Karyotypic variation in bisexual species and pseudogamous forms of the planthopper genusRibautodelphax(Homoptera, Delphacidae)
✍ Scribed by C. F. M. Bieman
- Publisher
- Springer Netherlands
- Year
- 1988
- Tongue
- English
- Weight
- 803 KB
- Volume
- 76
- Category
- Article
- ISSN
- 0016-6707
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✦ Synopsis
Chromosome numbers of Ribautodelphax collinus. R. angulosus, R. pungens, R. imitans, R. fanari, R. pallens, R. albostriatus, and of four undescribed species, provisionally indicated as Taxon 1 to 4, were determined. The chromosome number of all species was found to be 2n = 30 (14II + XX-XO); however, in several species some females with 2n = 31 or 32 also occurred. One female of R. collinus and one of Taxon 1 possessed eggs with 16 bivalents and one egg with 32 bivalents. One female of R. pungens contained only tetraploid eggs. Pseudogamous triploid females occurred in populations of R. pungens and Taxon 4. Their chromosome numbers ranged from 3n = 40 to 46 in R. pungens and 3n = 41 to 45 in Taxon 4. In several pseudogamous females from two R. pungens populations, eggs with 45 univalents and with various numbers of univalents, bivalents and trivalents were found. The mode of origin of pseudogamous triploid females is discussed and it is concluded that karyotypic data are consistent with an autopolyploid origin.