Limits...
Preimaginal stages of the emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae): an invasive pest on ash trees (Fraxinus).

Chamorro ML, Volkovitsh MG, Poland TM, Haack RA, Lingafelter SW - PLoS ONE (2012)

Bottom Line: A combination of 14 character states were identified that serve to identify larvae of A. planipennis.Our results support the segregation of Agrilus larvae into two informal assemblages based on characters of the mouthparts, prothorax, and abdomen: the A. viridis and A. ater assemblages, with A. planipennis being more similar to the former.Additional evidence is provided in favor of excluding A. planipennis from the subgenus Uragrilus.

View Article: PubMed Central - PubMed

Affiliation: United States Department of Agriculture, Agricultural Research Service, Systematic Entomology Laboratory, Washington, DC, United States of America. lourdes.chamorro@gmail.com

ABSTRACT
This study provides the most detailed description of the immature stages of Agrilus planipennis Fairmaire to date and illustrates suites of larval characters useful in distinguishing among Agrilus Curtis species and instars. Immature stages of eight species of Agrilus were examined and imaged using light and scanning electron microscopy. For A. planipennis all preimaginal stages (egg, instars I-IV, prepupa and pupa) were described. A combination of 14 character states were identified that serve to identify larvae of A. planipennis. Our results support the segregation of Agrilus larvae into two informal assemblages based on characters of the mouthparts, prothorax, and abdomen: the A. viridis and A. ater assemblages, with A. planipennis being more similar to the former. Additional evidence is provided in favor of excluding A. planipennis from the subgenus Uragrilus.

Show MeSH

Related in: MedlinePlus

Agrilus planipennis instar IV including prepupa.A, instar IV, dorsal view; B, prepupa, thoracic microspinulae; C, prepupa, thoracic microspinulae and setae; D, prepupa, microdenticles (top), microsetae (bottom); E, prepupa, pleural region of abdomen, setae and microspinulae; F, instar IV, dorsal view, detail of peristome, pro-, meso-, metathorax, and 1st abdominal segment with spiracles; G, prepupa, same as F.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3306392&req=5

pone-0033185-g006: Agrilus planipennis instar IV including prepupa.A, instar IV, dorsal view; B, prepupa, thoracic microspinulae; C, prepupa, thoracic microspinulae and setae; D, prepupa, microdenticles (top), microsetae (bottom); E, prepupa, pleural region of abdomen, setae and microspinulae; F, instar IV, dorsal view, detail of peristome, pro-, meso-, metathorax, and 1st abdominal segment with spiracles; G, prepupa, same as F.

Mentions: Length 30–36 mm. Larva of typical agrilinoid type with enlarged prothoracic and abdominal segments 1–7 and heavily sclerotized paired terminal processes (Figure 6). Body whitish with yellowish prothoracic plate, highly pigmented (brown) peristome, prothoracic (notal and sternal) grooves, spiracles, and terminal processes. Head and mouthparts. Epistome (Figure 1a) strongly transverse, 3.5–5.5 times wider than long; bearing 2 pairs of epistomal sensillae medially, arranged one directly ventral to the other, each pair consists of single anterior sensillum and 2 sunken posterior basiconic sensillae in the common pit (Figures 1a, 7); anterior margin concave between paired mandibular condyles; posterior margin bisinuate; latero-basal angles prominently rounded, blunt. Anteclypeus (Figures 1a, 2h, 3a) narrow, membranous, glabrous, anterior margin almost straight. Labrum (Figures 1a, 2h, 3a) elongate, 1.5 times longer than wide, anterior margin widely arcuate and glabrous, lateral margins subparallel, mostly membranous bearing distinct paired palatine sclerites, each divided into medial and lateral subparallel branches and slightly divergent from longitudinal midline of labrum; median sensillae of labrum along medial branches consist of a long subapical seta and 2 subbasal campaniform sensillae situated subequally (Figure 1a); anterolateral sensillae (Figure 1a) of each palatine sclerite with long dorsal anterior and short dorsal posterior seta, 4 flattened blunt anterior ventral setae arranged linearly. Epipharynx with microsetae situated only along median branches with central and lateral parts glabrous (Figure 1a). Paired antennae (Figures 1d, 7j, 7l) each 2-segmented, 1st segment subcylindrical, sclerotized, about 1.5 times wider than long, with campaniform sensillum on lower half of internal lateral margin and fringe of microspinulae around apex (anterior margin); 2nd segment as long as wide, subcylindrical with very long, sharp trichosensillum, prominent sensory appendage (sa), 2 palmate sensillae (ps), 2 basiconic sensillae at base of sensory appendage and tuft of long microspinulae apically. Paired mandibles (Figures 1c, 7g) each triangular, heavily sclerotized, bearing 2 apical teeth and subapical projection, internal margin with large penicillum consisting of elongate microtrichia, short external seta adjacent to condyle (sometimes broken off). Labio-maxillary complex (Figures 1b, 8): Paired maxillae (Figures 1b, 8f, 8g) each with cardo completely membranous with laterobasal sclerite absent, only 2 setae on membrane; stipes (Figure 1b) moderately sclerotized, long seta at base of mala, campaniform sensillum (cs) and seta laterally, fringe of microspinulae along anterior margin (Figure 8f). Paired maxillary palpi (Figure 1b) each 2-segmented, 1st segment about as long as wide, with long, sharp seta arising near anterolateral margin and campaniform sensillum almost below long seta closer to base, anterior margin glabrous with group of microspinulae at anterolateral corner; 2nd segment about 2 times longer than wide, heavily sclerotized, with campaniform sensillum medially along external (lateral) margin, curved (digitiform) sensillum along internal margin, apically 7–8 small, sensory cones. Paired mala (Figures 1b, 8f, 8g) strongly sclerotized, about 1.5 longer than wide, basiconic sensillum medially, 2–3 thick setae externally and 5 large, thick, mostly blunt setae internally with numerous microspinulae present. Labium (Figures 1b, 4a, 8c, 8e): prementum transverse about as long as wide with widely arcuate anterior margin; externally (ventrally) with dense microsetae forming microsetal area along anterior margin, posterior border of this area zigzag-shaped, extending about 1/3 distance from anterior margin to base of apical seta of paired corner sclerites of prementum (Figure 1b, csp); each corner sclerite bearing basal and 4–5 small apical campaniform sensilla (Figure 8h), short apical seta not extending to posterior border of microsetal area (Figure 4a). Hypopharynx with microsetae along anterolateral corners. Postmentum (Figure 1b) glabrous. Thorax (Figures 6f, 9). Prothorax approximately as wide as abdominal segments 1–7, meso- and metathorax each slightly narrower than prothorax (Figures 6f, 6g). Prothoracic plate pigmented, anterior half darker, round, completely covered with heavily sclerotized microdenticles situated on small rounded tubercles changing to small microspinulae toward periphery of plate (Figures 6b, 6d top, 10), with sparse short setae (Figures 10d, 10e). Pronotal groove (Figures 6f, 6g, 10d, 10e) very distinct, dark brown, bifurcating from almost posterior 1/5. Prosternal groove (Figures 10b, 10c) very distinct, dark brown, fragmenting anteriorly, with surrounding microdenticles more heavily sclerotized, asperate, remaining dark (Figure 10c). Pro-, meso-, and metathorax with microspinulae, laterally with microspinulae and setae (Figure 6e). Pair of thoracic spiracles anterolaterally on mesothorax (not visible from above), of the agriloid circular type (Figures 10f, 10g), heavily sclerotized, cribriform with relatively short, spiracular trabeculae. Thoracic and abdominal spiracles similar, differing in size and trabeculae number. Abdomen (Figure 6a). Abdominal segments pale cream colored, segments 2–7 becoming increasingly trapezoidal, almost bell-shaped (predominantly 5–7), of approximately equal width and length, segment 1 almost 1/3 shorter than subsequent segments, segments 8–9 about half as tall as preceding, each narrower than preceding segment; segments 1–8 dorsally and ventrally bearing shallow longitudinal lateral depressions, dorsally situated almost posterad to spiracles; bottom of depressions covered with darker internal reticulation. Segment 10 (anal segment, Figures 11, 12) deltoid, bearing setae laterally, zones of microspinulae around anal opening; apically with heavily sclerotized paired terminal processes with apical, median, and basal excretory ducts present (Figures 11e, 11h, 11i, 12e) and numerous secondary subdivisions (ledges) (Figures 11e, 12e) [27]. Dorsal surface of abdomen almost glabrous, segments 1–9 with paired oval, subparallel bands of very light microspinulae, laterally with setae, microspinulae posterolaterad; segments 8–9 with transverse posterior zones of microspinulae. Paired spiracles anterodorsally on abdominal segments 1–8.


Preimaginal stages of the emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae): an invasive pest on ash trees (Fraxinus).

Chamorro ML, Volkovitsh MG, Poland TM, Haack RA, Lingafelter SW - PLoS ONE (2012)

Agrilus planipennis instar IV including prepupa.A, instar IV, dorsal view; B, prepupa, thoracic microspinulae; C, prepupa, thoracic microspinulae and setae; D, prepupa, microdenticles (top), microsetae (bottom); E, prepupa, pleural region of abdomen, setae and microspinulae; F, instar IV, dorsal view, detail of peristome, pro-, meso-, metathorax, and 1st abdominal segment with spiracles; G, prepupa, same as F.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3306392&req=5

pone-0033185-g006: Agrilus planipennis instar IV including prepupa.A, instar IV, dorsal view; B, prepupa, thoracic microspinulae; C, prepupa, thoracic microspinulae and setae; D, prepupa, microdenticles (top), microsetae (bottom); E, prepupa, pleural region of abdomen, setae and microspinulae; F, instar IV, dorsal view, detail of peristome, pro-, meso-, metathorax, and 1st abdominal segment with spiracles; G, prepupa, same as F.
Mentions: Length 30–36 mm. Larva of typical agrilinoid type with enlarged prothoracic and abdominal segments 1–7 and heavily sclerotized paired terminal processes (Figure 6). Body whitish with yellowish prothoracic plate, highly pigmented (brown) peristome, prothoracic (notal and sternal) grooves, spiracles, and terminal processes. Head and mouthparts. Epistome (Figure 1a) strongly transverse, 3.5–5.5 times wider than long; bearing 2 pairs of epistomal sensillae medially, arranged one directly ventral to the other, each pair consists of single anterior sensillum and 2 sunken posterior basiconic sensillae in the common pit (Figures 1a, 7); anterior margin concave between paired mandibular condyles; posterior margin bisinuate; latero-basal angles prominently rounded, blunt. Anteclypeus (Figures 1a, 2h, 3a) narrow, membranous, glabrous, anterior margin almost straight. Labrum (Figures 1a, 2h, 3a) elongate, 1.5 times longer than wide, anterior margin widely arcuate and glabrous, lateral margins subparallel, mostly membranous bearing distinct paired palatine sclerites, each divided into medial and lateral subparallel branches and slightly divergent from longitudinal midline of labrum; median sensillae of labrum along medial branches consist of a long subapical seta and 2 subbasal campaniform sensillae situated subequally (Figure 1a); anterolateral sensillae (Figure 1a) of each palatine sclerite with long dorsal anterior and short dorsal posterior seta, 4 flattened blunt anterior ventral setae arranged linearly. Epipharynx with microsetae situated only along median branches with central and lateral parts glabrous (Figure 1a). Paired antennae (Figures 1d, 7j, 7l) each 2-segmented, 1st segment subcylindrical, sclerotized, about 1.5 times wider than long, with campaniform sensillum on lower half of internal lateral margin and fringe of microspinulae around apex (anterior margin); 2nd segment as long as wide, subcylindrical with very long, sharp trichosensillum, prominent sensory appendage (sa), 2 palmate sensillae (ps), 2 basiconic sensillae at base of sensory appendage and tuft of long microspinulae apically. Paired mandibles (Figures 1c, 7g) each triangular, heavily sclerotized, bearing 2 apical teeth and subapical projection, internal margin with large penicillum consisting of elongate microtrichia, short external seta adjacent to condyle (sometimes broken off). Labio-maxillary complex (Figures 1b, 8): Paired maxillae (Figures 1b, 8f, 8g) each with cardo completely membranous with laterobasal sclerite absent, only 2 setae on membrane; stipes (Figure 1b) moderately sclerotized, long seta at base of mala, campaniform sensillum (cs) and seta laterally, fringe of microspinulae along anterior margin (Figure 8f). Paired maxillary palpi (Figure 1b) each 2-segmented, 1st segment about as long as wide, with long, sharp seta arising near anterolateral margin and campaniform sensillum almost below long seta closer to base, anterior margin glabrous with group of microspinulae at anterolateral corner; 2nd segment about 2 times longer than wide, heavily sclerotized, with campaniform sensillum medially along external (lateral) margin, curved (digitiform) sensillum along internal margin, apically 7–8 small, sensory cones. Paired mala (Figures 1b, 8f, 8g) strongly sclerotized, about 1.5 longer than wide, basiconic sensillum medially, 2–3 thick setae externally and 5 large, thick, mostly blunt setae internally with numerous microspinulae present. Labium (Figures 1b, 4a, 8c, 8e): prementum transverse about as long as wide with widely arcuate anterior margin; externally (ventrally) with dense microsetae forming microsetal area along anterior margin, posterior border of this area zigzag-shaped, extending about 1/3 distance from anterior margin to base of apical seta of paired corner sclerites of prementum (Figure 1b, csp); each corner sclerite bearing basal and 4–5 small apical campaniform sensilla (Figure 8h), short apical seta not extending to posterior border of microsetal area (Figure 4a). Hypopharynx with microsetae along anterolateral corners. Postmentum (Figure 1b) glabrous. Thorax (Figures 6f, 9). Prothorax approximately as wide as abdominal segments 1–7, meso- and metathorax each slightly narrower than prothorax (Figures 6f, 6g). Prothoracic plate pigmented, anterior half darker, round, completely covered with heavily sclerotized microdenticles situated on small rounded tubercles changing to small microspinulae toward periphery of plate (Figures 6b, 6d top, 10), with sparse short setae (Figures 10d, 10e). Pronotal groove (Figures 6f, 6g, 10d, 10e) very distinct, dark brown, bifurcating from almost posterior 1/5. Prosternal groove (Figures 10b, 10c) very distinct, dark brown, fragmenting anteriorly, with surrounding microdenticles more heavily sclerotized, asperate, remaining dark (Figure 10c). Pro-, meso-, and metathorax with microspinulae, laterally with microspinulae and setae (Figure 6e). Pair of thoracic spiracles anterolaterally on mesothorax (not visible from above), of the agriloid circular type (Figures 10f, 10g), heavily sclerotized, cribriform with relatively short, spiracular trabeculae. Thoracic and abdominal spiracles similar, differing in size and trabeculae number. Abdomen (Figure 6a). Abdominal segments pale cream colored, segments 2–7 becoming increasingly trapezoidal, almost bell-shaped (predominantly 5–7), of approximately equal width and length, segment 1 almost 1/3 shorter than subsequent segments, segments 8–9 about half as tall as preceding, each narrower than preceding segment; segments 1–8 dorsally and ventrally bearing shallow longitudinal lateral depressions, dorsally situated almost posterad to spiracles; bottom of depressions covered with darker internal reticulation. Segment 10 (anal segment, Figures 11, 12) deltoid, bearing setae laterally, zones of microspinulae around anal opening; apically with heavily sclerotized paired terminal processes with apical, median, and basal excretory ducts present (Figures 11e, 11h, 11i, 12e) and numerous secondary subdivisions (ledges) (Figures 11e, 12e) [27]. Dorsal surface of abdomen almost glabrous, segments 1–9 with paired oval, subparallel bands of very light microspinulae, laterally with setae, microspinulae posterolaterad; segments 8–9 with transverse posterior zones of microspinulae. Paired spiracles anterodorsally on abdominal segments 1–8.

Bottom Line: A combination of 14 character states were identified that serve to identify larvae of A. planipennis.Our results support the segregation of Agrilus larvae into two informal assemblages based on characters of the mouthparts, prothorax, and abdomen: the A. viridis and A. ater assemblages, with A. planipennis being more similar to the former.Additional evidence is provided in favor of excluding A. planipennis from the subgenus Uragrilus.

View Article: PubMed Central - PubMed

Affiliation: United States Department of Agriculture, Agricultural Research Service, Systematic Entomology Laboratory, Washington, DC, United States of America. lourdes.chamorro@gmail.com

ABSTRACT
This study provides the most detailed description of the immature stages of Agrilus planipennis Fairmaire to date and illustrates suites of larval characters useful in distinguishing among Agrilus Curtis species and instars. Immature stages of eight species of Agrilus were examined and imaged using light and scanning electron microscopy. For A. planipennis all preimaginal stages (egg, instars I-IV, prepupa and pupa) were described. A combination of 14 character states were identified that serve to identify larvae of A. planipennis. Our results support the segregation of Agrilus larvae into two informal assemblages based on characters of the mouthparts, prothorax, and abdomen: the A. viridis and A. ater assemblages, with A. planipennis being more similar to the former. Additional evidence is provided in favor of excluding A. planipennis from the subgenus Uragrilus.

Show MeSH
Related in: MedlinePlus