(Z)-9-tetradecenal: a potent inhibitor of pheromone-mediated communication in the oriental tobacco budworm moth,Helicoverpa assulta

The behavioural significance of (Z)-9-tetradecenal to male H. assulta was tested by comparing the number of moths attracted to lures containing a standard synthetic female sex pheromone with lures in which (Z)-9-tetradecenal was also added. The standard pheromone mixture used contained 1000 g (Z)-9-hexadecenal, 50 g (Z)-11-hexadecenal, 300 g (Z)-9-hexadecenyl acetate and 15 g (Z)-11-hexadecenyl acetate impregnated on rubber septa. Addition of (Z)-9-tetradecenal to the standard pheromone was shown to significantly reduce the caught of male H. assulta when added in amounts greater than 10 g or 1% of the major pheromone component in both field and net-house experiments. The reduction in catch was found to be dependent on the quantity of (Z)-9-tetradecenal added to the standard pheromone. The implications of these results on conspecific and inter-specific pheromone-mediated communication in H. assulta and related sympatric heliothine species is discussed.Abbreviations Z9-16:AL (Z)-9-hexadecenal - Z11-16:AL (Z)-11-hexadecenal - Z9-16:AC (Z)-9-hexadecenyl acetate - Z11-16:AC (Z)-11-hexadecenyl acetate - Z9-14:AL (Z)-9-tetradecenal - Z9-16:OH (Z)-9-hexadecen-1-ol - Z11-16:OH (Z)-11-hexadecen-1-ol - RH relative humidity     

Fitness of a translocation homozygote in cage experiments with the onion fly,Hylemya antiqua (meigen)

Summary In Hylemya antiqua, a stock homozygous for an autosomal reciprocal translocation was isolated using egg-hatch reduction and karyotype analysis. Sibling translocation homozygous (TT) and heterozygous (T+) females were compared in respect to egg production and longevity. In one full-sib (5 TT and 8 T+ females) significantly higher values for both parameters for T+ than for TT females were scored, in four others (a total of 35 TT and 28 T+ females) no significant differences were found. Cage experiments were started with populations composed of equal numbers of wild type flies (++) and translocation homozygotes. The frequencies of the different karyotypes in three successive, non-overlapping generations, did not suggest substantial differences in fitness between ++ and TT flies. Possible causes of a surplus of T+ individuals found in these experiments are discussed together with the usefulness of the translocation for genetic control of H. antiqua.     

Simulation of the Viking biology experiments: An overview

Summary Several ground-based investigations have been carried out since the Viking biology results were received from Mars. Many of these have resulted in reasonable simulations of the Martian data, using as analogues of Mars either strong oxidants, UV-treated materials, iron-containing clays, or iron salts. The ambiguity between the GCMS experiment, in which no organic compounds were found on Mars, and the Labeled Release experiment, in which added organics were decomposed, may well be accounted for by these simulations.     

Correction of severe manganese deficiency in wheat with chemical fertilizers

Summary Manganese, N and P fertilizers were applied to wheat in field experiments on a soil so deficient in Mn that it caused the wheat to die before heading. Yields of wheat were increased linearly by soil banded Mn to 44.8 kg/ha, giving a yield of 3.03 tonnes/ha. Yields were increased to a lesser extent by foliar-applied Mn and least by soil-broadcasted Mn. Soil N and P appeared to be adequate, yet ammonium sulphate at 56 kg N/ha where applied alone caused a yield of 1.69 tonnes/ha and ammonium sulphate nitrate gave a yield of 0.98 tonnes/ha, the increases being primarily due to the release of Mn to the plants. Calcium nitrate and triple superphosphate were much less effective in releasing Mn.     

The demography of trout lily (Erythronium americanum Ker.) in Nova Scotia

The age structures of both native and transplanted populations of the perennial herb, trout lily (Erythronium americanum), were analysed and found to have age-independent mortality rates. Cohort survival was greatest in populations growing on hardwood forested flood plains (60%), less in populations from gently sloping terraces with pit-and-mound microrelief (53%) and smallest (45%) for colonies on slopes steeper than 15°. The former habitat-type is the optimum for trout lily in Nova Scotia and in it the proportion of flowering bulbs can reach 35%. The second named habitat is widespread and characterised by fewer flowering bulbs (5–10%). In the latter habitat flowering bulbs are uniformly rare. Trout lily bulbs tend to be sterile until at least their eighth year. The high mortality rates of populations on steeply sloping, hardwood forested ground ensure minimal survival of bulbs beyond their sixth year. In the other two named habitats sufficient numbers of bulbs reach ages of 8 or 9 years for some to make the translation from the sterile to the flowering form. In all the habitats studied in Nova Scotia, propagation is typically by either runners or, less importantly, daughter bulbs, with the peak of activity in the bulbs third and fourth years. The plants of flood plains showed the greatest rates of vegetative propagation, by cohort, but many of the bulbs from colonies growing on steep slopes lacked runners or daughter bulbs. As all bulbs for the transplant experiments came from a single clone it can be concluded that trout lily plants in Nova Scotia have a sufficiently large genetic endowment for them to behave in the same manner as native populations of the species in the several habitats represented in the province.The figures were drafted in the cartography section of the University of Canterbury. The National Research Council of Canada supported the research with a series of grants.     

Flight behaviour of the cabbage seedpod weevil

The influence of host odour, windspeed, position of the sun, and temperature on flight behaviour of the cabbage seedpod weevil (Ceutorhynchus assimilis Paykull) were studied. This weevil showed a positive anemotaxis (upwind flight) inside the odour plume of a host crop (Brassica napus L.). Outside the odour plume the weevil showed a pronounced phototaxis at windspeeds below 1.5 m/s. At higher windspeeds, the seedpod weevils flew downwind. The cabbage seedpod weevil flies most readily at low windspeeds (less than 0.5 m/s) and at temperatures above 22 °C.     

The effects ofAnabaena flos-aquae inoculation,pH elevation,and N/P manipulation on the algal biomass and species composition of an acid lake

Three bag experiments were performed in Cheat Lake, West Virginia, an acid lake, to determine whether a blue-green alga,Anabaena, could be introduced coupled with a pH change to neutrality and nutrient addition.     

Provenance selection and site conditions determine growth performance of pedunculate oak

Forests of the future need to cope with adverse climatic conditions, in particular drought, to ensure forest stability and productivity. Given the usually long rotation period of forests, forest managers need to select appropriate, i.e. productive and climate-change resilient tree species and/or provenances, to lower tree-mortality risks and sustain current wood production rates at the end of the 21^st century. A frequent means of assessing which provenances of a given species are adapted to anticipated climate conditions is common garden experiments, where trees from different provenances are planted under similar climate conditions. However, in this context soil conditions also play an important role, since they govern how climate translates into plant-available water and hence plant’s ability to cope with extreme drought events. Here, we examine the effects of soil conditions on pedunculate oak (Quercus robur L.), by studying 10 different Dutch oak provenances that were planted in three provenance trials on different soil types in 1988 in the Netherlands. Using dendroecological methods, we quantified provenance-specific productivity and assessed provenance- and site-specific growth patterns. Our results indicated clear differences in productivity among provenances as well as soil-type specific growth patterns. Consequently, our study highlights the importance of incorporating soil characteristics when evaluating the growth performance of provenances within common garden experiments.