Maintenance of soldier-producing aphids on an artificial diet.

In our efforts to understand the biology of soldier-producing aphids, we attempted to maintain them in the laboratory using a chemically defined artificial diet. The ability of 16 species from the subfamilies Eriosomatinae and Hormaphidinae, most of which are soldier-producing species, to survive on the artificial diet was examined. Some species neither fed nor grew on the diet, whereas other species accepted the diet, grew to some extent, and managed to produce a small number of short-lived offspring. Although they performed poorly on the diet in general, aphid performance was correlated with the stage in the life cycle and the developmental stadium in that aphids of the gall generation tended to accept the diet and survive on it, whereas aphids of the non-gall generation did not. Also, old insects tended to perform better on the diet than young nymphs. Notably, only one species, Tuberaphis styraci, a gall-forming aphid that produces 2nd instar sterile soldier, showed good performance on the diet. Insects collected from galls (generation G0) survived on the diet, grew well, and produced many progeny. Three successive generations (G1, G2 and G3) were produced on the diet. Developmental period, adult body size, and age of first reproduction were almost constant through G0, G1 and G2 whereas fecundity, adult longevity and daily offspring production declined as the generations proceeded. These results are comparable to previous studies in which pest aphids have been maintained on similar artificial diets for several generations. Therefore, it is suggested that the artificial-diet rearing system will provide a useful tool to investigate various biological aspects of the soldier-producing eusocial aphid, T. styraci.

Genetically distinct populations in an Asian soldier-producing aphid, Pseudoregma bambucicola (Homoptera: Aphididae), identified by DNA fingerprinting and molecular phylogenetic analysis.

To estimate genetic structure of a soldier-producing aphid, Pseudoregma bambucicola, samples from natural populations throughout southeastern Asia were analyzed by a DNA fingerprinting technique. We unexpectedly found that P. bambucicola comprises two geographic groups, the northern group and the southern group, which are genetically distinct from each other but morphologically almost indistinguishable. Molecular phylogenetic and statistical analyses based on mitochondrial ribosomal DNA sequences demonstrated that the northern and southern groups of P. bambucicola are not closely related but constitute distinct lineages in the genus Pseudoregma. Detailed morphological reexamination revealed that the two groups could be distinguished by the number of setae on the 8th abdominal tergite of 1st instar nymphs and soldiers. From these results, it was suggested that P. bambucicola should be divided into two species. The northern group from Japan, Taiwan, Hong Kong, and northern Vietnam retains the name P. bambucicola, whereas we suggest that the name P. carolinensis (R. Takahashi, 1941, Tenthredo 3, 208-220) should be used for the southern group from Thailand, Malay Peninsula, Java, Irian Jaya, and Micronesia. The morphological resemblance between P. bambucicola and P. carolinensis might be due to shared ancestral characters of the genus Pseudoregma.

Ataxia cerebelosa autosómica dominante con prolapso de la válvula mitral / Autosomic dominant cerebellar ataxia with prolapse of the mitral valve

Reportamos una familia de 69 personas cuyos miembros nacieron en una ciudad ubicada a 2,700 metros sobre el nivel del mar, 20 de los cuales fueron afectados con ataxia cerebelosa progresiva autosómica dominante. Las edades de los pacientes estaban entre 16 y 69 años. En todos ellos se comprobó prolapso de la válvula mitral. La ataxia se asoció con piramidalismo, disminución de la agudeza visual por alteraciones del pigmento retiniano, degeneración pigmentaria de la mácula, así como palidez y atrofia del nevio óptico. El estudio con tomografía axial computarizada del cerebro demostró atrofia del cerebelo, del tronco cerebral y de los hemisferios cerebrales. Hubo diversos grados de alteraciones en la motilidad conjugada de los ojos. Las pruebas neuropsicológicas para determinar el nivel de inteligencia, en doce pacientes, demostraron deficiencia mental en todos ellos.