Agrilus gillespiensis

The species is distinguished from other Agrilus by geographic distribution in west Texas and adjacent New Mexico, combined with collection records from cactus flowers. It has been found sympatrically with Acmaeodera riograndei, A. starrae (now regarded as A. robigo), A. neoneglecta, and A. quadrivittatoides on strawberry cactus flowers, from which it can be distinguished by size and coloration patterns. Accurate identification likely requires examination of male genitalia, as is typical for the genus.

Adults are small to medium-sized jewel beetles typical of the genus Agrilus. Specific coloration and morphological details are not well documented in available sources, though the species is presumably metallic in coloration as is characteristic of the family. The species belongs to a genus where most members are 4–8 mm in length, though some reach 12–14 mm.

Associated with Chihuahuan Desert and adjacent grassland habitats in the Big Bend region of Texas and southeastern New Mexico. Adults have been found in juniper chaparral and pinyon-oak-juniper woodland edges. The species occurs in areas where its floral hosts—Echinocereus enneacantha carnosus and Opuntia camanchica—grow, typically on rocky slopes, canyon walls, and sand dune margins.

North America: primarily west Texas (Val Verde County, Presidio County area) and adjacent southeastern New Mexico (Eddy County, Otero County). The species represents a west Texas specialty with a restricted regional distribution. Records suggest it may be more widespread in the Chihuahuan Desert region than initially recognized, with recent collections extending its known range into New Mexico.

Adults have been collected in late May and early June, with peak activity likely coinciding with flowering of Echinocereus and Opuntia species. Activity appears to be tied to cactus bloom phenology rather than calendar date, with beetles observed flying to flowers during mid-day heat.

• Echinocereus enneacanthus carnosus - adult floral hostAdults collected from flowers of strawberry cactus in Val Verde County, Texas
• Opuntia camanchica - adult floral hostAdults collected from flowers of tulip pricklypear in Eddy County, New Mexico

Adults have been observed flying to cactus flowers during mid-day, with activity ceasing when flowers close in late afternoon. The species exhibits flower-visiting behavior atypical for the genus Agrilus, which generally does not visit flowers. This behavior is shared with several co-occurring Acmaeodera species, suggesting convergent exploitation of cactus flower resources in this arid environment.

• Acmaeodera riograndeiOccurs sympatrically on strawberry cactus flowers; similar size and habitat preferences, but belongs to different genus with distinct morphology
• Acmaeodera robigo (formerly A. starrae)Co-occurs on same cactus flowers; similar flower-visiting behavior but readily distinguished by genus-level characters
• Acmaeodera neoneglectaCommon co-occurring species on cactus flowers; more abundant and with different elytral pattern
• Acmaeodera quadrivittatoidesFrequently found on same flowers; has distinct four-vittate elytral pattern

• jewel beetle
• metallic wood-boring beetle
• cactus flower visitor
• Chihuahuan Desert
• Big Bend
• rare
• west Texas endemic

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• Catalogue of Life
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