Question

Scientists have demonstrated that as herbivory on orange jewelweed (Impatiens capensis) flowers increases, the proportion of selfing to outcrossing flowers increases. This occurs because

a. herbivores prefer the nectar of outcrossing flowers because of their increased sugar content.
b. the plant requires rapid reproduction to compensate for biomass loss due to herbivory.
c. selfing flowers contain more phenolics and tannins that herbivores avoid.
d. the loss of resources due to herbivory causes plants to make less expensive selfing flowers.

Answer 1

Increased herbivory on orange jewelweed flowers leads to more self-pollinating flowers as a survival strategy, compensating for biomass loss and ensuring reproduction with lower resource investment.

Step-by-step explanation:

Scientists have found that increased herbivory on orange jewelweed (Impatiens capensis) results in a higher proportion of selfing flowers compared to outcrossing flowers. This phenomenon is likely a survival strategy for the plant, where it adapts to ensure reproduction despite biomass loss due to herbivory. Plants must balance the cost of flower production with the need to reproduce, especially when resources are limited. In the case of high herbivory, plants might allocate resources to producing selfing flowers, which are less costly compared to outcrossing flowers that require more investment for attracting and rewarding pollinators.

Flowers and pollinators have a mutualistic relationship where flowers attract pollinators with food rewards like nectar. Yet when herbivores consume the plants, this relationship is disturbed. The influenced flowers either need to adapt by enhancing defenses like producing more phenolics and tannins, or by altering their reproductive strategy to compensate for the loss of pollinators due to the decrease in attractiveness and nectar production. One survival strategy is increasing self-pollination (selfing) as it requires fewer resources compared to outcrossing, because it doesn't rely on pollinators which might be less available due to herbivory.