An Analysis of the Lepidoptera of the San Joaquin Desert of California, with Notes on their Herbivory and Host Plant Relationships.

Abstract. We sampled the Lepidoptera fauna of the Californian San Joaquin Desert (SJD) over 12 years (2004-2016) and supplemented our results with species reported on iNaturalist and SCAN websites. We recorded 468 species representing 45 families in 20 superfamilies. In addition, there were another 200-250 specimens which we could not identify, in the Nepticuloidea, Tineoidea, Gracillarioidea and Gelechioidea superfamilies. These were not included in the general tally. Based upon known or published larval hosts, 70% of the recorded species are monophagous, feeding on plants in 45 families. Asteraceae was the most frequently used host plant family, sustaining 51 herbivore species. The remaining 29% are polyphagous. Many of the latter are potential crop pests and are more prevalent in the northeastern region of the Valley where agricultural activities are most intense. We found only one SJD endemic species, Schinia carrizoensis Osborne (Noctuidae) and one near-endemic, Euproserpinus euterpe Edwards (Sphingidae). The most diverse area was the southern region with 302 recorded species, while the least diverse was the Valley Floor area, with 162 species. Recognition of the historical aridity of this region and the establishment of restoration measures that consider the past and current desert-like environment and the effects of human activities and climate changes would benefit the entire flora and fauna of the SJD. [ABSTRACT FROM AUTHOR]