Comparative morphometrics of male and male genital and abdominal characters
Nephotettix virescens (Distant) populations from Bangladesh and the Philippines
R. C. Saxena, principal research scientist, International Centre of Insect Physiology
and Ecology, Nairobi, Kenya, and entomologist, IRRI
A. A. Barrion, research fellow;
M. V. Soriano, research aide,
Entomology Department, IRRI
Differential reactions of resistant rice varieties to populations of the green leafhopper (GLH) Nephotettix
virescens (Distant) in Bangladesh and the Philippines prompted us to study morphological-morphometric
variations between males and females of the two populations.
Males. GLH males were taken from stock cultures at the Bangladesh Rice Research Institute (BRRI) and
IRRI and preserved in 70% ethanol. Visual comparison of the insects showed two distinct color morphs:
one with black-spotted corium on tegmen and the other with uniformly green tegmen. The spotted morph
occurred more frequently in both populations. Most of the non-spotted insects had relatively higher
morphometric values for genital and abdominal characters than the spotted GLH.
Morphological dimensions and setal counts (Table 1) of genital components (Fig. 1) of spotted and nonspotted GLH from Bangladesh and the Philippines were similar, but those from Bangladesh had wider
terminal abdominal segments and parameres, and more aedeagal setae. GLH males from the Philippines
had more setae on the subgenital plate and anal tube. Spotted Philippine males had significantly longer
parameres than those from Bangladesh. Also, the subgenital plate of non-spotted GLH males from the
Philippines was significantly longer.
Females. GLH females were taken from stock cultures at BRRI and IRRI and preserved in 70% ethanol.
Like the males, they had two distinct color morphs: one with black-spotted corium on the tegmen and the
other with uniformly green tegmen. The spotted morph occurred more frequently in both populations, but
had relatively lower morphometric values (Table 2) in most genital and abdominal characters (Fig. 2).
GLH populations from both countries were similar in most morphological dimensions, except for the 10th
abdominal segment. Differences were particularly distinct in chaetotaxy. There were significantly more
spines on the left and right pygofers of GLH females from Bangladesh than on those from the Philippines.
Philippine GLH had significantly more setae on the anal segment and the third valvula of their ovipositor.
The genital and abdominal dimensions and chaetotaxy of the two populations were stable morphological
characters adequate enough to differentiate allopatric GLH populations from Bangladesh and the
Philippines.
1. Abdominal and genitalic characters of N. virescens male. A = ventral, B = dorsal, C = lateral
views. a = paramere, b = basal plate, c = aedeagus, d = pygofer.
Table 1. Morphometric mean of genital and abdominal characters of male GLH populations from Bangladesh and the
Philippines, IRRI, 1984.
Spotted corium
Character
Anal tube setae (no.)
Anal tube length (mm)
Pygofer spines (no.)
Left
Right
Pygofer length (mm)
Subgenital plate length (mm)
Abdominal segment X width (mm)
Abdominal segment XI width (mm)
Aedeagal setae (no.)
Aedeagal length (mm)
Basal plate length (mm)
Paramere length (mm)
Paramere width (mm)
Subgenital plate setae (no.)
Left
Right
a
Non-spotted corium
b
Bangladesh
8.4
0.0982
Philippines
9.0
0.0946
Difference /
–0.6 ns
0.0036 ns
Bangladesh
8.9
0.1082
Philippines
9.1
0.099
Difference b/
-0.2 ns
0.0092 ns
4.0
4.2
0.6222
0.5939
0.0521
0.1014
4.5
0.5078
0.415
0.5157
0.2166
3.6
4.1
0.6211
0.6036
0.0468
0.0858
3.4
0.5141
0.4057
0.5478
0.2054
0.4 ns
0.1 ns
0.0011 ns
–0.0097 ns
0.0053 ns
0.0156**
1.1**
–0.0063 ns
0.0093 ns
–0.0321*
0.0112 ns
4.5
4.5
0.6285
0.5956
0.056
0.112
4.46
0.5286
0.4164
0.5621
0.2256
4.1
4.0
0.6314
0.6193
0.0493
0.0928
4.0
0.55
0.4136
0.5614
0.2055
0.4 ns
0.5 ns
–0.0029 ns
4.0237**
0.0067 ns
0.0192**
0.46 ns
–0.0214 ns
0.0028 ns
0.0007 ns
0.0201*
8.4
8.4
9.2
9.5
4.8 ns
-1.1 **
8.8
8.8
10.5
9.7
-1.7 *
-0.9 ns
/ Averages based on observations made on 20 individuals of each color morph.
b
/ **, * signifcant at 1% and 5% level, and ns = not significant by the t-test.
Table 2. Morphometric means of genital and abdominal characters of female GLH populations from Bangladesh and the
Philippines, IRRI, 1984. a/
Spotted corium
Character
Anal lobe setae (no.)
Anal lobe length (mm)
Pygofer spines (no.)
Left
Right
Pygofer length (mm)
Subgenital plate length (mm)
Abdominal segment X width (mm)
Abdominal segment XI width (mm)
1st valvula length (mm)
2d valvula length (mm)
3d valvula setae (no.)
Left
Right
3d valvula length (mm)
a
Non-spotted corium
Bangladesh
12.0
0.146
Philippines
12.5
0.1455
Difference b/
–0.5 ns
0.0005 ns
Bangladesh Philippines Difference b/
12.9
13.8
-0.9 *
0.1448
0.145
–0.0002 ns
18.2
18.0
1.2545
0.6175
0.2433
0.161
1.9845
1.8315
15.2
15.8
1.247
0.6208
0.2592
0.157
2.0318
1.8378
3.0**
2.2*
0.0075 ns
0.0075 ns
–0.0159**
0.0040 ns
–0.0473 ns
–0.0063 ns
17.8
17.4
1.2712
0.6182
0.245
0.159
2.0658
1.899
15.6
15.8
1.2528
0.6178
0.2655
0.1562
2.0358
1.8455
2.2**
1.6*
0.0184 ns
0.0004 ns
–0.0205**
0.0028 ns
0.0300 ns
0.0535 ns
8.0
8.2
1.7292
9.0
8.8
1.7333
–1.0*
–0.6 ns
–4.0041 ns
8.6
8.7
1.7602
9.4
9.4
1.7285
–0.8 ns
–0.7 ns
0.0317 ns
/ Averages based on observations made on 20 individuals of each color morph.
b
/ **,* = significant at 1% and 5% levels, and ns-not significant by the t-test.
Saxena, R.C., A.A. Barrion and M.V. Soriano. 1985. Comparative morphometrics
of male and female genital and abdominal characters Nephotettix virescens
(Distant) populations from Bangladesh and the Philippines. Int. Rice Res.
Newsl. 10(3):27-28.