Adaptations in the common cuckoo (Cuculus canorus) to host eggs in a multiple-hosts system of brood parasitism

The common cuckoo Cuculus canorus parasitism greatly reduces the reproductive success of its hosts and imposes strong selection pressure for hosts to evolve defences against parasitism, such as the ability to recognize and reject dissimilar parasitic eggs, which, in turn, selects for better egg mimicry by the cuckoo. In the co-evolutionary interaction, however, it remains unknown how the cuckoo successfully expanded its range of host usage and how they developed egg mimicry. Most previous studies were conducted in areas where a very few number of host species (i.e. one or two at most) are sympatric with the cuckoo. Several host species, however, breed sympatric with the cuckoo and have been parasitized in the study site in Nagano, central Japan. Such a multiple-hosts system will provide valuable insights for understanding the cuckoo–hosts interactions in the past. In the present study, we report quantitative profiles of eggs based on spectrometer reflectance for four major host species and the corresponding cuckoo gentes. The hosts include the oriental reed warbler ( Acrocephalus orientalis ), bull-headed shrike ( Lanius bucephalus ), azure-winged magpie ( Cyanopica cyana ), and black-faced bunting ( Emberiza spodocephala ). We show that (1) egg morphs of each host and corresponding cuckoo gens can be categorized by two chromatic components of reflectance spectra and (2) there is a significant difference in a particular chroma component between hosts and the cuckoo. We suggest that the cuckoo parasitism in central Japan originated from parasitism on the black-faced bunting.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 98 , 291–300.     

Phenylalanine ammonia-lyase in strawberry fruits

PAL activity and the anthocyanin content in strawberry fruitsharvested at various stages of development were investigated.Concomitant increases in PAL activity and anthocyanin productionwere found, suggesting that a rise in PAL activity may be requiredfor a high rate of anthocyanin synthesis. (Received July 2, 1971; )     

Light-induced absorbance changes at 475-515 nm, and electron flow close to photosystem II in Tris-washed chloroplast fragments

Rapid, reversible light-induced absorbance changes at 475 and515 nm in chloroplast fragments were diminished by washing thefragments with Tris. These diminished absorbance changes wererestoredby the donation of electrons to photosystem II by hydrogen peroxide (Received November 17, 1970; )     

Carbon Flow from Nodulated Roots to the Shoots of Soybean (Glycine max L. Merr.) Plants: An Estimation of the Contribution of Current Photosynthate to Ureides in the Xylem Stream

Kouchi, H. and Higuchi, T. 1988. Carbon flow from nodulatedroots to the shoots of soybean {Glycine max L. Merr.) plants:An estimation of the contribution of current photosynthate toureides in the xylem stream.–J. exp. Bot. 39: 1015–1023. Well-nodulated, water-cultured soybean plants were allowed toassimilate ¹³CO₂ at a constant specific activity for 10 h andthe ¹³C-labelling of total carbon and ureides in xylem sap wasinvestigated. Labelled carbon appeared very rapidly in the xylem stream. Percentageof labelled carbon (relative specific activity, RSA) in xylemsap was 18% at 2 h after the start of ¹³CO₂ assimilation andreached 53% at the end of the 10 h assimilation. The amountof labelled carbon exported from nodulated roots to the shootsvia the xylem during the 10 h labelling period accounted for33% of total labelled carbon imported into the nodulated roots.Ureides (allantoin and allantoic acid) in xylem sap were stronglydependent on currently assimilated carbon. The RSA of ureidesin xylem sap had reached 83% at the end of the assimilationperiod. Labelled carbon in ureides accounted for 51% of totallabelled carbon returned from nodulated roots to the shootsvia the xylem during the 10 h assimilation period. A treatmentwith 20 mol m^–3 nitrate in the culture medium for 2 ddecreased the ureide concentration in the xylem sap slightly,but greatly decreased the RSA of ureides. By comparing the data with the results of analysis of the xylemsap of nodule-detached plants, it was concluded that the majorityof labelled carbon exported to the xylem stream from noduleswas in ureide form. A considerable amount of carbon was alsoreturned from roots to shoots via the xylem stream but it wasmore dependent on (non-labelled) carbon reserved in the roottissues. Key words: Soybean(Glycine max L.), root nodule, carbon partitoning, ¹³CO₂ assimilation, xylem     

INDOLE-3-ACETIC ACID IN CHICK EMBRYOS

The occurrence of IAA, a plant-growth-regulating substance of the auxin group, was investigated in developing chick embryos. Paperchromatography followed by the Avena curvature test revealed the presence of a substance with auxin activity and the same Rf as IAA. This substance was identified as IAA by combined gas chromato-graphy-mass spectrometry. The amount of IAA in a unit weight of embryo was almost identical during embryo development, the total amount of IAA in an embryo increasing as it developed. The amount of IAA in the whole egg was also examined and it was found that an egg incubated for 9 days at 37°C contained a larger amount of IAA than one not incubated.     

X-Ray Microanalysis and Phagocytotic Activity of Cultured Retinal Pigment Epithelial Cells in Hypoxia

Purpose: To investigate the influence of the functional and morphological changes induced in retinal pigment epithelial (RPE) cells by retinal ischemia, we evaluated the phagocytotic activity, the concentration of various elements, and ultrastructure in cultured RPE cells in hypoxia. Methods: The concentrations of oxygen in incubators were adjusted to 20, 10, and 1% by the addition of nitrogen for 72 hr. To observe phagocytotic activity and its relationship to actin filaments, the filaments of RPE cells incubated with fluoresbrite carboxylate YG microspheres were stained with rhodamine phalloidin. Some of the specimens were subjected to X-ray microanalysis by scanning electron microscope after being fixed, freeze-dried, and coated with carbon to investigate the cytoplasmic concentration of elements. A part of the latter specimens was also observed by transmission electron microscope after being embedded in epon and cut into ultrathin sections to see the ultra-structural changes inside cell. Results: Lowering oxygen concentrations from 20% to 1% swelled RPE cells and decreased the number of fluoresbrite carboxylate YG microspheres phagocytized by RPE cells. Phagocytosis of a large amount of latex beads (30 μl) for 24 hr in 1% oxygen caused a disruption of RPE cells. Na, S, and P were detected in RPE cells cultured in 20% oxygen. Reducing the oxygen concentration from 20 to 10 or 1% significantly decreased Na and increased S. Mitochondria were observed in RPE cells in 20 and 10% oxygen, but many vacuoles were observed in the cytoplasm in 1% oxygen. Conclusion: Hypoxia as low as 1% oxygen induced malfunction of phagocytosis and the fragility of RPE cells. We could speculate the imbalance of the electrolytes such as Na or a decrease of antioxidants such as glutathione containing S as a reason of disturbance of cell viability.     

Signal through the noise? Phylogeny of the Tachinidae (Diptera) as inferred from morphological evidence

The oestroid family Tachinidae represents one of the most diverse lineages of insect parasitoids. Despite their broad distribution, diversity and important role as biological control agents, the phylogeny of this family remains poorly known. Here, we review the history of tachinid systematics and present the first quantitative phylogenetic analysis of the family based on morphological data. Cladistic analyses were conducted using 135 morphological characters from 492 species belonging to 180 tachinid genera, including the four currently recognized subfamilies (Dexiinae, Exoristinae, Phasiinae, Tachininae) and all major tribes. We used characters of eggs, first‐instar larvae and adults of both sexes. We examined the effects of implied weighting by reanalysing the data with varying concavity factors. Our analysis generally supports the subfamily groupings Dexiinae + Phasiinae and Tachininae + Exoristinae, with only the Exoristinae and the Phasiinae reconstructed as monophyletic assemblages under a wide range of weighting schemes. Under these conditions, the Dexiinae, which were previously considered a well‐established monophyletic assemblage, are reconstructed as being paraphyletic with respect to the Phasiinae. The Tachininae are reconstructed as a paraphyletic grade from which the monophyletic Exoristinae arose. The Exoristinae are reconstructed as a monophyletic lineage, but phylogenetic relationships within the subfamily are largely unresolved. We further explored the evolution of oviposition strategy and found that the oviparous groups are nested within ovolarviparous assemblages, suggesting that ovipary may have evolved several times independently from ovolarviparous ancestors. This counterintuitive pattern is a novel hypothesis suggested by the results of this analysis. Finally, two major patterns emerge when considering host associations across our phylogeny under equal weights: (i) although more than 60% of tachinids are parasitoids of Lepidoptera larvae, none of the basal clades is unambiguously associated with Lepidoptera as a primitive condition, suggesting that tachinids were slow to colonize these hosts, but then radiated extensively on them; and (ii) there is general agreement between host use and monophyly of the major lineages.