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    Phenotypic plasticity in host choice behavior in black bean aphid, Aphis fabae (Homoptera: Aphididae)
    (SPRINGER, 2007) Gorur, G.; Lomonaco, C.; Mackenzie, A.
    The study of phenotypic plasticity in host choice behavior is crucial to predict evolutionary patterns of insect-plant interactions. The presence of sufficient variation in plasticity may facilitate host race formation and sympatric speciation. In this study, 13 Aphis fabae Scopoli genotypes reared both on broad bean and nasturtium exhibited statistically significant genotypic variability in host selection behavior. Some genotypes displayed increase in preference and acceptance in a novel host plant through generations. There are also strong conditioning effects of nasturtium as nasturtium reared genotypes are more willing to choose nasturtium over broad bean while broad bean reared genotypes do not show differences in choosing between the two host plants. There are also positive relationships between fitness and host choice behavior particularly for nasturtium. Results of the study supported the hypothesis that phenotypic plasticity in host choice behavior may be one of the major determinants of the evolutionary trajectory of a parasitic species, such as aphids.
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    Relationships between developmental instability in morphological characters and fitness of Aphis fabae population reared on two host plants
    (MAIK NAUKA/INTERPERIODICA/SPRINGER, 2007) Gorur, G.; Lomonaco, C.; Mackenzie, A.
    Fluctuating asymmetry (FA) and the coefficient of within-environment variation (CV(e)) are often used as measures of developmental instability and indicators of developmental deviations. Aphis fabae genotypes generally manifest higher developmental instability on novel host plants, but there is genotypic variability in this respect. Some genotypes have manifested lower developmental instability on nasturtium, where their fitness is higher. At the population level, aphids reared on nasturtium have shown higher developmental instability and lower fitness. When large samples are analyzed and the nonsignificant pattern of correlations is taken into account. the results of the study do not support the hypothesis that developmental instability is always a reliable indicator of fitness.