Mayflies (Ephemeroptera)
Have gills laterally along or on back of abdomen, usually has
three cerci (tails). Dolphin-like motion of body. Mostly scraper-grazers (feed
on rock algae and attached diatoms) or collector-gatherers (feed on detritus
(FPOM) and associated attached diatoms).
Clingers--Dorsal-ventrally flattened bodies
Heptageniidae (Cinygma, Cinygmula†,
Epeorus† (3), Rhithrogena†):
Generally scraper-grazers of biofilm or collector-gatherers (detritus, diatoms).
Gills of Epeorus longimanus, E. grandis, and Rhithrogena
futilis modified to form a sucker-like structure to hold on to rocks in
fast current. A third Epeorus is present (probably E. deceptivus)
where the first set of gills are extended under the abdomen but do not meet
to form a sucker-like structure. Cinygma lyriforme lives on wood substrate
usually in quieter water. Possible species of Cinygmula include C.
par and C. subaequalis.
Swimmers--Cylindrical body shape, tails may have interlocking hairs
Baetidae (Baetis bicaudatus†,
B. tricaudatus†, Diphetor hageni?):
Collector-gatherers (detritus, diatoms), scraper-grazers. One of the first EPT
taxa to colonize rivers that emerge from deglaciation (Milner et al. 2000).
Leptophlebiidae (Paraleptophlebia†
debilis): Collector-gatherers (coarse detritus, diatoms). May be a
facultative shredder. Found in erosional habitats (sediments and detritus).
Ameletidae (Ameletus validus): Strong swimmers but
found in slower parts of the river. Collector-gatherers (detritus, diatoms),
or scraper-grazers.
Sprawlers, Clingers--Stout bodied
Ephemerellidae (Drunella (3), Serratella):
D. grandis flavitincta† is a scraper-grazer
and/or a collector-gatherer of FPOM (detritivores), and possibly a predator
(observed predatory behavior 4/30/2005). It is found in slower current or in
protected areas in faster current (e.g., underside of rocks and interstitial
space). D. doddsi† has hairs that form
a sucker-like disk on the underside of the abdomen for a holdfast and is found
in fast current. They are predators on midge larvae and/or scrappers. D.
coloradensis is a grazer or possibly a predator. Serratella tibialis
is a collector-gatherer of detritus. They live in depositional or protected
areas. Early instars were found in moss 7/18/03 and 6/30/04; mature nymphs found
in moss 8/17/03 and on rocks 7/14/2004 in SITK. Emerge in August/September.
Stoneflies (Plecoptera)
No lateral gills on abdomen, two cerci (tails). Fish- or snake-like
motion of body. Generally sprawlers-clingers. Stoneflies in Indian River are
shredders of leaf material, etc. or predators of other macroinvertebrates. Some
may also be scavengers.
Shredders-detritivores
Capniidae (Capnia*†):
C. nana, C. excavate, C. melia (Ellis 1975)? Winter
stoneflies. Early emergers (March-June). Nymphs may consume about 30% of their
body weight daily, even at low winter temperatures, reflecting their importance
in conversion of CPOM to finer particles.
Leuctridae (Paraleuctra†,
Despaxia)
Paraleuctra occidentalis*: Inhabits coarse sediments, debris jams,
leaf packs.
Despaxia augusta*: Found in small creeks and spring outflows. Recorded
at Sashin Creek, SE Baranof Island (Ellis 1975). An autumnal species with adults
found from July to October.
Nemouridae (Zapada cinctipes*†,
Z. hays/oregonensis*, Podmosta decepta (<6 mm)*): Detritivores
of leaf litter. Zapada spp. scavenge on dead salmon or feed on what
is growing on carcasses (e.g., mold-like growth). Life histories may be geared
to leaf input and salmon return. For Zapada and Capnia nymphs,
consumption of detritus may be greatest in midwinter when water temperature
is near 0 degrees C.
Taeniopterygidae (Doddsia occidentalis*): Nymphs grow
steadily from July through the winter. Scrapers? Emerge from February to May,
depending on elevation and/or latitude.
Predators
Chloroperlidae (Sweltsa*†
(7 species in AK), Kathroperla*, Suwallia*†
( S. dubia, S. forcipata, S. starki in AK): Engulfers
of midge, blackfly larvae. Sweltsa borealis, S. oregonensis,
S. exquisite, others (Ellis 1975)? May be scavengers in the hyporheic
zone. Less prone to be subterranean then other Chloroperlids, however, may survive
summer drought and flood events in the hyporheic zone. Suwallia starki*
are englufers of midge and blackfly larvae. Nymphs occur deep in stream sediments
until just prior to emergence. May be herbivore-detritivores in fall after summer
recruitment and then shift to omnivory and carnivory respectively. Kathroperla
perdita* (to 25 mm (1”)) primarily hyporheic, emerges in late May
and early June. (Collector-gatherers/scrapers?)
Perlodidae (Kogotus†,
Megarcys†)
Kogotus nonus*: Engulfers of midge, blackfly, mayfly, and stonefly
larvae. Feeds primarily at night (on Chironomids) but not exclusively. Feeds
on Baetis mayflies during the day. Probably univoltine. Final instars
present through August. Large nymphs collected 7/18/03, 7/14/04; small nymphs
collected 4/9/02.
Megarcys signata*: Nymphs are omnivorous, feeding on diatoms as well
as engulfers of midge, blackfly, caddisfly, stonefly, and mayfly larvae. Fastest
growth occurs in summer when carnivory is greatest. Emerge from April to July.
Large (over 25 mm (1”+)).
Caddisflies (Trichoptera)
Most build cases made of small stones or vegetation. Exhibit great
diversity in food capturing adaptations. Indian River caddis are predators,
algae grazers, shredders, collector-gatherers, filter-collectors, and opportunistic
scavengers. Generally, caddisflies are scrapers if their case is mineral and
shredders if their case is vegetation material. Case material often changes
as life cycle and food habits change.
Predators
Rhyacophilidae (Rhyacophila†):
Free living and do not build cases, but can spin a silk anchor line that enables
the larvae to move without being swept away by the current. Most are predators
of macroinvertebrates (engulfers), but species in the Verrula Group are phytophagous
with hypognathous heads (oriented downwards) and they feed on algae, diatoms,
and bryophytes. Several species present. R. verrula†
and R. grandis confirmed in the Indian River drainage. Species in the
Brunnea Group (R. vao?) and Sibirica Group†
(R. narvae?) have also been identified from the Indian River (Neal
et al. 2004, Smith 2005). R. alberta, R. grandis, R. narvae,
R. rickeri, R. verrula, R. vao, and R. vaccua
recorded at Sashin Creek, SE Baranof Island by Ellis (1978a).
Phryganeidae (Ptilostomis ocellifera): Specimens found
in muskeg ponds within the Indian River Basin and on nearby Krusof Island. Can
also live in cool streams and temporary pools. Case is ring-like sections of
leaf pieces joined end to end, up to 60 mm (2.4”). Late instars primarily
predacious. Early instars may be shredders.
Scraper-grazers
Glossosomatidae (Glossosoma penitum): Tortoise shell-case
(mineral). Lives in swift water and feeds mostly on periphytic algae (diatoms)
on upper rock surfaces.
Limnephilidae (Ecclisomyia†,
Ecclisocosmoecus)
Ecclisomyia conspersa: Slender, long case, sometimes with slight curve,
little taper, made with coarse stones often with some long vegetation material
(e.g., spruce needles) included. Found in all types of running water. Very abundant
in southeastern Alaska. Shifts from a diet of diatoms in early instars (scrapers)
to plant detritus (collector-gatherers and shredders) in later instars when
leaf material is abundant. Also commonly found on dead salmon (scavengers).
Ecclisocosmoecus scylla: Curved, tapered case made of small stones.
Scrappers and shredders. Food includes diatoms, plant material, and FPOM. Found
in cold, swift-moving mountain streams. Often concealed in sand and gravel.
Brachycentridae (Micrasema†
gelidum/bactro): Micrasema confined to small, cold streams. Found on
rocks in clumps of aquatic moss, on logs, and other protected places. Case is
silk and ribbon-like pieces of plant material. They are grazers on periphytic
algae during the first instar. In later instars, also known to be herbivore-chewers
(shredders) on moss etc. and as collector-gatherers.
Uenoidae (Neophylax rickeri): Confined to flowing
water. Grazes on diatoms and FPOM. Cases are relatively short and thick; constructed
with coarse rock fragments with larger ballast stones along each side. Larva
grow mostly in autumn and winter, pupate in spring and early summer, but remain
in diapause for a period ranging from a few weeks to six months. They pupate
in large aggregations on the underside of rocks. Adults emerge in late summer
and autumn. Larvae grow to 15 mm. Collected in a small high gradient creek on
the slope of Gavin Hill. Bottom substrate was gravel and cobble.
Filter-Collectors
Philopotamidae (Dolophilodes pallidipes): Filterer-collectors
of FPOM and diatoms. Found in headwater streams in this area. Requires cool,
clear water flowing steadily over clean rubble. Larvae spin and live in tubular
silk capture nets with extremely fine meshes. Nets up to 60 mm long; larvae
grow to 16.5 mm. Collected in a small high gradient creek on the slope of Gavin
Hill. Bottom substrate was gravel and cobble.
Hydropsychidae (Parapsyche†
elsis): Builds a retreat of small stones and detritus pieces. Spins
a silken capture net (mesh size larger then most Hydropsychidae). Food is mainly
fine detritus and animal material.
Shredders
Limnephilidae (Dicosmoecus, Psychoglypha,
Onocosmoecus, Chyranda, Lenarchus, Limnephilus,
Glyphopsyche):
Dicosmoecus atripes: Generalized predator-grazer-shredder. Larva to
28 mm (1”+). Has robust mandibles. D. atripes changes its food
preference with age. During first year of life cycle, feed primarily as a scrapper
on periphyton (diatoms and filamentous algae). Middle and late instars are shredders
and occasionally predators. Second year larvae overwinter as diapausing fifth
instars attached in large aggregations under large boulders and then become
active again in the spring (Lessard et al. 2003). May be opportunistic scavengers
(found on dead salmon 8/17/2003), particularly between first and second year
of development. Emerge late in the season (October). Abundant in the Indian
River.
Psychoglypha subborealis: Mixed mineral and vegetation cases (needles,
wood pieces, bark, etc.). P. subborealis is primarily a shredder but
may feed on biofilm and as a collector-gatherer depending on food availability
and life stage. Larva to 26 mm. Grows best on quality food such as stream-conditioned
leaves. Often observed on dead salmon. May feed on salmon flesh as scavengers
or on what is growing on dead salmon. May emerge in the fall and overwinter
as adults while gonads mature (Ellis 1978b). Deposition of eggs may begin in
early March. Abundant in the Indian River.
Psychoglypha spp.: At least one other species of this genus present
in the river. Most likely P. alascansis, which is found from California
to Alaska (Several records from SE Alaska, Vineyard 1981) and/or P. bella.
Appears to be confined to plant debris accumulations in quiet stream edges,
pools, or slow current. Large shredder that presumable feeds on dead wood, leaves,
and bark in which it is found. Cases constructed of bulky pieces of wood and
leaves, sometimes with mineral elements. Uncertain whether these species have
the same propensity for dead salmon carcasses as P. subborealis.
Onocosmoecus unicolor: Large shredder (to 25 mm) with case constructed
of wood, bark, and leaves. Eats a variety of food including CPOM, FPOM, moss,
and other aquatic insects. Larvae hatch in the fall and grow quickly to fifth
instars and then remain at that stage over the winter and spring, pupating and
emerging in the summer. Most of the larval growth occurs in winter. Commonly
associated with salmon carcasses in Pacific Northwest. Life history is keyed
to take advantage of returning salmon and/or fall leaf litter inputs.
Chyranda centralis: Lives in small spring streams and is usually found
in accumulations of leaves. Case unique; made of bark or stout leaves with a
prominent flange-like seam along each edge. Presumably feeds on leaves, bark,
and possibly moss. Found case and pupa while sampling the east fork of the Indian
River in tributaries and just below the falls 7/8/2005. They were located in
leaf, bark, and wood accumulations.
Lenarchus vastus: Found in temporary ponds in the Indian River flood
plain and in muskeg ponds within the Indian River Basin. Can also live in marshes
and at the edge of small lakes. Cases variable but usually of irregular leaf
and bark fragments and sometimes with lengths of sedge arranged longitudinally.
Feeds on and creates trails through loose organic bottom sediments in muskeg
ponds and on CPOM in forested habitats. A highly adaptable lentic species. Actively
feeds throughout fall and winter months. Grows to 30 mm. May have similar adaptations
for living in transient pools and temporary pond as Limnephilus.
Limnephilus spp.: Collected in temporary ponds in or near the Indian
River flood plain. The genus has a broad ecological tolerance and a strong affinity
for lentic habitats. Adaptations to temporary pools include diapause that delays
sexual maturity in adults until the shorter days of late summer triggers egg
development during the season when rains become more frequent, eggs deposited
in damp substrates or on the underside of damp logs, eggs and larvae that remain
within a thick gelatinous matrix (mucopolysaccharide matrix) that can resist
dissociation for several months until ponds refill, rapid larval development,
and wide dispersal of adults (Wiggins 2004). Species collected from the Sashin
Creek area S.E. Baranof Island and verified by Dr. D.G. Denning include L.
harrimani, L. nogus, and L. sitchensis (Ellis 1978a).
L. sitchensis was initially described from Sitka as Goniotaulius (1859)
by Kolenati (Nimmo 1986); L. harrimani was first described from Sitka
by Banks 1900 (Vineyard 1981). Limnephilus feed mainly on detritus. Cases variable,
usually made of leaves, hemlock needles, and wood in this area.
Glyphopsyche irrorata: Found in Swan Lake. G. irrorata is
a species of marshes and the edges of slow streams. Larvae associated with an
abundance of decaying vegetation. Cases made of rock and plant pieces to larger
wood pieces arranged longitudinally, mostly irregular in this area. Final instars
develop in late summer. Case length up to 34 mm.; larva to 21 mm. May emerge
in the fall and overwinter as adults while gonads mature (Ellis 1978b). Deposition
of eggs may begin in early March.
Lepidostomatidae (Lepidostoma roafi, others?): Four-sided
case of bark and leaves. Food primarily detritus (detritivore-chewers). Attracted
to dead fish and may scavenge on dead salmon.
True flies (Diptera)
Midges (Chironomidae): A very diverse group.
Found in all aquatic habitats, including marine. All functional feeding groups
represented. Many sprawler/collector-gatherers, but also predators (e.g., Macropelopia†),
shredders, wood burrower-shredders (e.g., Brillia†),
scrapers, filter-collectors, and scavengers on dead salmon. Large numbers may
indicate degrading aquatic conditions.
Blackflies (Simuliidae: Prosimulium
sp.†): Fine filter-collectors of bacteria etc. (particle
size: < 1 um to >350 um). Can also be scrappers of biofilm and FPOM and
they occasionally ingest animal prey. May absorb or ingest DOM directly by an
unknown mechanism (e.g., possibly feeding on colloidal particles (< 0.1 um)
of DOM). Much of the intake of FPOM and DOM becomes fecal pellets which can
be produced by each larvae at the rate of >100/day. High densities of blackflies
can indicate moderately degraded water quality.
No-see-um biting midges (Ceratopogonidae):
Predators or collector-gatherers
Crane Flies (Tipulidae: Hesperoconopa
sp.†, Dicranota sp.†):
Shredders-detritivores or predators.
Dance Flies (Empididae: Clinocera,
Chelifera/Metachela†, Oreogeton†):
Generally predators. Clinocera are clingers. Oreogeton maybe
associated with moss and are sprawlers-burrowers. They are engulfing predators
on blackflies and caddisflies.
Moth Flies (Psychodidae): Collector-gatherers.
Found in lentic (still water) habitats and margins of streams. Very tolerant
of organic pollution.
Other Macroinvertebrates
Aquatic Beetles, (Coleoperta)
Trout-stream Beetles (Amphizoidae): Amphizoa
sp. Found on driftwood and trash floating in frothy eddies, along undercut banks
among roots, or among accumulations of submerged coniferous needles. Larvae
are predacious and seem restricted to feeding on stonefly larvae.
Predaceous Diving Beetles (Dytiscidae): Predators
(piercers). In lakes and ponds (permanent and temporary). Also in slow or ponded
parts of creeks and rivers.
Predaceous Ground Beetles (Carabidae†):
Predators (engulfers). Rock crevice dwellers; found on marine rocky coasts.
Springtails (Collembola) †:
Collector-gatherers.
Aquatic earthworms (Oligochaeta: Lumbriculidae†,
Naididae†, Enchytraeidae†):
Collector-gatherers of FPOM.
Planarian flat worms (Class Turbellaria†):
Predators, scavengers (on dead salmon).
Aquatic mites (Subclass Acari†,
Subcohort Hydrachnidia): Larvae are parasites and adults are
predators on macroinvertebrates, e.g., stoneflies and caddisflies. Larval Chironomids
are particularly important as hosts, Larval mites suck the body fluids from
adult midges. Adult mites are predators of Chironomid eggs and larvae.
Clams, Bivalvia (Sphaeriidae):
Pisidium sp.†
Roundworms (Nematoda)†
Benthic diatoms† and other algae found in the Indian River, a nutrient-poor stream (Neal et al. 2004): Achnanthidium pyrenaicum, A. minutissimum, Aulacoseira ambigua, Brachysira brebissonii, Cocconeis placentula var pseudolineata, Cymbella hybrida, C. mesiana, Diatoma anceps, D. mesodon, Encyonema minutum, E. silesiacum var. altensis, E. reichardtii, Eunotia minor, E. soleirolii, Fragilaria capucina, F. vaucheriae, Frustulia vulgaris, Gomphonema spp. (G. drutelingense, G. mexicanum, G. sarcophagus, G. minutum, G. olivaceoides, G. parvulum), Hannaea arcus, Meridion circulare var. constrictum, Melosira varians, Navicula lanceolata, Planothidium lanceolatum, Psammothidium bioretii, P. grischunum f. daonensis, Reimeria sinuate, Rhoicosphenia abbreviate, Spirogyra sp. (filamentous algae), Staurosirella lapponica, S. leptostauron, Stephanodiscus hantzschii, Synedra ulna, Tabellaria ventricosa, and the cyanobacteria Pseudanabaena sp.
Chironomidae midge geneses present or expected in the Indian River: Brillia† (burrowers in rotten wood, shredders-detritivores, or collector-gatherers), Chironomus (burrowers-tube builders, collector-gatherers, a few filterers, shredder-miners), Corynoneura† (collector-gatherers), Eukiefferiella† (collector-gatherers, scrapers, predators), Heterotanytarsus, Heterotrissocladius (collector-gatherers, scrapers?), Macropelopia (sprawlers and engulfing predators on Protozoa, Cladocera, Ostracoda, Crustacea, Ceratopognidae, Chironomidae), Micropsectra† (collector-gatherers), Paramerina (predators?), Parametriocnemus† (collector-gatherers), Paraphaenocladius (collector-gatherers), Phaenopsectra (scrapers, collector-gatherers, filterers?), Polypedilum (shredder-miners, collector-gatherers, predators ), Psuedodiamesa (collector-gatherers), Rheocricotopus† (collector-gatherers, shredders of living plant tissue, predators), Stilocladius†, Thienemanniella† (collector-gatherers), Thienemannimyia group (engulfing predators of Protozoa, Cladocera, Ostracoda, Chironomidae), Tvetenia (collector-gatherers), Zavrelimyia (predators on Oligochaeta, Ostracoda, Chironomidae). (Also Micropsectra/Tanytarus sp.† and Cricotopus/Orthocladius sp.†)
* Identification verified by Dr. Kenneth Stewart. Megarcys signata
verified by Robert Hood (USGS).
† Families, geneses, and species found in the Indian
River during a recent study (Neal et al. 2004).
Selected References