Investigating the factor influencing the flow behavior and performance of condensate gas reservoirs

No Abstrac

The effect of choice and no-choice access on host (Aphis fabae) instars preference, in different ages and sizes of Lysiphlebus fabarum (Hymenoptera: Braconidae: Aphidiinae)

The influence of parasitoids on population dynamics is affected by host instar preference. The preference pattern of host instars is not fixed and is modified by the availability and relative abundance of host instars, intensity of defensive behaviors in a particular instar, and also maternal effects of the female forager. In this study, host instar preference of the thelytokous strain of Lysiphlebus fabarum (Marshall) was studied in relation to progeny performance in choice and no-choice experiments, using the first, second, and fourth host instars of Aphis fabae (Hemiptera: Aphididae) as hosts. In addition, we investigated whether the maternal effects (age and size) influenced preference-performance associations. Based on the results, offsprings emerging from hosts that were parasitized as the first instar stage were smaller and took longer to develop than offsprings emerging from hosts that were parasitized as the second and fourth instars, irrespective of the age and size of their mothers. The results also showed that when females were offered different host instars under no-choice access, there was no preference for a specific instar, irrespective of the size and age of the female. However, in a choice situation, for the both age and size classes of the parasitoid mother, the number of mummies declined with increasing host instar, suggesting that host instar preference does not reflect offspring performance. For mass rearing of L. fabarum, it would be better if female foragers be introduced to lower density of first instar, under choice situation because of increasing offspring performance

Evolution of sex determination and heterogamety changes in section Otites of the genus Silene

Abstract Switches in heterogamety are known to occur in both animals and plants. Although plant sex determination systems probably often evolved more recently than those in several well-studied animals, including mammals, and have had less time for switches to occur, we previously detected a switch in heterogamety in the plant genus Silene: section Otites has both female and male heterogamety, whereas S. latifolia and its close relatives, in a different section of the genus, Melandrium (subgenus Behenantha), all have male heterogamety. Here we analyse the evolution of sex chromosomes in section Otites, which is estimated to have evolved only about 0.55 MYA. Our study confirms female heterogamety in S. otites and newly reveals female heterogamety in S. borysthenica. Sequence analyses and genetic mapping show that the sex-linked regions of these two species are the same, but the region in S. colpophylla, a close relative with male heterogamety, is different. The sex chromosome pairs of S. colpophylla and S. otites each correspond to an autosome of the other species, and both differ from the XY pair in S. latifolia. Silene section Otites species are suitable for detailed studies of the events involved in such changes, and our phylogenetic analysis suggests a possible change from female to male heterogamety within this section. Our analyses suggest a possibility that has so far not been considered, change in heterogamety through hybridization, in which a male-determining chromosome from one species is introgressed into another one, and over-rides its previous sex-determining system