Sexual behaviour of immature male eastern mosquitofish: a ... - CPRG

No. of
females
Successful copulatory attempts (%)
10
7.5
5.0
2.5
0.0
0–10 min
P < 0.05 N.S. N.S. N.S.
10–20 min
20–30 min
Fig. 1. Frequency of successful gonopodial thrusts (mean with 1 s.d.) of males with precocious sexual
experience () compared with that of males grown in the absence of females ().
Table IV. Effect of sex ratio during male development on the body size (means.d.)
No. of
immatures
tested
T.L. of adults (mm) T.L. of immature (mm) Total length
increase
Large male Small male Stage 1 to 2 Stage 10 (%)
1 19 24·852·66 22·122·05 17·482·08 25·862·21 49·418·8
4 16 25·002·51 21·781·47 17·681·57 23·951·57 35·912·9
Table V. Mean number (s.d.) of aggressive interactions with adult males, of copulatory attempts,
and of time spent in the same sector where at least an adult male was also present for immature males
in different sex ratio conditions
Adult
sex ratio
M:F
732 a. bisazza et al.
No. of
females
No. of
replicates
Attacks by
adults
EFFECT OF THE SEX RATIO EXPERIENCED BY IMMATURE MALES ON
THEIR SIZE AT MATURITY (Tables IV and V)
Immature males that grew in aquaria with a low sex ratio increased on average
their body size at maturation by about 35% of their original size. Males that
grew in aquaria with a high sex ratio increased their size by about 50%; the
Total
Aggressive interactions Time spent
Attacks by
immature
Total
with adult
male(s)
Copulatory
attempts
2 : 1 1 19 41·726·4 6·211·5 47·924·0 26·410·2 3·6 5·2
1 : 2 4 16 37·923·3 8·713·9 46·626·6 20·710·1 13·111·7
Immature males used for this experiment were at stages 5 and 6 of their gonopodium maturation.