TROPICS Vol. 3 (2): 131-142 Issued January, 1994

Parasitoids of the Banana thrax (L.J in Sumatera Barat, Indonesia, with Notes on their Life History, Distribution and Abundance1,2

Ahsol HASYIM Sukarami Research Institute for Food Crops, P. O. Box 34, Padang, Indonesia Nusyirwan HASAN Sukarami Research Institute for Food Crops, P. O. Box 34, Padang, Indonesia SYAFRIL Sukarami Research Institute for Food Crops, P. O. Box 34, Padang, Indonesia HERLION Sumani Research Institute for Horticulture, P. O. Box 5, Solok, Indonesia Koji NAKAMURA Ecological Laboratory, Faculty of Science, Kanazawa University, Kanazawa 920, Japan

Abstract To breed parasitoids, eggs, larvae and pupae of the banana skipper were regularly sampled from banana fields at 7 localities in the Province of Sumatera Barat, Indonesia from November 1990 to December 1992. The sampling sites covered a wide spectrum of elevations up from the sea level and also of rainfall conditions. Twelve primary parasitoid wasps were recorded, belonging to 6 families, Braconidae (1 sp.), Chalcididae (2 spp.), Encyrtidae (2 spp.), Eulophidae (2 spp.), Pteromalidae (1 sp.) and Ichneumonidae (4 spp.), and 6 hyperparasitoid wasps, Braconidae (1 sp.), Chalcididae (1 sp.), Eurytomidae (2 spp.), Ichneumonidae (1 sp.) and Eulophidae (1 sp.). Of these wasps, a chalcid, Brachymeria lasus was both primary and hyperparasitic. Four parasitoid fly species were bred from E. thrax larvae and pupae. These belong to the Tachinidae (2 spp.), Sarcophagidae and Phoridae (each 1 sp.). Documentation is provided for each parasitoid species of (1) its distribution and abundance for each sampling site, (2) the developmental stage of E. thrax on which it oviposited and from which it emerged, and (3) the number of individuals which emerged from a single host. Local differences in the parasitoid fauna in different sampling sites are compared.

Key words: Erionota thrax / banana skipper / parasitoids / Sumatra / population dynamics

In Southeast Asia, the banana skipper, Erionota thrax (L.) is a widespread pest of the banana and its relatives (). On the mainland it ranges from Sikkim to Indochina, and it occurs also on the archipelagoes of Indonesia and the Philippines (Evans, 1949; Corbet & Pendlebury, 1978). It is conspicuous by its large size, having adult wing extension reaching up to 70 mm and the final (= fifth) instar being over 50 mm. The larva constructs a shelter by rolling the margin of a banana leaf and it then feeds from within the shelter (Kalshoven, 1981). Although the banana skipper is in general a minor pest, occasionally very heavy infestations occur and these result in crop defoliation (Kalshoven, 1981; Hill, 1983;

1 This study was carried out with the permission of Lembaga Ilmu Pengetahuan Indonesia (LIPI), and funded partly by the International Scientific Research Program of the Ministry of Education, Science and Culture, Japan (Nos. 02041033 & (5041086). 2 Please send reprint request to K. N. r32 A. HnsvrM, N. HASAN, Svnrnrl, Hr,RLroN & K. NITAMURA

Fig. 1. Location of study sites in Sumatera Barat. Closed circle: four Experimental Stations of Sukarami Research Institute for Food Crops with monthly rainfall (histogram, mm), annual rainfall (numeral in the histogram, mm) and the elevation (numeral above the histogram, m). Closed triangle: three supplemental sampling sites. Inset map indicates location of Sumatera Barat. Modified from Inoue and Nakamura (1990).

N

4 Rambatan SOOm

Equetor 100 m, 1772mm Palangki J TMJSN Muaro Kalaban I

Sitlung lOOm

IOOOm < 2OO - IOOOm o-2oom U*n

Waterhouse & Norris, 1989). E. thrax has invaded , Guam, Saipan, Mauritius and, most recently, Papua New Guinea, probably as a result of human activities. It has caused economic damage to bananas in newly colonized areas, but the introduction of biological control agents has been successful (Waterhouse & Norris, 1989, and see literature therein; Sands er aI.,1991,1993 for the situation in Papua New Guinea). In Indonesia, the outbreaks are sporadic but more frequent in the eastern part of the country. It has been suggested that natural enemies, especially parasitoid wasps, are important in keeping the skipper density at a low level in endemic areas (Ashari & Eveleens, 1974; Kalshoven, 1981), although this process has not been convincingly demonsfated. Parasitoids of the banana skipper in Sumatra r33

Table 1.. Sampling periods and the number of E. thrax collected. Localities Sampling period No. of individuals collected

Bandar Buat Nov.90-Dec.92 (26*)t 1285 28i52 i 81 94 33 209 28 259 Sukarami Nov.91-Der.92 (19*) 104 4, 9 i 29 265 1,4 2l Sitiung Nov.90-Ds.92 (26*) 3381 120,225:'387 228 88 '1, 264 21 363 Lubuk Minturun Dec.90-Aug.92 (7) 176 2, 30i 26 1,4 1.0 2 9 3 13 Rambatan Nov.90-lul.92 (6) 229 22i 32 i 54 9 1L9 2 1"1 2 1,4 Palangki ]un.91-Apr.92 (8) 306 10! 26'76 706 33 11. 25 Muaro Kalaban Ditto 94 57 27 35 2 t9 Total no. of individuals 2S i4s8 288 71,4 ' Numeral in parenthesis: total number of samplings. *Monthly sampling. 'Italic and ' bold numerals indicate the number of E. thrax larvae, which had been killed by Casinaia sp. and Cotesia donotae, respectively, before the sampling. The cocoons of these parasitoids were reared in the laboratories to breed the hyperparasitoids (see the text for the details).

To deal with pest problems in Indonesia the following points should be noted: (1) The of many important insect pest species and their natural enemies is still in great confusion; (2) There is a need for seasonal fluctuations in abundance of pest insect populations to be documented in detail (Nakamura et a1.,1990); (3) The environmental conditions, both physical and biological, are extremely diversified, so that, results obtained from one location can rarely be applied to another (Inoue & Nakamura, 1990). Since November 1990, we have been studying the population dynamics of E. thrax at several localities with different elevations and rainfall conditions around the Province of Sumatera Barat, Indonesia. This article, the first of a series, will present the faunal make-up, life history abundance and disribution of parasiloids of E. thrax in Sumatera Barat.

MATERIAL AND METHODS

Sampling siles: For breeding parasitoids, eggs, larvae and pupae of E. thrax were collected from banana fields at 7 localities in Sumat€ra Barat. Cocoons of Casinaria sp. and Cotesia (= Apanteles) erionotae (Wilkinson), both of which are primary parasitoids of E. thrax larvae, were also sampled to obtain hyperparasitoids (Fig.l and Table 1). Four of the sampling sites were situated in and around Field Experimental Stations of Sukarami Research Institute for Food Crops (SARIF) at Bandar Buat, Sitiung, Sukarami and Rambatan. These stations have distincfly different elevations and rainfalls: Bandar Buat, 6 km east of Padang, the provincial capital, is located on lowland (20 m altitude), facing the Indian Ocean with an annual rainfall of > 4000 mm without any dry months. Sukarami is on highland (928 m alt.) and is very wet with drizzling rain almost everyday, although the annual rainfall is only 2900 mm. At Sitiung, located inland (ll0 m alt.), rainfall is about the same (2884 mm) as in Sukarami, but is seasonal. At Rambatan (500 m alt.), located in the rain shadow of the Barisan mountains, the rainfall is least of all, 1800 mm, with typical differentiation of rainy and dry periods (Fig. I r34 A. HasvrM, N. HASAN, SyRrnn-, HERLTON & K. NnTAMURA and Table l, also see Inoue and Nakamura, 1990). Additional samples were collected from Palangki (250 m alt.), Muaro Kalaban (190 m alt.) and Lubuk Minturun (80 m alt.) (Table l). The samples were reared in the laboratories of SARIF at Sitiung, Sukarami and Bandar Buat under room temperatures. Sampling schedulc; The sampling period extended from November 1990 to December 1992. The samples were taken monthly from Sitiung, Bandar Buat (both 26 times), Sukarami (19 times), Palangki, Muaro Kalaban (both 8 times), and only sporadically from Rambatan (6 times) and Lubuk Minturun (7 times) (Table 1). Voucher specimens: These are kept at the Ecological Laboratory of Kanazawa University, Kanazawa, Japan and the Bogor Zoological Museum, Java, Indonesia.

RESULTS Parasitoids (i) Primary parasitoids Hymenoptera: Table 2 liss the 12 primary parasitoid wasps of the banana skipper belonging to 6 families. As mentioned below, Brachymeria lasus (Walker) is both primary and hyperparasitic (Tables 2 & 4). E. thrax (L.) had 4 species of egg parasitoids. One parasitoid species emerged from second instars, 2 from third instars, 3 from fourth instars, I from fifth instars and 4 from pupae (Table 2). In the present rearings Xanthopimpla gampsura (Krieger) was not bred from Lubuk Minturun and Muaro Kalaban but was recorded in a routine census, which was simultaneously done for construction of life tables (Tables 2) (Hasyim et al.,inpreparation). Diptera: Parasitoid flies of E. thrax include 4 species:2 tachinids, I sarcophagid and I phorid. One parasitoid fly species emerged from third instars, I from fourth instars, 3 from fifth instars and I ftom pupae (Table 3).

( ii) H y p e rp arasit oi.ds Six hyperparasitoid species were recorded from E. thrax parxitoids (Table 4). B. lasus, Eurytoma sp. B (Eurytomidae) and Theronia pseudozebra pseudozebra (Gtpta) were bred from field-collected cocoons of Casinariai and Eurytoma sp. A and Pediobius elasmi (Ashmead) (Eulophidae) were bred from cocoons of C. erionotae. Only I adult wasp emerged per host cocoon. It should be noled that B. /asus has been recorded as both primary and hyperparasitoids (Tables 2 & 4). Only I specimen of Aspilota sp. (Braconidae) was bred from 1 of 13 pupae of E. thrax collected in Lubuk Sulasih (950 m altitude, 8 km SW of Sukarami) on 13 November 1990 (Table 3). It is probably a hyperparasite of a dipteran attacking E. thrax (Maeto, personal communication). A substantial number of E. thrax larvae were collected from the field and reared in the laboratory (Table 1). Of these, 442 and 132larvae, respectively were killed by Casinaria and Cotesia erionotae (Table 5), but no hyperparasitoids emerged. The hyperparasitoids mentioned above were obtained only from the field-collected cocoons of Cotesia erionotae Parasitoids of the banana skipper in Sumafta 135

Table 2. Primary Parasitoid wasps bred from different developmental stage of E. fftrax in Sumatera Barat. Localitiesl No. parasitoids Family Species Stage emerged per host BD LBM RBT SKR MK PLK ST Aver. (Range) N'

-?::::*9::...''.....-c:!.:.::l.r:'r:.!*...... ''.'...... -L-!:.-H-....9-....'-o-.....-o-....'9-'...'9.''...9-.'...'....''.9Z: Chalcididae Brachymria lasus Pupa O O O O O O 8.8 (1-24)s2

Encyrtidae Ooencyrtuserionotae Egg O O O O O O O 2.83 - 184 Anastatils sp. Egg 2 "o-o-o--o-o--o-o 01 ----- .lli Europhidae p'aiiwiiiiiiili -"8;^ o--?^ - Elasmus sp. L2 Otz1, Pteromalidae Agiommatus sumatraensis Egg O O OO 1 18 Ichneumonida e Casinaria sp. L3,L4 0 0 0 0 0 0 0 1, 280 Charops sp. L3,L4 O O01 10 Theronia zebra zebra Pupa O 1 2 Xanthopimpla gampsura Pupa O js O o iso o I 29

I BD = Bandar Buat LBM = Lubuk Minturury RBT = Rambatary SKR = Sukarami, MK = Muaro Kalaban, PLK = Palangki, ST = Sitiung. 2 Number of parasitized hosts exarnined. 3 Italic numerals; the number of parasitized egg masses. 4 Bold numerals: the number of wasps emerged from an egg. 5 Not obtained in the present sampling but recorded in the regular census (see the text for the details).

Table 3. Parasitoid flies bred from different developmental stages of E. thrax inSumatera Barat.

Family Species Stage of Localities E. thrax BD LBM RB SKR MK PLK ST Tachin idae P aI e x orist a sol en sis L3,L4,L5 oo a) BlEharipa sp. L5 t, Sarcophagidae sp. L5 o (, Phoridae sp. Pupa tl

1 Explanations as in Table 2.

and Casinana (indicated by bold and italic numerals in Table l). This indicates that the hyperparasitoids oviposited in the cocoons of the primary parasitoids in the field.

Distribution and abundance (i) Primary parasitoids Hymenoptera: The l2 species listed in Table 2 can be classified into 3 categories: widespread, intermediate and localized species. Five species were widespread, being bred from all 7 study sites (Table 2). These were 2 egg, Ooencyrtus erionotae (Fenidre) and Pediobius erionotae (Kenich), 2larval, Cotesia erionotae and Casinaria, and, I pupal parasitoids, X. gampsura. B. lasus and B. thracis (Crawford) were bred from 6 sites, but not from Rambatan where the number of hosts sampled was small (Table l). However, B. lasus was recorded from Rambatan as a hyperparasitoid of Casinaria (Table 4). These widespread 136 A. HnsvrM, N. HASAN, Sverrul, HERLToN & K. NITAMURA

Table 4. Hyperparasitoids attacking the parasitoids of E. thrax. Host parasitoid Hyperparasitoid Localitiesl Species Stage Stage of E. thrax Family Species BD LBM RBT SKR MK PLK ST LS

Casinaria sp. Cocoon L4 Eurytomidae Eurytoma sp. B C Cocoon L3,L4 Chalcididae Brachymqinlasus CCC ooo Cocoon L4 Ichneumonida e Ther wtia p s ail o - zebra pxudozebra C Cotesia rionotae Cocoon L4,Ls Eurytomidae Eurytomasp. A occ CCC Cocoon L5 Eulophidae Pediobius elasmi C Diptera sp. ? Pupa Braconidae Aspilota sp. o

1 Explantions as in Table 2. LS refers to Lubuk Sulasih"

Table 5. Diagram showing the developmental stage of E. thrax stxeptible to oviposition by parasitoids (see the text for the details).

Parasitoid Developmental stage of E. thrax Order Family Species Ll L2 L3 L4 L5 Pupa N1

Hymenoptera Braconidae Cotesia rionotae + 11 29 4zzft3l3SOlrrql + L32 Chalcididae Brachymqia lasus + ++1859[68] 68 B. thracis + +++9651741 74 Eulophidae Elasmus sp. + 1[1] + + + + L Ichneumonidae Casinaria sp. 21 91, 237197) 93[345] + + M2 Charops sp. 2 3 9[8] t6l + + t4 Thqonia zebra zebra + ++++2121 2 Xantopimpla gampsura + +1+642[49] 49 Diptera Tachinidae Palexorista solensis + + 5[1] 4 711'51 + 1,6 Blqhartpa sp. + + + + 1[1] + 1 Sarcophagidae sp. + +++5t51 + 5 Phoridae sp. + ++++3t31 3 Total number of E. thrax reared t87 383 70r 498 575 71,4

L Total number of hosts from which parasitoids emerged. 2 Numeral without brackets: the number of parasitized hosts brought into rearing. 3 Numeral with brackets: the number of hosts from which parasitoids emerged.

parasioids were also very abundan[ (l) O. erionotae (Feniere) and P. erionotae kllled lO- 4OVo of eggs; and (2) Casinaria killed l0-80%o of larvae, B. thracis and B. lasus 5-2O7o of pupre, respectively (Hasyim et al., in preparation). X. gampsura were widespread but low in density at each locality except Bandar Buat (only 49 individuals were bred, see Discussion) (llable 5). The following species were localized: Elasmus was obtained only from Sitiung (only I second instar was parasitized) and Theronia zebra zebra (Yollenhoven) only from Bandar Buat (2 specimens from pupae). Anastatus was found only in Sitiung and Rambatan, where only O.2Vo and 2.67o of eggs, respectively, were killed (Tables 2 & 5, Hasyim et al., in preparation). Parasitoid species in the intermediate category were the egg parasitoid Agiommatus Parasitoids of the banana skipper in Sumaffa t37

sumatraensis (Crawford), the larval parasitoid Charops and the pupal parasitoidX. gampsura (Table 2). It should be noted that the number of the hosts parasitized by these wasps was not related to the sample size. Thus (l) Ag. sumatraensis was found in Sitiung, Palangki, Lubuk Minturun and Rambatan, parasitizing 1.3-8.0Vo of eggs. However, it was not found in Bandar Buat, where the sample size was the second largest (Table l); (2) Charops were bred from

Sitiung, Muaro Kalaban and Rambatan. Out of 14 parasitized host larvae (Table 5), only 1 Charops was found in Sitiung and none in Bandar Buat, whereas more were found in Muaro Kalaban and Rambatan. Diptera: The distribution and abundance of dipterous parasitoids were much more limited (Table 3). Palexorista solensis (Walker) was the commonest of the 4 species, but only 16 host larvae were parasitized from Sitiung, Muaro Kalaban and Palangki. Sarcophagids were reared from only 2 sites, Sitiung and Palangki. Blepharipa (5 host larvae) and Phoridae sp. (3 host pupae) were bred only from Sitiung (Tables 3 & 5).

( ii) H ype rparasitoid w asp s : Cocoons of Casinaria were hyperparasitized by B. lasus, Eurytoma sp. B and T. pseudozebra pseudozebra (Table 4). B.lasus hyperparasitism was widespread and abundant. Thus, 108 out of 3ll (34.7Vo) cocoons of Casinaria collected from all sites except Sukarami (Table l) were parasitized by B. lasus. Eurytoma sp. B was obtained only from Sitiung (l.OVo were parasitized) and 7. pseudozebra pseudozebra only from Rambatan (0.8Vo). Cocoons of C. erionotae were hyperparasitized by Eurytonn sp. A in all sites except Sukarami, while P. elasmi was obtained only from Rambatan. Eurytoma sp. A emerged from 28 out of 8l (37.0Vo) field-collected aggregations of C. erionotae cocoons (Table l), while P. elasmi parasitized only I aggregation (l.2Vo).

The number of parasitoids emerged from a single host (i) Primary parasiloids Table 2 indicates that only I parasitoid emerged per host for 3 of the 4 egg parasitoids, p. erionotae, Ag. sumatraensis and Anastatus, and that the same applies to all 4larval parasitoids, Casinaria, Charops, T. zebra zebra and x. gampsura. On the other hand, more than one wasp emerged from a single host in other species: an average of 3 O, erionotae from a single E. thrax egg, 12 Elasmus from a second instar, 57 C. erionotae from a fourth or fifth instar, and 9 B. lasus and B. thracis from a pupa (Table 2).

(ii) Hyperparasitoids Only I adult was produced per host by all 5 hyperparasitoids (Tables 2 & 4).

Stages of E. thrax susceptible to oviposition by parasitoids Since we reared field-collected eggs, larvae of all stages and pupae of E. thrax were held in the laboratory until they emerged as adults or were killed by parasitoids, we can trace the earliest stages of the hosts susceptible to each parasitoid. Table 5 shows the number of 138 A. HesvrM, N. HASAN, Svlrnu-, HERLIoN & K. NnTAMURA parasitized hoss in each stage (indicated by the numeral without brackets) and the number of the hosts from which the parasitoids emerged (indicated by the bracketed numeral). For example, 97 Casirnria emerged from third instars and 345 from fourth instars. Of these 442 Casinaria,2l were bred from larvae which had been reared from first larval stadium onward, 9l from second stadium, 237 from third and 345 from fourth stadium. Thus, Table 5 clearly indicates that the earliest parasitized stage of E. thrax was the first stadium, but it does not make clear whether or not the parasitoids oviposited the later stages. To determine whether a particular stadium is susceptible or not, unparasitized larvae would have to be exposed at each stadium, and thereafter reared in the laboratory. The dissection of larvae at successive stadia would enable the developmental stages of the parasitoids to be checked. Table 5 shows that the earliest susceptible stage was the fust instar for Casinaria, second instar for C. erionotae and Elasmus, third instar for Clnrops and X. gampsura, fourth instar for B . Iasus, fifth instar for B. thracis and the pupa for T. zebra zebra. For the parasitoid flies, the earliest stage of oviposition was: third instar for P. solensis, fifth instar for Blephnripa and the sarcophagid and pupa for the phorid. Since the sample size of these flies and some wasps, such as Elasmus andT. zebra zebra,was small, the actual earliest stage might be earlier than that shown in Table 5.

Co-occurrence of parasitoids on I host A single egg mass was frequenfly shared by more than one parasitoid species. For example, in Sitiung, where the egg mass size of E. thrax averaged 10.9 eggs, a single egg mass was frequently parasitized by any combination of 2 of the 4 species, P. erionotae, O. erionotae and Ag. sumatraensis and Anastatus. Rarely 3 species emerged. However, only I individual emerged from each egg. Only I parasitoid wasp or fly species usually emerged from a single larva or pupa of E. thrax.In this study we did not check whether or not a single host (egg, larva and pupa) was oviposited by more than one parasitoid species.

DISCUSSION

Local differences in the parasitoid fauna in Sumatera Barat A total of 16 wasps (10 primary, 5 hyperparasitic and I both primary and hyperparasitic) and 5 flies were recorded as parasitoids of E. thrax. The number of primary parasitoid wasp species bred from a single site ranged from 7 (Rambatan and Sukarami) to 11 (Sitiung)' although the sampling efforts varied considerably among the sites (Table 1). Therefore the parasite fauna, as a whole, was rather uniform over the study sites. The local differences resulted from (l) the presence/absence of minor wasp species (e.g. Elasmus, T. zebra zebra and Anastatus sp. B) and (2) a rather localized disfiibution of parasitoid flies. The number of species recorded from a site is determined by a combination of factors including sampling efforts, host population density, and climatic conditions. Below some features specific to each site will be pointed out (1) Sitiung had ll out of 12 parasitoids and Parasitoids of the banana skipper in Sumatra r39

3 out of 6 hyperparasitoids and had the largest number of samples; (2) Despite having the second largest number of samples, Bandar Buat recorded only 8 primary species. Four minor species Ag. sumatraensrs and Anastatus, Charops and Elasmus were absent, whereas T. zebra zebra was found only there as a primary pupal parasitoid; (3) In Sukarami, where E. thrax density was very low during the 19 monthly sampling period, only 7 primary species and no hyperparasitoids were recorded; (4) Although 4 other sites were sampled less ftequently than the above 3 sites, they each had 7-8 primary parasitoids and 2-4 hyperparasitoid species; (5) Rambatan, where only 6 samples were taken at irregular intervals, is characterized with the richest hyperparasitoid fauna (5 out of6 were recorded, Table 4); and also recorded very high larval parasitism by Casinaria (Table I and in preparation). Rambatan has a very distinct seasonal rainfall pattem (Fig. 1), but its relation to the very rich parasite fauna remains to be clarified.

Parasitoids oI E. thrax in Indonesia and other southeast Asian countries Waterhouse and Norris (1989) neatly summarized the information on E. thrax in Southeast Asia and the Pacific islands as below: in West Java, Indonesia, egg, larval and pupal parasites kill some 94Vo of the population and control measures are seldom required (Ashari and Eveleens, 1974). Several egg parasites, o. erionotae, AgiommatuJ sp., Anastatus sp., are present, resulting in 5O-70Vo egg parasitism (Kalshoven, 1981). About half of the larvae are attacked by C. erionotae and, 4l to 66Vo of pupae are attacked, chiefly by Brachymeria euploeae, but also by Xanthapimplc sp. or a tachinid fly (Ashari and Eveleens, 1974). In Malay Peninsula, Sabah, and Thailand, O. erionotae, C. erionotae and Brachymeria spp. are recorded among the important parasitoids. Biologicat control of E. thrax has been achieved by introduction of parasitoids such as O. erionotae andC. erionotae in Guam, Hawaii, Saipan, Mauritius and Papua New Guinea where the banana skipper recently invaded (Waterhouse and Norris, 1989; Sands et al.,1993\.

Comparison of the parasitoid fauna of E. thrax and the rice-plant skipper parnara guttota gufrato (Bremer & Grey) in Japan In Japan, life table studies of the rice-plant skipper Parnara guttata guttata were carried out in several localities and its parasitoid fauna well documented: (l) Nakasuji (1982) found l0 primary and 6 secondary parasitoids from 4 localities of central and westem Japan, where the skipper can overwinter; (2) Matsumura (1992a, b, c) recorded 23 primary parasitoids and 7 secondaries from the northem peripheral areas of its distribution, Niigata, where the skipper cannot overwinter. The primary parasitoids consist of l0 Ichneumonidae, 1 Braconidae, I Eulophidae, I Trichogrammatidae, 2 Chalcididae, I Scelionidae and 7 Tachinidae. It is ecologically interesting that the faunal richness of P. guuata guttata in Japan is larger in the peripheral than the central areas of the distribution. The results of the present study indicate that the parasitoid fauna of E. thrax in Sumara was not more diversified than that of the rice- plant skipper in Japan. It is often considered that the species richness of many groups of 140 A. HASYIM, N. HASAN, SYAFRIL, HERLION & K. NAKAMURA parasitoid Hymenoptera does not increase rapidly with decreasing latitude as does the species richness of most groups of that serve as parasitoid hosts (Gauld et al., 1992 and literature cited therein). This could be applied to the parasitoid fauna of the skippers.

ACKNOWLEDGMENT We deeply thank the following researchers for their kind help during this study: Drs. Z. Zaini and E. Soenarjo (the former and present Directors of Sukarami Research Institute for Food Crops) generously permitted us to use their facilities and encouraged us. Dr. D. E Waterhouse (Australian Center for International Agricultural Research) gave comments on and corrected English grammar of a draft of this manuscript. Dr. H. Chiba (Hawaii University) identified the banana skipper Erionota thrax and provided general information on Hesperiidae. Parasitoids were identified by Dr. K. Kamijyo (Hokkaido Forest Experiment Station) for Chalcididae, Eulophidae and several other groups, Dr. K. Maeto (Hokkaido Branch of Institute for Forest Science and Forestry Products) for Braconidae, Mr. K. Konishi (National Institute for Agricultural Environment) for Ichneumonidae, and Dr. H. Shima (Kyushu University) for flies. Dr. K. Matsumoto (Tropical Agriculture Research Center) cooperated with us at the beginning of this study. Mr. M. Umebayashi (Kanazawa University) drew the figures in this article.

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Ahsol HASYIM , Nusyirwan HASAN , SYAFRIL , HERLION ，中村浩二 インドネシア共和 固スマトラ西部州におけるバナナセセリ Erionota thrax (L.) (鱗盟国:セセリチョウ科) の寄生性昆虫の種類相司生活史司分布勾生息密度

(1) バナナセセリは，幼虫がバナナの葉を摂食する害虫であり，インドネシアではときどき大 発生する.スマトラ西部州に設置した環境条件の異なる 7 調査地から，卵，幼虫，踊を採集し， 実験室内で飼育して捕食寄生性のハチ類とハエ類(以下では寄生者と呼ぶ)を羽化させた. (2) 調査地には，インド洋岸の多雨地帯 (Bandar Buat，海抜 20m ，年間雨量 5000 mm) ，弱い乾 季がある内陸部 (Sitiung，海抜 100 m，年間雨量 2800 mm) ，年間雨量が少なく強い乾季のあ る内陸部 (Ranbatan，海抜 500 m ，年間雨量 171∞ mm) ，湿潤な高地 (Sukarami，海抜 928 m, 年間雨量 2900 mm) を含む. Bandar Buat と Sitiung では 2 年間(1 990 年11 月から 1992 年12 月 まで)， Sukarami では 1 年間 (1991 年 11 月から 1992年 12 月まで)， 1 ~ 2 週間に l 回ずつ定期採 集し，その他の調査地では不定期に 6~8 回調査した. (3 (3 ) バナナセセリの一次寄生者としてとして 6 科12種のハチ類[コマユパチ科 (Braconidae ， 2 種) ，アシプトコパチ科にha1c ididae ， 2 種)，トピコパチ科 (Encyrtidae ， 2 種)，ヒメコパチ 科但ulophidae ， 2 種)，コガネコパチ科(pteromalidae ， 1 種)，ヒメパチ科(lchneumonidae ， 3 種)]と 4 種のハエ類[ヤドリパエ科(Tachinidae ， 2 種)，ニクパエ科 (Sarcophagidae ， 1 干島，ノミパエ科(phoridae ， 1 種)J，二次寄生者として 6 種のハチ類[コマユパチ科，アシプト コパチ科，ヒメパチ科，ヒメコパチ科の各 l 種とカタピロコパチ科但urytomidae) の 2 種]を 記録した.このうち Brachymeria lasus (アシブトコパチ科)は，一次および二次寄生者として記 録された. (4 ) バナナセセリの発育段階ごとにみると，卵にはハチ 4 種，幼虫にはハチ 4 種とハエ 3 種， 踊にはハチ 4 種とハエ 1 種が寄生した. (5 (5 ) 寄生者の調査地あたり種類数，寄生者の種類ごとの分布，寄生頻度，寄主 1 個体あたり羽 化数，産卵される寄主の発育段階についても報告した.