Research Article |
Corresponding author: Xanthe A. Shirley ( xanthe.shirley@gmail.com ) Academic editor: Hannes Baur
© 2017 Xanthe A. Shirley, James B. Woolley, Keith R. Hopper.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Shirley XA, Woolley JB, Hopper KR (2017) Revision of the asychis species group of Aphelinus (Hymenoptera: Aphelinidae). Journal of Hymenoptera Research 54: 1-32. https://doi.org/10.3897/jhr.54.10457
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Aphelinus (Hymenoptera: Aphelinidae) is a genus of parasitoid wasps that has a long history of use in biological control programs against aphids. Past research shows that species delimitation within Aphelinus is greatly complicated by lack of comprehensive literature and the existence of cryptic species complexes. One of these complexes is the Aphelinus asychis species group. Through the development of a morphological character set, a revision of the Aphelinus asychis species group was conducted. Two new species, Aphelinus sinensis sp. n., and Aphelinus kazakhstanensis sp. n., are described, and the two existing valid species within the asychis group, Aphelinus asychis and Aphelinus semiflavus are redescribed and lectotypes are designated for Aphelinus semiflavus and Aphelinus brevipennis (a junior synonym of A. semiflavus). We also provide a key for identifying species in the asychis group.
Taxonomy, Chalcidoidea , sibling species, description, distribution
Aphelinus Dalman, 1820 is a genus of chalcidoid wasps in the family Aphelinidae, subfamily Aphelininae (see
Aphelinus asychis is common in both the Old World and New World, and it is an important parasitoid of aphids (ca. 60 documented aphid hosts). It has been used in biological control of at least six aphid species (
A major factor that impedes the success of biological control programs is delayed recognition of cryptic species. Testing for reproductive compatibility is one way to discover cryptic species.
A second issue in this species group is considerable confusion over whether A. asychis and A. semiflavus are different species.
Further work in the asychis species group is needed to (1) understand the nature and relationships among the three groups found by
Following
Specimens used in this study were killed in 95% ethanol and stored in freezers. Most were then critical-point-dried using a Samdri 790 CPD unit. Critical-point-dried specimens were card mounted with Franklin International’s water soluble Titebond Liquid Hide Glue. Selected specimens were slide-mounted following
Images for figures were acquired using digital imaging and image-stacking. Specimens photographed for coloration were removed from alcohol storage, placed on a layer of water-based, water-soluble jelly in a small watch glass, submerged in alcohol, and photographed using a Leica M205 FA stereomicroscope and Leica Applications Suite software (ver. 4.5) as were card-mounted or point-mounted specimens. Slide-mounted specimens were photographed using an Olympus BH2 microscope with DIC illumination and Image-Pro Plus software (ver. 7.0). Zerene Stacker (http://zerenesystems.com) was used for all image stacking. Adobe Photoshop CS6, Adobe Lightroom 5, and Adobe InDesign CS6 were used for final modifications to images and layout of plates. All images were deposited in mx, a web-based content management database system. Morphological codings were conducted in mx. The mx system is open source, with further documentation available at http://mx.phenomix.org.
See Appendix Table
Measurements from slide mounts were taken using an eyepiece reticle in a Zeiss standard 16 microscope. Measurements from card mounts were taken using an eyepiece reticle in a Leica MZ16 microscope. Raw measurements are only reported for body length, which is followed by the range and the number of specimens measured. The remaining measurements are reported as ratios.
Head. The length of the head was measured from the anterior to the posterior margin in dorsal view (Fig.
Meso/Metasoma length. Meso/metasoma length of specimens was measured from the anterior margin of the pronotum to the apex of the epiproct using slide-mounted specimens. The lengths of the mesosoma, the mid lobe of mesoscutum, and the scutellum were measured from their anterior to posterior margins along the mid line and widths were measured at their widest points.
Wings. Fore wing measurements are shown in Figure
Male Genitalia and Ovipositor. The length of the phallobase was measured from the anterior margin of the genital capsule to the posterior end of the digiti (Fig.
Measurements and terminology. 1a Aphelinus kazakhstanensis sp. n. female, head, dorsal view (
1 | Procoxa yellow (Fig. |
sinensis Shirley & Woolley, sp. n. |
– | Procoxa brown (Figs |
2 |
2 | Profemur entirely yellow or pale (Figs |
semiflavus Howard |
3 | Profemur brown at base (Figs |
3 |
4 | Mesotibia entirely yellow (Figs |
kazakhstanensis Shirley & Woolley, sp. n. |
5 | Mesotibia brown at base or dark with apex pale (Figs |
asychis Walker |
Aphelinus
asychis
Walker, 1839, lectotype designation by
Aphelinus
euthria
Walker, 1839, synonymy and lectotype designation by
Myina
affinis
Förster, 1841, synonymy and lectotype designation by
Aphelinus affinis (Förster, 1841): Dalla Torre (1898).
Aphelinus
brevicalcar
Thomson, 1876, synonymy and lectotype designation by
Aphelinus
brachyptera
Kurdjumov, 1913, synonymy and lectotype designation by
Aphelinus
dubia
Kurdjumov, 1913, synonymy and lectotype designation by
Females and males. Legs with procoxa brown (Fig.
Aphelinus asychis, card-mounted specimens 3a male, antennae and head, lateral view (
Female (Figs
Color (Fig.
Body length. 0.9 mm (n=2; slide mounts).
Head (Figs
Mesosoma (Figs
Fore wing (Fig.
Aphelinus asychis, slide-mounted specimens 4a male, antenna, lateral view (
Hind wing (Fig.
Metasoma (Figs
Description. Male (Figs
Color (Fig.
Head (Figs
Metasoma (Fig.
Aphelinus asychis Walker, 1839, lectotype female (
Aphelinus euthria Walker, 1839, lectotype female and paralectotype female (
Myina affinis Förster, 184, lectotype female (NHW, examined). Card-mounted. Label data: “Myina affinis | Förster | Lectotype ♀|| M. affinis Förster || Collect. G. Mayr”. Paralectotype female (NHW, examined). Card-mounted. Label data: “M. affinis | Förster, Type || Collect. | G. Mayr”.
Aphelinus brevicalcar Thomson, 1876, lectotype female (LUZN, examined). Card-mounted. Label data: “Aphelinus brevicalcar | Lectotype ♀. Thomas. | M. de V. Graham || Lectotype || Type No. 1574:1”.
Aphelinus brachyptera Kurdjumov, 1913, lectotype female (NHW, examined). Card-mounted. Label data: “Aphelinus brachyptera | (Först. MS). | Lectotype | M. de V. Graham || A. brachyptera | Förster Type || Collect. G. Mayr || 182”.
Aphelinus dubia Kurdjumov, 1913, lectotype female (NHW, examined). Mounted on minuten pin on block. Label data: “Aphelinus | (Föst. MS.) K | Lectotype || M. dubia | Förster, Type || Collect. | G. Mayr”. Paralectotypes, five females. Mounted on minuten pins on block. Label data as lectotype.
AUSTRALIA:Australian Capital Territory: 1 sex unknown, 3 males, 17 females.
Acyrthosiphon kondoi Shinji, 1938, Acyrthosiphon pisum (Harris, 1776), Aphis gossypii (Glover, 1877), Aphis umbrella (Börner, 1950), Brevicoryne brassicae (Linnaeus, 1758), Chaetosiphon fragaefolii (Cockerell, 1901), Diuraphis noxia, Hyperomyzus lactucae (Linnaeus, 1758), Myzus persicae, Rhopalosiphum maidis (Fitch, 1856), Schizaphis graminum, Therioaphis trifolii, and Toxoptera Koch, 1856 sp.
Old World and some New World populations, discussed below.
The collections from France, Italy, Morocco, and Spain correspond to those discussed in
Numerous populations of A. asychis are present in North America. The population from Randall Co., Texas, is presumed to have originated from biological control program releases of A. asychis against the Russian wheat aphid in that area. The population from Wayne Co., Missouri, was collected from a Malaise trap, and one specimen from Florida was collected by a flight interception trap, both in the late 1980’s. The populations from Stillwater, Oklahoma, originated from a lab culture of A. asychis for Schizaphis graminum biological control. The two specimens collected from Manhattan, Kansas, from spotted alfalfa aphid in a greenhouse probably result from agricultural research at Kansas State University. The series from Alameda Co., California, 1962, is from the former UC Insectary, Oxford Tract, and was possibly being researched as a candidate for biological control of yellow clover aphid or other pest aphids.
However, in a few cases, A. asychis was found in North America before any documented biological control releases. An A. asychis specimen was collected in Florida in 1952, which does not have any associated host data. Two specimens from Maryland, one from Myzus persicae and one from strawberry aphids were collected in 1962 and 1950, respectively. One specimen from Maine in 1958 was collected from a Capitophorus aphid mummy. Two specimens from Colorado were collected from Myzus persicae mummies, one in 1940 and the other in 1988. These records are especially interesting because they are geographically close to the type locality and host of A. semiflavus. The specimens from Minnesota, Ohio, and California (
The lectotype and paralectotype females of affinis Förster were examined (NHW, Vienna). They are point-mounted specimens in good condition. We concur with
The type material of dubia Kurdjumov (NHW, Vienna) which consists of a female lectotype and five female paralectotypes, mounted together on a small wooden block on minuten pins, and a second pin with a wooden block bearing five additional female paralectotypes, was examined. A red dot next to one pin identifies the lectotype. The specimens are dirty and in poor condition and the minuten pins are rusting. Although we note some color variation in the metasoma of these specimens, we concur with
Females and males. Legs with procoxa brown (Fig.
Aphelinus kazakhstanensis, paratypes in 95% ethanol 5a male, antennae and face, anterior view (
Female (Figs
Color (Fig.
Body length. 0.7–0.9 mm (n=3; slide mounts) (Holotype 0.7 mm).
Head (Figs
Mesosoma (Figs
Fore wing (Fig.
Hind wing (Fig.
Metasoma (Figs
Description: Male (Figs
Color (Fig.
Head (Figs
Metasoma (Fig.
Holotype (deposited in
Paratypes (deposited in
Aphelinus kazakhstanensis, slide-mounted paratypes 6a male, antenna, lateral view (
None.
The original material was collected from Diuraphis noxia in the field in Dmitrievka, Kazakhstan. In lab culture, Diuraphis noxia on wheat was used as the host.
The species is known only from type material from Dmitrievka, Kazakhstan.
Discussion. The collections from Kazakhstan, Dmitrievka correspond exactly to those discussed in
Aphelinus semiflavus Howard, 1908.
Aphelinus
brevipennis
Girault, 1917, synonymy by
Females and males. Legs with procoxa brown (Fig.
Aphelinus semiflavus, point-mounted specimens 7a male, antennae and face, lateral view (
Female (Figs
Color (Fig.
Body length. 0.5–1.0 mm (n=3; slide mounts) (Paralectotypes 0.5–0.6 mm).
Head (Figs
Mesosoma (Figs
Fore wing (Fig.
Hind wing (Fig.
Metasoma (Figs
Description. Male (Figs
Color (Fig.
Head (Figs
Metasoma (Fig.
Aphelinus semiflavus, slide-mounted specimens 8a male, antenna, lateral view (paralectotype) 8b female, antenna, lateral view (paralectotype) 8c male, fore wing, dorsal view (paralectotype) 8d female, fore wing, dorsal view (paralectotype) 8e female, hind wing, dorsal view (paralectotype) 8f female, metasoma, ventral view (
Aphelinus semiflavus
Aphelinus brevipennis
CANADA: 2 sex unknowns, 18 females, 8 males.
Acyrthosiphon malvae (Mosley, 1841), Acyrthosiphon pisum, Aphis eugeniae van der Goot, 1917, Brachycaudus helichrysi (Kaltenbach, 1843), Coloradoa rufomaculata (Wilson, 1908), Capitophorus xanthii (Oestlund, 1886), Diuraphis noxia, Illinoia liriodendra (Monell, 1879), Macrosiphoniella ludovicianae (Oestlund, 1886), Myzus persicae, Myzaphis rosarum (Kaltenbach, 1843), Neomyzus circumflexus (Buckton, 1876), Rhopalosiphum maidis, Rhopalosiphum nymphaeae (Linnaeus, 1761), Schizaphis graminum, Therioaphis trifolii, and Toxoptera sp.
New World, with few populations in Old World (from France, Korea and Spain).
There has been confusion in the past about whether or not A. asychis and A. semiflavus are separate species. Based on the material examined, leg coloration patterns clearly differ between them. Regarding the New World populations examined, we are treating most North American populations as semiflavus, noting that in the Mexico and Winnipeg, Canada, populations, the metatibia are yellow/brown [not dark brown at base with apex pale].
We consider the Bangalore, India, and Dezful, Iran populations as sp. nr. semiflavus, noting that the India population has mid tibia and mid femora with brown [not yellow] and the Dezful, Iran, population has legs like semiflavus except one female with brown [not yellow] on mid tibia and mid femora. There is one specimen from Virginia that we are treating as possibly semiflavus, noting that the fore femora and fore tibia are brown [not yellow].
We have examined the lectotype female and paralectotype male of brevipennis Girault and agree with the conclusion of
Future work should use reciprocal crosses and perhaps molecular data to determine whether populations of A. semiflavus in Old World vs. New World are in fact one species, are races of one species with different host ranges, or are two distinct cryptic species.
Females and males. Legs with procoxa yellow (Fig.
Aphelinus sinensis n.sp., paratypes in 95% ethanol 9a male, antennae and face, anterior view (
Female (Figs
Color (Figs
Body length. 0.6–0.9 mm (n=3; slide mounts) (Holotype 0.8 mm).
Head (Figs
Mesosoma (Figs
Fore wing (Fig.
Hind wing (Fig.
Metasoma (Figs
Description. Male (Figs
Color (Fig.
Head (Figs
Metasoma (Fig.
Holotype (deposited in
Paratypes (deposited in
Aphelinus sinensis n.sp., slide-mounted paratypes 10a male, antenna, lateral view (
CHINA: Harbin: 3 males, 5 females.
The original material was collected from Diuraphis tritici (Gillette 1911) (the junior synonym Diuraphis agropyronophaga is given on the holotype label) in the field in China. In lab culture, Diuraphis noxia on wheat was used as the host.
Northern China and Japan.
The collections from China, Pingluo, Ningxia correspond exactly to those discussed in
There are two additional potential new species, but there is not enough material to describe them. One potential new species is from Harrow, Canada, and has leg coloration like asychis, but includes a brown metafemur [not yellow]. There are two other Canadian series with one specimen in each series that also has this leg coloration. The other potential new species is from Dorking, England, and is represented by a single specimen that has leg coloration with all segments very dark brown.
We would like to thank Jewel Coffey, Bryant McDowell and Itzel Cetina, Texas A&M lab technicians, for digital imaging/processing, plate preparation, database management, and specimen preparation. Thanks to Courtney Hendler, Bethany Lefner and Ada Morales, Texas A&M undergraduate student workers, for digital imaging, and thanks to Kathryn Lanier, USDA-ARS-BIIRL, for maintaining cultures of Aphelinus and shipping specimens. So many museum curators and colleagues have helped with this research that we cannot list them all, but we would like to recognize Serguei Belokobylski (ZIS), Natalie Dale-Skey (
Morphological terms used, their definitions, and URI locations on the Hymenoptera Anatomy Ontology web site (
Term | Definition | URI |
---|---|---|
antenna | The anatomical cluster that is composed of the scape, pedicel and flagellum. | http://purl.obolibrary.org/obo/HAO_0000101 |
base | The tergum that is located on abdominal segment 2 AND The tergum that is located on the abdominal segment 3. | http://purl.obolibrary.org/obo/HAO_0000053 and http://purl.obolibrary.org/obo/HAO_0000056 |
body | The anatomical cluster that is composed of the whole organism but which excludes the antennae, legs and wings. | http://purl.obolibrary.org/obo/HAO_0000182 |
club | The anatomical cluster composed of the apical flagellomeres that are differentiated by size from the basal flagellomeres. | http://purl.obolibrary.org/obo/HAO_0001185 |
compound eye | The compound organ that is composed of ommatidia. | http://purl.obolibrary.org/obo/HAO_0000217 |
costal cell | The membranous region of the fore wing anterior to the submarginal vein, measured from the basal constriction that delimits the apex of the humeral plate of the wing to the point at which the submarginal vein touches the leading edge of the wing. | http://purl.obolibrary.org/obo/HAO_0000226 |
coxa | The leg segment that is connected to the body and to the trochanter via conjunctivae and muscles. | http://purl.obolibrary.org/obo/HAO_0000228 |
digitus | The sclerite that is located distally on the parossiculus. | http://purl.obolibrary.org/obo/HAO_0000385 |
edge | The margin that extends along the border of two areas that are oriented differently. | http://purl.obolibrary.org/obo/HAO_0000285 |
eye margin | The margin of the compound eye. | http://purl.obolibrary.org/obo/HAO_0000672 |
F1 | The flagellomere that is proximally attached to the pedicel. | http://purl.obolibrary.org/obo/HAO_0001148 |
F2 | The flagellomere that is located distal to the first flagellomere. | http://purl.obolibrary.org/obo/HAO_0001883 |
F3 | The flagellomere that is located immediately distal to the second flagellomere. | http://purl.obolibrary.org/obo/HAO_0001895 |
femur | The leg segment that is distal to the trochanter and proximal to the tibia. | http://purl.obolibrary.org/obo/HAO_0000327 |
Fore wing | The wing that is located on the mesothorax. | http://purl.obolibrary.org/obo/HAO_0000351 |
frontovertex | The anatomical cluster that is composed of the vertex and the dorsal area of the upper face dorsal to the frontofacial ridge. | http://purl.obolibrary.org/obo/HAO_0001823 |
genitalia | The anatomical cluster that is composed of the cupula, gonostyle, volsella and the aedeagus | http://purl.obolibrary.org/obo/HAO_0000312 |
head | The tagma that is located anterior to the thorax. | http://purl.obolibrary.org/obo/HAO_0000397 |
hind wing | The wing that is located on the metathorax. | http://purl.obolibrary.org/obo/HAO_0000400 |
leg | The anatomical cluster that is composed of the coxa and all distal leg segments and is connected to the pectus. | http://purl.obolibrary.org/obo/HAO_0000494 |
longitudinal sensillum | The multiporous plate sensillum that is elongate. | http://purl.obolibrary.org/obo/HAO_0001936 |
margin | The line that delimits the periphery of an area. | http://purl.obolibrary.org/obo/HAO_0001133 |
marginal vein | The abscissa that is located along the anterior margin of the fore wing and is thought to correspond to the anterior abscissa of the radius (R1). | http://purl.obolibrary.org/obo/HAO_0000635 |
mesobasitarsus | The basitarsus that is located in the mid leg. | http://purl.obolibrary.org/obo/HAO_0001131 |
mesocoxa | The coxa that is located on the mid leg. | http://purl.obolibrary.org/obo/HAO_0001490 |
mesofemur | The femur that is located on the mid leg. | http://purl.obolibrary.org/obo/HAO_0000576 |
mesoscutum | The area that is located anterior to the transscutal articulation. | http://purl.obolibrary.org/obo/HAO_0001351 |
mesosoma | The anatomical cluster that is composed of the prothorax, mesothorax and the metapectal-propodeal complex. | http://purl.obolibrary.org/obo/HAO_0001120 |
mesotibia | The tibia that is located on the mid leg. | http://purl.obolibrary.org/obo/HAO_0001142 |
mesotibial spur | The tibial spur that is located on the mesotibia. | http://purl.obolibrary.org/obo/HAO_0001142 |
metabasitarsus | The basitarsus that is located on the hind leg. | http://purl.obolibrary.org/obo/HAO_0000587 |
metacoxa | The coxa that is located on the hind leg. | http://purl.obolibrary.org/obo/HAO_0000631 |
metasoma | The tagma that is connected anteriorly to the metapectal-propodeal complex at the pro- podeal foramen and consists of abdominal segments. | http://purl.obolibrary.org/obo/HAO_0001121 |
metatibia | The tibia that is located on the hind leg. | http://purl.obolibrary.org/obo/HAO_0000679 |
metatibial spur | The tibial spur that is located on the metatibia. | http://purl.obolibrary.org/obo/HAO_0000706 |
mid lobe of mesoscutum | The area that is located between the notauli. | http://purl.obolibrary.org/obo/HAO_0000520 |
occipital margin | The edge that separates the occiput from the vertex. | http://purl.obolibrary.org/obo/HAO_0001963 |
ocellus | The multi-tissue structure that is located on the top of the head, composed of the corneal lens, pigment cell, rhabdoms and synaptic plexus. | http://purl.obolibrary.org/obo/HAO_0000661 |
ovipositor | The anatomical cluster that is composed of the first valvulae, second valvulae, third valvu- lae, first valvifers and second valvifers . | http://purl.obolibrary.org/obo/HAO_0000510 |
pedicel | The antennal segment that is the second segment of the antenna and is connected proxi- mally with the scape and distally with the flagellum. | http://purl.obolibrary.org/obo/HAO_0000512 |
phallobase | The anatomical cluster that is composed of the cupulae, gonostipites and volsellae. | http://purl.obolibrary.org/obo/HAO_0000713 |
posterior ocellus | The ocellus that is paired. | http://purl.obolibrary.org/obo/HAO_0000481 |
procoxa | The coxa that is located on the fore leg. | http://purl.obolibrary.org/obo/HAO_0001122 |
profemur | The femur that is located on the fore leg. | http://purl.obolibrary.org/obo/HAO_0001124 |
protibia | The tibia that is located on the fore leg. | http://purl.obolibrary.org/obo/HAO_0000350 |
radicle | The area that is located proximally on the scape, is limited distally by a constriction and bears proximally the basal knob. | http://purl.obolibrary.org/obo/HAO_0000889 |
row | The anatomical cluster that is composed of repeated units of anatomical structures. | http://purl.obolibrary.org/obo/HAO_0000901 |
scape | The antennal segment that is proximal to the pedicel and is connected with the head via the radicle. | http://purl.obolibrary.org/obo/HAO_0000908 |
scutellum | The area that is located posteriorly of the transscutal line and is composed of the axillae and the mesoscutellum. | http://purl.obolibrary.org/obo/HAO_0000572 |
secretory pore | The anatomical space that corresponds to the distal end of an exocrine gland. | http://purl.obolibrary.org/obo/HAO_0001966 |
seta | The sensillum that is multicellular and consists of trichogen, tormogen, and sense cells. The area that is located between the notaulus and the parascutal carina. | http://purl.obolibrary.org/obo/HAO_0000935 |
side lobe of mesoscutum | The area that is located between the notaulus and the parascutal carina. | http://purl.obolibrary.org/obo/HAO_0000466 |
stigma | The patch on the wing that is sclerotized and is located on the anterior margin of the fore wing. | http://purl.obolibrary.org/obo/HAO_0000957 |
submarginal vein | Basal-most portion of the fore wing vein complex that occurs behind the costal cell; measured from the constriction that delimits the humeral plate to the point at which the vein touches the leading edge of the wing apically. | http://purl.obolibrary.org/obo/HAO_0000972 |
tarsus | The leg segment that is apical to the tibia. | http://purl.obolibrary.org/obo/HAO_0000992 |
third valvula | The sclerite that is located posterior to the second valvifer and is connected to the second valvifer via conjuntiva. | http://purl.obolibrary.org/obo/HAO_0001012 |
wing | The appendage that is between the notum and the pectus and is connected to the body by the axillary sclerite muscles. | http://purl.obolibrary.org/obo/HAO_0001089 |