Research Article |
Corresponding author: Stéphanie Boucher ( stephanie.boucher@mcgill.ca ) Academic editor: Owen Lonsdale
© 2022 Stéphanie Boucher, Jade Savage.
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:
Boucher S, Savage J (2022) DNA barcoding of the leaf-miner flies (Diptera, Agromyzidae) of Mitaraka, French Guiana. ZooKeys 1083: 147-168. https://doi.org/10.3897/zookeys.1083.76651
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Species level identification of Agromyzidae based on morphology is often challenging due to their small size and morphological homogeneity. DNA barcoding has been used regularly to assist with the identification of economically important species of Agromyzidae, but rarely as a tool for species delineation or identification in biodiversity surveys. The main objective of this study was to investigate whether DNA barcoding and the BIN (Barcoding Index) system could assist with species identification, species delineation, male/ female association, and diversity assessment of Agromyzidae material previously determined to morphospecies from Mitaraka, French Guiana. Amplification success was low, with sequences over 400 bp recovered for only 24 (48%) of the selected specimens. Sequences assigned to 17 morphospecies formed 16 distinct branches or clusters separated by very high (minimum of 10%) sequence divergence. Following the reassessment and subsequent reassignment of one specimen, congruence between morphology and DNA barcodes was high with a single instance of two morphospecies sharing identical sequences. While DNA barcoding did not assist with identification (none of our sequences matched those of named taxa in BOLD or GenBank), it did provide support for most of our morphospecies concepts, including male/female associations. The BIN system also provided access to information about the distribution and habitat preferences of several taxa. We conclude that DNA barcoding was a useful approach to study the species diversity of our samples but that much work remains to be done before it can be used as an identification tool for the Agromyzidae fauna of Mitaraka and the rest of the Neotropical region.
Agromyzidae, Barcode Index Number (BIN), CO1, DNA barcoding, French Guiana, Neotropical
The Agromyzidae is a family of small flies, measuring on average 2–4 mm in wing length, although they can be smaller than 1 mm or measure up to 6.5 mm. Their coloration is variable, from yellow and/or black, brown, or grey, sometimes with metallic greenish, bluish, or coppery coloration. Most have clear wings, but they may be patterned or infuscated in a few tropical species. The family contains approximately 3200 described species found worldwide (
DNA barcoding, the sequencing of a short fragment of DNA sequence of the mitochondrial cytochrome c oxidase 1 (CO1) gene, is being increasingly used as an identification tool, especially for very diverse and/or morphologically difficult taxa. DNA barcoding was initially proposed as a tool for the identification of animal species (
In the family Agromyzidae, the use of the CO1 gene has been used mainly as a tool to differentiate and identify economically important and invasive species (e.g.,
DNA barcoding has rarely been used as a tool for Agromyzidae species identification, morphospecies delineation or gender association in biodiversity surveys, although its use could provide faster and more accurate identification results. Two large biotic surveys occurring in Ontario have used barcoding to provide species identification of thousands of taxa including 21 species (Telfer et al. 2005) and 13 species (
A recent and relatively short biotic survey conducted in 2015 at the Mitaraka massif, a mostly unexplored region of French Guiana (
Prior to the 2015 Mitaraka expedition, approximately 500 agromyzid species were recorded in the Neotropical region including only four species in French Guiana (Liriomyza huidobrensis (Blanchard), Liriomyza trifolii (Burgess), Liromyza sativae Blanchard, Nemorimyza maculosa (Malloch)) (
The main objective of this study was to investigate whether DNA barcoding could assist with species identification, species delineation, male/ female association, and diversity assessment of the Agromyzidae specimens collected from the Mitaraka Massif (French Guiana) and previously identified as morphospecies (
Agromyzid specimens were collected in 2015 as part of the Mitaraka expedition, French Guiana (
List of Mitaraka specimens sent for barcoding and for which a sequence was retrieved. Includes specimen number for in-text reference, morphospecies name (from
Specimen number | Morphospecies | BOLD process ID | BIN assignment (*added for new BIN) | Sex | CO1 Sequence length | GenBank number |
---|---|---|---|---|---|---|
1 | Melanagromyza Mit-1 | BUICD1529–19 | BOLD:ADX5410* | M | 613 | OK623732 |
2 | Melanagromyza Mit-2 | BUICD1440–18 | BOLD:ADR6853* | M | 658 | OK623717 |
3 | Melanagromyza Mit-2 | BUICD1441–18 | BOLD:ADR6853* | M | 658 | OK623728 |
4 | Melanagromyza Mit-2 | BUICD1443–18 | BOLD:ADR6853* | F | 631 | OK623740 |
5 | Melanagromyza Mit-2 | BUICD1444–18 | BOLD:ADR6853* | F | 658 | OK623741 |
6 | Melanagromyza Mit-3 | BUICD1446–18 | BOLD:ADR6852* | M | 658 | OK623742 |
7 | Melanagromyza Mit-4 (previously identified as M. Mit-2) | BUICD1445–18 | BOLD:ACJ8134 | F | 658 | OK623727 |
8 | Melanagromyza Mit-4 | BUICD1532–19 | BOLD:ACJ8134 | F | 549 | OK623722 |
9 | Melanagromyza Mit-4 | BUICD1447–18 | BOLD:ACJ8134 | M | 658 | OK623729 |
10 | Melanagromyza Mit-6 | BUICD1534–19 | BOLD:ADW8881* | F | 602 | OK623723 |
11 | Melanagromyza Mit-7 | BUICD1536–19 | BOLD:ADW8881* | F | 658 | OK623726 |
12 | Melanagromyza Mit-9 | BUICD1538–19 | BOLD:ADB0898 | F | 658 | OK623739 |
13 | Melanagromyza Mit-10 | BUICD1539–19 | BOLD:ADW8248* | F | 571 | OK623721 |
14 | Melanagromyza Mit-10 | BUICD1540–19 | BOLD:ADW8248* | F | 596 | OK623733 |
15 | Melanagromyza Mit-11 | BUICD1541–19 | BOLD:ADX5409* | F | 555 | OK623738 |
16 | Melanagromyza Mit-12 | BUICD1542–19 | BOLD:ADW8247* | M | 570 | OK623737 |
17 | Melanagromyza Mit-12 | BUICD1543–19 | BOLD:ADW8247* | F | 570 | OK623735 |
18 | Melanagromyza Mit-13 | BUICD1544–19 | BOLD:ADX3977* | F | 658 | OK623724 |
19 | Melanagromyza Mit-14 | BUICD1545–19 | BOLD:ADW2860* | F | 658 | OK623734 |
20 | Melanagromyza Mit-15 | BUICD1546–19 | BOLD:ADX5411* | F | 590 | OK623736 |
21 | Ophiomyia Mit-10 | BUICD1558–19 | BOLD:ADW4594* | F | 564 | OK623718 |
22 | Ophiomyia Mit-12 | BUICD1561–19 | Not assigned | F | 417 | OK623725 |
23 | Nemorimyza Mit-1 | BUICD1564–19 | BOLD:ADW8176* | F | 590 | OK623720 |
24 | Nemorimyza Mit-2 | MOBIL8769–18 | BOLD:ADB9391 | F | 600 | OK623730 |
25 | Liriomyza Mit-1 | MOBIL11198–20 | Not assigned | F | 356 | OK623731 |
26 | Liriomyza Mit-1 | MOBIL11196–20 | Not assigned | F | 356 | OK623719 |
Specimens sent for barcoding for which no sequence was retrieved. Includes specimen number for in-text reference, morphospecies name (from
Specimen number | Morphospecies | BOLD process ID | Sex |
---|---|---|---|
27 | Melanagromyza Mit-2 | BUICD1442–18 | F |
28 | Melanagromyza Mit-4 | BUICD1530–19 | F |
29 | Melanagromyza Mit-4 | BUICD1531–19 | F |
30 | Melanagromyza Mit-5 | BUICD1533–19 | M |
31 | Melanagromyza Mit-6 | BUICD1535–19 | F |
32 | Melanagromyza Mit-6 | Lifescanner Vial ID: BOLD AT1 | F |
33 | Melanagromyza Mit-6 | Lifescanner Vial ID: BOLD DM0 | F |
34 | Melanagromyza Mit-7 | Lifescanner Vial ID: BOLD 8E4 | F |
35 | Melanagromyza Mit-8 | BUICD1537–19 | F |
36 | Ophiomyia Mit-1 | BUICD1547–19 | M |
37 | Ophiomyia Mit-1 | BUICD1548–19 | M |
38 | Ophiomyia Mit-2 | BUICD1549–19 | M |
39 | Ophiomyia Mit-3 | BUICD1550–19 | M |
40 | Ophiomyia Mit-3 | BUICD1551–19 | F |
41 | Ophiomyia Mit-4 | BUICD1552–19 | M |
42 | Ophiomyia Mit-5 | BUICD1553–19 | M |
43 | Ophiomyia Mit 6 | BUICD1554–19 | F |
44 | Ophiomyia Mit-7 | BUICD1555–19 | M |
45 | Ophiomyia Mit-8 | BUICD1556–19 | F |
46 | Ophiomyia Mit-9 | BUICD1557–19 | F |
47 | Ophiomyia Mit-11 | BUICD1559–19 | M |
48 | Ophiomyia Mit-12 | BUICD1560–19 | F |
49 | Ophiomyia Mit-13 | BUICD1562–19 | F |
50 | Ophiomyia Mit-14 | BUICD1563–19 | M |
51 | Liriomyza Mit-1 | BUICD1449–18 | M |
52 | Liriomyza Mit-1 | BUICD1448–18 | M |
53 | Liriomyza Mit-1 | Lifescanner Vial ID: BOLD 5K8 | M |
54 | Cerodontha Mit-1 | Lifescanner Vial ID BOLD NO6 | M |
55 | Cerodontha nigrihalterata | Lifescanner Vial ID BOLD 1N9 | F |
DNA amplification and Sanger sequencing were performed at the Centre for Biodiversity Genomics (CBG) (previously known as the Canadian Centre for DNA Barcoding (CCDB)) except for specimens #24, 25, 26, 32–34, 51–54 (Tables
Amplification success was low (48%), with COI sequences recovered for only 26 of the 54 submitted specimens (Tables
Neighbor-joining tree based on K2P-distance of the 24 specimens of Mitaraka Agromyzidae for which a sequence over 400 bp were retrieved. Information includes specimen number (from Table
Following the reexamination and subsequent reassignment of specimen #7 (Table
Specimen records (public) included in BIN(BOLD:ACJ8134) with associated specimen data.
BOLD identification | BOLD process ID | Sex | CO1 sequence length | Locality/ coordinate/ elevation | Habitat/collecting technique /sampling date |
---|---|---|---|---|---|
Melanagromyza Mit-4 | BUICD1445–18 | F | 658 | Mitaraka, French Guiana, 2.233, -54.463, 471m | Minor inselberg with savane-roche vegetation /6 m Malaise trap/August 2015 |
Melanagromyza Mit-4 | BUICD1532–19 | F | 549 | Mitaraka, French Guiana 2.233, -54.463, 471m | Minor inselberg with savane-roche vegetation /6 m Malaise trap/August 2015 |
Melanagromyza Mit-4 | BUICD1447–18 | M | 658 | Mitaraka, French Guiana 2.233, -54.463, 471m | Minor inselberg with savane-roche vegetation /6 m Malaise trap/August 2015 |
Agromyzidae | GMAFN352–15 | ? | 633 | Reserva El Bagual. Formosa, Argentina -26.3028, -58.815, 57m | Unknown/Malaise trap/November 2013 |
Agromyzidae | GMCRM972–13 | F | 658 | Area de Conservacion Guanacaste. Guanacaste, Costa Rica 10.8438, -85.6138, 300m | Forest/Malaise trap/May 2012 |
Detailed results by genus are presented below.
Sequences more than 500 bp were successfully recovered for 20 specimens (69%) belonging to 13 morphospecies and distributed into 12 BINs (Table
Sequences from one specimen each of Melanagromyza Mit-6 and Melanagromyza Mit-7 displayed identical barcodes and were therefore assigned to the same BIN (BOLD:ADW8881) (Table
Of the six specimens of Melanagromyza Mit-2 submitted for barcoding, only one (#27, Table
Another case of uncertainty in morphospecies determination involved two female specimens (#13–14; Table
Although agromyzid male genitalia are usually species-specific, providing useful characters for species differentiation, it was not the case for males of Melanagromyza Mit-3 and M. Mit-4 who exhibited very similar genitalia. They were assigned to separate morphospecies based on a few subtle external characters, including a smaller size for M. Mit-4 and, in spite of their morphological similarities, material from these morphospecies produced very distinct DNA barcodes with interspecific distances ranging from 11.99% to 12.60%.
When sequences were recovered for more than one specimen of a single morphospecies, as seen in M. Mit-2, M. Mit-4, M. Mit-10, and M. Mit-12, intraspecific divergences were low, with maximum intraspecific distance (0.37%) recorded in Melanagromyza Mit-4 (BIN (BOLD:ACJ8134) (Fig.
Of the 12 BINs assigned to the Mitaraka Melanagromyza specimens, most were new, except BOLD:ACJ8134 and BOLD:ADB0898 (Table
Specimen records (public) included in BIN (BOLD:ADB0898) with associated specimen data.
BOLD identification | BOLD process ID | Sex | CO1 sequence length | Locality /coordinate/elevation | Habitat /collecting technique /sampling date |
---|---|---|---|---|---|
Melanagromyza Mit-9 | BUICD1538–19 | F | 658 | Mitaraka, French Guiana 2.233, -54.463, 471m | Minor inselberg with savane-roche vegetation /6 m Malaise trap/August 2015 |
Agromyzidae | JICAZ278–16 | F | 543 | Area de Conservacion Guanacaste. Guanacaste, Costa Rica 10.764, -85.335, 828m | Subtropical/tropical moist lowland forest/Malaise trap/March 2014 |
Distribution map for BOLD records for BIN: BOLD:ACJ8134 (Melanagromyza Mit-4). Distribution data points include Guanacaste, Costa Rica; Formosa, Argentina and Mitaraka, French Guiana (created with SimpleMappr).
Distribution map for BOLD records for BIN: BOLD:ADB0898 (Melanagromyza Mit-9) and BIN (BOLD:ADB9391) (Nemorimyza Mit-2). Distribution data points include Guanacaste, Costa Rica and Mitaraka, French Guiana (created with SimpleMappr).
Amplification success for Ophiomyia material was very low, with sequences retrieved from only two of the 17 selected specimens (Tables
The five Nemorimyza specimens (one male, four females) collected in Mitaraka were originally treated as one morphospecies (Nemorimyza Mit-1), until subtle morphological differences were found in two females that were subsequently treated as a distinct morphospecies (Nemorimyza Mit-2) (
Specimen records (public) included in BIN (BOLD:ADB9391) with associated specimen data.
BOLD identification | BOLD process ID | Sex | CO1 sequence length | Locality /coordinate / elevation | Habitat /collecting technique /sampling date |
---|---|---|---|---|---|
Nemorimyza Mit-2 | MOBIL8769–18 | F | 600 | Mitaraka, French Guiana/ 2.233, -54.463/, 471m | Minor inselberg with savane-roche vegetation /6 m Malaise trap/August 2015 |
Agromyzidae | JCCCY4402–16 | F | 576 | Area de Conservacion Guanacaste. Guanacaste, Costa Rica 10.763, -85.334, 820m | Subtropical/tropical moist lowland forest/ Malaise trap/ November 2014 |
One of the morphospecies (Liriomyza Mit-1) collected at Mitaraka was very similar to Liriomyza sativae, a species previously recorded in French Guiana, but was treated as distinct based on small male genitalic differences. Of the five male L. Mit-1 specimens selected for barcoding, only #25 and #26 produced short sequences of 356 bp (Table
One morphospecies (Cerodontha Mit-1) (Fig.
There are several possible reasons explaining the low amplification success of the sampled specimens such as the fact that they were not freshly collected and had been kept in 70% ethanol before being dried and mounted, instead of 95% ethanol as recommended for DNA preservation (
While DNA barcoding is regularly used as a method of identification for economically important species of Agromyzidae (see introduction), it was not helpful in providing species identification for any of the Mitaraka specimens. This is in part due to the fact that some (if not most) of our material belongs to undescribed taxa. This has been confirmed at least for Nemorimyza, where Nemorimyza Mit-1 and N. Mit-2 do not match any of the five described species (including N. maculosa, a species previously reported from French Guiana (
As for Liriomyza, most reference sequences in BOLD belong to economically important species and this barcode library is important to facilitate the identification of the most important agromyzid pests. As of September 2021, there were 3411 public records of Liriomyza in BOLD representing 49 species. More than half (1803) of these records belong to four agricultural pests: L. sativae (677 records); L. trifolii (668 records); L. brassicae (Riley) (339 records) and L. huidobrensis (119 records), all recorded from the Neotropical region. Other than these four species, no other named Neotropical species of Liriomyza have been barcoded, except for five specimens of L. nigra Spencer (with short sequences of 307 bp) belonging to a private project managed by the first author. The short sequence retrieved for Liriomyza Mit-1 did not match those of any Liriomyza species found in BOLD. Further investigation will be required to confirm the identity of Liriomyza Mit-1. The genus Liriomyza is the most diverse agromyzid genus in the Neotropical region with approximately 105 species known. Species level identification is difficult due to the lack of recent keys to the Neotropical species and the fact that some species that have been described based on female specimens only (e.g., L. mikaniovora Spencer from Venezuela; L. pagana (Malloch) from Argentina and L. quiquevittata Sasakawa from Chile).
Although DNA barcoding and the BIN system were not useful to assign names to any of our morphospecies, they did provide information relevant to the taxonomy and diversity of the Mitaraka agromyzid fauna. They allowed us to flag and reassess the identification of some specimens (see results under Melanagromyza) and assisted with male/female associations. Due to the importance of male genitalic character for species recognition in agromyzids, females are often left unidentified in taxonomic and faunistic studies (
Very little data was available on the agromyzid fauna of French Guiana before the 2015 Mitaraka survey. The high congruence between DNA barcodes/ BIN assignments and morphology presented here suggests that DNA barcoding is an effective approach to estimate the Agromyzidae species diversity of Mitaraka and beyond, especially when females are abundant in samples. Additional studies will be necessary to further evaluate the robustness of the approach since it is widely recognized that levels of congruence between species limits and DNA barcodes/ BINS vary according to the study group. While causes such as hybridization and incomplete lineage sorting (
The genus Melanagromyza was the most diverse at Mitaraka with 15 morphospecies (
We also found that the Barcode Index Number (BIN) system, along with the metadata associated with each barcoded specimen in BOLD, provided important insight into the distribution pattern, habitats, and elevation preference of some species (Tables
Considering the difficulty associated with species-level identification of Neotropical Agromyzidae and the risks associated with the postal transport of type material, a reference library of DNA barcodes for named species of Neotropical Agromyzidae (including sequences from type material whenever possible) would not only help with identification but also reduce taxonomic errors that may lead to long lists of synonyms such as seen for several species of economic importance such as L. sativae and L. brassicae.
This study has contributed a total of 23 new barcode-compliant CO1 sequences (more than 500 bp), of Neotropical Agromyzidae, distributed into 15 BINs (including 12 unique BINs). Although these sequences lack species-level determination, they set a stronger base for future taxonomic work and facilitate the discovery of conspecific supplementary material for morphological studies.
We would like to thank the LifeScanner team at the Centre for Biodiversity Genomics, in particular Megan Milton, Michelle Pyle, and Sujeevan Ratnasingham who provided helpful information and support for the barcoding results obtained through their barcoding service. We would also like to thank Valerie Levesque-Beaudin at the Centre for Biodiversity Genomics for her great assistance with BOLD, and Andréanne Lessard for the lab assistance at Bishop’s University. Financial support for DNA barcoding was provided by Bishop’s University to J. Savage. All the material for this study was collected during the Our Planet Reviewed Guyane-2015 expedition in the Mitaraka range, in the core area of the French Guiana Amazonian Park, organized by the