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The performance of the pea aphid, Acyrthosiphon pisum Harris (Homoptera: Aphididae) was studied on several Fabaceae species including: pea (Pisum sativum), broad bean (Vicia faba), alfalfa (Medicago sativa), bean (Phaseolus vulgaris) and red clover (Trifolium pratense). Alfalfa, bean and red clover were less accepted by the pea aphid than pea and broad bean. The pea aphid fed on the alfalfa, bean and red clover showed longer pre-reproductive, and shorter reproductive and post-reproductive periods. Alfalfa, bean and red clover also shortened and decreased fecundity of the pea aphid. Mean survival of the pea aphids fed on red clover and bean plants was reduced in comparison to pea aphid fed on pea and broad bean. The other studied population parameters: intrinsic rate of natural increase (rm), net reproduction (R0) and mean generation time were also reduced in the case of the pea aphid on alfalfa, red clover and bean. The study of aphid development and reproduction demonstrated that pea and broad bean are suitable host plants for A. pisum while alfalfa, red clover and bean are not. It is likely that the rejection of alfalfa, red clover and bean by A. pisum was caused by chemical factors in these hosts.
The work presents information about the range, occurrence conditions, geographical and historical status and dynamic tendencies of Melilotus wolgica in Eurasia and Poland. In Poland, the species was noted for the first time in Szczecin at the end of 19th century. Later, it was observed in the anthropogenic localities in the Opole Province, Kraków and Warszawa. In Wielkopolska, M. wolgica was observed for the first time in 2012, south of Gosławice (Konin district), where a large population was found on the embankment of a coal ash storage reservoir of the Konin Power Plant in the former brown coal mine area.
This study focuses on seed development in Astragalus cemerinus and A. ruscifolius, two endemic species of Astragalus in Iran. In both species the ovules are campylotropous, bitegmic and crassinucellate. Two polar nuclei fuse before fertilization, forming the diploid secondary nucleus. Division of the primary endosperm nucleus gives rise to coenocytic endosperm; however, part of it becomes cellular at the late globular stage. The first division of the zygote is transverse and the embryo proper forms after several divisions of the terminal cell. The mature suspensor consists of a mass of cells equal in size to the globular embryo proper, with several inflated cells towards its base. This massive suspensor seems to be plesiomorphic, as compared with the biseriate suspensor known only in section Incani. Abnormalities in the embryo proper as well as in the suspensor are observed at the globular stage. In both A. cemerinus and A. ruscifolius, fusion of the polar nuclei occurs in the median regions of the central cell and before fertilization occurs, as is the rule in most of the Papilionoideae, but in species of section Incani as in a few other species of the family, the polar nuclei approach the egg apparatus before fertilization and do not fuse until fertilization. The embryological characters of A. cemerinus and A. ruscifolius are compared with those of other species of Astragalus, and the taxonomic application of these characters as well as their phylogenetic significance are discussed.
The first apparent nectarivorous weevil, Smicronyx squalidus, is documented on Desmanthus illinoensis. Although found feeding from extra-floral nectaries (EFN’s) located between the petioles of D. illinoensis, it is believed that S. squalidus merely supplements its diet with nectar, due to an apparent lack of mouthpart modifications for a more efficient uptake of fluids. Photographs of the adult S. squalidus, as well as the EFN’s on D. illinoensis, are provided.
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