| Budget Amount *help |
¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2002: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2001: ¥500,000 (Direct Cost: ¥500,000)
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| Research Abstract |
1) Spermatogenesis of diploid males in the formicine ant, Lasius sakagamii : Six out of 30 studied colonies (20%) contained many diploid males. There was no reduction in chromosome numbers in either diploid or haploid males during spermatogenesis, indicating that diploid males produce diploid sperm.
2) Triploid individuals sired by diploid males in the polygynous ant, Lasius sakagamii : Triploid workers were born from the queens that had been inseminated by diploid males in the laboratory. They were greater than diploid workers in average body size. However, no morphological difference was detected between them. The triploid workers engaged in colony tasks in the same manner as diploid workers. Furthermore, a triploid male was obtained from a field nest. The chromosomal preparation of the testis revealed no reduction of chromosome numbers throughout maturation division.
3) A new type of male dimorphism in Cardiocondyla ants: A new type of male dimorphism, consisting of ergatoid and brach
… More
ypterous males was found in the myrmicine ant, Cardiocondyla kagutsuchi from Uiu Gombak, Malaysia. The ergatoid males showed the typical morphological and behavioral characteristics of those of many other C. spp. The brachypterous males have an intermediate nature between ergatoid males and typical winged males. The loss of flight should cause adaptive changes for underground life including aggressive behavior toward each other through intranidal competition for mating inside the nest. Short wings seemed to be effective to protect petiolar joints. However, the brachypterous males have not become so specialized as the ergatoids, keeping the winged male's nature to some extent.
4) Studies on diploid males in ants : Frequency of diploid males in field colonies in monogynous and polygynous ants. In monogynous ant, Lasius japonicus and polygynous ant, L. sakagamii, diploid males were found from 0 of 15 colonies and from 6 of 30 colonies, respectively. In monogynous ant Leptothorax congruous and polygynous ant L. sp, diploid males were found from 3 of 9 colonies and from 4 of 13 colonies, respectively. Diploid male producing rate in field colonies seemed to be different among ant taxa. Less
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