Mating Behavior and sperm competition in fruit flies, with reference to difference between Hawaiian and Japanese melon flies.

在野外和室内观察的基础上，对夏威夷和冲绳瓜蝇的交配行为进行了比较。在冲绳，雄性瓜蝇晚上在非寄主植物上形成莱克，每只雄性坐在树叶上等待雌性。当雌性来的时候，雄性Cout，有时在雌性选择配偶之后，会被她接受。另一方面，在夏威夷，雄性不会形成猎犬，而是主动飞行寻找雌性。它们向坐着的雌性求爱。我们的实地研究表明，这种差异是由于两个地区的人口密度不同造成的。即使在冲绳，雄性在密度低的时候也会寻找雌性，在那里雄性的等待战术找不到雌性。因此，雄性在不同的社会条件下会自适应地改变交配策略。夏威夷甜瓜蝇雄性的求偶声音与冲绳雄性几乎相同，但有细微的差异。与性信息素释放有关的行为和形态特征夏威夷瓜蝇雄虫与冲绳雄蝇一致。对冲绳瓜蝇的实验研究表明：(1)雌性受精囊的精子寿命较短，这对P2值随交配间隔的变化具有重要意义；(2)长时间交配抑制了雌性的繁殖，可能是由于雄性附腺物质向雌性体内运输所致。精子在受精囊中的存在与否不影响精子的存活抑制。

Comparison of mating behavior of Hawaiian and Okinawan melon flies (Bactrocera cucurbitae) was made based on field and laboratory observations. In Okinawa, melon fly males form lek on non-host plants in evening and each male waits female sitting on a leaf. When a female comes the male couts and sometimes, after female mate choice, is accepted by her. In Hawaii, on the other hand, males don't form leks, but actively fly to find females. They court to sitting females. Our field studies showed that this difference is due to difference in population density in the two areas. Even in Okinawa, males seek for females when the density was low, where the wating tactics of males was not effective to find females. Thus males adaptively change their mating tactics in different social conditions.Courtship sounds of Hawaiian melon fly males were almost the same as those of Okinawan males, but there was subtle difference. Behavior and morphological characters in relation to sex pheromone emission of Hawaiian melon fly males were the same as those of Okinawan males. These facts suggest that there is no species-level difference between Hawaiian and Okinawan melon flies.Experimental studies with Okinawan melon flies showed that (1) sperm longevity in female spermathecae was short and this was important for variation of P2 values in relation to mating interval, and (2) remating of females was suppressed by long copulation, possibly due to transportation of male accessary gland substance to female body. Existence or absence of sperm in spermathecae did not affect the remating suppression.