You are here
Xyleborini classification
Xyleborinus octiesdentatus (Murayama, 1931)
EOL Text
Beaver and Liu, 2010: Various aspects of the biology are described by Hanula et al. (2008). Although not of economic importance in its native range, the species is an invasive pest in the U. S. A. where it transmits a pathogenic fungus to a variety of Lauraceae trees (e.g. Hanula et al. 2008; Fraedrich et al. 2008; Koch & Smith 2008). Rabaglia et al. 2006: Specimens were first found in North America in a funnel trap outside of a warehouse in Georgia in 2002. It was unclear at that time whether the species was established or the specimens were intercepted from the warehouse. In 2004, a large series of specimens were examined from red bay trees in dying on Hilton Head, SC. It is clear that the species is now established in the area and may be aggressively attacking trees. The host list of this species suggests that it may be attracted to aromatic species especially in the Lauraceae. X. glabratus seems to be restricted to its host range of species in Lauraceae in Asia and North America (in Asia, Shorea robusta, a non-Lauraceae is a host but is also very aromatic). Host odors may be serving as primary attractants for this species. In addition, red bay trees attacked are quickly dying and are infested with an apparently aggressive wilt fungus possibly vectored by this species.
License | http://creativecommons.org/licenses/by/3.0/ |
Rights holder/Author | hulcr, Xyleborini Ambrosia Beetles |
Source | http://xyleborini.myspecies.info/node/99 |
Diagnosis.
Specimens of Xyleborinus octiesdentatus can be easily distinguished from other members of Xyleborinus occurring in North America by the sulcate shape of the elytral declivity, and the elevated lateral declivital margins which bear four pairs of long, narrow, sharply pointed spines, increasing in length approaching the posterior margin.
Revised Key to Xyleborinus in America north of Mexico.
The following key, modified from the key to Xyleborinus in Rabaglia et al. (2006) , will enable the identification of the five species of Xyleborinus known from America north of Mexico. It includes the recently established Xyleborinus andrewsi in Florida ( Okins and Thomas 2010 ).
1Posterior margin of elytra strongly convergentXyleborinus andrewsi (Blandford) -Posterior margin of elytra broadly rounded22(1)Declivital interstriae 1 with small granules, 1 and 3 equally, weakly elevated3-Declivital interstriae 1 without granules and not elevated43(2)Granules on declivital interstriae 1 and 3 larger, those on 3 pointed, spine-like, slightly incurved; granules on ventrolateral area large, sharply pointed, spine-like, curved slightly downwards and to the suture; declivital interstriae 2 flattened; 2.5-2.8 mmXyleborinus alni (Niisima) -Granules on declivital interstriae 1 and 3 smaller, obtusely pointed; granules on ventrolateral areas small, less pointed; declivital interstriae 2 slightly impressed; 2.0-2.4 mmXyleborinus saxesenii (Ratzeburg) 4(2)Declivity flattened, declivital interstriae 3 slightly elevated with 3 pairs of small denticles, the pair near the posterior margin largest and often blunt; 1.6-1.9 mmXyleborinus gracilis Eichhoff -Declivity sulcate, declivital interstriae 3 strongly elevated with 4 pairs of long, narrow, pointed spines increasing in size approaching posterior margin, 2.1-2.4 mmXyleborinus octiesdentatus Murayama
Description.
The species was redescribed by Nunberg (1982)
Female. Length 2.1-2.4 mm (from anterior margin of pronotum to posterior margin of elytra, excluding spines), 2.5 × as long as wide; color brown to dark brown, matt. Frons convex, strongly reticulate, with large, shallow, rather dense punctures. Antennal club round with two round sutures on its anterior side and one strongly apically displaced suture on posterior side. Pronotum cylindrical, 1.2 × as long as wide, frontal edge broadly rounded bearing small tubercles as continuation of very fine asperities on anterior half, posterior half finely shagreened, with minute, shallow punctures. Scutellum typical for the genus, conical, visible between the emarginated bases of the elytra. Elytra cylindrical 1.5 × as long as wide, 1.3 × as long as pronotum, side straight on anterior half, narrowed on posterior half; striae on the disk very shallowly impressed, regularly and rather densely punctured; interstriae flat, finely and regularly punctured; interstriae 1, 2 and 3 with small tubercles just before the upper margin of the declivity. Elytral declivity long, nearly from the middle of elytra, sulcate, sutural interstriae weakly elevated on upper part, not elevated below, without granules; lateral edges formed by strongly elevated continuation of 3rd interstriae, which bears four pairs of long, narrow, posteriorly directed sharply pointed spines, which increase in length approaching posterior margin, the last two pair exceeding outline of the elytral edge; several small, fine spines on the lateral raised margin of declivity. Vestiture consisting of moderately long, fine setae in uniseriate rows on interstriae, longer on declivity. Legs yellowish, brown.
Male. Not examined.
Distribution.
China, Japan, South Korea ( Wood and Bright 1992 ). United States (all records new to North America, numbers of specimens collected at each location shown in parentheses.): ALABAMA, Tuscaloosa County: Vance, 14 August 2008 , ethanol-baited funnel trap (1);LOUISIANA, Winn Parish: Kisatchie National Forest, 6 miles w. of Winnfield, 24 April 2008 , α-β-pinene (70:30) and ethanol-baited funnel trap (1); 23 March 2009 , α-β-pinene (70:30) and ethanol-baited funnel trap (3), ethanol-baited funnel trap (3), phoebe oil-baited funnel trap (2); 9 April 2009 , α-β-pinene (70:30) and ethanol-baited funnel trap (1),: ethanol-baited funnel trap (2); 21 April 2009 , α-β-pinene (70:30) and ethanol-baited funnel trap (7), ethanol-baited funnel trap (4); 29 April 2009 , α-β-pinene (70:30) and ethanol-baited funnel trap (3), ethanol-baited funnel trap (6),: phoebe oil-baited funnel trap (2); 21 May 2009 ,: α-β-pinene (70:30) and ethanol-baited funnel trap (1); 3 June 2009 , trap on girdled yaupon (14); 9 June 2009 ,: trap on girdled yaupon (3); 15 June 2009 , trap on girdled yaupon (3); 14 July 2009 , trap on girdled yaupon (2); 4 August 2009 ,: trap on girdled yaupon (2). All specimens collected in North America are females.
Biology , habits, and host.
In its native Asian range, the known hosts for Xyleborinus octiesdentatus are Carpinus laxiflora (Siebold and Zuccarini) Blume ( Corylaceae ), Cleyera sp., Eurya japonica Thunberg ( Theaceae ) and Illicium religiosum Siebold ( Illiaceae ) ( Wood and Bright 1992 ), and Illex rotunda Thunberg ( Aquifoliaceae ) ( Murayama 1934 ).
Although this species is certainly established in the Winnfield area of Louisiana (Winn Parish) and probably in Alabama (Tuscaloosa Co.), it has not been collected from any host trees. In May, 2009, on the Kisatchie National Forest, Ilex vomitoria Aiton (yaupon), Ilex opaca Aiton (American holly) ( Aquifoliaceae ) and Carpinus caroliniana Walter (ironwood) ( Corylaceae ) were girdled and a sticky band placed on the trees to act as attractant/trap trees for the beetle. These species were selected because known hosts of the beetles belonging to these genera occur in Asia. During the month following this treatment 27 specimens were collected on the sticky band on the girdled yaupon whereas no specimens were collected from the other species. No specimens of Xyleborinus octiesdentatus were found boring into the yaupon tree.
The impact Xyleborinus octiesdentatus will have in North America is still uncertain. All species of xyleborines carry symbiotic ambrosia fungi that are usually benign to hosts in their native range. However, as recently discovered with Xyleborus glabratus Eichhoff, 1877, another ambrosia beetle introduced from Asia, certain ambrosial fungi may prove to be very pathogenic on new, novel hosts in North America ( Fraedrich et al. 2008 ). Future studies with Xyleborinus octiesdentatus will attempt to identify fungal associates, and test their pathogenicity against North American host trees.
License | |
Rights holder/Author | No known copyright restrictions |
Source | http://dx.doi.org/10.3897/zookeys.56.528 |
Beaver, 2010: Recorded from 5 families and 6 genera of angiosperm trees.
License | http://creativecommons.org/licenses/by/3.0/ |
Rights holder/Author | hulcr, Xyleborini Ambrosia Beetles |
Source | http://xyleborini.myspecies.info/node/100 |