Larvae Of The Nearctic Species Of The Stonefly Genus Megarcys Klapálek (Plecoptera: Perlodidae)
Author
Stewart, Kenneth W.
Department of Biological Sciences, P. O. Box 305220, University of North Texas, Denton, Texas, U. S. A. 76203 E-mail: stewart @ unt. edu
stewart@unt.edu
Author
Kondratieff, Boris C.
Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, Colorado, U. S. A. 80523 E-mail: Boris. Kondratieff @ Colostate. edu
Boris.Kondratieff@Colostate.edu
text
Illiesia
2012
8
3
16
36
journal article
http://doi.org/10.5281/zenodo.4760667
dd6866c0-c326-4347-8419-b2e688a89062
1854-0392
4760667
Megarcys yosemite
(
Needham & Claassen 1925
)
(
Figs. 1
,
54-59
,
69
,
74
,
78, 83
,
88
a-b,
Table 1
)
Distribution.
California
,
Washington
(high elevation streams).
Material examined.
California
:
Inyo Co.
,
Ruby Creek
, about
56.33km
from the
Mt. Lyell
Type
Locality, El.
3444m
, water temp. 12.2°C,
20-VIII- 2010
,
L. Serpa
, 1 pre-emergent
♂
larva (died in rearing), 4 early instar larvae (on a previous date in 2008,
1♂
determined by
R
.
Baumann
, and
1♀
larva, were collected by
L. Serpa
at this site; personal correspondence);
Mono Co.
,
Coldwater Creek
,
37°34
’
27.4
’’
N
118° 59
’
16.7
’’
W
,
El.
3063m
, water temp. 4.44°C,
19-VIII-2010
, L. Serpa, 2 reared brachypterous
♂
(
one ♂
determined by
R
.W.
Baumann
), 2 brachypterous
♂
larvae, 4 brachypterous
♀
larvae, 6 early instar larvae with average head capsule width of
1.14mm
, and average body length of
5.64mm
;
Coldwater Creek
,
Sky Meadow
,
2.7km
above Coldwater Creek Campground
,
El.
3067m
, water temp. 4.49°C, 2 reared
♂
, 1 reared
♀
(
Fig. 1
),
6 larvae
(5 died in rearing:
07-IX-2010
collection date,
17-IX- 2010
emergence date) (personal correspondence, J.
Sandberg
).
Characters.
Head capsule width
♂
2.88-3.36mm
,
♀
3.60-3.84mm
; pronotal width
♂
2.76-3.30mm
,
♀
3.54-3.66mm
; body length
♂
17.64-20.2mm
,
♀
22.4- 22.9mm (
Table 1
). Color and pigmentation (
Figs. 54- 59
), lacinia, and dorsomesal band of erect silky white hairs typical of genus. Wingpads of
♂
(
Figs. 55
,
78
) and
♀
brachypterous, reflective of adults. Gill number and arrangement typical of genus (
Fig. 69
). Submental gill length
♂
0.27-0.36mm
,
♀
0.33- 0.45mm; anterior supracoxal gill length
♂
0.18- 0.30mm,
♀
0.24-0.33mm
(
Table 1
). Legs (
Fig. 56
) with setation typical of genus. Y-arms of mesosternum (
Fig. 57
) typical of genus. Cercal segments
♂
24-26 (
Table 1
), with setation typical of genus. Developing membranous windsock-like process of male epiproct (
Figs. 59
,
74
) evident in late instar individuals, and pointed posteroventrally in lateral view (
Fig. 83
). Developing female subgenital plate of 8
th
sternum (
Fig. 88a, b
) shallowly notched mesally.
Comments.
Males and females (
Fig. 1
) of this high elevation
California
population are brachypterous, reflected by the very short wingpads of preemergent larvae. The submental and anterior supracoxal gill lengths of both sexes of larvae, like the brachypterous male larvae of
M. subtruncata
larvae of Quinn Spring,
Oregon
, and brachypterous male and macropterous female larvae of
M. watertoni
from Iceberg Creek,
Montana
, were substantially shorter than those of the macropterous populations studied (
Table 1
). Otherwise, coloration and pigmentation, generic, and other specific characters of larvae were not separable from the other four species.