyzed what environmental variables were implied in the caddisfly assemblage variation. Mastigoptila sp. (Glossosomatidae) and Eosericostoma aequispina (Helicophidae), Myotrichia murina (Sericostomatidae), Brachysetodes quadrifidus (Leptoceridae), and Neoatopsyche brevispina (Hydrobiosidae) showed univoltine life cycles, with an extended recruitment with no overlapping cohorts and a relatively well-synchronized imaginal emergence taking place during spring summer seasons. However, Myotrichia murina (Sericostomatidae) displayed a complex life cycle with mixed populations taking 10-12 months to develop, and pupae being collected almost continuously. The annual secondary production per species varied from 11.06 (E. aequispina) to 310.5 mg m -2 year -1 (M. murina), being overall caddisfly production (0.5 g m -2 year -1 ) similar to that reported for cold springs in other regions. The highest growth rates (K) were observed during late winter and spring (mostly September) and ranged from 0.70 to 3.70% day -1 in M. longicornuta and N. brevispina, respectively. Redundancy analysis indicated that seasonally dynamic variables, water temperature, discharge, and detritus biomass were the main predictors of caddisfly assemblage variation; consequently at this cold stream (mean annual 5.9°C), with a regular availability of food supply, these parameters ruled Trichoptera life histories and secondary production. As documented for other mountainous temperate areas, synchrony would be a dominant trait on life histories of Trichoptera species inhabiting Patagonian streams.

Life cycle phenology, secondary production, and trophic guilds of caddisfly species in a lake-outlet stream of Patagonia

“…Extended recruitment is widely spread among aquatic insects (Elliot 1995;Lytle and Poff 2004), and may have an important role in the recolonization of streams after disturbances (Huryn and Wallace 2000), as for example spates after rainfall and snowmelt that can be particularly intense at Patagonian mountain streams. In agreement with described by Brand and Miserendino (2011b) synchrony in adult emergence was relatively high in most of the species reported here, with pupae and adults present only in spring-summer months. As stated by Butler (1984), this seems to be the most common point where synchrony is re-established within populations.…”

“…The caddisfly species M. longicornuta, S. annulicornis, S. frequens, B. quadrifidus and P. ovale, displayed simple, univoltine life cycle with extended recruitment and flight period; this is in agreement with Brand and Miserendino (2011b), who found similar patterns for related species at a cold headwater stream in Patagonia. However, N. brevispina and N. tricarinatum described here had a complex non seasonal life cycle, with overlapping cohorts, differing with the univoltine pattern described in the aforementioned work for N. brevispina.…”

“…In our study, M. longicornuta was clearly univoltine which is consistent with documented for the congeneric Mastigoptila sp. at Chiquito stream (∼2200 degree days) in the same year (Brand and Miserendino 2011b). Comparatively M. longicornuta grew faster than Mastigoptila sp.…”

“…Recently, Brand and Miserendino (2011b) analyzed the life history and production of five univoltine trichopteran species at a non lake-outlet, headwater stream in the Patagonian Mountains. This study revealed an extended recruitment in most species and relatively well synchronized life histories.…”

Biological traits and community patterns of Trichoptera at two Patagonian headwater streams affected by volcanic ash deposition

“…Ecological larval traits included information related to hydraulic condition preferences (exclusively depositional, depositional and erosional, and erosional only), substratum and habitat selectivity (coarse, gravel, sand, macrophyte and organic detritus litter), food preferences (detritus, plant detritus, living macrophytes, living microphytes, and living macroinvertebrates), and feeding behavior (deposit feeder, shredder, scraper, filter-feeder, piercer, predator) (Poff et al 2006;Brand and Miserendino 2011a, b;Dolédec et al 2011;). Only traits with information available for all species were selected; and trait assignment was performed using regional databases and available publications (Brand and Miserendino 2011a;Brand and Miserendino 2011b;). Species trait information was then rescaled according to the number of states (from 1 to x, with x being the total number of states in each trait).…”