Research Article |
Corresponding author: Michael W. Gates ( michael.gates@ars.usda.gov ) Academic editor: Petr Janšta
© 2020 Michael W. Gates, Y. Miles Zhang, Matthew L. Buffington.
This is an open access article distributed under the terms of the CC0 Public Domain Dedication.
Citation:
Gates MW, Zhang YM, Buffington ML (2020) The great greenbriers gall mystery resolved? New species of Aprostocetus Westwood (Hymenoptera, Eulophidae) gall inducer and two new parasitoids (Hymenoptera, Eurytomidae) associated with Smilax L. in southern Florida, USA. Journal of Hymenoptera Research 80: 71-98. https://doi.org/10.3897/jhr.80.59466
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Aprostocetus smilax Gates & Zhang, sp. nov., is described from stem and leaf galls on Smilax havanensis Jacq. in southern Florida, USA. It is the third species of Aprostocetus Westwood known to induce plant galls. Two parasitoids of A. smilax are also described: Phylloxeroxenus smilax Gates & Zhang sp. nov. and Sycophila smilax Gates & Zhang, sp. nov. We conclude that A. smilax is the true gall inducer on Smilax L., and thus the host records of Diastrophus smilacis Ashmead and its inquiline Periclistus smilacis Ashmead, both from Smilax, are erroneous.
Chalcidoidea, Cynipidae, Diastrophus, Sycophila, Phylloxeroxenus, Periclistus
Gall induction in Chalcidoidea was summarized by
Aprostocetus Westwood is the largest genus within the subfamily Tetrastichinae, containing >800 species distributed worldwide that are most frequently associated with insect galls induced by four insect orders and Acari as parasitoids or inquilines (
Illustration of the stem gall on Smilax havanensis induced by Aprostocetus smilax (top right), with the inset showing the internal structure and an egg. Two eurytomid parasitoids, Phylloxeroxenus smilax (middle right), and Sycophila smilax (bottom right) are included. Illustration by Taina Litwak.
Smilax L. are monocots in the family Smilaceae, with ~350 species found mostly in tropical and subtropical regions of the world (
Freshly collected stem and leaf galls of S. havanensis were dissected during field work in the Miami area in 2010 by MWG and MLB. A Nikon 20× Mini Field stereoscope, fine forceps, and GEM Blue Star Super Single Edge razors were used. Slices of galls were successively removed, gradually exposing individual locules. We dissected ~20 multilocular galls and notes were made about the contents of each locule in terms of its condition and occupant prior to each occupant being assigned a code and preserved in 80% ethanol. We noted six ectoparasitoid specimens. Pertinent taxon-specific notes are included in results below.
Ethanol-preserved specimens were dehydrated through increasing concentrations of ethanol, and transferred to hexamethyldisilazane (HMDS) (
We used several species keys to determine whether our material belonged to any described species (
Terminologies used for surface sculptures follow
Specimens were extracted, amplified, and sequenced at USDA Beltsville Agricultural Research Center (BARC) using the DNeasyTM Tissue Kit protocol (Qiagen, Valencia, CA, USA). Specimens were digested for circa three hours using 20 μL of 20 mg/mL Proteinase K at 55 °C. The DNA was resuspended with 150 μL of Qiagen elution buffer. Fragments of mtDNA COI (620 bp) were amplified using LCO1490 5’-GGTCAACAAATCATAAAGATATTGG-3’ and HCO2198 5’-TAAACTTCAGGGTGACCAAAAAATCA-3’ (
ID | Voucher | COI | 28S |
---|---|---|---|
Aprostocetus smilax | G0006A | MT576085 | MT560740 |
G0008A | N/A | MT560741 | |
G0008B | MT576086 | MT560742 | |
G0009 | MT576087 | MT560743 | |
G0010A | MT576088 | MT560744 | |
G0010C | MT576089 | MT560745 | |
G0010E | MT576090 | MT560746 | |
G0010F | MT576091 | MT560747 | |
G0013A | MT576092 | MT560748 | |
G0014 | MT576093 | MT560749 | |
Phylloxeroxenus smilax | G0015 | MT576094 | MT560750 |
Aprostocetus smilax | G0016 | MT576095 | N/A |
G0017 | MT576096 | MT560751 | |
G0018 | MT576097 | MT560752 | |
G0019 | MT576098 | MT560753 | |
G0021 | MT576099 | MT560754 | |
G0022 | MT576100 | MT560755 | |
G0023 | MT576101 | MT560756 | |
G0024 | MT576102 | MT560757 | |
G0025 | MT576103 | MT560758 | |
G0026 | MT576104 | MT560759 | |
G0030 | MT576105 | MT560760 | |
G0031 | MT576106 | MT560761 | |
G0034 | MT576107 | MT560762 | |
G0036 | MT576108 | MT560763 | |
G0041 | MT576109 | MT560764 | |
Tetrastichinae sp. | G0042 | MT576110 | MT560765 |
Aprostocetus smilax | G0043 | MT576111 | MT560766 |
G0044 | MT576112 | MT560767 | |
Sycophila smilax | G0045 | N/A | MT560768 |
Aprostocetus smilax | G0046 | MT576113 | MT560769 |
G0047 | MT576114 | MT560770 | |
G0049 | MT576115 | MT560771 | |
G0050 | MT576116 | N/A | |
Phylloxeroxenus smilax | G0051 | N/A | MT560772 |
Brasema sp. | G0052 | MT576117 | MT560773 |
Sycophila smilax | G0053 | N/A | MT560774 |
Phylloxeroxenus smilax | G0054 | MT576118 | MT560775 |
Sycophila smilax | G0055 | N/A | MT560776 |
G0056 | MT576119 | MT560777 | |
Phylloxeroxenus smilax | G0057 | N/A | MT560778 |
G0058 | N/A | MT560779 | |
Aprostocetus smilax | G0059 | MT576120 | MT560780 |
G0061 | MT576121 | MT560781 | |
G0063 | MT576122 | MT560782 | |
G0064 | MT576123 | MT560783 | |
G0065 | N/A | MT560784 | |
G0066 | MT576124 | MT560785 | |
G0070 | MT576125 | MT560786 | |
Phylloxeroxenus smilax | G0071 | N/A | MT560787 |
Sycophila smilax | G0076 | MT576126 | MT560788 |
G0077 | MT576127 | MT560789 | |
Aprostocetus smilax | G0078 | MT576128 | MT560790 |
G0080 | MT576129 | MT560791 | |
Phylloxeroxenus smilax | G0082 | N/A | MT560792 |
COI was aligned using default MAFFT v7.45 settings (
This species keys to Aprostocetus subgenus Aprostocetus, couplet 103 in
Holotype
, female: USA • FL: Dade Co.: SE Miami, Rockdale Pineland, Ex Smilax havanensis stem gall; 19.Dec.2001, C. Rodriguez & T. Smith leg.; USNMENT01735185 (deposited at
Female. Body length 1.7 mm (Fig.
Color.
Mostly whitish-yellow, pedicel, flagellomeres, clava, axillula, and marginal vein, sides of gastral tergites brown. Fore and midlegs white (Fig.
Head.
Squareish in dorsal view, 1.2× as wide as long in dorsal view (Fig.
Forewing. Three setae on submarginal vein, 7 setae on marginal vein. Ratio of marginal vein:postmarginal vein:stigmal vein as 22.5:1:6.
Mesosoma.
Mesosoma coriaceous, 1.14× as long as broad (Fig.
Metasoma.
Metasoma smooth, Gt1 and Gt2 dorsally glabrous (Fig.
Male. 1.1 mm. Color and sculpture as described for female (Fig.
Size ranges from 1.6–1.8 mm for females, and 1.1–1.2 mm for males. The number of setae on marginal vein ranges from 6–8.
It induces round galls on the stems of Smilax havanensis, often coalescing to form irregularly rounded, polythalamous swellings. Individual galls can also be found on the edge of leaves. Green when fresh and of a pithy structure (Figs
Southern Florida, USA.
Phylloxeroxenus smilax can be easily distinguished from the only other known North American species, Phylloxeroxenus phylloxerae (Ashmead), which is suspected to be a parasitoid of the cecidomyiid inquiline within Phylloxera Boyer de Fonscolombe galls on hickory (Carya Nutt.) (
Holotype
, female: USA • FL: Dade Co.: SE Miami, Rockdale Pineland, Ex Smilax havanensis stem gall; 18.Apr. 2010; M. Gates & M. Buffington leg.; USNMENT01735174 (deposited at
Female. Body length 1.88 mm (Fig.
Color.
Orange-yellow; antennal segments light brown; edges of ocelli, scutellum, metasoma mediodorsally with black band, eyes pinkish red (Fig.
Head.
Rounded in dorsal view, 1.3× as wide as long in dorsal view, umbilicate with appressed setae (Fig.
Forewing. Eight submarginal setae, 3 on parastigma. Ratio of marginal vein:postmarginal vein:stigmal vein as 2:1:1.
Mesosoma.
Mesosoma umbilicate, 1.45× as long as broad; notauli complete, shallow (Fig.
Metasoma.
Metasoma smooth, Gt4–syntergum setose, Gt6 and syntergum microreticulate; petiole 0.78× as long as broad in dorsal view, with ventral anterior groove and carina (Fig.
Male. 1.51 mm. Color and sculpture as described for female (Fig.
Size ranges from 1.76–1.91 mm for females, and 1.45–1.52 mm for males. The coloration on the body can range from almost completely yellow, to mostly black on the dorsolateral surfaces, particularly in males.
Associated with galls of Aprostocetus smilax, likely a parasitoid of the gall inducer.
Southern Florida, USA.
This species is recognized by its small size, pale yellow coloration and small/faint stigmal band. It keys to couplet 9 of
Holotype
, female: FL: Dade Co.: SE Miami, Rockdale Pineland, Ex Smilax havanensis stem gall; 19.Dec.2001, C. Rodriguez & T. Smith leg.; USNMENT01735197 (deposited at
Female. Body length 1.8 mm (Fig.
Color.
Mostly pale yellow; antennal segments dark yellow; edges of ocelli, scutellum, hindtibia laterally, tarsal claw, tip of ovipositor black, pterostigma dark brown, wing band light brown, eyes pinkish red (Fig.
Head.
Rounded in dorsal view, 1.22× as wide as long in dorsal view, umbilicate with appressed setae (Fig.
Forewing. Dark brown band on the wing about the same width as pterostigma and does not reach uncus, faint, reaching about ½ down the wing width, 8 submarginal setae, 3 on parastigma, 1 in basal cell, surrounded by basal and costal setal lines. Pterostigma covering marginal, postmarginal, and stigmal vein.
Mesosoma.
Mesosoma umbilicate, 1.52× as long as broad; notauli complete, shallow (Fig.
Metasoma.
Metasoma smooth, ovipositor sheath microreticulate (Figs
Male. 1.88 mm. Mediodorsal of Gt3–5 black, wing band very faint. Otherwise color and sculpture as described for female (Fig.
Sycophila smilax 45 ventral view of mesosoma 46 lateral view of female metasoma 47 ventral view of female petiole 48 lateral view of female petiole 49 closeup of female ovipositor 50 male antenna 51 dorsal view of male petiole 52 ventral view of male petiole 53 lateral view of male metasoma.
Body ranges 1.7–1.8 mm for females, 1.65–1.88 mm for males. The wing band can range from very faint, mesosoma and metasoma dorsally can be yellow or with a tinge of black.
Associated with galls of Aprostocetus smilax, likely a parasitoid of the gall inducer.
Southern Florida, USA.
A total of 55 individuals had both or at least one of the two genes sequenced. BLAST and BOLD search results confirmed the family and sometimes genus level identification, but did not return any hits at the species level. This Smilax gall contains 3 different families of chalcidoids: the majority of the gall inhabitants consisted of the suspected gall inducer Aprostocetus smilax (n = 40), and two eurytomid parasitoids Phylloxeroxenus smilax (n = 7) and Sycophila smilax (n = 6) (Fig.
As the result of this study, the validity of Diastrophus smilacis (Figs
Working with the type material of both D. smilacis and Periclistus smilacis Ashmead (Figs
Adding to this confusing picture is that it appears A. Ritchie intended to include P. smilacis in his dissertation work on Periclistus in 1984, and even went so far as to designate a lectotype for this species (Fig.
The original collections made in Florida in 2010 that led to the chalcidoids described herein were also focused on the (now) erroneous records of D. smilacis on Smilax havanensis mentioned in
Lastly, the
Concatenated 28S and COI phylogram of the Smilax gall inhabitants estimated using Maximum Likelihood framework in IQ-TREE2. Black dots at the nodes indicate ≥90% ultrafast bootstrap support. Inset images in counterclockwise order: Stem gall induced by Aprostocetus smilax on Smilax havanensis, with emergence holes (photo by MWG); A. smilax, Sycophila smilax, Phylloxeroxenus smilax.
Here we describe the new eulophid species Aprostocetus smilax, the second recorded case of gall induction by Aprostocetus in North America. This new species is the true gall inducer on Smilax, and previous records of cynipid species Diastrophus smilacis and the inquiline Periclistus smilacis associated with this host plant are erroneous. Additionally, we described two eurytomid parasitoids associated with this Smilax gall. The distribution of all three new species is on the southern tip of mainland USA, but it is likely that they are also found in the Caribbean region in which the host plant S. havanensis is found (
We thank the following museum collections and curators for providing loans: Archbold Biological Station (Mark Deyrup), Florida State Collection of Arthropods (Elijah Talamas). Staff at the Charles Deering Estate permitted access for collecting galls and staff from Miami-Dade County (C. Rodriguez and T. Smith) provided specimens and access to Rockdale Pineland for gall collecting. We would also like to thank Gary Oullette for performing all DNA extractions and amplifications, Taina Litwak for the illustration and image editing, and Zhiwei Liu for discussion on the validity of Diastrophus smilacis. Finally, we would like to thank Paul Hanson and an anonymous reviewer that have provided comments that improved the manuscript. Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the USDA. USDA is an equal opportunity provider and employer.