48
Table 1. Sex ratio estimates for natural populations of clam shrimps. Sample types are: adults from field
collections (field) and laboratory-reared adults from sediment samples (lab.). Numbers in brackets refer to
original data tabulated in Appendix I.
Taxon
Sample
size
Lynceidae
Lynceiopsis sanctijohanni Thiery
56
Lynceus aequatorialis Daday
128
Lynceus brachyurus MUller
>400
Lynceus gracilicornis (Packard)
78
Paralimnetis texana Martin & Belk
50
Cyclestheriidae
Cyclestheria hislopi (Baird)
>1800
Paracyclestheria sinensis Shen & Dai
6
Cyzicidae
Caenestheria dictyon? (Spencer & Hall)
95
Caenestheria lutraria? (Brady)
73
Caenestheria davidi (Simon)
31
Cyzicus cal(fornicus (Packard)
380
Cyzicus californicus
59
Cyzicus cycladoides (Joly)
30
Cyzicus cycladoides
Cyzicus elizabethae (Sars)
Cyzicus elongatus Mattox
58
Cyzicus g(fuensis (Ishikawa)
231
Cyzicus gynecia (Mattox)
>200
Cyzicus mexicanus (Packard)
Cyzicus morsei (Packard)
Cyzicus tetracerus (Krynicki)
Eocyzicus concavus (Mackin)
Eocyzicus klunzingeri? (Wolf)
Eocyzicus spin(fer Durga-Prasad,
Radhakrishna, Khalaf & AI-Jaafery
testheriidae reared in the laboratory than for samples
from the field (Table 1).
Although the data are more quantitative and taxonomically more representative, the summary in Table 1
largely supports the generalizations made almost 100
years ago by Sars (1902) and re-iterated by Mathias
(1937) on the overall patterns of sex ratio variation:
(1) most conchostracans are apparently gonochoric
with both sexes in approximately equal frequencies;
(2) notable exceptions occur in the Limnadiinae (sen214
145
1364
589
31
30
% Sample
References
male
type
75
field
Thiery, 1986
71
field
[I]
13-50
field
Mathias, 1937;
Valtonen, 1966; [2]
49
field
[3]
36
field
[4]
0-20
field
Nair, 1968; Nayar & Nair,
1968; Paul & Nayar, 1977;
Sissom, 1980; Roessler &
Sanchez, 1986; Roessler,
1994c
0
field
Shen & Dai, 1987
46
lab
[5]
56
lab
[6]
74
field
Veno, 1940
54
field
Wolt, 1972; [7]
54
lab
[8]
80
field
Joly, 1842
75
lab
Mathias, 1937
50
lab
Sars, 1898
48
field
Mattox, 1957
50
field
Yoon & Kim, 1992
0
field
Mattox, 1950
51
lab
[9]
40
field
Wiltshire, 1973
28
field
Mathias, 1937
50
lab
[10]
42
lab
[II]
53
lab
Khalaf & AI-Jaafery, 1985
su Straskraba, 1965a); and (3) Cyclestheria hislopi is
often characterized by populations with few, if any,
males.
These generalizations can be extended and amplified somewhat. It is still the case that all Lynceidae,
and the vast majority of Cyzicidae and Leptestheriidae
appear to be sexual. Males are known for most species,
even those described from small samples. (There are a
few species still known only from a few female specimens, just as there are some species still known only
Table 1. Sex ratio estimates for natural populations of clam shrimps. Sample types are: adults from field
collections (field) and laboratory-reared adults from sediment samples (lab.). Numbers in brackets refer to
original data tabulated in Appendix I.
Taxon
Sample
size
Lynceidae
Lynceiopsis sanctijohanni Thiery
56
Lynceus aequatorialis Daday
128
Lynceus brachyurus MUller
>400
Lynceus gracilicornis (Packard)
78
Paralimnetis texana Martin & Belk
50
Cyclestheriidae
Cyclestheria hislopi (Baird)
>1800
Paracyclestheria sinensis Shen & Dai
6
Cyzicidae
Caenestheria dictyon? (Spencer & Hall)
95
Caenestheria lutraria? (Brady)
73
Caenestheria davidi (Simon)
31
Cyzicus cal(fornicus (Packard)
380
Cyzicus californicus
59
Cyzicus cycladoides (Joly)
30
Cyzicus cycladoides
Cyzicus elizabethae (Sars)
Cyzicus elongatus Mattox
58
Cyzicus g(fuensis (Ishikawa)
231
Cyzicus gynecia (Mattox)
>200
Cyzicus mexicanus (Packard)
Cyzicus morsei (Packard)
Cyzicus tetracerus (Krynicki)
Eocyzicus concavus (Mackin)
Eocyzicus klunzingeri? (Wolf)
Eocyzicus spin(fer Durga-Prasad,
Radhakrishna, Khalaf & AI-Jaafery
testheriidae reared in the laboratory than for samples
from the field (Table 1).
Although the data are more quantitative and taxonomically more representative, the summary in Table 1
largely supports the generalizations made almost 100
years ago by Sars (1902) and re-iterated by Mathias
(1937) on the overall patterns of sex ratio variation:
(1) most conchostracans are apparently gonochoric
with both sexes in approximately equal frequencies;
(2) notable exceptions occur in the Limnadiinae (sen214
145
1364
589
31
30
% Sample
References
male
type
75
field
Thiery, 1986
71
field
[I]
13-50
field
Mathias, 1937;
Valtonen, 1966; [2]
49
field
[3]
36
field
[4]
0-20
field
Nair, 1968; Nayar & Nair,
1968; Paul & Nayar, 1977;
Sissom, 1980; Roessler &
Sanchez, 1986; Roessler,
1994c
0
field
Shen & Dai, 1987
46
lab
[5]
56
lab
[6]
74
field
Veno, 1940
54
field
Wolt, 1972; [7]
54
lab
[8]
80
field
Joly, 1842
75
lab
Mathias, 1937
50
lab
Sars, 1898
48
field
Mattox, 1957
50
field
Yoon & Kim, 1992
0
field
Mattox, 1950
51
lab
[9]
40
field
Wiltshire, 1973
28
field
Mathias, 1937
50
lab
[10]
42
lab
[II]
53
lab
Khalaf & AI-Jaafery, 1985
su Straskraba, 1965a); and (3) Cyclestheria hislopi is
often characterized by populations with few, if any,
males.
These generalizations can be extended and amplified somewhat. It is still the case that all Lynceidae,
and the vast majority of Cyzicidae and Leptestheriidae
appear to be sexual. Males are known for most species,
even those described from small samples. (There are a
few species still known only from a few female specimens, just as there are some species still known only