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Vol. 50 No. 4, 2011
Effects of Parental Care and Body Size on the Reproductive
Success of the Paradise Fish Macropodus
opercularis (L.) in a
Small Area
Wen-Bin
Huang1,2,* and Chih-Chieh Chang2
1Department
of Natural Resources and Environmental Studies, National Dong Hwa
University, 1 Da Hsueh Rd., Sec. 2 Shoufeng, Hualien 974, Taiwan
2Graduate Institute of Biological Resources and
Technology, Meilun Campus, National Dong Hwa University, Hualien 974,
Taiwan
Wen-Bin
Huang and Chih-Chieh Chang
(2011) The
paradise fish Macropodus opercularis
(L.) is a species famous for its predominant behaviors of male parental
care, and in this territorial species, a larger male seems to have an
advantage in terms of reproductive success. This study was conducted to
examine the effect of parental care on the reproductive success of the
paradise fish using different parental-care treatments of male-only
care, female-only care, bi-parental care, and no-parental care.
Hatching success of the paradise fish significantly differed among the
4 parental-care treatments. Hatching rates (HRs) averaged 94% for the
male-only and bi-parental care treatments, 82% for female-only care,
and 62% for no-parental care. There was no significant difference in
HRs between maleonly and bi-parental care, suggesting that when the
male is present, the female’s contribution toward hatching success is
insignificant. Also, there were significant positive correlations of
egg numbers (ENs) and HRs to standard lengths (SLs) of parental males
(SLmale). Their regression relationships were: ln(EN) =
5.336 × 10-2 SLmale + 4.207 (r2 = 0.461) and HR =
2.511 SLmale - 53.806 (r2
= 0.661). These results suggest that reproductive success of the
paradise fish primarily depends on male parental care. Based on the
HRs, male fish were divided into 2 distinctive size groups: a small-
(43.7-45.7 mm) and a large-size group (49.2-62.1 mm) with mean HRs of
48.6% and 90.0%, respectively. Accordingly, a minimum body length of
about 49 mm was the size for the male to attain the plateau of a
maximum HR.
Key words: Hatching
rate, Egg number, Size effect, Breeding success, Labyrinth fish.
*Correspondence: Tel: 886-3-8227106 ext. 2261. Fax:
886-3-8230093. E-mail:bruce@mail.ndhu.edu.tw
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