Lepturinae

Swift, Ian, 2008, Ecological and biogeographical observations on Cerambycidae (Coleoptera) from California, USA, Insecta Mundi 2008 (26), pp. 1-7 : 4-6

Lepturinae

Brachysomida californica (LeConte) . No larval host plants were previously known for this genus or this species. Most of the known localities are in northern California ( Linsley and Chemsak 1972). Adults were reared from Lomatium lucidum (Torrey and A. Gray) Jepson (Apiaceae) , as well as collected from the tops of grasses amongst fields of the host plant in the Laguna Hills, Orange County, California (DSVC, ISPC). Larval behavior and development are similar to B. vittigera Linsley and Chemsak described below.

Brachysomida vittigera Linsley and Chemsak. Adults where reared from the living roots of Lomatium utriculatum (Torrey and A. Gray) J. M. Carter and Rose , a geophyte, growing in disturbed grasslands in the southern San Joaquin Valley, Kern County, California in the vicinity of the type locality (CASC). The eggs are laid at the base of live plants and larvae bore into the center of the taproot, working their way down to the narrowest part of the root, then boring back to the middle and exiting to pupate. Larval development appears to require one year. Pupation may take place in the soil, as some of the larvae exited the roots of the plant and pupated at the bottom of the rearing chamber in the lab. Both species of Brachysomida discussed herein have a clear larval host preference for the genus Lomatium Rafinesque. While other hosts may be involved, this preference could be valuable in determining or confirming host associations of other species in this genus where larval hosts and biology are unknown.

Centrodera osburni Knull. The host plant of this rare species was previously unknown. Two male specimens were reared from the living root crowns of Ceanothus integerrimus in the San Gabriel Mountains of Los Angeles County, California (ISPC, LACM). The type locality is the New York Mountains in the Mojave Desert, a very different biogeographic region than that of the more coastal populations, and likely more than one host is involved. The female of this species remains undescribed.

Encyclops californica Van Dyke. This species was previously known from coastal regions of northern California. It was collected in Lindgren funnel traps at Forest Falls , San Bernardino County, California, a 420 km range extension to the south (CSCA). The two regions of known occurrence have very little, if any, floristic elements in common, and this record suggests that different host(s) may be utilized in the southern portions of its range.

Judolia sexspilota (LeConte) . No host plant has been previously recorded for this species. Adults and pupae were extracted from the upper portions and exposed roots of Juniperus californica Carriere (Cupressaceae) , that were dug up as part of a road widening in the San Gabriel Mountains, Los Angeles County, California (ISPC). The larval work appears to be similar to that of Judolia erratica (Dalman) from Asia, detailed by Cherepanov (1988).

Leptalia macilenta (Mannerheim) . Linsley and Chemsak (1972) list Alnus , Umbellularia californica (Hooker and Arnott) Nuttall , and Salix as hosts for this species. To this list can be included Quercus agrifolia , from Marin County, California (ISPC, CASC). Adults were reared from long-dead logs that were covered in thick moss and lichens. The larval development is similar to that reported by Chemsak and Powell (1971).

Leptura hovorei Linsley and Chemsak. No host plant for this species has been previously recorded. Adults and pupae were cut out of the base and root crown of a standing dead Pinus jefferyi Gerville and Balfour (Pinaceae) in the San Gabriel Mountains, Los Angeles County, California (ISPC). This record extends the range of the species into southern California. In the series of seven specimens from this locality, the elytral apices are black and confluent with the subapical transverse band. Linsley and Chemsak (1976) distinguished L. hovorei , in part, from L. obliterata (Haldeman) by the separation of the apical and subapical black markings. Therefore, this character should be used with caution when identifying this species. In all other characters the series agrees with L. hovorei . This species is part of a complex of closely-related taxa, including L. obliterata and L. propinqua Bland , of which the characters are quite subjective and tend to overlap.

Leptura pacifica (Linsley) . The excellent account by Skiles et al. (1978) of the biology of this species indicates larval host preferences with Quercus dumosa Nuttall. However , in the intervening years since that publication, the taxonomy of the genus Quercus in southern California has undergone considerable revision. Quercus dumosa is now restricted to the immediate coast of southern California from Santa Barbara to northern Baja California, Mexico, and does not coincide with the range of L. pacifica . Based on photographs in Skiles et al. (1978), it appears that the host plant of L. pacifica is in fact Q. john-tuckeri , a common scrub oak at the type locality (San Jacinto Mountains, California) of this species. Further, this species was reared from Q. john-tuckeri as well as taken in fermenting bait traps at several sites in Los Angeles County, slightly extending the range of this species, which was previously known only from the San Jacinto Mountains of California. Based on these observations and those of Skiles (1978), it appears that L. pacifica is likely host-specific to Q. john-tuckeri , an ecological strategy somewhat common to cerambycid species utilizing living larval hosts ( Linsley 1959).

Necydalis barbarae Rivers. This rarely collected and distinctive species is represented by only a few specimens in collections. It was previously known from coastal California from Santa Barbara County to San Mateo County . It was recently collected in Lindgren funnel traps near Forest Falls , San Bernardino County , California (CSCA), and in Placerita Canyon , Los Angeles County , California in fermenting bait traps (ISPC). A search of the latter locality revealed an approximately one-year dead Quercus chrysolepis Liebmann from which a desiccated specimen of this species was chopped out. Based on its gallery, it appears that the larvae immediately bore into the heartwood of the host near the base of the tree, extending their galleries down the main trunk for up to 60 cm, then bore back up and pupate in a chamber that is plugged with fine frass on either end, approximately 3 cm from the emergence hole. In this case it appears that the larval development is one year.

Neobellamira delicata australis Linsley and Chemsak. This species’ hosts include members of the genus Juglans Linnaeus. It is also present in urban areas where adults were reared from Alnus rhombifolia Nuttall and the introduced Fraxinus excelsior Linnaeus (Oleaceae) , both street trees in the San Fernando Valley, Los Angeles County, California (ISPC, CASC, LACM). In all known cases, the host trees were killed. However, it is unknown if the beetles killed the trees or simply contributed to it.

Pachyta armata (LeConte) . A series of this species was collected near Devil’s Postpile, Mono County, California (ISPC), on flowers of Sphenosciadium capitellatum A. Gray (Apiaceae) and a female was collected ovipositing on the dead basal portion of a living Pinus monticola Douglas ex. D. Don. As noted by Linsley and Chemsak (1976), all the California specimens have considerably more black on the elytra, in addition to being much smaller than those from Oregon and Washington. In the series of eight specimens from Mono County, the size ranged from 7-9 mm, vs. 13-17 mm in more northern specimens.

Stenocorus alteni Giesbert and Hovore. This recently-described species has no previously confirmed host plants. However, Giesbert and Hovore (1998) speculated the host may be Quercus berberidifolia Liebmann. The type locality is composed of xeric desert chaparral, with dominant stands of Quercus john-tuckeri , while Q. berberidifolia occurs only along the coast of southern California. This species was subsequently reared from the upper roots and root crowns of Q. john-tuckeri that were destroyed as part of road grading, in Bouquet Canyon, Los Angeles County, California (ISPC). It was previously known only from the type locality. In addition to this new locality, a series was collected in Lindgren funnel traps near the San Luis Reservoir State Recreation Area, Merced County, California, extending the range of this species into central California (CSCA). All three localities are on the xeric, desert slopes of the coastal ranges in chaparral dominated by Q. john-tuckeri . This cryptic species may be the second cerambycid that is host-specific to this plant.