Anthonomus juniperinus (Sanborn)

Clark, Wayne E. & Burke, Horace R., 2010, The Anthonomus juniperinus group, with descriptions of two new species (Coleoptera: Curculionidae), Insecta Mundi 2010 (119), pp. 1-10 : 4-6

Anthonomus juniperinus (Sanborn)

( Figure 1, 2 , 9, 12)

Erirhinus juniperinus Sanborn 1868:81 . Lectotype: [Mass. / F.G. Sanborn / Type.] [Cotype / No.] [M.C.Z./ Type / 27116] [LECTOTYPE / Anthonomus / juniperinus/ / Sanborn / designated by/ H.R. Burke] (female, MCZC).

Anthonomus juniperinus (Sanborn) : LeConte 1876:195, 199 (key, desc.); Dietz 1891:202, 225, 227 (key, desc.); Blatchley and Leng 1916:308 (key, desc.); Leng 1920:323 (cat.); Blatchley 1928:249 (distr. note); Schenkling and Marshall 1934:46 (cat.); Burke 1968:20, 67, 89 (pupa key, desc. illus., biol.); Ahmad and Burke 1972:38, 63, 78 (larva key, desc., illus., biol.); Gates and Burke 1972:1222 (biol.); O’Brien and Wibmer 1982:108 (cat.); Downie and Arnett 1996:1552, 1556 (key, desc.); Salsbury 2000:11, 23 (key, desc., illus.).

Description. Length 2.0-2.5 mm. Body elongate-oval ( Figs. 1, 2 ); yellowish to pale reddish with distinct, dark V-shaped fascia on elytra behind middle; vestiture of elongate scales, sparse and fairly evenly distributed dorsally and ventrally. Head sparsely, minutely punctate, with elongate, acuminate, fulvous scales; eyes round, moderately strongly raised posteriorly, slightly larger in male. Rostrum nearly straight, slightly longer and more slender in female, with irregular lateral and lateromedian sulci proximally, smooth, shining, sparsely, shallowly punctate distally; with sparse elongate scales in proximal 1/ 3; dorsal margin of lateral rostral groove carinate; slightly narrowed to antennal insertions, widened to apex in dorsal view. Pronotum subcylindrical, slightly, broadly constricted subapically; densely punctate; with uniform vestiture of elongate, narrow, acuminate, fulvous scales. Scutellum with dense, pallid, elongate scales. Elytra narrow, slightly widened posteriorly; with sparse uniform vestiture of elongate, narrow, acuminate, fulvous scales; integument pallid, darker fuscous on sutural and 11th interstriae and in transverse posteromedian band extending across interstriae 2-5. Pygidium with sparse, narrow setose scales; tergum 7 with posteromedian fovea in male and female. Sterna subequal in length, with sparse, pallid fulvous scales laterally, sparse setae medially. Legs with femora stout, pallid basally and apically, darker in between; with sparse, pallid, setose scales; profemur with stout, conical, acute ventral tooth; mesofemur with smaller tooth; metafemur with minute tooth. Protibia with inner margin slightly sinuate, with acute, black, apical uncus that extends at right angles to long axis of tibia (Fig. 12); mesotibia with more slender, acute uncus; metatibial mucro slender, slightly curved, diagonal (Fig. 12). Tarsal claws each with small, distinct, acute basal tooth. Median lobe subparallel-sided, slightly narrowed to rounded apex in dorsal view (Fig. 9). Discussion. Anthonomus juniperinus is distin-

guished from the other species in the group by the

characters presented in the key, especially by the

well-defined dark postmedian fascia on the elytra

forming a V-shaped pattern. The vestiture on the

pronotum and elytra is about equally distributed

while in A. sanborni the pronotal vestiture is more

dense than on the elytra ( Fig. 3 ). This difference is

quite evident in well preserved, unabraded speci-

mens. Also, A. juniperinus is typically intermedi-

ate in size between A. sanborni and A. rileyi .

Distribution. Anthonomus juniperinus is wide-

spread in the eastern United States as far west as

the eastern areas of Texas and Kansas. Specimens

have been examined from the following states: FL,

GA, KS, LA, MA, MD, MS, PA, SC, TX, VA, WI,

and WV. Outside of the eastern United States, a Figure 9-11. Anthonomus juniperinus group spp., median specimen has been examined in USNM from Paget, lobe, dorsal views. 9) A. juniperinus , 10 mi. SW Elkhart, Bermuda and O’Brien and Wibmer (1982) listed Texas. 10) A. sanborni , 13 mi. W Lehi, Utah County, Utah. Oregon among the states where the species occurs. 11) A. rileyi , vic. Cypress Creek, Travis County, Texas. These disjunct localities are surprising and need

further confirmation. It is possible that the Oregon locality is based on a misidentification. Anthonomus juniperinus and A. sanborni may have been confused before the latter species was recognized, especially if the specimen in question was abraded or otherwise poorly preserved. Juniperus virginiana L. (Eastern redcedar) occurs in Oregon, probably being introduced there in commerce, so it is possible that A. juniperinus also occurs there. Eastern redcedar also occurs in Ontario and Quebec, Canada but we have not seen records of the weevil being present there.

Biology. Until relatively recently, the only biological information available on A. juniperinus was that which Sanborn (1868) included in the original description of the species. According to Sanborn, the weevil was common during May in eastern Massachusetts where it deposited it eggs in fungus galls, Podosoma juniperina (now known as Gymnosporangium juniperi-virgininae ) on juniper. The larvae were observed to develop in numbers within the gall and pupated there. Although the species name of the juniper involved was not stated, it was surely Juniperus virginiana . The biological information provided by Sanborn has been frequently repeated by subsequent authors. The junior author has examined adult weevil specimens pinned with juniper berries having exit holes, indicating that the larvae also develop in fruit. Verification of such development in fruit was provided by entomologists in Georgia in 1989 when heavy infestations by A. juniperinus were discovered in juniper fruit in a seed orchard (Mike Young, Terry Price and Cecil Smith, pers. comms.). The larvae were feeding in the pulp of the fruit around the periphery of the seed. Only a single emergence hole was found in each fruit. This and the small amount of available food in a fruit that is almost completely filled with one or two seeds suggest that a single larva develops in each fruit. The practice of some species of Anthonomus that normally develop in flower buds and/or fruit also utilizing plant galls as alternate developmental sites was discussed by Gates and Burke (1972). These alternate sites persist for a longer period of time than reproductive structures, thus increasing the number of weevil generations possible. They also provide food for the development of larger numbers of individuals, and are possibly more nutritious than the original sites. Anthonomus juniperinus follows this pattern in utilizing the original developmental site, the juniper fruit, as well as the fungus gall.

Gates and Burke (1972) provided additional information on the biology of A. juniperinus in Gymnosporangium galls on Eastern redcedar in eastern Texas. These observations revealed that eggs were deposited when the gall tissue was soft in March and April. The young larvae burrowed through the gall tissue leaving frass-filled tunnels. As many as 10 larvae were found to develop in one gall, eventually reducing the tissue of the gall to a powder. As an additional contribution to its taxonomy and biology, the pupal and larval stages of A. juniperinus were de-

scribed by Burke (1968) and Ahmad and Burke

(1972), respectively.

Dietz (1891) stated that A. juniperinus has a

“remarkable similarity” to the Palaearctic species

Nanophyes transversus Aubé (now Nanodiscus

transversus (Aubé) ). The two distantly related

species (of different curculionoid families) share a

similar body shape and color and both have a V-

shaped fascia on the elytra. However, the fascia of

N. transversus occupies a larger area of the elytra

than does that of A. juniperinus and is not as dis-

tinctly defined. According to Miguel Alonso-

Zarazaga (pers. comm. to H.R. Burke, August 19,

2009), the hosts of N. transversus in the Iberian

Peninsula are species of Juniperus and Cupressus .

There the species somewhat resembles buds and

short axillary twigs that are usually covered with

dry scales. It is more likely to be collected by sweep-

ing or beating than by visual search for individual

specimens. A possible case of such camouflage may

also exist for A. juniperinus .

With the exception of the Bermuda specimen

that was collected on Juniperus bermudiana , A.

juniperinus is only known to be associated with

Juniperus virginiana .

Figures

Figure 1-6. Anthonomus juniperinus group spp., habitus, lateral and dorsal views. 1, 2) A. juniperinus, male, 10 mi. SW Elkhart, Texas. 3, 4) A. sanborni, female, 15 mi. N Alvord Ranch, Harney County, Oregon. 5, 6) A. rileyi, female, vic. Long Hollow Creek, Travis County, Texas.