Date of Award

6-2010

Degree Name

MS in Agriculture - Crop Science

Department

Horticulture and Crop Science

Advisor

David Headrick

Abstract

A novel lepidopteran sex pheromone lure which was thought to be species-specific to the citrus pest Marmara gulosa (Lepidoptera: Gracillariidae) Guillén (McElfresh et al. 2009) has attracted male moths exhibiting two distinct morphologies. The morphological features examined were the sclerotized parts that make up the male genitalia; which include the valvular lobes, costal lobes, cucullar lobes, and the aedeagus. The sclerotized parts were methodically dissected and mounted on microscope slides. Digital images captured of the slide-mounted specimens proved to be inconsistent with the illustrations provided in the original Marmara gulosa species description (Guillén et al. 2001).

The morphologies of all specimens from both the San Joaquin and Coachella valley show remarkable consistency; regardless of host plant origin, collection method, and collection date. Two specimen groups (one from an orchard in Northern Mexico and the other from backyard citrus in Riverside, California) exhibited entirely different morphological features in which the three lobes mentioned above are fused together. This difference in morphology can only be noticed when examining the sclerotized parts of the male genitalia under a microscope; it is otherwise indistinguishable from M. gulosa via macroscopic features such as antennae shape and wing pattern. These two specimen groups with fused lobes are considered a new species belonging to the genus Marmara and currently remain undescribed.

A genetic study conducted at UC Riverside, which concentrated on the CO1 region of mitochondrial DNA, reported significant differences in genetics based on the geographic origins of specimens (Vickerman and Stouthammer 2006). Geographically, the genetic distribution described in the 2006 study does not coincide with the distribution of morphologies described in this paper. The species description of Marmara gulosa is in need of revision. In addition, further collection and research is required in order to describe and name the newly discovered Marmara species.

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