Trichinorhipis knulli
Barr, 1948
Knull's Metallic Wood-boring Beetle
Trichinorhipis knulli is a minute ( ) to southern California, where it occurs in Riverside and Imperial Counties. It is the sole member of its , distinguished from related genera by its entire covering the full and broadly rounded lacking margins. Males exhibit highly modified with expanded bearing numerous olfactory sensillae, an for detecting female . The is rarely encountered in the field; most specimens have been reared from dead branches of jojoba (Simmondsia chinensis). At 3.6 mm, it is among the smallest buprestids.
Pronunciation
How to pronounce Trichinorhipis knulli: /trɪˌkaɪnoʊˈrɪpɪs ˈknʌli/
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Identification
Distinguished from in tribe Xenorhipidini by entire (non-) that fully cover the and broadly rounded without distinct margins. Males possess highly modified with / beginning with the second ; females have unmodified antennae. The antennal sensillae organization differs from that of Hesperorhipis and Xenorhipis. Extremely small size (3.6 mm) and California distribution further aid identification.
Habitat
Arid regions of southern California; specifically associated with jojoba (Simmondsia chinensis) in the vicinity of Mountain Springs, Imperial County.
Distribution
to California, United States. Documented from Riverside County and Imperial County, with most records from the Mountain Springs area near the Mexican border.
Seasonality
have been reared from caged branches collected in October with occurring in August of the following year, suggesting a spanning approximately two years.
Diet
bore in dead branches of jojoba (Simmondsia chinensis); feeding habits unknown.
Host Associations
- Simmondsia chinensis - larval dead branches
Life Cycle
Development occurs within dead branches of . Field-collected infested branches caged in October 1992 yielded in August 1994, indicating a prolonged developmental period. Specific larval and details undescribed.
Behavior
Males possess expanded antennal covered with olfactory sensillae, an for detecting female . Related (Xenorhipis brendeli) males have been observed attracted in large numbers to caged females, suggesting similar in T. knulli. rarely observed in nature; most specimens obtained through rearing.
Similar Taxa
- Xenorhipis brendeliShares tribe Xenorhipidini and male , but differs in scarcely covering almost entire and eastern North distribution.
- Hesperorhipis spp.Shares tribe and male antennal modification, but differs in and quadrate with distinct margins; flabellae begin with third versus second in Trichinorhipis.
- Xenorhipis osborniShares tribe and male antennal modification, but differs in slightly (more so in males) and western Texas distribution; associated with Acacia .
More Details
Taxonomic placement
Placed in its own subtribe Trichinorphidina within Xenorhipidini due to unique combination of entire and rounded . The tribe is currently under revision by Dr. Charles Bellamy.
Rumored undescribed species
An undescribed from west Texas has been suggested but not formally documented.