Sericostoma vittatum (Trichoptera) Larvae Are Able to Use Pine Litter as an Energy Source

Abstract

We tested the effect of conditioning time of Pinus sylvestris litter on food consumption and growth of laboratory-reared Sericostoma vittatum larvae. In all cases, larval mass was positively correlated with consumption rates but negatively with growth rates and gross production efficiencies. Conditioning time (4, 8 or 30 weeks) had an effect on feeding rates: they were lowest for the least conditioned pine litter, but no effect of conditioning time on growth rates was observed. Contrary to previous reports on conifer litter use by aquatic detritivores, our results indicate that S.vittatum larvae were able to transform the highly refractory pine litter into secondary production even when it was conditioned for only 4 weeks.

Effects of pine plantations on structural and functional attributes of forested streams

“…Pine needles present a tough cuticle, very low nutrient content (Girisha et al, 2003;Quinn et al, 2000a) and high levels of toxic compounds (Bärlocher and Oertli, 1978). These characteristics make them a recalcitrant resource for benthic macroinvertebrates (Valdovinos, 2001;Collen et al, 2004, but see Quinn et al, 2000bCampos and González, 2009). Similar studies focusing on the effects of Eucalyptus globulus Labill.…”

“…These authors pointed out that the lack of an alternative resource induces detritivores to concentrate on pine needles. Similarly, Quinn et al (2000b) and Campos and González (2009) observed that the trichopterans Olinga feredayi, in the sourthern hemisphere, and Sericostoma vittatum, in the northern, could consume and grow on pine needles probably due to the low mobility, large mandibles and low respiration rates of these taxa (Friberg and Jacobsen, 1994). However, in our study, we found very low densities of trichopterans in the benthos of streams under pine plantations, especially Sericostoma (absent in two of them), contrary to previous observations in streams under natural conifer forest (Molles, 1982).…”

“…In low-order forested streams, in which food-webs are based on detrital inputs from surrounding forest , modifications in watershed vegetation can alter the quantity, quality and seasonality of leaf-litter inputs (Abelho and Graça, 1996;Pozo et al, 1997;Molinero and Pozo, 2004). The variation in detritus quality may influence decomposer colonisation and activity (Bärlocher and Oertli, 1978;Dang et al, 2007;Kearns and Bärlocher, 2008) and the feeding rates, growth, densities and survival of detritivores (Graça, 2001;Albariño and Balseiro, 2002;Campos and González, 2009;Larrañaga et al, 2009). As a consequence, important ecosystem processes, such as leaf-litter decomposition, can be affected (Lecerf et al, 2005;Lecerf and Richardson, 2010).…”

Estimation of dry mass of caddisflies Phylloicus elektoros (Trichoptera: Calamoceratidae) in a Central Amazon stream

“…We observed that the dimensions (length and width) of the case provided good biomass estimates for P. elektoros. Other studies have used case dimensions efficiently to predict the biomass of other Trichoptera species (GRAFIUS & ANDERSON 1980, CRESSA 1999a, CAMPOS & GONZÁLEZ 2009). According to CRESSA (1999a), the relationship between case dimensions and biomass are predictable because changes in case size closely follow individual growth.…”

Seasonal variation of allochthonous and autochthonous energy inputs in an alpine stream

“…Coarse particulate organic matter (CPOM) collected in the Surber samples was hand-sorted and divided into two categories: larch (L. decidua) litter and other CPOM (grass fragments, leaf litter, and miscellaneous organic particles), to account for the different palatability of coniferous litter to macrobenthonic fauna (Campos and González, 2009;Collen et al, 2004). In the laboratory, larch litter and the other CPOM were air dried for 24 h, oven dried (105°C) for additional 24 h, and weighed with an electronic scale (accuracy±0.001 g).…”