Morphology and size of spermatids were analysed in the grasshopper Eyprepocnemis plorans by means of light and electron microscopy. At light microscopy, normal and abnormal (macro- and micro-) spermatids differed in size and number of centriolar adjuncts (CAs): 1 CA in normal spermatids and 2 or more CAs, depending on ploidy level, in macrospermatids. Males carrying the additional B24 chromosome showed significantly more macro- and microspermatids than 0B males. The frequency of macro- and microspermatids showed an odd-even pattern in respect to the number of B chromosomes, with a higher frequency of abnormal spermatids associated with odd B numbers. Transmission electron microscopy showed that macrospermatids carried more than one axoneme, depending on ploidy level: 2 for diploid, 3 for triploid, and 4 for tetraploid spermatids. In 0B males, the most frequent abnormal spermatids were diploid, whereas in 1B males they were the tetraploid spermatids and, to a lesser extent, triploid ones. This suggests that most macrospermatids derived from cytokinesis failure and nucleus restitution. The implications of aberrant spermatids on B chromosome transmission and male fertility are discussed.

1.
Bidau C: Effects on cytokinesis and sperm formation of a B-isochromosome in Metaleptea brevicornis adspersa (Acridinae, Acrididae). Caryologia 39:165–177 (1986).
2.
Camacho JPM: B Chromosomes in the Eukaryote Genome (Karger, Basel 2004).
3.
Camacho JPM: B chromosomes, in Gregory TR (ed): The Evolution of the Genome, pp 223–286 (Elsevier, San Diego 2005).
4.
Camacho JPM, Perfectti F, Teruel M, López-León MD, Cabrero J: The odd-even effect in mitotically unstable B chromosomes in grasshoppers. Cytogenet Genome Res 106:325–331 (2004).
5.
Chiavarino AM, Rosato M, Manzanero S, Jiménez G, González-Sánchez M, Puertas MJ: Chromosome nondisjunction and instabilities in tapetal cells are affected by B chromosomes in maize. Genetics 155:889–897 (2000).
6.
Gosálvez J, de la Vega CG, Rufas JS, López-Fernández C: Unstable B-chromosomes producing abnormal spermatid nuclei in Sphingonotus coerulans (Orthoptera). Arch Biol 96:15–22 (1985).
7.
Hewitt GM: Variable transmission rates of a B chromosome in Myrmeleotettix maculatus (Thunb.) (Acrididae: Orthoptera). Chromosoma 40:83–106 (1973a).
8.
Hewitt GM: The integration of supernumerary chromosomes in the Orthopteran genome. Cold Spring Harb Symp Quant Biol 38:183–194 (1973b).
9.
Hewit GM: Meiotic drive for B-chromosomes in the primary oocytes of Myrmeleotettix maculatus (Orthoptera: Acrididae). Heredity 35:375–387 (1976).
10.
Hewitt GM, East TM, Shaw MW: Sperm dysfunction produced by B chromosomes in the grasshopper Myrmeleotettix maculatus. Heredity 58:59–68 (1987).
11.
Jones RN: B-chromosome drive. Am Nat 137:430–442 (1991).
12.
Jones RN, Rees H: B Chromosomes (Academic Press, New York 1982).
13.
López-León MD, Cabrero J, Camacho JPM, Cano MI, Santos JL: A widespread B chromosome polymorphism maintained without apparent drive. Evolution 46:529–539 (1992).
14.
López-León MD, Pardo MC, Cabrero J, Camacho JPM: Dynamics of sperm storage in the grasshopper Eyprepocnemis plorans. Physiol Entomol 19:46–50 (1994).
15.
Manrique-Poyato MI, Muñoz-Pajares AJ, Loreto V, López-León MD, Cabrero J, Camacho JPM: Causes of B chromosome variant substitution in the grasshopper Eyprepocnemis plorans. Chromosome Res 14:693–700 (2006).
16.
Megías L, Renal J: Técnicas generales, in Renal J & Megías L (eds): Manual de Técnicas de Microscopía Electrónica (M.E.T.). Aplicaciones Biológicas pp 1–20 (Editorial Universidad de Granada, Granada 1998).
17.
Nur U: Mitotic instability leading to an accumulation of B-chromosomes in grasshoppers. Chromosoma 27:1–19 (1969).
18.
Pardo MC, López-León MD, Viseras E, Cabrero J, Camacho JPM: Mitotic instability of B chromosomes during embryo development in Locusta migratoria. Heredity 74:164–169 (1995).
19.
Rebollo E, Martin S, Manzanero S, Arana P: Chromosomal strategies for adaptation to univalency. Chromosome Res 6:515–531 (1998).
20.
Rufas JS, Iturra P, De Souza W, Esponda P: Simple silver staining procedures for the location of nucleolus and nucleolar organizer under light and electron microscopy. Arch Biol 93:267–274 (1982).
21.
Suja JA, Rufas JS: Mechanisms promoting the appearance of abnormal spermatids in B-carrier individuals of Eyprepocnemis plorans (Orthoptra). Genome 32:64–71 (1989).
22.
Suja JA, de la Vega CG, Rufas JS: Meiotic stability of B chromosomes and production of macrospermatids in Aiolopus strepens (Orthoptera, Acrididae). Genome 29:5–10 (1987).
23.
Talavera M, López-León MD, Cabrero J, Camacho JPM: Male germ line polysomy in the grasshopper Chorthippus binotatus: extra chromosomes are not transmitted. Genome 33:384–388 (1990).
24.
Zurita S, Cabrero J, López-León MD, Camacho JPM: Polymorphism regeneration for a neutralized selfish B chromosome. Evolution 52:274–277 (1998).
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