| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1995: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1994: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1993: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
Females of the sulfur butterfly, Colias erate, exhibit a genetic color dimorphism in which one form has white wings (alba) , and the other resembles the males with yellow wings (andromorph). Adults fed on and oviposited mainly on clovers, which are aboudant on the ridges of the paddy fields in Shirouma, Nagano Prefecture. Males outnumbered females, but the estimated number indicated a 1 : 1 sex ratio. The butterfly had a low frequency of andromorph in females (less than 15%). Females tended to remate during their life span. The resident times were similar for andromorphs and albas, but males had a higher recapture rate, suggesting site fidelity. The bursa copulatrix enlarged with the number of spermatophores contained. Fecundity of each morph after eclosion was about 800. There was no significant difference in the number of eggs loaded by andromorphs and albas, when they had copulated once. The number of eggs actually laid by alba depended upon the mating frequency. The dimorphism is p
… More
robably balanced by the number of eggs developed by the andromorphs, though their low mating frequency. Uninterrupted copula durations between virgin male and virgin female were successful copulations, lasting about 45 min in the laboratory. Without any harassments, the copula duration of virgin female with wild young males seemed to be similar with that in the laboratory. The spermatophore had increased in volume until 40 min after the start of copulation. Most copulations were prolong in the field from those in the laboratory due to lone males harassing, though no male ejaculated a larger spermatophore. The lone males significantly increased the duration of a harassment of the pair that copulated with old males. No severe harassment elicited any particular behavior of the paris. A few take-over of female by lone males harassing and a few females accepting re-mating with a lone male just after the first copulation were observed. The experienced females that accepted re-mating retained smaller ejaculate in the bursa copulatrix than those that refused re-mating. Severe harassments of pair with old males may be advantageous to lone males due to a small spermatophore ejaculated by the old males. Less
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