Geraeus penicillus (Herbst)

Prena, Jens, 2009, A Review of the Species of Geraeus Pascoe and Linogeraeus Casey Found in the Continental United States (Coleoptera: Curculionidae: Baridinae), The Coleopterists Bulletin 63 (2), pp. 123-172 : 147-149

Geraeus penicillus (Herbst)

( Figs. 13–16 , 72 )

Curculio penicillus Herbst 1797:29 . Not found in MNHUB; described from Herschel Collection; probably lost (see Madge 1994).

Baridius penicillus ; Say (1831), as B. penicellus .

Centrinus penicillus ; Schönherr (1836).

Geraeus penicillus ; Champion (1908), as G. penicellus .

Balaninus pistor Germar 1824:295 . Syntypes 3 (MLUH). New synonymy.

Centrinus pistor ; Schönherr (1836).

Geraeus pistor ; Schwarz in Leng (1920) [see Leng in Sherman (1929:392)].

Centrinus ? [sic] dilectus Harris 1836:80 . Type material not located (see note in text below). New synonymy.

Geraeus dilectus ; Schwarz in Leng (1920) [see Leng in Sherman (1929:392)].

Odontocorynus ? [sic] dilectus ; Hustache (1938), as synonym of O. salebrosus (Casey) ; name erroneously attributed to Hustache by anonymous (www. eol.org, last accessed 23.11.2008).

Centrinus holosericeus Gyllenhal 1836:760 . Synonymy by Gyllenhal (1836:760).

Baridius pubescens Uhler 1856:417 . Type material not located. Synonymy with C. pistor by Crotch (1873:122); synonymy with C. penicillus by LeConte (1876:308).

Centrinaspis tomentosa Casey 1920:403 . Syntypes, 4 males, labeled (1) ‘‘ Havana / Cuba. Baker ,’’ ‘‘ Casey / bequest/ 1925,’’ ‘‘ Type USNM/ 37849 ,’’ Casey’s handwriting ‘‘tomentosus/ Csy.’’; (2–4) ‘‘ Havana / Cuba. Baker,’’ ‘‘ Casey / bequest/ 1925,’’ ‘‘tomentosus-2 [other specimens numbered 3, 4]/ Paratype USNM/ 37849 ’’ (USNM). New synonymy.

Geraeus tomentosus ; O’Brien and Wibmer (1984).

Centrinaspis rhomboida Blatchley 1922:117 . Holotype female, Sanford, FL; supposedly not in Blachley collection (PURC), repository unknown. New

synonymy.

Centrinaspis rhomboidea [sic]; Leng and Mutchler (1927).

Geraeus rhomboidus ; O’Brien and Wibmer (1984).

Recognition. Geraeus penicillus is 2.8–4.6 mm long and relatively distinctive in the United States; G. euryonyx is the only similar species and has wide, ventrally sulcate claws and seems to be restricted to southern Arizona. Male G. penicillus always lack prosternal spines, which are present in fully developed males of G. euryonyx , G. podagrosus , G. senilis , and G. rectispinis , all of which are predominantly Mexican species with a similarly slender rostrum and elongate second desmomere. Geraeus nimbatus , which also lacks prosternal spines, has different male genitalia and the funicle bears erect setae.

Distribution. This species is common in the central and eastern United States ( Fig. 72 ). It extends south as far as Costa Rica and occurs in Cuba and Hispaniola.

Type locality. North America, site not specified.

Material examined. United States: Alabama ( USNM 29 ) , Arkansas ( USNM 1 ) , Delaware ( CWOB 1 , USNM 1 ) , District of Columbia ( USNM 5 ) , Florida ( CWOB 24 , TAMU 4 , USNM 134 ) , Georgia ( USNM 12 ) , Illinois ( USNM 13 ) , Indiana ( CMNC 1 , CWOB 15 , JPPC 3 , USNM 19 ) , Iowa ( TAMU 1 , USNM 7 ) , Kansas ( CWOB 3 , TAMU 1 , USNM 8 ) , Kentucky ( MLUH 3 ) , Louisiana ( CWOB 5 , TAMU 1 , USNM 17 ) , Maryland ( CMNC 1 , JPPC 18 , USNM 16 ) , Minnesota ( CWOB 1 ) , Mississippi ( CWOB 2 , USNM 33 ) , Missouri ( CWOB 10 , USNM 1 ) , Nebraska ( CWOB 4 , TAMU 9 , UNSM 8 , USNM 1 ) , New Jersey ( USNM 4 ) , New York ( USNM 27 ) , North Carolina ( CMNC 8 , CWOB 3 , USNM 11 ) , Ohio ( USNM 2 ) , Oklahoma ( USNM 10 ) , Pennsylvania ( USNM 4 ) , South Carolina ( CMNC 2 , TAMU 2 , UNSM 1 , USNM 9 ) , South Dakota ( USNM 2 ) , Tennessee ( CMNC 3 , TAMU 1 , USNM 1 ) , Texas ( CMNC 4 , CWOB 1 , TAMU 20 , USNM 39 ) , Virginia ( USNM 16 ) , West Virginia ( CMNC 1 ) , Wisconsin ( USNM 1 ) Costa Rica ( USNM 1 ) , Cuba ( CMNC 1 , USNM 64 ) , Dominican Republic ( USNM 1 ) , El Salvador ( USNM 1 ) , Haiti ( USNM 12 ) , Mexico ( CMNC 11 , TAMU 12 , USNM 2 ) , Nicaragua ( TAMU 2 ) . Total 681 specimens .

Temporal occurrence. Late April to early November.

Plant associations. Asteraceae : H. tenuifolia (R. A. Cushman, supposedly reared ex flower head). Chenopodiaceae : feeding on sugar beet [ Beta vulgaris L.] (Bruner 1891). Poaceae : root stem of Oryza sp. ( USNM, larval collection); P. dichotomiflorum (Ainslie 1920, reared specimens and larvae in USNM; Griswold, observation); Saccharum sp. (Mayer, observation); ‘‘breeding in grass stems’’ (W. G. Genung, observation); Z. mays (Ainslie 1920; numerous observations and interceptions); unrecognized grasses: ‘‘sea cane,’’ ‘‘water grass’’ ( USNM, larval collection).

Biology. The development of G. penicillus in Z. mays was studied by Ainslie (1920) and Kirk (1965). Eggs are laid in July and early August (Ainslie 1920), according to Kirk (1965) individually in the tissue of lateral branches of the corn tassel; rarely is a second egg laid on the same plant. The larva bores down through the center of the stalk to a point about 1 or 2 inches [ca. 2.5–5.0 cm] below the second to fourth node from the tassel. It returns to the nearest node, feeds for a while, then emerges from the stalk through a hole about 1 mm in diameter, usually at or within 0.5 inches [ca. 1.3 mm] of the node (Kirk 1965). The larva drops to the ground in about early October and overwinters in a spherical cell made in the soil (Ainslie 1920). However, five adult specimens in the USNM collection were obtained from seeds of P. dichotomiflorum in Beaumont, Texas early November. The life history of G. penicillus may therefore vary from region to region and from plant to plant.

Larval description. Böving (in Ainslie 1920:277–280), Anderson (1991).

Note. The variable vestiture of G. penicillus led to the suggesting of varieties and separate species. The typical form has spots of dark scales ( Fig. 13 ); specimens of the southeastern United States, particularly from Florida, have a rather uniform vestiture ( Fig. 15 ); a large series collected in Huntsville, northern Alabama shows all transitions between these extremes. Other morphological differences are not apparent. The Cuban population referred to as ‘‘var. beta’’ by Gyllenhal (1836) is morphologically indistinguishable from the mainland population. Specimens from Cuernavaca, Mexico identified by Champion (1909:491) as G. penicillus var., are G. nimbatus .

Note. Say (1831) clearly referred to C. penicillus Herbst (1797) when he inadvertently misspelled the epithet as penicellus . Gyllenhal (in Schönherr 1836:760) listed Say’s misspelling as an available name under C. holosericeus , whereas C. penicillus appeared on page 764 as a separate species with the note ‘‘ mihi invisus.’’ These two spellings were used synonymously in the subsequent literature.

The type of Centrinus dilectus Harris , a North American species described from the Halsey Collection, could not be located. LeConte (1876:309) suspected that C. dilectus is a synonym of C. penicillus ; Casey (1892:683) placed it tentatively near C. salebrosus Casey ; Leng (1920:328) listed it as unrecognized under Geraeus ; Hustache (1938:109) followed Casey (1892) and placed it in Odontocorynus ; and the Encyclopedia of Life project eventually recognized an Odontocorynus dilectus Hustache 1938 . Fortunately, the species is figured and the description provides several diagnostic details, such as body size and proportions of funicular segments. The name is placed here in synonymy with Geraeus penicillus (Herbst) ,

new synonym.

Blatchley (1922) described Centrinaspis rhomboida relying on Casey’s opinion, which is cited in the description. Based on the comparisons made in the discussion, morphological details provided in the description, and the species actually occurring in Florida, I tentatively place C. rhomboida in synonymy with Geraeus penicillus (Herbst) , new synonymy. According to A. Provonsha (PURC), specimens with this name are not represented in the Blatchley collection.

Figures

Figs. 9–16. Geraeus species, dorsal and lateral aspects; scale bar 1 mm. 9, 10) G. euryonyx, female; 11, 12) G. nimbatus, female; 13, 14) G. penicillus, male, maculate form; 15, 16) G. penicillus, female, unicolored form.

Figs. 71–72. Map of United States (without northwestern part) and Central America showing distributions of G. coarctatus, G. modestus, G. penicillus, and G. picumnus.