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Vol. 42 No. 1, 2003
Size-related Mating and Reproductive Success in a Drosophilid: Phorticella striata
Sarat C. Yenisetti1,* and Sreedhara N. Hegde2
1Department of Zoology, Nagaland University, PB no. 89, Mokokchung, Nagaland 798601, India.
2Department of Studies in Zoology, Manasagangothri, Mysore University, Mysore, Karnataka 570006, India
Sarat C. Yenisetti and Sreedhara N. Hegde (2003) Influence of male and female body size on mating preference in Phorticella striata
is studied with the help of male and female choice experiments. In
female preferential mating (female choice), males with long wings were
observed to be successful mating with both large and small females,
indicating the success of large over small males in male rivalry, which
may also be due to selection by females. In male preferential mating
(male choice) both large and small males preferred mating with large
females. These results prove that size-assortative mating exists in the
drosophilid P. striata.
Courtship latency, mating latency, copulation duration, fecundity, and
fertility were studied using 4 different crosses (large male x large
female; large male x small female; small male x large female; small
male x small female). Courtship latency and mating latency were shorter
for crosses in which 1 or both sexes were large. In the small male x
small female cross the longest courtship and mating latencies were
observed. Lower fecundity was noticed in the cross small male x large
female cross, and differences in fecundity with the other 3 crosses
were statistically insignificant. The large male x large female cross
showed the highest fertility, and differences between the other 3
crosses were statistically insignificant. Correlations among longer
copulation duration, higher fecundity, and the highest fertility exist
only for the cross involving both sexes of the large size. This reveals
that higher fertility depends on both duration of copulation and body
size of both sexes involved. The number of ovarioles present in larger
and smaller Phorticella was studied. As body size increases, the ovariole number also increases. In the light of results obtained in Phorticella striata, the authors support the hypothesis of‘bigger the better’proposed by Hegde and Krishna (1997).
Key words: Drosophilid, Phorticella, Body size, Mate choice, Reproductive success.
*Correspondence: E-mail: yschandrays@rediffmail.com
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