Triclistus nr. aitkeni (Hymenoptera: Ichneumonidae), an undescribed species not currently listed in the Hawaiian Terrestrial Arthropod Checklist, has been reared from caterpillars of six endemic moth species in the family Crambidae throughout the  Hawaiian Islands. This note reports collection localities, host species, parasitism rates and some key morphological characters that can help identify this species

Haines, William P.

Kaufman, Leyla V.

King, Cynthia B.A.

Leblanc, Luc

Proceedings of the Hawaiian Entomological Society

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TriclisTus nr. aiTkeni, a new adventive SpecieS 55P oc. Hawaiian enTomol. soc. (2008) 40:55–59Triclistus nr. aitkeni, a New Adventive Speciesto the Hawaiian IslandsLeyla V. Kaufman, Cynthia B. A. King, Luc Leblanc, and William P. HainesDepartment of Plant and Environmental Protection Sciences, University of Hawaii at Manoa,3050 Maile Way, HI 96822, USA. E-mail: leyla@hawaii.eduAbstract. Triclistus nr. aitkeni (Hymenoptera: Ichneumonidae), an undescribed species not currently listed in the Hawaiian Terrestrial Arthropod Checklist, has been reared from caterpillars of six endemic moth species in the family Crambidae throughout the Hawaiian Islands. This note reports collection localities, host species, parasitism rates and some key morphological characters that can help identify this species. The metopiine Triclistus nr. aitkeni (Cameron) (Hymenoptera: Ichneumonidae) is a koinobiont solitary larval-pupal endoparasitoid which is not currently listed in the Hawai-ian Terrestrial Arthropod Checklist (Nishida 2002). This species is undescribed, but most closely resembles T. aitkeni, which has a widespread distribution in the Eastern Paleartic and Oriental regions. In the Oriental regions it has been recorded as a parasitoid of the rice pest Cnaphalocrocis medinalis (Guenee) (Lepidoptera: Crambidae) (He 1984, He et al. 1996).  Data reported in this note were taken from two parallel studies that aimed at quantify-ing the non-target parasitism by alien parasitoids on selected endemic Hawaiian moths (Kaufman 2008, King 2008). Even though parasitism records reported here date only as far back as 2004, J.W. Beardsley included this genus in his unpublished key to the Hawaiian Ichneumonidae, compiled in 1998. This suggests that this species has been present in the Hawaiian Islands for over a decade, which may explain its current widespread distribution within Hawaii. Triclistus nr. aitkeni was reared from wild and sentinel larvae of six endemic moths in the family Crambidae: Omiodes accepta (Butler), O. anastrepta Meyrick, O. antidoxa Meyrick, O. continuatalis (Wallengren), O. monogramma Meyrick and Udea stellata (Butler) at 14 sites located on four of the six main Hawaiian Islands (Table 1). Collection sites ranged from low elevations dominated by non-native vegetation (e.g. Lyon Arboretum) to relatively pristine high elevations dominated by native vegetation (e.g. Mt. Kaala, Alakai Swamp).  Table 2 shows the number of wild larvae surveyed, total number of larvae parasitized, and number of larvae parasitized by T. nr. aitkeni. Parasitism by T. nr. aitkeni on U. stellata wild larvae ranged from 0.6 to 5.9 %, and accounted for 1.1 to 15.6 % of total parasitism (Table 2). Triclistus nr. aitkeni parasitism rates observed in wild Omiodes larvae varied by species and by collection locality; parasitism ranged from 4.3 to 33.3 % and contributed to 33.3 to 66.6 % of total parasitism (Table 2). Table 3 shows parasitism rates by T. nr. aitkeni on O. continuatalis and U. stellata sentinel larvae, deployed in control exposure trials (Kaufman 2008, King 2008). Parasitism rates by T. nr. aitkeni on U. stellata sentinel larvae ranged from 0.8 to 8.8 %, and accounted for 12.9 to 90.9 % of total parasitism (Table 3). Parasitism by T. nr. aitkeni was recorded to be 8.8% in larvae of O. continuatalis, and contributed to 26.1% of total parasitism (Table 3).   In U. stellata, second to sixth instar larvae (headcapsule measurement 0.3 to 1.7 mm) seem to be suitable for parasitism (Kaufman 2008). Nevertheless, over 95 % of the parasitism on 56 Kaufman et al.U. stellata sentinel larvae was observed in fourth and fifth instar, suggesting that it prefers parasitizing these larval stages. As a result, disparities in T. nr. aikeni parasitism rates with respect to total parasitism on U. stellata wild and sentinel larvae, might be attributed to the underrepresentation of fourth and fifth instar larvae during the surveys of wild larvae (Kaufman 2008). Similarly, fourth through eighth instar Omiodes larvae (headcapsule measurement 0.9–2.0mm) appear to be suitable hosts for T. nr. aitkeni, based on life stage observations at the time of collection and known exposure interval of sentinel larvae in controlled exposure trials (King 2008). While headcapsule widths do not correspond exactly to developmental stages across Omiodes species, larval development in the genus is broadly comparable. In all cases, T. nr. aikeni adults emerged directly from moth pupal cases, so parasitism did not become evident until after pupation of the caterpillar.  Triclistus nr. aitkeni might be confused with Hypsicera femoralis (Fourcroy), another Hawaiian metopiine of adventive origin (Nishida 2002). Both are readily identifiable as Metopiinae by the strongly swollen femora and strongly convex face, but they are easily distinguished by leg color and details of head structures. Hypsicera femoralis has reddish brown to brown legs, has a strongly protuberant face, forming a shelf-like protrusion that bears antennal sockets (Fig. 1A), and its antennal sockets are not separated by a high lamella (Fig. 1C). Triclistus nr. aitkeni has yellow legs, has a weakly protuberant face (Fig. 1B), and its antennal sockets are separated by a high lamella (Fig. 1D).   Our initial identification to the genus level was confirmed by Dr. David Wahl at the American Entomological Institute (Gainesville, Florida). Dr. Gavin Broad at the National Table 1. Geographical data (in decimal degrees) for collection sites.Site Elevation (m) Latitude Longitude Insect host Oahu    Mt. Kaala 1115 21.50327 –158.14714 O. antidoxaKunia   550 21.46290 –158.09953 U. stellataLyon Arboretum   228 21.33386 –157.80714 O. continuatalisPalikea   781 21.41279 –158.09953 U. stellataTantalus   460 21.32996 –157.82249 U. stellataKauai    Alakai Swamp Trail 1128 22.13526 –159.62582 O. monogrammaDitch Trail   981 22.13159 –159.63171 U. stellataPihea Trail 1189 22.15146 –159.61542 O. accepta    O. antidoxaMaui    Makawao FR 1152 20.81267 –156.27004 U. stellataMakawao FR 914 20.82472 –156.26487 O. anastreptaHawaiiKipuka Ki 1315 19.44339 –155.31633 U. stellataKipuka Puaulu 1229 19.43742 –155.30328 U. stellataOlaa 1245 19.47372 –155.26125 U. stellataThurston Lava Tube 1189 19.41298 –155.23771 O. acceptaTriclisTus nr. aiTkeni, a new adventive SpecieS 57History Museum (London, United Kingdom) confirmed that the species is undescribed, and provided the species-level identification of T. nr. aitkeni (Cameron). Voucher specimens are kept at the American Entomological Institute and Natural History Museum. Additional voucher specimens are to be deposited at the Bishop Museum (Honolulu, Hawaii) and University of Hawaii at Manoa Insect Museum. Acknowledgments We would like to acknowledge Dr. Mark Wright for providing funding for species iden-tification through a USDA TSTAR grant.Figure 1. Lateral and dorsal views of heads of Hypsicera femoralis (A,C) and Triclistus nr. aitkeni (B,D). Arrow in figure 1D points at lamella that separates antennal sockets.ABC D58 Kaufman et al.Table 2. Total number of wild larvae collected by species and parasitism rates by T. nr. aitkeni. Total larvae Survived Total Parasitized by surveyed lab rearing    parasitized  T. nr. aitkeni   n (%)  n (%)U. stellata    Ditch trail 1 865 583 96 (16.5) 15 (2.6)Kipuka Ki 2 149 113 22 (19.5) 1 (0.9)Kipuka Puaulu 1 901 564 274 (48.6) 4 (0.7)Kunia 1 527 345 190 (55.1) 2 (0.6)Makawao FR 2   54 43 18 (41.9) 1 (2.3)Olaa 2   37 34 17 (50.0) 2 (5.9)Palikea 1        1033 639 356 (55.7) 13 (2.0)Tantalus 1 134 93 38 (40.9) 2 (2.2)O. accepta    Pihea Trail 3 41 35 18 (51.4) 8 (22.8)Thurston Lava Tube 4 64 48 39 (81.3) 3 (7.7)O. anastrepta    Makawao FR 8 5 5 (100) 1 (20.0)O. antidoxa    Mt. Kaala 3 8 7 3 (42.8) 2 (28.5)Pihea Trail 5 9 9 9 (100) 3 (33.3)O. monogramma    Alakai Swamp Trail 5 62 46 4 (8.6) 2 (4.3)1 Monthly surveys carried out from July 2004 to July 20062 Surveys carried out on April’06, July’06, October’06 and January’073 Survey carried out in June’074 Surveys carried out in August’085 Surveys carried out in August’07 and October’07 TriclisTus nr. aiTkeni, a new adventive SpecieS 59Table 3. Total number of sentinel larvae deployed by species and parasitism rates by T. nr. aitkeni.    Larvae Total larvae Survived Total larvae parasitized deployed lab rearing parasitized  by T. nr. aitkeni    n (%) n (%) U. stellata    Ditch Trail 573 249 30 (12.0) 22 (8.8)Kunia 192 87 14 (16.1) 4 (4.6)Palikea 392 132 31 (23.5) 4 (3.0)Tantalus 370 133 3 (2.3) 1 (0.8)Kipuka Ki 176 71 8 (11.3) 6 (8.5)Olaa 272 153 11 (7.2) 10 (6.5)O. continuatalis    Lyon Arboretum 394 68 23 (33.8) 6 (8.8)Literature CitedHe, J.H. 1984. A checklist of Ichneumon-flies parasitic on rice pests from China (Hymenoptera: Ich-neumonidae). (In Chinese with English summary) Acta Agriculturae Universitatis Zhejiangensis 10:77–110.He, J.H., X.X. Chen, and Y. Ma. 1996 Hymenoptera: Ichneumonidae. Economic Insect Fauna of China. Science Press, Beijing, China. 697 p.Kaufman, L. 2008. Non-target impacts of introduced parasitoids and validation of probabilistic risk assessment for biological control introductions. Doctoral dissertation, Entomology, University of Hawaii at Manoa, 208 p.King , C.B.A. 2008. Assessing the non-target effects of non-native parasitoids on endemic Hawaiian leafroller moths (Omiodes: Crambidae). MS Thesis, Entomology, University of Hawaii at Manoa. 139 p.Nishida, G.M. 2002. Hawaiian terrestrial arthropod checklist, 4th edition. Technical Report 22, B.P. Bishop Museum, Honolulu, Hawaii. 263 p. 

Triclistus nr. aitkeni, a New Adventive Species to the Hawaiian Islands

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Triclistus nr. aitkeni, a New Adventive Species to the Hawaiian Islands

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