Crab and mollusc shell drilling by Octopus vulgaris (Mollusca: Cephalopoda) in the Ria de Vigo (north-west Spain)

Octopus vulgaris living in the Ria de Vigo, north-west Spain, sometimes drills a cavity in the carapace of crabs and shells of molluscs. These holes have features with the same characteristics as those made in molluscs by O. vulgaris and in crabs by Eledone cirrhosa when isolated in aquaria. This is the first report of drilling the carapace of crabs by Octopus vulgaris .     

Host range and some properties of groundnut rosette virus

Two isolates of groundnut rosette virus from East Africa (GRVE₁ and GRVE₂) and from West Africa (GRVW₁ and GRVW₂) were transmitted by Aphis craccivora obtained from West Africa. A third isolate from West Africa (GRVW₃) was not transmitted by A. craccivora from three widely separated sources. GRVW₁, GRVW₂ and GRVW₃ caused leaf-symptoms in groundnut of a mosaic pattern in light and dark green. GRVE₁ and GRVE₂ caused chlorosis or chlorosis and leaf distortion as well as mosaic symptoms. Groundnut plants with GRVW₁ could not be infected by means of aphids with GRVE₁, and GRVE₁ gave similar protection against GRVW₁, which suggests that they are strains of the same virus. All isolates were transmissible manually from groundnut to groundnut (Arachis hypogea), Trifolium incarnatum and T. repens, and caused systemic infection. Inoculated Nicotiana clevelandii and N. rustica developed symptoms but virus could not be recovered from them. Chenopodium amaranticolor, C. hybridum and C. quinoa showed local lesions on inoculated leaves. Virus could be acquired by aphids from groundnut or Trifolium repens infected by means of aphids, but not from those infected by manual inoculation. Virus could not be recovered from T. incarnatum manually or by aphids, but was transmitted by cleft-grafting from clover to groundnut. Saps extracted in borax buffer plus zinc sulphate at pH 9 from plants infected with GRVW₁ and GRVE₁ remained infective at 18° C. for 1 week, and at — 20° C. for up to 4 weeks. Virus could be recovered from frozen leaves. Buffered saps lost infectivity when heated above 50° C. for 10 min.; most were still infective when diluted 1/10 and some at 1/100. Electron micrographs of partially purified preparations contained spherical particles 25–28 mμ in diameter. There were usually only about five per microscope field and they resembled those of some other viruses.     

The Effect of the Female Gametophyte on the Growth of Cultured Douglas-fir Embryos

Several clones of Douglas-fir, Pseudotsuga menziesii (Mirb.)Franco, embryos grown in aseptic culture in the presence orabsence of the female gametophyte or a crushed aqueous extractof it, have shown striking differences in overall length, sizeand substance(s) responsible for this colour of the cotyledonsand in root length. The growth-promoting effect is diffusiblein agar, heat-stable and has detectable activity at a concentrationof about 0·1 to 1·0 per cent (v/v) in a basalnutrient medium. Evidence is provided that extracts of gametophytemay have synergistic effects with coconut water in promotingmorphogenesis of Douglas-fir cells in suspension culture. Pseudotsuga menziesii, Douglas-fir, female gametophyte, einbryo culture     

Sperm transfer by spermatophore in Diptera: new results from the Diopsidae

Sperm transfer by spermatophore is reported as a common and possibly primitive feature of the Diopsidae (Diptera, Schizophora). Spermatophores occur in four out of five investigated genera, in Cyrtodiopsis, Diasemopsis, Teleopsis , and in Sphyracephala , which is positioned close to the base of the family. Within the genus Diopsis the spermatophore is subject to reduction. Spermatophore size and copulation duration are positively correlated across the species. This is only partially explained by the time requirement of sperm transfer. Parsimony in time and material seems to be favoured in species with high mating frequency at special aggregation sites, whereas high investment in time and material occurs in species that do not mate preferentially at certain times or locations. The utilization of spermatophores has strong implications on the possibilities of sperm competition and cryptic female choice and may account for the occurrence of a postcopulatory passive phase or prolonged mating in some species. The increasing number of records of spermatophores in Diptera is reviewed.     

INTRA-POPULATION VARIATION OF THE SHELL OF LITTORINA RUDIS (MATON) (MOLLUSCA: PROSOBRANCHIA)

Shell variation within a single population of Litlorina rudis(Maton), collected near the Biological Station at Trondheim,Norway, was studied. The variation of the shell features studied, which includedthe shape of the basal part of the outer lip, and the relativeheight of the spire, width of the shell and of the aperture,were found to be at least partially related to shell height.Furthermore, the shell shape in the population investigated,besides varying with age, also varies due to shell damage. Nosignificant differences were found between the shapes of theshells of males and females. The shell characteristics of different populations of L. rudisalso vary greatly, one of the causes being differences in theenvironmental conditions. When studying this variation betweendifferent populations, however, it must be emphasized that onlyundamaged shells of individuals of about the same age shouldbe compared, in order to obviate the effects of the variabilitydue to age differences and shell damage within each individualpopulation. ^*Contribution from Trondhjem Biological Station no. 199 (Received 18 February 1980;