Email this page

Print this page

Article Addendum

Floral trait associations in hawkmoth-specialized and mixed pollination systems: Datura wrightii and Agave spp. in the Sonoran Desert

Jeffrey A. Riffell, Ruben Alarcón and Leif Abrell

This is an open-access article

 Download PDF

If the document does not open, please right-click on the link (control-click on a Macintosh) and select the option to save the file to disk.

Variation in floral traits including odor, color, and morphology, demonstrate the selective pressures imposed by specific pollinator taxa, such as insects and birds. In southern Arizona, Manduca (Sphingidae) hawkmoths are associated with Datura wrightii (Solanaceae) at both the larval (herbivore) and adult (nectar feeding) stages. However during most of the summer Manduca feeds on “bat-adapted” Agave spp. (Agaveacea) flowers, and only use Datura when it is at peak bloom. Manduca’s nectar-host use appears to be mediated through innate odor preferences and olfactory learning; they prefer Datura’s “hawkmoth-adapted” traits, which facilitate the maintenance of their coevolutionary relationship, yet they are flexible enough to explore and learn to utilize novel resources, such as agave. This behavioral flexibility is likely responsible for the frequent observation of generalized, or mixed, pollination systems. Given that Manduca visit agave species in southern Arizona, we hypothesize that the differences in flower phenotype between two closely related agave species may be associated with the importance of hawkmoths relative to bats. The southernmost agave, Agave palmeri (Agavacea), exhibits floral traits typical of bat pollination, whereas the northernmost species, Agave chrysantha (Agavacea), exhibits mixed floral traits which appear to be adapted to insects, and to a lesser extent, bats. The differences between these agaves are likely correlated with the geographic overlap in migratory bats from Mexico and resident hawkmoth populations. Thus D. wrightii, A. palmeri, and A. chrysantha populations represent a unique system in which to examine the evolution of floral traits in both specialized and mixed pollination systems associated with spatially variable pollinator assemblages.

Authors

Jeffrey A. Riffell

University of Arizona

Ruben Alarcón

University of Arizona

Leif Abrell

University of Arizona

This is an open-access article

 Download PDF

If the document does not open, please right-click on the link (control-click on a Macintosh) and select the option to save the file to disk.