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Table 3 Selectivity index (Ivlev) of prey in the diet of rainbow trout ( Oncorhynchus mykiss )

From: Selective foraging by non-native rainbow trout on invertebrates in Patagonian streams in Argentina

  

Early autumn

Late winter

Late spring

Late summer

Order

Species

NyF

CVA

NyF

CVA

NyF

CVA

NyF

CVA

Oligochaeta

Lumbriculidae sp.*

−1

−1

−1

−1

−1

−1

−1

−1

Gasteropoda

Chilina patagonica

0.11

0.91

−1

---

−1

0.95

−1

0.41

Biomphalaria peregrina

---

---

---

---

---

---

1

---

Crustacea

Hyalella araucana

0.75

---

0.98

---

0.31

---

1

---

Isopoda*

---

1

---

---

 

---

---

---

Araneae

Arachnidae*

---

---

1

---

1

---

---

---

Cladocera

Daphnia daphnia

---

---

1

---

---

---

---

---

Plecoptera

Aubertoperla illiesi

---

1

−0.30

0.71

---

−1

---

−1

Limnoperla jaffuelli

−1

---

−0.20

−1

0.57

−1

---

---

Antarctoperla michaelseni

−1

0.12

---

−1

−1

−1

−1

0.76

Notoperlopsis femina

−0.70

1

−1

---

---

---

−1

−1

Pelurgoperla personata

---

0.95

---

−1

---

−1

---

0.93

Potamoperla myrmidon

---

---

---

---

---

---

---

1

Udamocercia arumĂ­fera

---

---

---

---

---

−1

---

1

Adult*

---

---

---

---

1

---

---

---

Ephemeroptera

Nousia crena

0.41

−1

---

−1

−1

−1

−1

0.85

Meridialaris chiloeensis

1

0.64

−1

0.73

1

---

---

−1

Meridialaris laminata

−1

---

1

---

−1

−1

---

---

Penaphlebia chilensis

−1

−1

−0.30

---

0.74

−1

−1

1

Penaphlebia flavidula

---

---

1

---

---

---

---

---

Penaphlebia (A)*

---

---

---

---

1

---

---

---

Andesiops torrens

0.35

0.78

−1

---

−1

−1

0.34

0.03

Andesiops ardua

−0.90

−1

−1

−1

1

−1

−1

−1

Ephemeroptera sp.

1

---

---

---

1

---

---

---

Parasericostoma ovale

0.38

0.96

−0.80

−1

−0.70

1

0.48

1

Trichoptera

Hudsonema flaminii

0.50

0.72

1

−1

−1

−1

---

0.89

Brachysetodes sp.

−0.30

0.46

−1

−1

−1

0.14

−1

0.94

Triplectides sp.

---

−1

1

---

---

−1

---

−1

Oxyethira bidentata

1

---

1

---

−1

---

1

---

Neoatopsyche unispina

−1

0.97

−1

−1

1

−1

−1

−1

Neoatopsyche brevispina

−1

−1

−1

---

---

---

−1

0.14

Cailloma sp.

1

−1

−1

---

---

---

−1

0.93

Smicridea annulicornis

0.45

0.04

−1

0.90

0.53

0.90

−0.60

0.64

Smicridea frequens

−1

−1

−1

---

---

---

−1

---

Limnephilidae

---

---

1

---

---

---

---

---

Adult*

---

---

---

---

1

---

---

---

Stethelmis kaszabi

1

1

−1

---

−1

---

−1

1

Coleoptera

Luchoelmis sp.

−1

1

−1

−1

−1

−1

−1

−1

Elmidae (L)

−1

−1

---

1

−1

−1

−1

−1

Luchoelmis cekalovici

−1

−1

−1

−1

−1

−1

−1

−1

Austrolimnius sp.

−1

−1

−1

−1

---

−1

−1

−1

Rhantus signatus

---

---

---

---

---

---

1

---

Tropisternus setiger

---

---

---

---

---

---

1

---

Staphynilidae (A) *

1

---

---

---

---

---

---

---

Nitidulidae (A) *

---

---

---

---

1

---

---

---

Scirtidae (L)

---

---

---

---

1

---

---

---

Coleoptera sp. *

---

1

0.32

1

---

---

---

---

Athericidae (L)

−1

0.57

0.45

1

−1

−1

−1

---

Diptera

Muscidae (L)

---

1

---

1

1

---

---

---

Simuliidae (L)

−0.70

−0.20

−0.80

−0.30

1

−1

−1

−0.50

Empididae (L)

−1

−1

−1

−1

−1

−1

−1

1

Paratrichocladius sp.

−0.30

1

−1

−0.70

0.68

−1

−1

−1

Parapsectocladius sp.

−1

---

---

---

−1

−1

−1

−1

Pseudochironomus sp.

---

---

---

−1

−1

−1

−1

---

Thienemanniella sp.

1

−1

---

−1

---

−1

−1

−1

Orthocladius sp.

1

---

−1

---

---

−1

---

---

Lopescladius sp.

---

−1

---

−1

---

1

---

−1

Ceratopogonidae sp.

---

---

−1

−1

−1

−1

---

−1

Pupae sp.

1

   

1

   

Adult sp.*

1

1

1

 

1

 

1

 

Odonata

Cyanallagma interruptum

---

---

1

---

---

---

---

---

Homoptera

Homoptera sp.*

1

1

    

1

 

Hymenoptera

Hymenoptera sp.*

1

     

1

1

Orthoptera

Orthoptera sp.*

      

1

 

Hemiptera

Hemiptera sp.*

---

---

---

---

---

---

1

---

Fish fragment

Eggs

  

1

     
  1. From Nant y Fall (NyF) and Cabeza de Vaca (CVA) streams (Patagonia, Argentina) during the study period (early autumn, late winter, late spring of 2005, and late summer of 2006). Taxa absence at both environment and trout stomach were represented by --- and terrestrial prey (*).