The 58th Conference of the Israeli Zoology Association
In Israel, plants of arugula (Eruca sativa) reveal clear ecotypic differentiation in floral attraction traits: petal color that ranges from yellow, being dominant in the Mediterranean habitat, to cream, being dominant in the desert habitat. The Mediterranean habitat is characterized by greater floral diversity than the desert habitat, and honey bees (Apis mellifera) are the main pollinator in the Mediterranean habitat. Diamondback moths (DBM) (Plutella xylostella) are more prevalent in the desert habitat than in the Mediterranean habitat. Whereas adult moths are pollinators, the larvae are specialist herbivores on E. sativa. This study aims to investigate whether the yellow ecotype would have an advantage in the Mediterranean habitat, considering both processes of pollination and herbivory. Previous research confirmed that naïve honey bees are initially more attracted to the yellow flower morph than to the cream one. However, we found that the yellow ecotype produced lower quantities of nectar, and at lower total dissolved solids (TDS) concentrations, than the cream one. Furthermore, when bees could forage on the plants (and experienced the associated rewards), they shifted to equal visitation between the two ecotypes. Genotype analysis of the f1 generation supported these observations by revealing heterozygote dominance. Intriguingly, inducing the plant’s defense system (by administration of methyl jasmonate) reduced nectar volume and concentration in the cream morph while increasing it in the yellow morph. To study the outcome of competition between the two morphs in the Mediterranean habitat, we are running a long-term (four seasons) semi-field experiment in which the evolutionary process is mediated by honey bee pollination. By determining seed production, germination rate, and genotype analysis of the f1 generation, we established the “selected” population of the second generation. Overall, our results suggest trade-offs between floral advertisement, reward, and secondary metabolites production, mediated by herbivory and affecting pollination.
The 58th Conference of the Israeli Zoology Association
In Israel, plants of arugula (Eruca sativa) reveal clear ecotypic differentiation in floral attraction traits: petal color that ranges from yellow, being dominant in the Mediterranean habitat, to cream, being dominant in the desert habitat. The Mediterranean habitat is characterized by greater floral diversity than the desert habitat, and honey bees (Apis mellifera) are the main pollinator in the Mediterranean habitat. Diamondback moths (DBM) (Plutella xylostella) are more prevalent in the desert habitat than in the Mediterranean habitat. Whereas adult moths are pollinators, the larvae are specialist herbivores on E. sativa. This study aims to investigate whether the yellow ecotype would have an advantage in the Mediterranean habitat, considering both processes of pollination and herbivory. Previous research confirmed that naïve honey bees are initially more attracted to the yellow flower morph than to the cream one. However, we found that the yellow ecotype produced lower quantities of nectar, and at lower total dissolved solids (TDS) concentrations, than the cream one. Furthermore, when bees could forage on the plants (and experienced the associated rewards), they shifted to equal visitation between the two ecotypes. Genotype analysis of the f1 generation supported these observations by revealing heterozygote dominance. Intriguingly, inducing the plant’s defense system (by administration of methyl jasmonate) reduced nectar volume and concentration in the cream morph while increasing it in the yellow morph. To study the outcome of competition between the two morphs in the Mediterranean habitat, we are running a long-term (four seasons) semi-field experiment in which the evolutionary process is mediated by honey bee pollination. By determining seed production, germination rate, and genotype analysis of the f1 generation, we established the “selected” population of the second generation. Overall, our results suggest trade-offs between floral advertisement, reward, and secondary metabolites production, mediated by herbivory and affecting pollination.