Apanteles hemara Nixon, 1965

Fernandez-Triana, Jose, Beaudin, Melanie, van Achterberg, Kees, Agbodzavu, Mawufe K., Othim, Stephen T. O., Nyamu, Faith W. & Fiaboe, Komi K. M., 2017, DNA barcodes, expanded distribution, and redescription of Apanteles hemara Nixon, 1965 (Hymenoptera, Braconidae, Microgastrinae), a potential biocontrol species against amaranth leaf-webbers in Africa, Journal of Hymenoptera Research 58, pp. 1-15 : 1-7

Apanteles hemara Nixon, 1965

Apanteles hemara Nixon, 1965. Original description Nixon (1965: 58).

Apanteles caboverdensis Hedqvist, 1965. Synonymized by Papp (2003).

Apanteles proalastor Hedqvist, 1965. Synonymized by Papp (2003).

Apanteles bulgaricus Balevski & Tobias, 1980. Synonymized by Papp (1988).

Holotype.

INDIA, Dehradun. Female (deposited in the Natural History Museum, London), examined.

Other material examined.

DEMOCRATIC REPUBLIC OF THE CONGO: Iboubikro, Lesio-Loun Pk.; Pool , -3.2699 15.4711, 340mm, 25.xi.2008, coll. Braet & Sharkey, voucher code: CNCH2805 (1 specimen, CNC) ; KENYA: Eastern Province, Ukasi, Base of Ukasi Hill , -0.8210 38.5440, 613mm, Malaise trap, 11.xii.2012, coll. R. Copeland, voucher codes: 14703BraC10, 14703BraC12 (2 specimens, R. Copeland personal collection); Yatta , -1.2304 37.4579, 1184mm, reared, coll. ICIPE, voucher codes: CNC507541, CNC507542, CNC507543, CNC507544, CNC507545, CNC507546 (6 specimens, CNC) ; MADAGASCAR: Fianarantsoa, Parc National Ranomafana, Radio tower at forest edge, -21.251 47.412, 1130mm, 2.xii.2006, coll. Irwin & Harin’Hala, voucher codes: CASENT2163191, CNC666410 (2 specimens, CAS); -21.2510 47.4120, 1130mm, 7.ix.2006, coll. Irwin & Harin’Hala, voucher codes: CASENT2163390, CNC661376 (2 specimens, CAS) ; OMAN: Salalah , 17.00 54.06, 20m, 24.iv.1992, coll. M.D. Gallagher, voucher codes: CNC661377, CNC666409 (2 specimens, CNC) ; UNITED ARAB EMIRATES: Abu Dhabi, Al-Ajban, 24.6000 55.0167, Malaise trap, 7-28.xii.2006, coll. A. van Harten, voucher code: CNC666414 (1 specimen, CNC); Fujairah, Fujairah, 25.1333 56.350000, light trap, 13-29.xi.2005, coll. A. van Harten, voucher code: CNC666415 (1 specimen, CNC); NARC near Sweihan, 24.4 55.433, 20.iv.2005, coll. A. v. Harten, vouch er code: CNCH2681 (1 specimen, CNC); Sharjah, Sharjah Desert Park , 25.2833 55.7000, 21-29.iii.2005, coll. A. van Harten, voucher code: CNC666413 (1 specimen, CNC); 25.283 55.7, 21.iii.2005, coll. A. v. Harten, voucher code: CNCH2674 (1 specimen CNC); 29.iii.2005, coll. A. v. Harten, voucher code: CNCH2675 (1 specimen CNC); 9.iii.2005, coll. A. v. Harten, voucher code: CNCH2678 (1 specimen CNC) ; YEMEN: 12 km NW of Manakhah, Malaise trap, 15.ix-22.x.2003, coll. A. van Harten, voucher code: CNC666412 (1 specimen, CNC); Al Kowd, light trap, vii.2000, coll. A. van Harten & S. Al Haruri, voucher code: CNC666411 (1 specimen, CNC); Al Lahima, 15.xii.2000, coll. A. v. Harten & Hager, voucher codes: CNCH2690, CNCH2718, CNCH2723 (3 specimens, CNC); Malaise trap, 9.iv-5.vi.2001, coll. A. V. Harten, voucher code: CNC666406 (1 specimen, CNC); Al Mahrah, Al Ghaydah , 12-14.xi.1997, coll. A. Sallam & S. Ba Angood, voucher code: CNC666405 (1 specimen, CNC); Sana’a, Malaise trap, ii-iii.1998, coll. A. van Harten, voucher code: CNC666408 (1 specimen, CNC); Seyun , light trap, xi.2002, coll. A.V. Harten, voucher code: CNC661375 (1 specimen, CNC); Ta’izz, light trap, 3-24.i.1999, coll. A.V. Harten & M. Mahyoub, voucher code: CNC666407 (1 specimen, CNC); no specimen data, voucher code: WAM 0209 (1 specimen CNC) .

Distribution.

Afrotropical, Australian, Oriental and Palaearctic regions (Fig. 1 ). The species is widespread in the Old World tropics, especially Africa. We record here the presence of Apanteles hemara in eight additional countries. The new distribution records for Kenya, Madagascar, Republic of the Congo, United Arab Emirates, and Yemen are based on examined specimens from the CAS, CNC, ICIPE and RMNH collections. Additionally, three other countries (Egypt, Pakistan, and Saudi Arabia) are recorded based on BOLD records whose sequences match sequences of the species, although those specimens were not available to us for study. The new data expands the species distribution across mainland Africa (where it was already known from a few countries), to Madagascar and the Arabian Peninsula (where it had not been recorded before). Based on the specimens we examined, the species has been collected throughout the entire year.

Diagnosis.

Apanteles hemara can be recognized by having antenna slightly shorter than body length, with flagellomere 14 length 1.3-1.6 × its width; vein R1 about four times as long as distance between ends of veins R1 and 3RS; hind legs with black coxa, yellow trochanter and trochantellus, brown metafemur, metatibia yellow on anterior 0.5-0.6 and brown on posterior 0.4-0.5, metatibial spurs white, and metatarsus brown; propodeum mostly smooth, but with entire areola entirely defined by strong carinae; tergites 1 and 2 with strong, longitudinal striation; and ovipositor sheats shorter than metatibia (0.7-0.9 ×). Apanteles hemara belongs to the ater species group (sensu Nixon 1965), which unfortunately comprises "many aggregates of species that are not closely related but merge into one another through transitional forms" ( Nixon 1965: 25). The world species were keyed out by Nixon (1965), but many more species have been described since, and thus that paper is now outdated. Updates are available for species of the ater group from Europe ( Papp 1980), the former Soviet Union ( Tobias 1986), China (Chen and Song 2004) and Mesoamerica ( Fernandez-Triana et al. 2014) but unfortunately there is no updated key to world species.

Redescription.

Body color mostly black, tergites 3+ dark brown, laterotergites and sternites 3+ light yellow-brown. Head black, except for dark orange-brown labrum, light yellow-white palpi and dark brown antennae. Front and middle legs yellow (except for coxae and mesofemur light yellow-brown to brown); hind leg with black coxa, yellow trochanter and trochantellus, brown metafemur, metatibia yellow on anterior 0.5-0.6 and brown on posterior 0.4-0.5, metatibial spurs white, and metatarsus brown. Wings with most veins transparent or white, except for brown veins R1, r, 2RS and M; pterostigma mostly brown, with a very small white spot at base. Anteromesoscutum and scutellar disc with relatively coarse and dense punctures (distance between punctures smaller than diameter of individual puncture). Propodeum mostly smooth, with areola entirely defined by strong carinae. Tergites 1 and 2 with strong, longitudinal striation, contrasting with remaining tergites which are smooth. Body measurements (in mm) and ratios. Body length: 2.50-3.20, fore wing length: 2.50-3.00, ovipositor sheaths: 0.62-0.84, metafemur: 0.65-0.77, metatibia length: 0.87-0.95, tergite 1 0.36-0.49. Length of flagellomeres: 1st (0.18-0.22), 2nd (0.18-0.22), 3rd (0.17-0.21), 14th (0.08-0.10), 15th (0.08-0.10) and 16th (0.12). Length/width of flagellomere 2: 2.75-3.14; length/width of flagellomere 14: 1.28-1.60. Head height/width: 0.82-0.88; head slightly narrowing towards mandibles, width at clypeus base 0.88-0.88 × head width at antennal base. Malar line 1.12-1.50 × mandibular base. Ocular ocellar line 1.67-2.00 × posterior ocellus diameter; interocellar distance 1.71-2.17 × posterior ocellus diameter. Scutellar disc length 1.09-1.15 × width at base. Maximum height of mesoscutellum lunules 0.42-0.56 × maximum height of lateral face of mesoscutellum. Tergite 1 widening from anterior margin to two thirds of tergite length, then slightly narrowing towards posterior margin; tergite 1 length 1.64 -2.09 × tergite width at posterior margin; tergite widths (at anterior margin/maximum width/posterior margin): 0.19-0.25/0.27-0.30/0.22-0.25. Tergite 2 width at posterior margin 2.31-2.64 × length medially. Tergite 2 length medially 0.48-0.64 × tergite 3 length medially. Metafemur length 3.25-3.67 × metafemur width. Pterostigma length 2.55-2.86 its width. Vein R1 length 1.15-1.27 × pterostigma length. Vein r length 1.82-2.20 × vein 2RS length.

Variation.

Despite the widespread distribution of the species across four major biogeographical regions (mostly Old World tropics), the specimens we examined were very similar morphologically (Figs 4 - 8 ), with only minor variation in the color of the hind legs and tergites 3+ of the metasoma. However, we could not examine specimens from the Australian or the Palaearctic regions, which might be more variable than the specimens from Africa and Asia we studied.

Biology.

Solitary parasitoid (Fig. 4E ); over 41,280 parasitism cases were observed by us under laboratory condition at ICIPE in Kenya during a three years study. Hosts: Choreutidae , Tebenna micalis ; Crambidae , Cnaphalocrocis trapezalis , Herpetogramma stultalis , Hydriris ornatalis , Omiodes indicatae , Spoladea recurvalis , Udea ferrugalis . For additional details see Comments below.

DNA barcodes.

A total of 17 DNA barcodes were obtained from the specimens we studied. All sequences but one were over 600 base pairs (bp) long, with most representing full barcodes (658 bp). Additional sequences representing the species are found in BOLD, but we could not examine those specimens because they belong to projects that are not public yet. Overall, there are currently 32 sequences belonging to A. hemara in BOLD, 24 of them being public records and 19 being barcode compliant (Fig. 2 ). The species has been assigned the BIN number BOLD:AAB1927 (for the concepts of ‘BIN’ and 'barcode compliant’ see Ratnasingham and Hebert 2007). The DNA barcode intraspecific variation (p-distance) for A. hemara averaged 0.61% (4 bp), with a maximum of 1.91% (12 bp), but more than half of the analyzed sequences differed by only 0.2-0.4 % (1-2 bp). There were six different haplotypes recognized among the barcoded specimens. From a DNA barcode perspective, the nearest species in BOLD is Apanteles xanthostigma (Haliday, 1834), which differs from A. hemara by 6.93% (45 bp) (Figs 2 , 3 ).

Comments.

In Kenya, the parasitoid was collected during outbreaks of two amaranth leaf-webber species, Spoladea recurvalis and Udea ferrugalis on two species of amaranth, Amaranthus cruentus L. and A. dubius L. It was successfully reared under laboratory conditions on both amaranth leaf-webber species at ICIPE. However, it failed to attack the leafworm species Spodoptera littoralis (Boisduval, 1833) and S. exigua ( Hübner, 1808) ( Noctuidae ). During population dynamics studies carried out under field conditions at high and mid altitude levels in Central Kenya, field parasitism rates on S. recurvalis as low as 3% were obtained during outbreak periods while parasitism rates as high as 25 to 75% were achieved outside outbreak periods. These observations prompted studies for potential augmentative biological control strategies for early interventions aiming at preventing or reducing outbreaks of the amaranth leaf-webbers in farmers’ fields. Under laboratory conditions (25 ± 2°C, 60 ± 10% RH and 12L:12D photoperiod), A. hemara demonstrated high performance on S. recurvalis and U. ferrugalis both through high direct parasitism rates and significant non-reproductive mortalities caused to the hosts. The parasitized caterpillars can easily be distinguished from non-parasitized ones within the first two days after the parasitoid’s oviposition in the larva, through a significant reduction in feeding, movement and the lack of windowing on the leaf epidermis. Subsequently their growth rate is reduced and within four days after the parasitoid’s oviposition, parasitized caterpillars are considerably smaller in size than their non-parasitized counterparts, turn creamish and will all die whether the parasitoid successfully emerged or not. The developmental times are 12 and 13 days for male and female parasitoids respectively. Apanteles hemara is currently being considered for a conservative and augmentative biological control program against the amaranth leaf-webbers in Africa.

Figures

Figure 1. Worldwide distribution of Apanteles hemara.

Figure 2. Details of the Barcode Index Number Registry for Apanteles hemara, data from BOLD (http: // v 4. boldsystems. org /).

Figure 3. Neighbour Joining tree (K 2 P) of all known DNA barcoding sequences of Apanteles hemara and a representative of the closer species (Apanteles xanthostigma) in the BOLD database (as of April 2017).

Figure 4. Apanteles hemara, female holotype from India.

Figure 8. Apanteles hemara female specimen from Oman (Voucher code: CNC 661377).