Much less is known about the freshwater invertebrates of Palau (and about freshwater invertebrates of tropical islands in Oceania generally), so this list is a bit shorter, and more broad. Some of the references deal with the use of freshwater macroinvertebrates as biomonitoring tools, and some deal with the general ecology of stream invertebrates generally.
Freshwater invertebrates
Beatty, C.D., Sánchez Herrera, M., Skevington, J.H., Rashed, A., Van Gossum, H., Kelso, S., & Sherratt, T.N. Biogeography and systematics of endemic island damselflies: The Nesobasis and Melanesobasis (Odonata: Zygoptera) of Fiji. Ecology and evolution
Benstead, J.P., March, J.G., Pringle, C.M., Ewel, K.C., & Short, J.W. (2009) Biodiversity and ecosystem function in species-poor communities: community structure and leaf litter breakdown in a Pacific island stream. Journal of the North American Benthological Society, 28, 454–465.
Boulton, A.J., Boyero, L., Covich, A.P., Dobson, M., Lake, S., & Pearson, R. (2008) Are Tropical Streams Ecologically Different from Temperate Streams? Tropical Stream Ecology pp. 257–284. Elsevier
Carbonell, J.A., Velasco, J., Millán, A., Green, A.J., Coccia, C., Guareschi, S., & Gutiérrez-Cánovas, C. (2017) Biological invasion modifies the co-occurrence patterns of insects along a stress gradient. Functional ecology, 31, 1957–1968.
Chapuis, E., Lamy, T., Pointier, J.-P., Juillet, N., Ségard, A., Jarne, P., & David, P. (2017) Bioinvasion Triggers Rapid Evolution of Life Histories in Freshwater Snails. The American naturalist, 190, 694–706.
Covich, A.P. & Others (2006) Dispersal-limited biodiversity of tropical insular streams. Polish Journal of Ecology, 54, 523–547.
Craig, D.A., Currie, D.C., & Joy, D.A. (2001) Geographical history of the central-western Pacific black fly subgenus Inseliellum (Diptera: Simuliidae: Simulium) based on a reconstructed phylogeny of the species, hot-spot archipelagoes and hydrological considerations. Journal of biogeography, 28, 1101–1127.
Haase, M. & Bouchet, P. (1998) Radiation of crenobiontic gastropods on an ancient continental island: the Hemistomia-clade in New Caledonia (Gastropoda: Hydrobiidae). Hydrobiologia, 367, 43–129.
Haynes, A. (1990) The numbers of freshwater gastropods on Pacific islands and the theory of island biogeography. Malacologia, 31, 237–248.
Hobbelen, P.H.F., Samuel, M.D., Foote, D., Tango, L., & LaPointe, D.A. (2013) Modeling the impacts of global warming on predation and biotic resistance: mosquitoes, damselflies and avian malaria in Hawaii. Theoretical Ecology, 6, 31–44.
Joy, D.A., Craig, D.A., & Conn, J.E. (2007) Genetic variation tracks ecological segregation in Pacific island black flies. Heredity, 99, 452–459.
Kalkman, V.J., Clausnitzer, V., Dijkstra, K.-D.B., Orr, A.G., Paulson, D.R., & van Tol, J. (2008) Global diversity of dragonflies (Odonata) in freshwater. Hydrobiologia, 595, 351–363.
Maciolek, J.A. & Ford, J.I. (1987) Macrofauna and Environment of the Nanpil-Klepw River, Ponape, Eastern Caroline Islands. Bulletin of marine science, 41, 623–632.
March, J.G., Benstead, J.P., Pringle, C.M., & Luckymis, M. (2003) Benthic Community Structure and Invertebrate Drift in a Pacific Island Stream, Kosrae, Micronesia. Biotropica, 35, 125–130.
McINNES, S.J. & Pugh, P.J.A. (2007) An attempt to revisit the global biogeography of limno-terrestrial Tardigrada. Journal of limnology, 66, 90–96.
Oppel, S. (2005) Habitat associations of an Odonata community in a lower montane rainforest in Papua New Guinea. International journal of odonatology: official organ of the Worldwide Dragonfly Association, 8, 243–257.
Wade, L.M., Fanolua, F.S., Vargo, A.M., van Houte-Howes, K., Bardi, E., & Vargo, D.L. (2008) Exploiting Macrofauna Diadromy for Assessing Anthropogenic Impact in American Samoa Streams. Pacific science, 62, 177–190.
Freshwater invertebrates
Beatty, C.D., Sánchez Herrera, M., Skevington, J.H., Rashed, A., Van Gossum, H., Kelso, S., & Sherratt, T.N. Biogeography and systematics of endemic island damselflies: The Nesobasis and Melanesobasis (Odonata: Zygoptera) of Fiji. Ecology and evolution
Benstead, J.P., March, J.G., Pringle, C.M., Ewel, K.C., & Short, J.W. (2009) Biodiversity and ecosystem function in species-poor communities: community structure and leaf litter breakdown in a Pacific island stream. Journal of the North American Benthological Society, 28, 454–465.
Boulton, A.J., Boyero, L., Covich, A.P., Dobson, M., Lake, S., & Pearson, R. (2008) Are Tropical Streams Ecologically Different from Temperate Streams? Tropical Stream Ecology pp. 257–284. Elsevier
Carbonell, J.A., Velasco, J., Millán, A., Green, A.J., Coccia, C., Guareschi, S., & Gutiérrez-Cánovas, C. (2017) Biological invasion modifies the co-occurrence patterns of insects along a stress gradient. Functional ecology, 31, 1957–1968.
Chapuis, E., Lamy, T., Pointier, J.-P., Juillet, N., Ségard, A., Jarne, P., & David, P. (2017) Bioinvasion Triggers Rapid Evolution of Life Histories in Freshwater Snails. The American naturalist, 190, 694–706.
Covich, A.P. & Others (2006) Dispersal-limited biodiversity of tropical insular streams. Polish Journal of Ecology, 54, 523–547.
Craig, D.A., Currie, D.C., & Joy, D.A. (2001) Geographical history of the central-western Pacific black fly subgenus Inseliellum (Diptera: Simuliidae: Simulium) based on a reconstructed phylogeny of the species, hot-spot archipelagoes and hydrological considerations. Journal of biogeography, 28, 1101–1127.
Haase, M. & Bouchet, P. (1998) Radiation of crenobiontic gastropods on an ancient continental island: the Hemistomia-clade in New Caledonia (Gastropoda: Hydrobiidae). Hydrobiologia, 367, 43–129.
Haynes, A. (1990) The numbers of freshwater gastropods on Pacific islands and the theory of island biogeography. Malacologia, 31, 237–248.
Hobbelen, P.H.F., Samuel, M.D., Foote, D., Tango, L., & LaPointe, D.A. (2013) Modeling the impacts of global warming on predation and biotic resistance: mosquitoes, damselflies and avian malaria in Hawaii. Theoretical Ecology, 6, 31–44.
Joy, D.A., Craig, D.A., & Conn, J.E. (2007) Genetic variation tracks ecological segregation in Pacific island black flies. Heredity, 99, 452–459.
Kalkman, V.J., Clausnitzer, V., Dijkstra, K.-D.B., Orr, A.G., Paulson, D.R., & van Tol, J. (2008) Global diversity of dragonflies (Odonata) in freshwater. Hydrobiologia, 595, 351–363.
Maciolek, J.A. & Ford, J.I. (1987) Macrofauna and Environment of the Nanpil-Klepw River, Ponape, Eastern Caroline Islands. Bulletin of marine science, 41, 623–632.
March, J.G., Benstead, J.P., Pringle, C.M., & Luckymis, M. (2003) Benthic Community Structure and Invertebrate Drift in a Pacific Island Stream, Kosrae, Micronesia. Biotropica, 35, 125–130.
McINNES, S.J. & Pugh, P.J.A. (2007) An attempt to revisit the global biogeography of limno-terrestrial Tardigrada. Journal of limnology, 66, 90–96.
Oppel, S. (2005) Habitat associations of an Odonata community in a lower montane rainforest in Papua New Guinea. International journal of odonatology: official organ of the Worldwide Dragonfly Association, 8, 243–257.
Wade, L.M., Fanolua, F.S., Vargo, A.M., van Houte-Howes, K., Bardi, E., & Vargo, D.L. (2008) Exploiting Macrofauna Diadromy for Assessing Anthropogenic Impact in American Samoa Streams. Pacific science, 62, 177–190.