Freshwater invertebrates

In the laboratory experiments, amphipod Gammarus pseudolimnaneus prefer leaves of maple, Acer saccharum, conditioned by two fungi, Humicola grisea and Heliscus lugdunensis, over uncoditioned leaves (Bärlocher & Kendrick, 1975). Two species of caddisfly larvae (Trichoptera), Hesperophylax magnus and Psychoglypha sp., show feeding preferences to leaves of aspen, Populus tremuloides, colonized by fungi, Flagellospora curvula, Alatospora acuminata and more, over stream detrirus. (Arsuffi & Suberkropp, 1986). Amphipod G. pulex is most attracted to the aufwuchs on the conditioned discs made of poplar (Populus canadensis) leaves and less to the leaves themselves, fungi and bacteria are more important than green algae Scenedesmus obliquus (De Lange et al., 2005).

Generally, feeding preferences in macroinvertebrates are associated with the leaf decomposition rate that, in turn, is related to fungal colonization and protein content in conditioned leaves (e.g., Kaushik & Hynes, 1971). Freshwater amphipods and isopods exhibit feeding preferences in the same order as the leaf decomposition rate, approximately in the following sequence: elm > maple > alder > oak > beech.

In particular, in streams in the Western Oregon, USA, newly fallen leaves of alder, Alnus sp., are quickly colonized by larvae of Leindostonta quercina (Lepidostomatidae), other caddis larvae and snails (Oxytrema) (Anderson & Grafius, 1975). According to these authors, the relatively high consumption rate of the unconditioned leaves by L. quercina demonstrates an exceptional palatability or attractiveness of Alnus leaves.

Graça et al. (2001) have studied feeding preferences in caddisfly larvae, Nectopsyche argentata and Phylloicus priapulus from tropical Venezuela, Sericostoma vittatum from Portugal, as well as amphipod G. pulex from Germany. In general, all shredders exhibit the same high preference for conditioned leaves over unconditioned ones (beech, Fagus sylvatica, alder, Alnus glutinosa, and more), irrespective of the geographical origin of the trees or shredder species.

However, freshwater detritivore-shredders do not per se prefer leaf litter being be able to select actively other food items such as filamentous green algae or macrophytes. Friberg & Jacobsen (1994) have studied feeding preferences of the trichopteran shredder, Sericostoma personatum, and the amphipod shredder, G. pulex, in springbrook with the major food source represented by beech (F. sylvatica) litter. Six food items have been tested: conditioned beech leaves, conditioned alder (A. glutinosa) leaves, conditioned Sitka spruce (Picea sitchensis) needles, fresh beech leaves, fresh macrophyte (Potamogeton perfoliatus) and fresh filamentous green alga (Microspora sp.). Conditioned leaves and needles have been collected directly in the springbrook. Both shredders prefer conditioned Alnus leaves and fresh Microspora, conditioned Fagus leaves and Picea needles are less preferred food items. For larval populations of another trichopteran shredder,  Anabolia nervosa, from the two streams with the different food availability, conditioned Alnus leaves are the most consumed food item, then fresh pondweed P. perfoliatus (Jacobsen & Friberg, 1994). Larvae from the Alnus shaded stream prefer conditioned Alnus leaves over all other food items, while larvae from the stream with the abundant submerged macrophyte do not clearly discriminate between conditioned Alnus leaves and fresh Potamogeton. These data indicate the high attractiveness of conditioned alder leaves for many freshwater detritivore-shredders and their feeding plasticity.

Fish

Rinses of decaying leaf detritus are highly attractive to elvers of American eel, Anguilla rostrata, regardless of where detritus is collected (Sorensen, 1986). In contrast, rinses of living and fallen leaves collected from the forest floor are not attractive.

Coral reef clownfish, Amphiprion percula, and other reef fish use terrestrial chemical cues (leaf litter of beach tree called almond, Terminalia catappa) to find island homes (Dixson et al., 2008, 2011).

Basic References

Anderson N.H., Grafius E. 1975. Utilization and processing of allochthonous material by stream Trichoptera. Verh. Internat. Verein. Limnol. 19, 3083-3088

Arsuffi T.L., Suberkropp K. 1986. Growth of two stream caddisflies (Trichoptera) on leaves colonized by different fungal species. Journal of the North American Benthological Society 5, 297-305

Bärlocher F., Kendrick B. 1975. Leaf-conditioning by microorganisms. Oecologia 20, 359-362

De Lange H.J., Lürling M., Van Den Borne B., Peeters E.T.H.M. 2005. Attraction of the amphipod Gammarus pulex to water-borne cues of food. Hydrobiologia 544, 19-25

Dixson D.L., Jones G.P., Munday P.L., Planes S., Pratchett M.S., Srinivasan M., Syms C., Thorrold S.R. 2008. Coral reef fish smell leaves to find island homes. Proceedings of the Royal Society B: Biological Sciences 275, 2831-2839

Dixson D.L., Jones G.P., Munday P.L., Pratchett M.S., Srinivasan M., Planes S., Thorrold S.R. 2011. Terrestrial chemical cues help coral reef fish larvae locate settlement habitat surrounding islands. Ecology and Evolution 1, 586-595

Friberg N., Jacobsen D. 1994. Feeding plasticity of two detritivore-shredders. Freshwater Biology 32, 133-142

Gazzera S.B., Cummins K.W., Salmoiraghi G. 1993. Elm and maple processing rates: comparisons between and within streams. Annales de Limnologie 29, 189-202

Graça M.A.S, Cressa C., Gessner M.O., Feio M.J., Callies K.A., Barrios C. 2001. Food quality, feeding preferences, survival and growth of shredders from temperate and tropical streams. Freshwater Biology 46, 947-957

Jacobsen D., Friberg N. 1995. Food preference of the trichopteran larva Anabolia nervosa from two streams with different food availability. Hydrobiologia 308, 139-144

Kaushik N.K., Hynes H.B.N. 1971. The fate of the dead leaves that fall into streams. Archiv fűr Hydrobiologie 68, 465-515

Sorensen P.W. 1986. Origins of the freshwater attractant(s) of migrating elvers of the American eel, Anguilla rostrata. Environmental Biology of Fishes 17, 185-200