18 
TaBLE 9.—Continued 
a t™*S 
Mean Number of Food Organisms Per Stomach 
Big Creek 
Ferguson Creek 
Food O i 
00 rganism goth 21-30 31-40 41-50 51-60 
mm mm mm mm mm 
(10) (41) (43) (57) (16) 
Nematoda ae 0.02 
Oligochaeta = 0.02 0.07 0.02 
Gastropoda ve 0.02 0.07 0.12 0.25 
Arachnida 
Araneae NS he Ac 
Acarina 0.10 0.05 0.02 
Crustacea 
Cladocera TFA) LD 0.14 0.02 
Ostracoda 2.70 0.63 0.02 0.25 0.13 
Copepoda 0.80 1.68 0.51 Ont 0.13 
Isopoda 
Asellidae oe 0.07 0.09 0.16 0.94 
Amphipoda 0.10 0.10 0.37 0.28 1.00 
Decapoda 
Astacidae Ans an ree 0.04 0.19 
Insecta 
Plecoptera in 0.22 0.07 0.02 +e 
Ephemeroptera 0.30 0.37 0.30 0.68 0.44 
Odonata 
Zygoptera ane 0.02 a ae As 
Trichoptera oe 0.15 0.02 Qala 0.19 
Coleoptera 
Dytiscidae ee ath ie 0.02 ae 
Hydrophilidae ae A 0.02 ae 0.06 
Psephenidae Bee 0.32 0.02 0.02 0.06 
Elmidae ne 0.05 ee 0.02 
Diptera 
Tipulidae 
Simulidae as 6 co Er Sie 
Chironomidae 1.10 2229 4.07 1.44 0.75 
Ceratopogonidae 58 ah 0.07 st 
Others 0.10 0.07 0.05 0.04 
Miscellaneous ae 0.02 0.05 
ae 
> 60 eee 21-30 31-40 41-50 51-60 >» 60 
mm mm mm mm mm mm mm 
(6) (7) (10) (17) (14) (14) (5) 
0.07 0.20 
0.30 ane 0.07 
0.10 
5.43 
0.29 
5.14 
0.33 0.14 as 0.18 0.50 0.14 0.20 
1.83 0.14 0.10 0.65 ae 0.79 
0.17 
2 Be oe a 56 0.07 
0.33 0.71 0.30 0.12 0.29 0.43 
0.20 1.53 0.14 2.29 
0.14 
ne an 0.07 
aK Ne 1.20 0.18 ae “fe ie 
0.83 8.14 12.00 5.82 4.64 1.21 1.00 
3.83 0.06 0.07 0.07 
Miscellancons 0 eee 
INTERACTIONS WITH OTHER ORGANISMS 
Competition 
E. squamiceps occurs syntopically with all other 
described species of Catonotus, demonstrating a lack 
of total competitive exclusion between E. squamiceps 
and any closely related (and described) species. 
At the study areas, interspecific competition for 
habitat space seemed unlikely except possibly be- 
tween E. squamiceps and E. kennicotti in the slab 
pools of Big Creek. In Ferguson Creek no other 
riffle-inhabiting darters occurred.. In both Ferguson 
and Big creeks the slab pools generally had a small 
variety of fishes, and the species of Catonotus were 
almost always the most commonly occurring fishes. 
The number of nesting sites of E. squamiceps and 
other slab-rock users in a given area was often great 
and seemed nearly to account for all available sites. 
Competition for these sites was somewhat reduced 
by the partial staggering of spawning periods. The 
sequence of spawning by the species known 10 
spawn on the undersides of slab rocks in the study 
areas was, from earliest to latest: Eurycea bislineata 
(Amphibia), Etheostoma squamiceps, Etheostoma 
kennicotti, Etheostoma obeyense, and Pimephales 
notatus. No nests of Etheostoma mgrum were found 
although the species is known to spawn on the under- 
sides of stones (Winn 1958a:205-206 and 1958D:176- 
180). 
Predation 
As potential predators nine Esox americanus ant 
12 Lepomis cyanellus collected with E. squamucep: 
from Big and Ferguson creeks were preserved ant 
