Feeding ability of the agave weevil Scyphophorus acupunctatus (Coleoptera: Dryophthoridae) on different agave hosts susceptible to infestation

Abstract

The agave weevil Scyphophorus acupunctatus is a polyphagous pest of agave, yucca and related taxa. Although its many host species differ in their mortality rates, little is known about the factors involved in host selection by the weevil and the defensive response of the infested plants. We compared the suitability of Agave americana subsp. americana, A. americana var. franzosini and A. oteroi as a food source for adult individuals of S. acupunctatus. Feeding rates on leaf samples of the selected taxa were measured under laboratory conditions. The amount of the flavonoids flavone and kaempferol in the leaves was also quantified. The observed consumption rates were significantly lower for A. americana var. franzosini, but only for measurements made on a fresh weight basis and not when consumption was adjusted to leaf dry weight. The leaves of the three agave taxa did not differ in the contents of the two selected flavonoids. We conclude that the three agave taxa are equally suitable as a food source for the weevil, but the observed differences in the consumption of fresh material provides evidence that agaves can differ in the amount of damage caused by the feeding activities of S. acupunctatus.

Keywords:

• Invasive pests
• chemical ecology
• host selection
• plant traits
• flavonoids

Acknowledgements

The authors thank Cosimo Graniglia (CREA) and the personnel of the Giardini Botanici Hanbury for their technical support during the sampling and the handling of the agave leaves during the field and laboratory activities.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was carried out under the Memorandum of Understanding between the CREA and the Giardini Botanici Hanbury [CREA registry No. 98878, 22/12/2020].