Laemosaccus westcotti Hespenheide, 2019

Hespenheide, Henry A., 2019, A Review of the Genus Laemosaccus Schönherr, 1826 (Coleoptera: Curculionidae: Mesoptiliinae) from Baja California and America North of Mexico: Diversity and Mimicry, The Coleopterists Bulletin (MIMICRY AND LAEMOSACCUS In an earlier paper (Hespenheide 1996), I presented the hypothesis that species of Laemosaccus of the L. nephele group with red humeral spots on the elytra were Batesian mimics of members of the Chrysomelidae in the subfamily Clytrinae. There is no evidence that Laemosaccus species are distasteful, and what is either L. nephele and / or L. obrieni have been reported as prey items of birds (Beal 1912). In Cave Creek Canyon, Cochise County, Arizona, 21 forms (species and “ subspecies ”) of Clytrinae were hypothesized to be the primary models of 22 species of mimics in the families Anthribidae (one species), Bruchidae (two species), Buprestidae (four species), Chrysomelidae, subfamily Cryptocephalinae (three species), Coccinellidae (six species), Curculionidae, subfamily Baridinae (one species), and Laemosaccus (five species). Of these, the coccinellids and the cryptocephaline chrysomelids are probably distasteful Mullerian co-mimics. Ecologically, the species of Laemosaccus co-occurred with their clytrine models on both desert legumes and canyon oaks, although more clytrine species occurred in the desert and more Laemosaccus species occurred in the canyons. Species of clytrines showing the mimetic pattern are common throughout Mexico (Bellamy 2003, who renamed the Mexican buprestid genus Acherusia Laporte and Gory, 1837 as Mimicoclytrina Bellamy to reflect their resemblance to clytrines), but decline in numbers of species and in the proportion of the clytrine fauna through Central America to Panama (Hespenheide 1996, fig. 2). Laemosaccus seems to follow a similar pattern. Mimicry is more common in large faunas, especially in wet tropical areas (Hespenheide 1986, 1995); because the largest clytrine fauna is in Mexico, the clytrine mimicry complex is also larger there (Hespenheide 1996). This complex has more members than I first enumerated and deserves further study. The evolution of mimicry produces resemblances between unrelated species (Laemosaccus and other putative mimics, with clytrines and perhaps other Chrysomelidae and Coccinellidae as models; see Hespenheide 1976, 1996) and selects against the divergence of related species. In Batesian mimicry - hypothesized to be the form of relationship between Laemosaccus and clytrines - the selection for precision of mimicry is stronger on the mimic (Laemosaccus), so that resemblances among them should be closer, regardless of ancestry. Close morphological resemblances based on ecology rather than ancestry may be termed mimetic homoplasy (Hespenheide 2005) and can make recognition of species difficult (as in Laemosaccus) or complicate phylogenetic analyses. I have speculated (Hespenheide 1996) that the sympatric “ subspecies ” of the clytrine models (Moldenke 1970) may in fact be reproductively isolated sibling species. It will be interesting to see whether or not genomic studies show the closeness of relationships among Laemosaccus species that the morphology suggests) 73 (4), pp. 905-939 : 932-933

Laemosaccus westcotti Hespenheide , new species

Zoobank.org/ urn:lsid:zoobank.org:act:DE786D75-EEE1-4E8D-886A-3AD731D3708E ( Figs. 17 , 28 )

Description. Holotype Male. Length 3.20 mm, width 1.50 mm ( Fig. 17 ). Very robust, subcylindrical in cross section, broadly rounded behind, more narrowly so in front, black except each elytron with very small, oval, red posthumeral spot on elytral intervals 6 and 7, about 0.25 mm long; pronotum and elytra glabrous, thorax and abdomen ventrally and metafemora with punctures each with a silvery seta, setae obscuring or nearly obscuring surface except sparser on pronotum, head with conspicuous setae between and around eyes and on rostrum above antennal insertions, setae less dense and more slender on frons and middle legs and metatibiae, hair-like, inconspicuous and semierect on tergite 8, otherwise glabrous. Head hemispherical, 0.80 mm wide, rostrum rounded-terete, shiny, apically finely punctate, 0.40 mm long, antennae inserted at middle. Pronotum gibbous, slightly convex in cross section, constricted at base and before anterior margin, 1.10 mm long, 1.35 mm wide, broadest at basal third, with lateral margins very shallowly arcuate, more so in front than behind, slightly convex in lateral view, coarsely, evenly reticulate-punctate, punctures rounded and separate at base, becoming somewhat confluent longitudinally on apical half near midline, with indistinct medial carina. Elytra slightly wider than pronotum at base, sides nearly parallel, 2.10 mm long, 1.50 mm maximum width, elytral striae narrower than intervals, striae finely punctate, intervals carinate, interval 3 very weakly toothed on middle third, interval 5 weakly toothed on apical half. Profemora with broad, abruptly acute ventral tooth beyond middle, metafemora flattened in cross section, widest at middle. Abdominal ventrite 1 very slightly concave along midline; abdominal ventrite 5 0.5X length of ventrite 4 at middle, equal to length of ventrites 3 + 4 at lateral margin. Genitalia as in Fig. 28 ; aedeagus 0.80 mm long.

Allotype Female. As male but rostrum subcylindrical, polished, very finely, inconspicuously punctate, glabrous, forming obtuse angle with plane of eyes, antennae inserted near base; fronst with line of setae in front and behind eyes, broken above; tergite 7 convex, coarsely punctate, glabrous; 3.55 mm long, 1.65 mm wide.

Specimens Examined. Holotype: Mexico: Baja California Sur, 6.5 mi. S, 1 mi. E El Pescadero , 20/ 21.07.1977, Dozier & Westcott ( ASUHIC) . Allotype: Same data as holotype ( ASUHIC) . Paratypes: Mexico: Baja California: 2 mi. N Cabo Pulmo , 14.08.1955, J. P.Figg-Hoblyn (1, CASC) ; 25 mi. E El Rosario , 25.06.1980, D. S. Verity (1, CHAH) ; Agua Verde , 26.05.1921, E. P. Van Duzee (1, CASC) ; Buena Vista , 13.09.1988, E. G. Riley (1, TAMU) ; L. Cal., Chapala Dry Lake , 21.06.38 (1, CASC) ; L. Cal., Mesquital , 28.07.1938, Michelbacher & Ross (1, CASC) ; L. Cal., San Domingo, 19.07.38, Michelbacher & Ross (6, CASC) ; L. Cal. , 15 mi. N El Refugio, 4.07.1938, Michelbacher & Ross (1, CASC) ; L. Cal. , 10 mi. S Punta Prieta, 21.06.1938, Michelbacher & Ross (5, CASC) ; L. Cal. , 15 mi. N San Ignacio, 26.07.1938, Michelbacher & Ross (4, CASC) ; L. Cal. , 45 mi. N San Ignacio, 27.07.1938, Michelbacher & Ross (1, CASC) ; Coronados I., Gulf Calif , 18.05.1921, J. C. Chamberlin (1, CASC) ; Marquer Bay, Carmen Isd., Gulf Calif , 23.05.1921, E. P. Van Duzee (1, CASC) ; El Taste, Low , Cal., [coll of Chas Schaeffer] (2, BYU) , Low. Cal. , Santa Rosa, C. Schaeffer (1, BYU) , Ramal al Sta. Rosalillito , 3.5 km W Carr. 1, 90 m, 20.06.1993, R. L. Westcott (1, CMNC) ; 10 km S Valle de Trinidad, 02.07.1981, W. F. Barr, on Prosopis (1, WFBM) ; Bah´ıa de los Angeles , 2.05.1968, R. P. Papp (1, CASC) . Baja California Sur: Los Barriles , 27.09.1978, D. E. Foster (2, CMNC, WFBM) ; 8.7 km SE San Antonio , 12.08.1980, W. F. Barr (1, CMNC) ; 20–28 km W Ramal a los Naranjos , 28.08.1994, R. Turnbow (1, CMNC) ; 1 km W El Centenario , 23.09.1978, D. E. Foster, beating Prosopis (1, CMNC) , W. F. Barr, mesquite (1, WFBM); 2 km S Mulegé , 10.08.1992, H. & A. Howden (3, CMNC) ; 4 km S Mulegé , 15.08.1992, H. & A. Howden (2, CMNC) ; 5 km S Mulegé , 9.08.1992, H. & A. Howden (1, CMNC) ; 4 mi. S LA Paz , 14.09.1978, D. R. Whitehead (2, USNM) ; La Paz, 13.09.1978, D. R. Whitehead (1, USNM) , 22.09.1978, W. F. Barr, on mesquite (1, WFBM) ; San Pedro, 23.04.1977, W. F. Barr (1, WFBM) ; Las Cuevas , 27.09.1978, D. E. Foster (1, WFBM) ; Las Barracas , ca. 30 km E Santiago, 20/ 25.05.1983, P. DeBach, Malaise trap (1, EMEC) ; 7 mi. SE Guerrero Negro , 08.04.1976, Doyen & Rude, Prosopis juliflora (1, EMEC) ; 25 mi. N Todos Santos , 28.06.1978, W. F. Chamberlain (1, TAMU) ; 9.6 mi. W Hwy. 1 on Ramal Sn Antonio de la Sierra, 19.09.1988, E. G. Riley (1, TAMU) ; 15.4 mi. W Hwy. 1 on Ramal San Antonio de la Sierra, 19.09.1988, E. G. Riley (1, TAMU) ; same data as Holotype (23, BMNH, CHAH, ASUHIC) ; 1 mi. N, 8 mi. W San Jose del Cabo , 430 m, 19/ 20.07.1977, Dozier & Westcott (3, ASUHIC) ; 12.4 km S La Burrera , 21.07.1977, Dozier & Westcott (2, ASUHIC) ; 20 km S Punta Prieta , 25/ 26.07.1977, Dozier & Westcott, beating mesquite, Prosopis glandulosa var torreyana (1, ASUHIC) ; Isla San José , 19.04.1972, L. Cheng (1, CASC) ; 11.8 mi. N El Triunfo on Hwy. 1, 08.09.1988, E. G. Riley (1, TAMU) , 5.4 mi. S Todos Santos , 28.09.1981, D. Faulkner & F. Andrews (1, CSCA) , 36.6 mi. NE Todos Santos , 10.10.1983, Faulkner & Andrews (1, CSCA) , Santa Inez Dam, 8 m. i NE Todos Santos , 9.10.1983, F. Andrews & D. Faulkner (1, CSCA) , 26 mi. W Ejido Vizcaino , 19.04.1987, A. Gilbert & F. Andrews, on Prosopis juliflora (1, CSCA) , 26 mi. W Ejido Vizcaino , 19.04.1987, A. Gilbert & F. Andrews (1, CSCA) , 17.5 mi. W Ejido Vizcaino , 19.04.1987, F. Andrews & A. Gilbert (1, CSCA) , 16.1 mi. S San Antonio on Hwy 1, 8.09.1988, A. J. Gilbert (1, CSCA) , 12.2 mi. SE San Perdito near Rancho Saucito , 8.10.1981, F. Andrews & D. Faulkner (1, CSCA) , 9.0 mi. E Highway 19 nr. El Mezquitillo, 1300‘, 6.09.1990, F. Andrews, T. Eichlin & A. Gilbert (2, CSCA) , 12.5 mi. E Highway 19 nr. La Calera, 1500’, 6.09.1990, F. Andrews, T. Eichlin & A. Gilbert (1, CSCA) , 12 mi. S Ciudad Constitucion , 26.09.1981, F. Andrews & D. Faulkner (1, CSCA) , Mocorito , 13.09.1988, A. J. Gilbert (1, CSCA) , Los Barrilles , 5- 6.05.1979, J. Slansky, Malaise Trap 10AM-5PM (1, CSCA) , Los Barrilles , 29- 30.04.1979, M. Wasbauer, Malaise Trap 8AM-6PM (1, CSCA) , Rancho Lagunillas , 1118’, 22°57.496N / 109°52.605W, 15.09.2003, F. G. Andrews (1, CSCA) , 0.5 mi. E La Candelaria , 1000’, 4.09.1990, F. Andrews, T. Eichlin & A. Gilbert, host plant press (9, CSCA) , 2 mi. E La Candelaria , 1000’, 4.09.1990, F. Andrews, T. Eichlin & A. Gilbert (9, CSCA) , 2.5 km W Hwy 1 on road to Punta Conejo, 475 ft GPS, N24°10’09” W110°57’27 ”, 15.09.2006, C. L. Bellamy CLB971 (1, CSCA) .

Hosts. This species has been collected on mesquite, including P. glandulosa var torreyana (L. Benson) M. C. Johnston and P. juliflora .

Etymology. This species is named in honor of one of the collectors of the type, Richard L. Westcott of Salem, Oregon, who has extended our knowledge of the entomofauna of Baja California, especially of Buprestidae , by both collections and publications ( Westcott 1998, 2001; Hespenheide et al. 2011).

Discussion. The two species of Laemosaccus on the Baja California Peninsula are interesting in two ways. First, they are isolated from the nearest Laemosaccus populations in southern Arizona and Sonora (including L. burkei , which also uses mesquite as a host), with no collections known to me from southern California. Secondly, this and the next species have the smallest posthumeral red spots of any of the species treated here that are not in the L. texanus group, and some specimens lack them altogether. It is possible that the clytrines or other models do not occur on the peninsula, so that large red spots do not decrease protection by mimicry but increase it by conspicuousness. In addition to using the same hosts, L. westcotti is similar to L. burkei in having dense, bright white setae ventrally and on the front between the eyes but differs from that species in the reduced size of the red elytral spots and in the male genitalia. The relationships of this and the following species may be with those of mainland Mexico. Males vary in size from 2.25 to 3.80 mm (mean = 2.95 mm, n = 54); females from 2.50 to 4.25 mm (mean = 3.35 mm, n = 30).

Figures

Figs. 13–18. Laemosaccus species, dorsal habitus. 13) L. clytrinoides; 14) L. howdenae; 15) L. rileyi; 16) L. vaurieae; 17) L. westcotti; 18) L. texanus.

Figs. 25–30. Laemosaccus species. Dorsal and lateral views of aedeagus and paramere: 25) L. browerorum; 26) L. rileyi; 27) L. vaurieae; 28) L. westcotti; 29) L. peninsularis; 30) L. texanus, dorsal and lateral views of aedeagus only. 31) L. peninsularis, dorsal habitus.