Steinernema afriCanUm, Machado & Bhat & Abolafia & Shokoohi & Fallet & Turlings & Tarasco & Půža & Kajuga & Yan & Toepfer, 2022

Machado, Ricardo A. R., Bhat, Aashaq Hussain, Abolafia, Joaquín, Shokoohi, Ebrahim, Fallet, Patrick, Turlings, Ted C. J., Tarasco, Eustachio, Půža, Vladimír, Kajuga, Joelle, Yan, Xun & Toepfer, Stefan, 2022, Steinernema africanum n. sp. (Rhabditida, Steinernematidae), a New Entomopathogenic Nematode Species Isolated in the Republic of Rwanda, Journal of Nematology 54 (1), pp. 1-28 : 16-18

Steinernema afriCanUm n. sp. readily infests and develops in G. mellOnella larvae. However, the development of S. afriCanUm is unusually slow at

Species L BD EP NR

S. afriCanUm 3,205 180 89 105 (2,469 –4,215) (154–194) (67–111) (79–130)

S. akhUrSti 7,283 239 126 164 (5,625 –9,000) (200–270) (113–138) (150–175)

S. 4,692 255 129 190 ChOlaShanenSe (3,232 –6,363) (156–332) (111–148) (176–223)

S. Citrae 3,087 175 75 151 (2,038 –4,019) (137–212) (54–90) (130–179)

S. feltiae 3,380 204 82 84 (70–97) a (3,095 –3,774) (170–254) (68–97) a

S. hebeienSe 3,465 167 65 104 (3,972 –4,254) (142–245) (48–95) (88–123)

S. iChnUSae 5,514 269 126 NA (4,547 –6,186) (242–323) (106–156)

S. JOllieti 5,148 259 111 NA (3,746 –6,030) (219–298) (96–136)

S. kraUSSei 4,200 240 87 137 (2,500 –5,400) (153–288) (66–99) (127–146)

S. kUShidai 3,500 175 91 124 (2,100 –4,700) (54–59) (78–105) (111–144)

S. litOrale 4,462 191 88 146 (3,930 –5,048) (175–215) (65–105) (130–165)

S. nGUyeni 4,775 178 72 113 (2,290 –5,361) (130–216) (49–98) (84–139)

S. OreGOnenSe 5,200 242 103 147 (4,400 –6,200) (217–268) (217–268) (129–162)

S. 6,198 198 70 135 pUntaUVenSe (3,687 –8,335) (181–221) (51–85) (123–146)

S. Sandneri 4,628 210 84 147 (4,244 –5,014) (181–261) (61–102) (132–158)

S. SanGi 6,030 336 101 158 (4,830 –7,200) (270–360) (80–121) (140–170)

NL TL a b c c '

185 45 18 17 74 0.9 (170–201) (35–55) (13–27) (13–24) (51–104) (0.7–1.0)

239 49 29 b (NA) 31 b (NA) 141 b 0.6 b (NA) (213–258) (38–63) (NA)

196 57 13 25 83 0.8 (181–231) (46–70) (13–23) (18–32) (62–119) (0.6–1.0)

215 44 NA NA NA NA (189–220) (33–60)

237 52 17 14 65 1.0 (197–304) (39–70) (14–20) (12–17) (49–88) (0.7–1.2) a

147 35 21 24 103 0.7 (133–158) (25–50) (17–25) (21–29) (67–129) (0.5–0.9)

239 60 21 23 93 0.8 (215–262) (51–79) (17–24) (21–26) (68–113) (0.6–1.0)

214 43 20 26 128 NA (184–310) (31–55) (15–24) (19–31) (72–185)

192 48 17 22 88 NA (178–205) (33–59)

227 38 NA NA NA NA (204–255) (30–45)

196 39 23 23 117 0.6 (185–213) (25–60) (21–26) (20–26) (78–157) (0.5–0.9)

169 32 21 22 119 0.7 (137–194) (20–67) (15–30) (15–30) (53–165) (0.6–1.1)

210 37 NA NA NA 0.7 (NA) (186–220) (28–46)

192 49 NA NA NA NA (141–206) (41–66)

185 147 22 25 102 NA (173–194) (32–61) (17–25) (24–27) (75–140)

229 49 NA NA NA NA (216–240) (936–62)

V

52 (50–57)

51 (48–53)

53 (50–57)

54 (50–59)

56 (44–57)

54 (50–57)

53 (51–57)

51 (44–56)

54

56 (54–59)

56 (0.5–0.9)

56 (52–63)

52 (46–56)

53 (51–55)

54 (49–57)

51 (43–530)

ABD

52 (37–70)

86 (68–100)

77 (54–105

62 (43–79)

52 (47–62)

53 (45–65)

80 (70–94)

NA

45 (39–50)

64 (54–84)

62 (55–75)

178 (130–216)

56 (42–79)

76 (57–102)

94 (62–122)

111 (84–140)

D%

48 (36–62)

53 (NA)

50 (29–65)

37 (27–46)

46 (40–54) a

45 (36–66)

53 (47–63)

52

45

40 (37–46)

45 (33–57)

43 (30–56)

49 (43–57)

37 (25–45)

46 (36–54)

44 (35–51)

Mucron

Present

Present

Present

Present

Present

Absent

Present

Present

Present

Absent

Present

Absent

Absent

Present

Present

Present

(COntinUed)

Mucron Absent Absent Absent Present Present Present

)))

79 49 45

%

D 47 33 (

– NA 41 (32 – 40 – 38 (NA NA

))))))

53 71 92 67 72 80

ABD 35 26 (– 60 50 (– 69 56 – (61 – 50 (84 – (38 63 (51 –

))))))

57 55 54 57 62 58

– – – – – –

V 52 (44 52 (50 51 49 (52 (46 54 52 (53 (50

))))

1.8 0.9 0.8 0.8

– – – –

'

c

1.3 (1.0 NA 0.6 0.5 (0.6 0.5 (NA 0.7 (0.5

)))) 80 158 123 156 c 49 34 (– NA 117 72 – (106 79 (– NA 111 (– 87

))))

18 45 26 31

– – – –

b 15 10 (NA 29 (21 22 17 (NA 25 (22

))))

41 32 25 29

– – – –

a 19 (15 NA 23 17 (22 (19 NA 21 (17

))))))

79 52 69 53 66 59

– – – – – –

TL 45 33 (40 (30 45 40 (40 30 (55 43 (42 (38

.

)

188

–

)

189

–

263

–

))

–

192

–

)

274

)

–

226

length

NL 146 (121 172 (160 202 (186 186 (167 230 196 (184 (162

neck))))

,

)

175 135 144 141 154

NL

– – – –

NR 113 – (50 122 (111 136 111 (126 (106 NA 125 108 (

; ring

)

175

)

107

)

103) 87 –

)

148

86) nerve

EP 69 50 (

–

88 (78

–

84

–

82 (80 (70

–

148 117 (80 – (75, NR;

)

175

)

202 307

)

200

)

343

)

263

) pore

– – – – –.

)

BD 116

)

(– 50 163 (

)

130 251

)

(200 176 (159

)

257 (182

)

223 (

)

202 al (

. 2020 excretory

Continued L 2,150 – (3,290 1,520 3,058 (2,720 – 3,623 6,190 4,028 – (8,538 4,037 – 5,121 (3,025 5,092 – (8,181 4,181 4,610 (5,940 3,780 – et Aksary to Allotype from diameter; EP,

Table

4

.

Species S. SilVatiCUm S teXanUm . tielinGenSe . S S XinbinenSe . S. XUeShanenSe S. weiSeri aAccording bCalculated, BD body

24°C compared to several other Steinernema species including S. feltiae , S. weiSeri , S. iSChUnanenSe, S. litOrale , S. SUrkhetenSe , S. hermaphrOditUm , S. akhUrSti , S. ChOlaShanenSe , and S. XUeShanenSe . We typically observe that G. mellOnella larvae infested with 50 to 150 IJs of the above-mentioned species die within 2 d to 3 d, but insects take 5 d to 6 d to die when infested with S. afriCanUm . Nematode adults of the first and second generations are found in insect cadavers within 5 d to 6 d and 8 d to 9 d, respectively, when infested by the above-mentioned species, while they are found after 8 d to 9 d and 11 d to 12 d, respectively, when infested with S. afriCanUm . Pre-IJs emerge from insect cadavers after 12 d to 15 d upon infestation by the above-mentioned species, but only after 18 d to 21 d when infested by S. afriCanUm .

Type hOSt and lOCality

The type hosts are unknown as the nematodes of this genus can be hosted by different insect species ( Yan et al., 2016; Kajuga et al., 2018; Fallet et al., 2022) and were isolated from mixed soil samples by the Galleria baiting technique ( White, 1927; Bedding and Akhurst, 1975). Briefly, S. afriCanUm n. sp. RW14-M- C2b-1 and RW14-M-C2a-3 nematodes were isolated, using the “ Galleria baiting” method, from soil samples collected in a banana, pumpkin, and sorghum intercrop in a valley in the Republic of Rwanda (GPS coordinates: 1°28’11.1”S 29°41’36.2”E; 1,865 m. s. n. m.) ( Yan et al., 2016). Cultures of this species are maintained in the Institute of Biology, University of Neuchatel ( Switzerland), in the Rwanda Agriculture and Animal Resource Development Board (Rubona, Rwanda), and in CABI Swiss laboratories in Hungary.

Type material

RW14-M-C2b-1 nematodes are the type material for S. afriCanUm n. sp. Three slides of each stage, including first-generation adults (males and females), second-generation adults (males and females), and IJs, were deposited in the Nematology Collection of the Aquaculture Research Unit of the University of Limpopo, South Africa with the accession numbers ULRS-N1 to ULRS-N15 . Additional specimens were deposited at the nematode collection of the Department of Animal Biology , Plant Biology and Ecology of the University of Jaén, Spain with the following accession numbers: RWA004-01 to RWA004-20 and RWA005-01 to RWA005-15. Slides will be made available upon reasonable request. Nematode cultures are maintained in the Institute of Biology, University of Neuchatel, Switzerland and in the Rwanda Agriculture and Animal Resource Development Board, Rubona , Rwanda .