Parasitoid spectrum (Hymenoptera: Braconidae; Aphelinidae) of the soybean aphid Aphis glycines (Homoptera: Aphididae) in Japan and Indonesia (Java and Bali)

Aphidiine and aphelinid parasitoids collected from the soybean aphid, Aphis glycines, on Glycine max in Japan and Indonesia (Java and Bali) were identified to clarify the parasitoid spectrum of the aphid there. Nine parasitoid species from Japan (Aphidiinae: Aphidius gifuensis, Aphidius sp., Binodoxys communis, Diaeretiella rapae, Lipolexis gracilis, Lysiphlebia japonica; Aphelinidae: Aphelinus asychis, A. gossypii, A. varipes) and two parasitoid species from Indonesia (B. communis, A. gossypii) were found to be associated with A. glycines.     

A new anhydrobiotic midge from Malawi,Polypedilum pembai sp.n. (Diptera: Chironomidae), closely related to the desiccation tolerant midge,Polypedilum vanderplanki Hinton

The sleeping chironomid (Polypedilum vanderplanki Hinton) lives on temporary rock pools in the semi‐arid tropical regions of Africa. Its larvae are able to survive the dry season in a completely desiccated ametabolic state known as anhydrobiosis. So far, P. vanderplanki was the only species among all insects showing demonstrated anhydrobiotic ability. Here, we show that a new related species originating from Malawi, Polypedilum pembai sp.n. , is also anhydrobiotic and that its desiccation tolerance mechanism is probably similar to what is observed in P. vanderplanki. The new species, P. pembai sp.n. , is described with special attention to the common and different morphological features, compared with P. vanderplanki. Phylogenetic analysis showed that both species are closely related, suggesting that anhydrobiosis evolved only once in their common ancestor about 49 Ma somewhere in Africa, before the divergence of two species, one in the sub‐Saharan area and another in southeastern Africa.     

Emergence of the Extrachromosomal Circular DNA Complexes as One of the Earliest Signals of Cellular Differentiation in the Early Development of Mouse Embryo

A small number of mouse embryos and embryonal carcinoma cells were pressed by mica sheet; then the extruded DNA complexes were adsorbed to mica and processed for electron microscopy. Extrachromosomal circular DNA complexes longer than 1 μm emerged during the compaction process of mouse embryos and during the differentiation of embryonal carcinoma cells induced with retinoic acid. These DNA molecules are discussed as possible products of developmental gene rearrangements occurring in the chromosomal DNA.     

Distribution of the Germinal Vesicle Material during Progesterone-Induced Oocyte Maturation in Xenopus and in Cynops

The distribution of the germinal vesicle material in the oocyte during progesterone-induced maturation was studied in Xenopus and in Cynops. In both species, two distinctive masses of yolkfree cytoplasm appear in specific areas of the oocyte and at definite stages of maturation. One, the primary cytoplasmic mass, is formed at the basal side of the germinal vesicle during early maturation and is very RNA-rich. In Xenopus , a large part of the primary cytoplasmic mass persists as a mass during maturation and ends up as a thin disk at the boundary between the animal and the vegetal hemisphere in the mature oocyte. In Cynops , a rod-like primary cytoplasmic mass extends near to the equatorial zone and becomes indistinct in the mature oocyte. The other, the secondary cytoplasmic mass, is formed at or prior to germinal vesicle breakdown in areas around the germinal vesicle and is also RNA-rich. The secondary cytoplasmic mass is dispersed and constitutes the RNA-rich animal hemisphere cytoplasm in the mature oocyte. Observed results suggest that the primary and the secondary cytoplasmic mass contain different germinal vesicle materials.     

Worldwide mitochondrial DNA diversity and phylogeography of pilot whales (Globicephala spp.)

Pilot whales (Globicephala spp.) provide an interesting example of recently diverged oceanic species with a complex evolutionary history. The two species have wide but largely non‐overlapping ranges. Globicephala melas (long‐finned pilot whale; LFPW) has an antitropical distribution and is found in the cold‐temperate waters of the North Atlantic and Southern Hemisphere, whereas Globicephala macrorhynchus (short‐finned pilot whale; SFPW) has a circumglobal distribution and is found mainly in the tropics and subtropics. To investigate pilot whale evolution and biogeography, we analysed worldwide population structure using mitochondrial DNA (mtDNA) control region sequences (up to 620 bp) from a variety of sources (LFPW = 643; SFPW = 150), including strandings in New Zealand and Tasmania, and whale‐meat products purchased on the markets of Japan and Korea. Phylogenetic reconstructions failed to support a reciprocal monophyly of the two species, despite six diagnostic substitutions, possibly because of incomplete lineage sorting or inadequate phylogenetic information. Both species had low haplotype and nucleotide diversity compared to other abundant widespread cetaceans (LFPW, π = 0.35%; SFPW, π = 0.87%) but showed strong mtDNA differentiation between oceanic basins. Strong levels of structuring were also found at the regional level. In LFPW, phylogeographic patterns were suggestive either of a recent demographic expansion or selective sweep acting on the mtDNA. For SFPW, the waters around Japan appear to represent a centre of diversity, with two genetically‐distinct forms, as well as a third population of unknown origin. The presence of multiple unique haplotypes among SFPW from South Japan, together with previously documented morphological and ecological differences, suggests that the southern form represents a distinct subspecies and/or evolutionary significant unit. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98 , 729–744.