The classification, taxonomy, distribution, spread, food plants, early stages, natural enemies and biological control of South-East Asian Erionota spp. (Hesperiidae, Hesperiinae, incertae sedis) are reviewed with specific attention to Erionota thrax (Linnaeus), Erionota torus Evans and Erionota acroleuca (Wood-Mason and de Nicéville) (=E. hiraca (Moore)). Erionota thrax and E. torus are shown to be pests of Musa spp. but not palms, while E. acroleuca is a pest of various palms. Where they overlap in distribution in mainland South-East Asia and the Southern Philippines, E. thrax and E. torus have not been distinguished in the economic literature. The species which became established in Mauritius around 1968 and subsequently the target of a successful biological control programme is shown to be E. torus, and not E. thrax as hitherto reported. Research gaps are identified, including the need to find diagnostic features or tools to separate the immature stages of the three species in order to confirm these conclusions, and clarify the ecology and pest status of the pest species. Keywords: Erionota thrax, Erionota torus, Erionota acroleuca, Banana, Musa, Palm, Arecaceae. Review Methodology: Because these pests are large butterflies, there is an extensive literature based on regional butterfly books and lists as well as the applied entomological literature. The author attempted to track down and examine all available information on the genus Erionota, particularly the applied literature dealing with the biology, pest status and control of the pest species. The taxonomic work of Evans [1] and the CABI Crop Protection Compendium datasheet for E. thrax were important starting points. This was supplemented by searching CAB Abstracts, internet searching, and consulting selected reference works dealing with butterflies and pests in the region. The information sources were traced back to their original publication whenever possible. The author familiarised himself with the biology of the two banana skippers (E. thrax and E. torus) by examination of field material in West Malaysia, which helped considerably in interpreting the literature for this review. The Erionota spp. material in the insect collections of the Natural History Museum, London, the Hope Entomological Collections (Oxford University Museum) and the Forest Research Institute of Malaysia were examined to check for locality records, voucher specimens and biological information; the genitalia figures of Inoue´and Kawazoe´ [2] enabled several misidentifications in these collections to be recognised by examination of the externally visible genitalia. The taxonomy of the natural enemies and plant names were checked against key online databases. As indicated in the acknowledgements a variety of informed individuals were consulted on specific points. Erionota thrax (Linnaeus) is well known as 'the banana skipper' or 'banana leaf roller' in South-East Asia, and as an introduced pest in various Pacific territories. It is amongst the largest members of the family Hesperiidae (Figure 1) . A second species, Erionota torus Evans (Figure 2) , has a very similar biology, also occurs in SouthEast Asia and as an introduced in Mauritius, Taiwan and Japan (Okinawa). Both have been the target of successful biological control programmes where they have been introduced. A third, Erionota acroleuca (Wood-Mason and de Nicéville) (Figure 3 ) is similar in appearance but the larvae feed on palms. All three overlap in much http://www.cabi.org/cabreviews CAB Reviews 2015 10, No. 007 of their distribution in South-East Asia and there is an extensive literature which indicates considerable confusion as to the Erionota spp. concerned. In this review, I attempt to untangle this literature, correct some errors, and identify aspects needing further attention. Erionota Mabille is a genus in the subfamily Hesperiinae, family Hesperiidae. In his work on the Hesperiidae of Europe, Asia and Australia, Evans [1] grouped seven Figure 1 Pinned adults of E. thrax thrax, reared on Musa sp., Luzon Is, Philippines; male on the left, female on the right; dorsal surface above, ventral surface below; life size, the scale bar is 1 cm. Figure 2 Pinned adults of E. torus; male on the left, female on the right; dorsal surface above, ventral surface below; life size, the scale bar is 1 cm. Male: SE China, Macao, 20 Aug 1904, J. C. Kershaw; female: west Malaysia, Negri Sembilan, Seremban, Feb 1914, V.G Bell and J. W. B. Bell (specimens in Hope Entomological Collections, Oxford University Museum). The specimens illustrated are less dark than those of the other two Erionota spp. illustrated because they have faded with age. Erionota torus often cannot be reliably distinguished from E. thrax thrax (Figure 1) Warren [3] treated Erionotini as a provisional tribe of Hesperiinae in his Ph.D. thesis on the classification of the Hesperioidea, this was a much enlarged group of genera, which in his subsequent co-authored publications [4, 5] were placed incertae sedis. Of the seven genera that Evans grouped in his Erionota subgroup, no information has been located on the early stages of species of Zela De Nicéville, Ilma Swinhoe, Ge De Nicéville or Pudicitia De Nicéville, but there is information on Gangara, Erionota and Matapa. Gangara thyrsis (Fabricius) feeds on various palms and the early stages have been illustrated in Igarashi and Fukuda [6] and Cock et al. [7] among others. Matapa aria (Moore) is a bamboo-feeder [8] , and the early stages are illustrated by Bascombe et al. [9] and Saji et al. [10] . Erionota spp. feed on palms (Arecaceae), Musa spp. (Musaceae, bananas and plantains) and some related Zingiberales. Igarashi and Fukuda [6] illustrate the early stages of E. torus, E. thrax and E. grandis (Leech), while Bascombe et al. [9] also illustrate the early stages of E. torus. The leaf shelters of at least some members of all three genera are noteworthy for being tubes made by rolling palm leaflets or cut sections of Musa leaves into a tube, either in a spiral (Gangara, Matapa) or in a roll (Erionota). This behaviour separates them from all other Hesperiinae familiar to the author, and supports their recognition as a distinct group. There is information available on the early stages of the additional genera that Inoué and Kawazoé [2] suggested could be grouped with Erionota. Lotongus calathus (Hewitson) has an unusual biology as documented by Igarashi and Fukuda [11]. The distinctive ova are flattened with a grooved ring around the top. They were found laid singly, and the newly hatched larvae make individual leaf folds on their unidentified palm seedling food plant. The second instar larvae then aggregate to make a communal shelter, which is always co-occupied by a small ant, Dolichoderus bituberculatus Mayr, which does not attack the larvae. The mature larva has a four-lobed black marking on the face, reminiscent of those of some African Artitropa spp. [12, 13] . The larvae pupate in a stout cocoon within the shelter, and the pupa is pale brown with no striking features. Igarashi and Fukuda [11] document the life history of Unkana ambasa (Moore) and Unkana mytheca (Hewitson) on Pandanus odorifer (as P. odoratissimus, Pandanaceae). The ova are smooth and domed, similar to those of many other Hesperiinae; the larvae are translucent grey-green with dark, oval heads, and a dark anal plate in the case of U. ambasa; the leaf shelters are cylindrical and made by rolling the leaf along the axis of the mid-rib; the pupae are brown, the proboscis reaching the cremaster. Rearing revealed Figure 3 Pinned adults of E. acroleuca apicalis; male on the left, female on the right; dorsal surface above, ventral surface below; life size, the scale bar is 1 cm. Both collected as larvae on Caryota sp. (Arecaceae), Peninsular Malaysia, Selangor, Kedong, Forest Research Institute of Malaysia, 2 Apr 1988, L. G. Kirton, rearing reference B:5 (specimens in Forest Research Institute of Malaysia). The extent of the white apical forewing apex is variable, especially in the female, and when it is reduced this species is difficult to distinguish from E. thrax ( Figure 1 ) and E. torus (Figure 2 that the all-female species Erionota harmachis (Hewitson) is a synonym of the all-male species U. mytheca [14] , indicating affinities in adult structure characters. Hidari irava (Moore) makes leaf shelters between leaflets of its palm hosts where small numbers of larvae cohabit [11, 15, 16] . Pirdana hyela (Hewitson) and Pirdana distanti (Staudinger) feed on Dracaena spp. (Asparagaceae) [11] . The ovum is strongly ribbed; the head and body of the larva of P. hyela superficially resembles that of an Artitropa sp. [12, 13] , while that of P. distanti has a similar head, but the body is dark with a yellow dorsal line and yellow dorsolateral transverse bars; leaf shelters are made by rolling the food plant leaf longitudinally; the pupa has a short, blunt, frontal spike. The rather diverse life histories of representatives of these genera do not suggest any obvious affinities with Erionota, unlike that pointed out for Gangara and Matapa above. The checklist in Table 1 presents the current position. The species of immediate concern as pests are E. torus, E. thrax and E. acroleuca. However, as some or all the other species also feed on Musacaeae and Arecaceae as larvae, they are all of concern as potential quarantine pests. Linnaeus [22] Figure 2 ) can usually but not always be distinguished from those of E. thrax (Figure 1 ) by the more rounded distal margin of the forewing in E. torus compared to the straighter margin and apically more pointed forewing of E. thrax. Separation of the two species, particularly females, is only reliable if based on examination of the genitalia ([38], H. Chiba, personal communication, 2014; author's observations). It is fortunate that the male and female genitalia of both species have been accurately documented and drawn by Inoué and Kawazoé [2] and available on the internet. Corbet et al. [39] include figures of the male genitalia of both species, and the male genitalia and female venation of E. torus are illustrated by Bascombe et al. [9] from Hong Kong. The diagnostic characters of both male and female genitalia can usually be seen by brushing off the scales of the abdomen tip using a short, fine paint brush, obviating the need for traditional dissection. In particular, the strongly upturned, more heavily chitinized apical process of the valves of male E. torus, compared with the simple, blunt apical process of E. thrax can often be distinguished. A recent student thesis yet to be published [40] concluded that 'the banana skippers, E. thrax and E. torus, are a monophyletic group which represent a single host shift from Arecaceae or Zingiberaceae to Musaceae'. There is some confusion regarding the correct name for E. acroleuca [19] . It was first described by WoodMason and de Nicéville [25] in August 1881 as Telegonus acroleucus in the abstract of a paper which was not published in full until December that year when the combination Hesperia acroleuca was used [26] . In the interim, in September, Moore [27] independently described the same species as Hesperia hiraca. The description in the abstract [25] gives the new species name, indicates that it is new species, gives a brief description and comparison with E. thrax, and indicates many specimens from 'S. Andaman', i.e. it meets the requirements for the publication of the new name and so has precedence over Moore's name. Gender agreement has been applied under the ICZN [41], i.e. E. acroleuca is correct rather than E. acroleucus following the treatments of De Jong and Treadaway [17] and Xue and Lo [19] . The male of E. acroleuca has the apex of the forewing upper side white, which distinguishes it from the males of E. thrax and E. torus. The female is generally smaller than those of E. thrax and E. torus, but the white patch at the forewing apex is variable, and some specimens are not reliably distinguishable except by examination of the genitalia. Fortunately, Inoué and Kawazoé [2] again provide good drawings of both male and female genitalia of this species (ssp. apicalis). The authorship of ssp. apicalis also needed clarification. Xue and Lo [19] showed that when Evans [29] published the name as var. apicalis, this made it an unavailable infraspecific name under Article 45.5.1 of the International Code of Zoological Nomenclature [41] , and it should take the authorship from the first publication to use it as a valid name, i.e. De Jong and Treadaway [17] , as listed in Table 1 . Astictopterus harmachis Hewitson was described from Sumatra [42] , and was subsequently treated as a species of Erionota [1, 21] . However, it is now known to be the female of U. mytheca, which had previously only been known from the male [11, 14] . There are four subspecies of E. thrax recognized in South-East Asia: E. thrax thrax widespread from north-east India to the Philippines, Sulawesi and Java, E. thrax mindana Evans in the southern Philippines but overlapping with E. thrax thrax in the northern Philippines, E. thrax alexandra Semper from upland northern Luzon and E. thrax hasdrubal Fruhstorfer from Kep. Sula (Mangole, Sanana), http://www.cabi.org/cabreviews 4 CAB Reviews In view of the foregoing discussion and the confusion that has arisen, it is worth recognizing the possibility that in the last 65 years or so since Evans [1] completed his review of the Hesperiidae of the region, E. torus could have spread to areas where only E. thrax thrax was known (or vica versa), and easily been overlooked. This possibility merits checking with recent material, for example in the island of Borneo where there is already a single record of E. torus, and Sumatra and Java which are in relatively easy reach of Peninsular Malaysia. I have reviewed much of the literature on food plants of Erionota spp. and find considerable confusion and indications of errors. Accordingly, I present my analysis in some detail below. Erionota thrax thrax and E. torus are similar in adult appearance [1, 21] and life history [6, 39] , and where their ranges overlap, have almost certainly been confused -with each other and with other Erionota spp., particularly E. acroleuca. Reports from localities where only E. thrax or only E. torus occur are more likely to be reliable, but where both occur there will be confusion between the two. The situation is rendered more difficult to interpret by the habit of many authors of compiling food plant records from multiple sources without attribution, so that it is not clear whether any particular observation, such as a food plant record, is an original observation or repeated from an earlier source, which may be misidentified, represent a different subspecies, or be from a different geographical area [72] . I have found reports on the food plants and biology of E. thrax thrax only, and none on the other subspecies of E. thrax, although it seems likely that they will have a similar food plant range. In its indigenous range, many references (e.g. [15, 39, [73] [74] [75] [76] [77] ) indicate that E. thrax feeds primarily on Musa spp. (Musaceae), especially banana (M. Â paradisiaca, = M. sapientum and M. paradisiaca) and M. textilis (abaca or Manila hemp). Sands et al. [58] surveyed E. thrax in PNG when it first spread through the island of New Guinea. They report collecting immature stages of E. thrax from Musa Â paradisiaca, M. textilis, other Musa spp. (including sections Australimusa and Eumusa) and several varieties. Waterhouse and Norris [45] point out that in its introduced range, E. thrax thrax is known only from cultivated and wild species of banana (based on personal communications of experienced entomologists who worked on the introduced pest), although their observation to this effect from Mauritius is actually based on E. torus. However, records from other recorded food plants, especially in the older literature, need critical examination. It is possible that different species of Erionota are responsible for the records on bamboo and palms. Probably the oldest record of E. thrax as a pest of banana (pisang, Musa paradisiaca) is that of Horsfield & Moore [78] in A Catalogue of the Lepidopterous Insects in the Museum of the Hon. East-India Company. As these observations were from Java, where E. torus is not reported, they should be reliable. Soon afterwards, Distant [79] Mau and Kessing [88] give Strelitzia (Strelitziaceae) as a food plant genus in Hawaii, but this does not seem to have been formally published. Nevertheless, it is a possible food plant, although perhaps as a spill-over effect (below). Similarly, Mau and Kessing [88] list the genus Heliconia as a food plant in Hawaii. In PNG, the ornamental native species Heliconia papuana is a widespread host for E. thrax thrax (F. M. Dori and D. P. A. Sands, personal communication, in [47] ), although the introduced Neotropical Heliconia bihai is not, and is not in the laboratory [58] . Igarashi and Fukuda [6] list C. angustifolia (wild or Indian arrowroot; Zingiberaceae) as a food plant. No other source has been located for this record (which is repeated in 43), but given that C. angustifolia has large leaves, similar to those of Musa, Ravenala and Heliconia, it seems a possible food plant. A record of Canna (Cannaceae) as a food plant genus in Hawaii [88] could be interpreted in this way, but could also be due to a spill-over effect. At this point it is worth noting that Musaceae and Strelitziaceae are closely related families in the order Zingiberales, while Heliconiaceae, Cannaceae and Zingiberaceae although also placed in Zingiberales are less closely related [89, 90] . Oligophagous species are mostly, but not always, more likely to feed on species closely related to their main food plant, than on those less closely related (e.g. [91] ). The remaining food plant records are of species from other plant orders, and correspondingly less likely. The original records of E. thrax [thrax] feeding on Arecaceae seem to be those of Piepers and Snellen [73] from Java, who in addition to Musa spp., list Cocos nucifera (coconut), Rhapis excelsa (as R. flabelliformis), Metroxylon sagu (sago palm), Arenga pinnata (as A. saccharifera) (sugar palm), and based on a verbal report Elaeis guineensis (West African oil palm) as food plants. Keuchenius [92] and Leefmans [93] also report E. thrax as a coconut pest in Indonesia (Dutch East Indies). However, since Piepers and Snellen [73] treat E. acroleuca as a synonym of E. thrax, it is suggested here that the records from palms are more likely to relate to E. acroleuca, which has since been documented as a palm pest (below). Specimens from P. C. T. Snellen's collection (which includes material from M. C. Piepers) are in the Naturalis Biodiversity Centre, Leiden, Netherlands but they cannot be examined at present during rearrangements of the collection (R. De Jong, personal communication, 2014); perhaps in the future examination of this collection will clarify some of these records. It is furthermore suggested that Piepers and Snellen's records are the basis of the continuing references to palms as food plants of E. thrax in the literature. includes E. thrax as a minor pest, but the illustration of the adult (plate XIVb above) is of a male E. acroleuca apicalis with the distinctive white fore wing tips. There is a relatively recent record of E. thrax hasdrubal as a pest of oil palm in New Britain [105] . The adult illustrated in the paper is not E. thrax hasdrubal, but it is not clear whether it represents E. thrax thrax, E. torus, an individual of E. acroleuca lacking the pale forewing apex, or some other taxon of Erionota. Of these, only E. thrax thrax is known from New Britain, but above we have discounted all records of palms as food plants for this subspecies. It will be necessary to examine and dissect voucher specimens to confirm or clarify this record. There are further records from Arecaceae catalogued by Robinson et al. [84]. In their 'List of economic pests, host plants, parasites and predators in West Malaysia (1920-1978)' Yunus and Ho [106] include Caryota and Nypa fruticans as food plants of E. thrax, but do not specify the source for this record, and Pholboon [107] and Hutacharern and Tubtim [98] in their compilations of plant pests in Thailand, list Licuala grandis as a food plant of E. thrax. These records from palms have not been tracked back to their original source for this review, but below we document that in West Malaysia E. acroleuca apicalis is recorded to feed on Caryota spp. and E. sybirita on a Licuala sp., indicating that these records are likely to be based on misidentifications. Kitamura [108] reared a single Erionota sp. from a leaf shelter on coconut on Panay Island, Philippines, and illustrated the larva, pupa and shelter (a longitudinally rolled leaflet). He identified the resultant adult female as E. thrax. Could it have been another species such as E. acroleuca or E. surprisa De Jong and Treadaway? Kitamura [109] subsequently reared E. acroleuca apex from a palm and compares the larva with his coconut-reared specimen, so clearly considered them different. Nevertheless, given the concerns raised here, and the similarity of adult females, this record based on a single female merits checking by examination of the genitalia before accepting. In their survey of E. thrax in New Guinea, Sands et al. [58] specifically report that no immature stages were found on Ensete glaucum (Musaceae), H. bihai (Heliconiaceae), R. madagascariensis (Strelitziaceae), N. fruticans, Metroxylon sp., Calamus spp., C. nucifera, Areca catechu or E. guineensis (Arecaceae), even when infested Musa spp. plants were growing close by. Furthermore, in the laboratory, groups of ten newly-hatched of E. thrax died without feeding when placed on fresh foliage of H. bihai, C. nucifera and E. guineensis, whereas all larvae placed on M. Â paradisiaca (as M. sapientum) as controls, began feeding. Furthermore, the leaf shelters that E. thrax and E. torus make on banana (see below) involve behaviour patterns that would not be readily transferable to a pinnate leaved palm. Hence, the evidence indicates that E. thrax thrax does not use palms as food plants, and it is anticipated that all the records from Arecaceae, should be referred to E. acroleuca. It is unfortunate, therefore, that the records from palms have led to E. thrax being mentioned repeatedly as a pest of palms in the pest literature (e.g. [75, [110] [111] [112] [113] [114] [115] ). It is equally unfortunate that the common name 'palm redeye' has been applied to this species. The oldest use of this name appears to derive from Evans [116, 117] , and is assumed to be based on the food plant records referred to above, ignoring the welldocumented damage to bananas. Although Brigadier W. H. Evans was an excellent morphological taxonomist, there is almost no reference to food plants and early stages in any of his works, so it seems likely that he was not that well-informed on this aspect, hence the use of this inappropriate name. I recommend that the use of this common name should be discontinued for all species of Erionota to avoid future confusion. There are also records from Poaceae.  As has become evident during this analysis of E. thrax, there has been confusion between E. thrax and E. torus where the two co-occur in mainland South-East Asia. Accordingly, food plant records without voucher specimens can only be accepted for E. torus with full confidence where E. thrax does not occur. It is clear that like E. thrax, E. torus is primarily a pest of Musa spp. Only E. torus occurs in Hong Kong and adjacent China, and here it has been documented to feed on Musa spp. but not on other plants since the late nineteenth century as E. thrax [119] [120] [121] , and more recently as E. torus (e.g. [9, 122] Since the early stages of E. thrax and E. torus cannot be distinguished, and they are both common pests of Musa spp., it follows that where both species co-occur in mainland South-East Asia and the Southern Philippines, then any studies on the pest status, natural enemies, control, etc. which do not address the presence of the two species can be assumed de facto to treat either or both. This would be the case for the detailed studies by J. Okolle and colleagues in Peninsular Malaysia on the population dynamics, within-field and within-plant distribution of the banana skipper and its parasitoids [70, [123] [124] [125] [126] [127] [128] [129] . There are a few published records of palms as food plants for E. torus.  In a laboratory study in Taiwan, Tsai et al. [131] fed cohorts of each of the five instars of larvae of E. torus with cut portions of leaves of banana, Strelitzia reginae (bird of paradise flower; Strelitziaceae), C. nucifera (coconut; Arecaceae), areca nut (A. catechu; Arecaceae), Bambusa oldhamii (bamboo; Poaceae) and sugar cane (Saccharum officinarum; Poaceae). Feeding was most extensive on banana, but almost as heavy on Strelitzia reginae; there was very little feeding on coconut (none for the cohort of instar 1), less on areca nut and none on bamboo or sugar cane. Average survival for all instar cohorts was 50% on S. reginae, 5% on coconut and 0% on bamboo and sugar cane. This is a measure of the survival of larvae transferred to a plant other than banana, and does not reflect what would happen following oviposition on that plant in the field. If there was no feeding in instar 1 on coconut, all larvae would die in the field, while the data does not allow us to interpret what total mortality would be on S. reginae, it would be more than 50%. In this experiment, the larvae on banana are reported to have all completed development, but in a parallel experiment, only 34 and 21% of individuals completed their metamorphosis on banana at 20 and 30 C, respectively, most mortality occurring in instars 1 and 2. It is difficult to know how to interpret these two apparently conflicting results. However, we can conclude that sugar cane, bamboo, areca nut and coconut are unsuitable food plants, whereas S. reginae is less suitable than banana. There are internet records of E. torus using Canna sp(p). (Cannaceae) as food plants (e.g. [132] ), but these have not been traced to any formal publication, and may well be derived from the records for E. thrax, when the name E. torus was misapplied to that species. As noted above and discussed below, the early stages and leaf shelters of E. thrax and E. torus are very similar. The shelters can only be built using a leaf with a large flat lamina, e.g. Musa spp. Heliconia spp., some Strelitziaceae, Marantaceae, Zingiberaceae, etc. (all in the Zingiberales), and unlikely to be used on pinnate palms. It is concluded that all food plant records of E. torus from palms should be disregarded, and although the possibility of other Zingiberales being used as food plants cannot be discounted, none should be considered confirmed at this time. Erionota acroleuca acroleuca has been recorded using palms as food plants in the Andaman Islands: C. nucifera, Pinanga kuhlii, Calamus sp. [87] . Erionota acroleuca apicalis from South-East Asia also feeds on palms. In Peninsular Malaysia, it is recorded from 'oil palm' ([104] Kirton (in 103, 130) has suggested that all records of Erionota spp. from rattan palms (Calamus spp.) should be treated as E. acroleuca, and here this generalization is extended to all records from palms (although some of these could be errors for H. irava). In particular, the records of E. thrax from C. nucifera, R. excelsa, M. sagu, A. pinnata and E. guineensis in Java [73] and the various repetitions of these in the literature (see above) are considered to be in error for E. acroleuca. L. G. Kirton (personal communication, 2014) transferred larvae of E. acroleuca apicalis of various sizes from palms to Musa sp. and they all died. The record of E. thrax from oil palm in New Britain, PNG [105] needs clarification by examination of voucher specimens; it might prove to be E. acroleuca. In conclusion, E. acroleuca is the Erionota species that is commonly found on a wide range of palms, and until such time as there are authoritative records of E. thrax or E. torus breeding on palms, all such existing records should be considered misidentifications, most probably for E. acroleuca. The Chinese species, E. grandis feeds on palms [6], as does E. sybirita (Hewitson). The former is a gregarious species and so unlikely to be mistaken for other Erionota spp. Steiner [130, 133] records the later feeding on Licuala kunstleri in Peninsular Malaysia. It is a rare species found from Southern Myanmar and Thailand to Borneo and Palawan [1, 18] , so is unlikely to account for many of the records of other Erionota spp. from palms. The food plants of the remaining Erionota spp. are unknown. Erionota thrax, E. torus and E. acroleuca are similar in adult appearance [1, 21] . The life history and food plants of E. thrax and E. torus are very similar [6, 39] . However, while the early stages of E. acroleuca are also similar, the food plants and shelters are not. Hence, at this time, the early stages cannot be reliably separated by diagnostic characters, and E. acroleuca can only be provisionally separated by its food plants and shelters. The larvae of E. thrax and E. torus make their leaf shelters by cutting and rolling the lamina of their food plant leaves. More detailed observations of shelter formation are needed for both species, with information on individual variation, feeding habits, etc. At present, the shelter making behaviour cannot be used to separate E. thrax and E. torus. In contrast, although hardly documented, the leaf shelter of E. acroleuca on palm leaves may be constructed similarly to those of E. thrax and E. torus, but is also made by longitudinally rolling a leaflet or pulling together two leaflets or parts of a larger leaf. This latter type of shelter seems typical for palm-feeding Hesperiinae [7] , and contrasts with the shelters of E. thrax and E. torus where the leaf is rolled transversely. Horsfield and Moore [78] provide the first illustrations of the larva and pupa. As these observations were from Java, where E. torus is not reported, they should be reliably associated with E. thrax. The figure portrays the larva as white, with long erect setae on the body, and a dark brown-black head. The pupa is incorrectly shown, in that it has a short, strong, pointed, slightly upturned frontal spike. Horsfield's emerged pupa is preserved in the NHM, and is accurately drawn, so is here assumed to belong to some other species. Distant [79] reproduces these figures of the larva and pupa in Rhopalocera Malayana, perpetuating this error regarding the pupa. Semper [24] illustrates the larva, correct pupa and a large leaf shelter implicitly from Manila, Luzon Is, Philippines, in which case they are safe to associate with E. thrax. Piepers and Snellen [73] document the biology: the larva 'lives in a part of a leaf that is rolled up into a case and fastened with threads, it is chalk-white with a black head overgrown with very short hairs and wholly covered with a white waxy powder, that also entirely fills its abode'. Although Piepers and Snellen treat E. acroleuca as a synonym of E. thrax, it seems likely given the description of the shelter on Musa in Java that they are dealing with the immature stages of E. thrax. Their painting of the pupa also appears to represent this species, having no frontal spike, and a long proboscis extending beyond the cremaster. In Lepidoptera Indica Vol. X, Swinhoe [80] gives the food plants as 'wild or cultivated Musa' and states that the larva 'lives in a shelter made of a portion of rolled-up leaf. To make this shelter it has to cut into the edge of the enormous leaves of the wild or cultivated Musa, or plantains, to obtain a suitable segment to be rolled up.' The larva is figured from 'Grote's original drawing'. Arthur Grote prepared the first catalogue of the butterfly collection of the Asiatic Museum in 1857-1859; he also took notes on the life histories, making use of a Munshi Zynulabdin, a local artist [134] , so the material for these figures was likely to have been collected in the vicinity of Kolkata (Calcutta), and could represent either E. thrax or E. torus. Although not acknowledged, the figure of a pupa is copied from [78] and so is incorrect. Evans [1] indicates that the adult illustrated by Swinhoe [80] is E. thrax; however, the observations on early stages and http://www.cabi.org/cabreviews Matthew J. W. Cock 11 the figure of the larva could refer to either or both E. thrax or E. torus. Williams [82] describes the biology on banana on Luzon Island, Philippines, which should be correctly associated with E. thrax. 'The eggs are hemispherical and well ribbed from the apex and are not quite 2 mm in diameter. The little larvae cut obliquely inward from the edge of the banana leaf and form a tube by fastening this rolled strip with silk; a large larva makes a large roll as illustrated. Here it also pupates. A full-fed larva is fusiform-cylindrical with a large head set on a small neck, as is usual among the Hesperiidae, and is covered with a whitish flocculent substance.' Williams [82] includes drawings of a banana leaf with many small shelters, a leaf with a single large shelter, and a parasitized pupa. The figure of the large shelter is not entirely clear, nor is it explained in the text. It can be interpreted as indicating that the larva makes two parallel cuts along the leaf and rolls the resultant flap, leaving the leaf edge intact. An alternative explanation is that the area of leaf adjacent to the edge of the lamina reflects the portion of the leaf that is eaten or not eaten by the larva. The following account is synthesized from several sources. Ashari and Eveleens [135] provide drawings of the life cycle and provide some additional information. More recent observations are similar, but some have been made from areas where E. thrax and E. torus occur together and so cannot be allocated to species with confidence (e.g. [16, 70] ). Igarashi and Fukuda [6] include the life history of E. thrax from India (in their text they only mention Sikkim). As noted above, Igarashi and Fukuda [6] refer to the species that has spread to the Pacific and Asia as E. torus, rather than E. thrax. As they do not refer to the diagnostic differences in the genitalia, one cannot be sure that their identifications were thus confirmed. However, although both E. torus and E. thrax occur in Sikkim, India, and the possibility of confusion cannot be ignored, the adults that they illustrate are correctly associated (the difference in male forewing shape is very clear), so it is assumed that the early stages are also correctly associated. Although there are photographs and brief descriptions of the biology of E. thrax in its introduced range [45, 136] no detailed accounts have been located in this review. Eggs are laid singly or in groups, mostly on the underside of the leaves, but also on the upper side. Eggs are 2.3 mm wideÂ1.1 mm high, with about 22 fine ribs stopping short of the micropyle. Detailed descriptions of the leaf shelter building behaviour are not available. The newly hatched larvae form a little leaf roll from the edge of the leaf, inside which they feed [135]; it is not clear whether the first shelters are simple leaf folds from the leaf edge, or the transverse leaf roll observed later -or both. Igarashi and Fukuda [6] note that 'the larva rolls a part of a food plant leaf inwards . . . to make a nest in which to rest with its head directed upwards. . . . The larva eats the wall of the nest from below . . . Feeding occurs only during the night Átime. The bottom of the nest is usually closed, and often filled with a large amount of frass pellets. . . . the larva moves and nests are renewed several times. Moving takes place in the direction towards the basal part of the leaf. It takes a few days to make a new nest. Some larvae, however, may show behaviour patterns exceptional to the habits described above.' Leaf rolls made by the mature larvae extend all the way from the edge to the leaf midrib, which leads to considerable loss of leaf area (Figure 4 .2). The leaf rolls in Figure 4 .1 appear to have five rolls of leaf, and dangling from the bottom is a narrow strip of leaf margin which has not been eaten. This can be interpreted as the larva feeding on the leaf edge within its shelter, but not the section furthest from the midrib, which would form the distal end of the leaf roll, where a feeding larva might be vulnerable to predators or disturbance. This may be the reason for the two lines in Williams' [82] drawing mentioned above. There are five larval instars and the final instar grows to 50 mm or more. All instars have dark brown to black heads and pale bodies. After the second instar there is an increasingly dense cover of white powder on the body. The body has fairly inconspicuous pale, erect setae; the head is dark brown, rounded, indent at vertex, widest near base, with setae similar to those on the body; the pronotum, spiracles, true legs and prolegs are all pale, http://www.cabi.org/cabreviews 12 CAB Reviews more or less concolorous with the body. It can be seen that there is minimal white powder on the head, thorax and ventral part of the abdomen of the individual shown in Figure 5 .1, but the covering becomes more extensive as the larva becomes fully grown. The pupa (Figure 6 .1) is pale white-brown, nearly cylindrical but deeper and wider at the thorax; no frontal projection and the proboscis sheath projects beyond the cremaster. The pupa and the inside of the pupal shelter are lined with white waxy powder. Walker [119] wrote about the butterflies of Hong Kong, and was the first to comment on the leaf-roll shelters, stating that E. thrax (i.e. E. torus) has been reared 'in 1892 from larvae found in rolled-up leaves of banana'. Mackinnon and de Nicéville [64] include a brief description of the larva in northern India, and mention that pupation is in a portion of a rolled-up leaf. In the Palaearctic butterflies section of the Macrolepidoptera of the World, Seitz [137] wrote 'The larvae of Erionota . . . feed on the gigantic leaves of Musa, which are yards long. In forming their shelter they commence by making two incisions from the edge of the leaf towards the midrib at a distance of about 8-10 cm one from the other, and then proceed to roll this piece of the leaf up like a cigar, the larva living in the cylindrical hollow within this roll.' When dealing with the Indo-Australian butterflies, Seitz [94] expands on this 'The larva is snow-white, covered with a very short wax-like pubescence, and with a black head. It is easily discovered, as it gnaws out of the gigantic banana leaves, by two parallel-cuts a longitudinal piece which it rolls up like a cigar, in the centre of which it lives. These characteristic cuts you can see in the Musa-plantations from a distance of 20 or more paces, so that the larvae, and still more easily the pupae, may be collected in numbers ad lib. The pupa is of a dingy pale yellow with a very long case of the proboscis projecting beyond the end of the body like a spear . . .'. These seem to be Seitz' own observations as he refers to collecting many specimens in Hong Kong, i.e. they are E. torus not E. thrax. The reference to two cuts to make the shelter are not clear, but may parallel those shown by Williams [82] for E. thrax, and perhaps explained by the feeding behaviour of the larvae inside the shelters as extrapolated above for E. thrax based on Figure 4 .1, i.e. the cut nearer the midrib is used to make the shelter, but the second 'cut' is actually where the larva stops feeding within the shelter in order not to expose itself at the bottom. Based on his observations at Hong Kong and Canton (Guangdong, China), Hoffmann [121] provided a quite detailed description of the early stages and their biology, together with drawings of the ovum, larva and pupa, and photographs of adults and shelters. Eggs are laid singly or in irregular groups on the upper and lower surfaces of leaves (more frequently the latter). They measured 2 mm in diameter and 1.13 mm in height, with the flat area on top 0.45 mm wide; there are 24-29 fine ribs. They are usually orange in colour, but there is considerable variation over time and within batches. There are five larval Figure 5 Final instar larva of E. thrax thrax and E. torus..1, E. thrax, Maui, Hawaii (g Forest and Kim Starr); 2, E. torus, Mauritius (g T. C. E. Congdon). The apparent difference in head colour is not considered diagnostic. Figure 6 Pupa of E. thrax thrax and E. torus on banana, lateral view. 1, E. thrax, Papua New Guinea (g C. Dewhurst); 2, E. torus, Mauritius (g T. C. E. Congdon). http://www.cabi.org/cabreviews Matthew J. W. Cock 13 instars. The first instar is 3 mm long when recently hatched, pale green with the head and pronotum black, and no wax powder. The width of the head capsules of the five instars were 1.08, 1.45, 2.08, 2.9 and 4.26 mm. After the first moult, the larva is covered with an increasingly dense layer of white powder. The fifth instar measures about 44 mm long; the surface of the blackish-brown head is 'more or less granulose', with a moderate covering of weak, silky setae, thicker on the front. The pupa measures 40-46 mm, and is about 7 mm wide and deep at the thorax and is covered with white powder. It is pale dirty yellow apart from the dark brown cremaster; the proboscis extends 5 mm beyond the cremaster; spiracles brown; the eyes become reddish about halfway through the development period. After the early reports considered above, there seems to be little in the way of original observations, as opposed to repeating information from the literature, until late last century, when accounts illustrated with photographs started to appear. There is a brief summary from Mauritius in Monty [59] as E. thrax. Bascombe et al. [9] describe and illustrate the early stages of from Hong Kong, and Igarashi and Fukuda [6] include the life history from Japan. Additional information is provided from the observations of T. C. E. Congdon (personal communication, 2014) and the author's unpublished observations. The following is largely based on Bascombe et al.'s [9] account, except as indicated. The egg ([9], Plate 103.1-2) is 1.8-2.2 mm in diameter, dome-shaped with 22-24 fine ribs stopping short of the micropyle; they are pink or variegated pink and yellowish-white when laid, becoming paler as they develop. They are usually laid on the leaf underside, and may be laid singly, but more often in clusters of up to 30, rarely 50. In contrast, Igarashi and Fukuda [6] state that the ova are 2.2 mm in diameter, and normally laid singly on the leaf upper side, although batches of 3-36 are recorded; this may reflect a generalization on a relatively small number of observations. On hatching the larva eats the egg shell, and then moves to the edge of the leaf to make its first shelter, which is either a simple fold parallel and close to the edge of the leaf ([9], Plate 103.3), or a cone shaped roll formed by making a curved cut from the edge of the leaf and rolling the resultant flap under. This first cut may be curved towards the leaf base or away from it, but all subsequent shelters are made with the cut curved towards the base of the leaf. Larvae feed on the inner parts of the roll, which is closed at the inner end (nearest midrib) and open at the distal end, where frass may accumulate. As the larva grows, it extends the cut and rolls more of the leaf into the shelter. Additional shelters are constructed if the shelter is damaged, unable to roll further or encounters another shelter. Igarashi and Fukuda [6] indicate that the leaf shelters of E. torus and E. thrax are rolled in opposite directions, although it is not clear from the text and diagrams whether this means clockwise and anticlockwise when seen from above, or one with the leaf under surface on the inside of the shelter and the other with the leaf under surface on the outside of the shelter. In any case, they seem to be incorrect, as both species roll the leaf flap clockwise or anticlockwise depending on which side of the leaf the shelter is formed, and the shelters normally have the leaf underside inside the shelter for both species. Igarashi and Fukuda [6] also indicate that the top end of the larval leaf shelter is open and that the larva comes out of this opening to feed on the leaf by night; this also seems to be incorrect as photographs of the leaf shelters indicate no feeding outside the shelters [9, 66, 121, 138] , and the indications are that the larvae feed inside the tube, as discussed below. Working in Japan, Makibayashi [139] provides a detailed description with clear diagrams to show how a final instar caterpillar makes a new leaf shelter. His diagrams show that the leaf roll is pulled into position by silk strands between the leaf roll and the adjacent unaffected part of the leaf, which is in due course, is pulled into the shelter in turn. The following notes on E. torus in Mauritius were prepared by T. C. E. Congdon (personal communication, 2014). The larva makes a cut in the leaf, and rolls the cut portion, extending the cut across the leaf as it grows. No evidence of eating can be seen outside the shelter, and when the tube is unrolled, the unrolled leaf does not refill the space it originally occupied. It appears that the larva feeds by eating the inner layers of the tube, thus avoiding the dangers inherent in emerging from its shelter. One effect of this is that the inside diameter of the tube becomes much greater than is usual in Hesperiinae tube shelters. The bottom end of the shelter is loosely sealed with silk, retaining the frass, thus hindering access by predators. The top of the shelter is crudely closed with silk, but must be opened when the larva extends the cut, and rolls more of the leaf. Old strands of silk are cut and remain visible along the cut on the section not incorporated into the shelter. This detail is at variance with the description and diagrams of Makibayashi [139] above, and the author's unpublished observations from western Malaysia that the silk strands used to form the shelter are attached to parts of the leaf that are subsequently incorporated into the shelter. Further observations are needed to clarify whether these are local or individual variation in behaviour. The larva pupates within the shelter, head up and without a girdle. From an early age, the larva is covered with an increasingly thick layer of white powder, so that the body appears white with erect pale setae partially covered with the powder, and the uniformly dark head is partially obscured with the white powder ( Figure 5 .2). The larva grows to 55 mm in length [6] and is covered with white flocculence as it prepares for pupation. Pupation takes place in the final leaf roll shelter which is 15-20 mm long, lined with a thin layer of silk and closed at the distal end by a thin mesh, which is easily broken by the emerging adult. Ito and Nakamori [140] refer to the http://www.cabi.org/cabreviews 14 CAB Reviews pupal shelters in Japan as 'trumpet shaped', 1.5-2.0 cm diameter at the smaller [basal] opening, and 3.0-3.5 cm at the terminal opening. This does not seem to be typical. Igarashi and Fukuda [6] note that the pupal shelter is simpler than the larval shelter, having 3-4 layers rather than 5-6, and the pupa is formed with the head upwards, although the adult butterfly emerges from the bottom of the shelter. The pupa (Figure 6 .2) is 45 mm long, pale brown with a variable and patchy covering of white powder. The proboscis extends almost to the cremaster. It is attached at the cremaster, and unlike many Hesperiinae does not construct a silk girdle. Life history of E. acroleuca Wood [104] treats E. acroleuca apicalis as E. thrax and includes a photograph of a hesperiid larva and shelter (plate XIVa) without explicitly stating whether it represents E. thrax or Cephrenes chrysozona (Plö tz), the two named species of Hesperiidae treated. The angle of view does not permit a definitive identification to be made, but it is more likely to be E. acroleuca than C. chrysozona. The colouring of the larva suggests an Erionota sp., rather than a Cephrenes sp., which has a green body and white head with dark lines [9, 39] . The leaf shelter appears to have been formed by making a diagonal fold across the oil palm leaflet, but since this may have been constructed in captivity, it is not necessarily indicative of what happens in the field. Mature C. chrysozona larvae roll palm leaflets parallel to the mid rib (author's unpublished observations). Steiner [133] records observations on the ova of E. acroleuca apicalis (as E. hiraca). The ova are white, with a smooth surface and hemispherical in shape. They can be found on all leaves of C. manan, but the majority are found on the youngest leaf, and although found on both surfaces of the leaf, they are mostly found on the upper surface. Xue and Lo [19] indicate that the ova of E. acroleuca apicalis are laid in a cluster on the frond underside. Maziah et al. [101] treat E. acroleuca apicalis as E. torus in their illustrated account of the pests of rattan, and illustrate the larva with a photograph. They note that the larva 'rolls up the leaf from the tip parallel to the veins and lives and feeds from one end of the leaf in this shelter'. This wording is not completely clear, but in view of subsequent observations, it is clear that the leaflet is rolled transversely (more or less at right angles to the mid rib), unlike the longitudinally rolled shelter (parallel to the midrib), made by most palm-feeding Hesperiinae [7] . They describe the larva as 'pale green covered with short silky hairs and a whitish powdery substance and has a dark brown head capsule'. Their photograph shows a larva similar to those of E. thrax and E. torus. Steiner's [133] description and photograph of a 34 mm larva match earlier observations. To make the larval leaf shelter, larvae cut the leaflets near the base about two-thirds of the distance to the midrib, and wrap the distal part in several turns to form a roll (Steiner refers to this as a longitudinal roll, but I would interpret this term as parallel to the midrib, which is not the case here). The larva rests and feeds inside the leaf roll. Prior to pupation, the larva creates a similar kind of leaf roll, which is heavily lined with wax. L. G. Kirton (personal communication, 2014) confirms these observations, and has also observed that on Caryota sp(p)., which have laminate fishtail pinnae, the larva makes a shelter in a similar manner to those of E. thrax and E. torus on Musa spp., i.e. by cutting an arc from the edge of the lamina and rolling the resultant flap into a tube, in which the larva hides and feeds. Xue and Lo [19] provide some additional information regarding E. acroleuca apicalis. Larvae, hatching from egg clusters develop in separate pinnae on the same rachis, rolling the pinnae into a 'coneshape shelter'. They illustrate in colour a larva similar to those above, with a dark brown head with short setae, conspicuous long setae on the body, and the head and body covered with white waxy powder. Maziah et al. [101] record that pupation is in the final larval shelter and 'the pupa is long, slender and also covered with the same whitish powdery substance present on the larva. When disturbed the pupa wriggles violently in the shelter'. Xue and Lo [19] indicate that the pupa is 33 mm, pale cream in colour with brown spiracles, the proboscis extending beyond the cremaster. It is 'sealed in a cocoon' in a shelter formed by 'rolling the undersurface of the apex half of the rachis [pinna?] laterally'. This description of the shelter is not entirely clear, and although their illustrations of the shelter and pupa show a silk cocoon within a leaf shelter, the structure of the shelter cannot be interpreted, although it appears to be aligned longitidinally with the pinna veins. Finally, Kitamura ([109], Figure 18 , upper photo) includes a photograph of the final instar of E. acroleuca apex in his report on this butterfly feeding on L. rotundifolia on Samar Island, Philippines. The larva is similar to those reported above (and to other Erionota spp.), but the leaf shelters are not documented. The shelter building behaviour of the larvae seems to vary with the leaf structure of the food plant palm. Further observations from different food plants and from different parts of the range of this species and its subspecies, supported with voucher specimens, are needed to clarify the biology of this species. There are also some details on the life history of E. sybirita on L. kunstleri in Steiner's [133] thesis. The eggs are white to grey, hemispherical with a smooth surface; almost all were found on the underside of the leaflets. The larvae have a whitish green body, but unlike the other http://www.cabi.org/cabreviews Matthew J. W. Cock 15 Erionota spp. treated above, no wax layer. The head capsule is dark brown to black. The pupae are brownish, covered with wax, and about 36 mm long. The very long proboscis sheath extends beyond the abdomen by up to 40 mm. The pupae are attached only by the cremaster and do not have a silk girdle. Like the larvae of E. hiraca, the larvae of E. sybirita cut the leaflets near the base and wrap the distal part into a roll with several turns (again referred to as longitudinal, but this term should be avoided for the leaf rolls of Erionota spp.). The larva stays in the roll and eats it from the inside. Prior to pupation the lower end of the tube is sealed with silk. It appears that the absence of a covering of white waxy powder on the larva (and perhaps also on the pupa) as well as the specific host plant should facilitate separation of the early stages from E. acroleuca. Waterhouse and Norris [45] summarized the available information on the natural enemies of E. thrax, many only identified to genus or family, but as has become apparent above this summary would not have separated natural enemies of E. thrax from those of E. torus where they occur together. This table is updated as three separate tables below, broken up into records that can be unequivocally associated with E. thrax (Table 2 ), E. torus (Table 3) , or because of their location could be associated with either species ( [127] report seven per host for B. albotibialis. The inconsistency of names used in different publications, even from the same area, suggests that at least some material has been misidentified in the past. This species was better known as O. erionotae Ferrière, which was described from Peninsular Malaysia from 'eggs of E. thrax L. and of an unknown Lepidopteron on wild plantain leaf ' [169]. Given the locality, this could have been from either E. thrax or E. torus. Huang and Noyes [150] point out that O. pallidipes is the senior synonym. Ashmead [173] described O. pallidipes from the Philippines from 'two specimens bred by Father W. A. Stanton from an undetermined aphid'. This now seems to be a host error, perhaps because a mummified aphid may be similar in size, shape and colour to a parasitized ovum of E. thrax. Ooencyrtus pallidipes is a common and widespread egg parasitoid of E. thrax ( Table 2 ) that also parasitizes ova of E. torus (Table 4) . It is reported parasitizing E. thrax (or E. torus) from Nepal, Thailand, Malaysia, Sumatra, Java, PNG and Guam, although the last two may represent accidental introductions. It has been introduced as a biological control agent in Mauritius and Hawaii for the control of E. thrax (although the pest in Mauritius is now known to be E. torus). Females are reported to prefer younger ova for oviposition [45] and once the larvae start to form within the ovum, they are not parasitized [127] . Females avoid parasitized ova for oviposition [127] . In Sumatra, it is reported to cause 10-27% mortality [148, 151] and Hasyim et al. [147] reared an average of 3.8 adults per parasitized egg. It has been recorded from several Lepidoptera, including Eupterotidae, Gracillariidae, Nymphalidae, Papilionidae and Pieridae [141] , but the ova of Gracillariidae are most probably too small to support this species. A record from ova of a buprestid represents a misidentification [150] . This species was described from specimens reared from ova of E. thrax (or E. torus) in peninsular Malaysia, and the type series includes material from Java, and R. A. Syed's material from Sabah, Malaysia reared from ova, larvae and cocoons of Cotesia erionotae (Wilkinson) [149, 155] . Kerrich [155] does not seem entirely convinced by the records from E. thrax larvae and even less so by the record from a C. erionotae cocoon. This is another common egg parasitoid of E. thrax (or E. torus), which has also been recorded Sumatra, where it causes 16-39% egg mortality [148, 151] . This gregarious larval parasitoid was described from E. thrax (or E. torus) in West Malaysia [157] , and is known to attack one or both Erionota spp. in Thailand, West and East Malaysia, Sumatra and Java (Table 3) ; it attacks E. thrax in Sabah, Malaysia (Table 2 ) and E. torus in Mauritius (Table 4 ). It was originally described in the genus Apanteles, but Austin and Dangerfield [174] transferred it to Cotesia. Larvae of instars 2-4 are parasitized and the mature parasitoid larvae emerge mainly from instar 5 [127] . Hasyim et al. [147, 148] This is a common larval parasitoid of E. thrax in Sumatra and Java. In Java, 10-80% larval parasitism is reported, and it is commonly hyperparasitized by Brachymeria lasus, and rarely by Eurytoma sp. B and Theronia zebra [147] . It is possible that the records of a Scenocharops sp. a common larval parasitoid of E. thrax in Sabah [149] represent the same species as the two genera are similar and closely related in the tribe Campoplegini. This is a common pupal parasitoid of E. thrax in Sumatra and Java. It was described from Borneo and Sumatra [178] , and has also been recorded as a parasitoid of the palm-feeding hesperiids H. irava and Cephrenes chrysozona. Earlier records from Java of Xanthopimpla sp. are referable to this species, but it is not clear whether the record of X. regina from Sabah represents a different species or a misidentification. There have been several programmes of biological control against E. thrax (Guam, Saipan, Hawaii, PNG) and E. torus (Mauritius, Taiwan). Waterhouse and Norris [45] provide a review of the earlier programmes against E. torus and E. thrax (summarized below and in Table 5 ). There are numerous natural enemies in the indigenous range of E. thrax (previous section, Tables 2-4), and several have been used as biological control agents ( Congdon, personal communication, 2014), so E. torus continues as an uncommon species of no significant pest status in Mauritius, almost certainly kept under effective biological control by its introduced parasitoids. None of the other species of Hesperiidae found on Mauritius are known to be parasitized by any of the parasitoid species introduced against E. torus (J. Monty, personal communication, 1987 in 45). Based on the programme already carried out for Mauritius (purportedly on E. thrax but actually on E. torus) when E. thrax appeared in Hawaii, a biological control programme was immediately started [45] . In 1973, O. pallidipes was introduced from Guam where it seemed to be an accidental introduction itself, and in 1974 C. erionotae was introduced and released, initially from Thailand (early 1974) and then from Sabah (late 1974). Based on the information presented above (e.g. Tables 3 and 4), the population of C. erionotae from Sabah would have been collected from E. thrax only, since E. torus does not occur there, whereas that from Thailand is likely to have been reared from both E. thrax and E. torus. Control in Hawaii was rapid, and the strain of C. erionotae from Thailand was probably already established and bringing the pest under control before that from Sabah was released. In 1974, C. erionotae cultures of the Thailand strain were sent from Hawaii to Guam, and from Guam to Saipan in 1974-75, in both cases giving good control [45, 49] . Both parasitoids were also sent from Hawaii to Taiwan for the control of E. torus; they were released in 1987 and both became established [182] . The impact has not been fully reported, although Teruya [138] found E. torus to have 'a low pest status', infestation ranging from 0.1 to 7% with an average of 4%, but he did not find the introduced parasitoids. Erionota thrax may have spread into Irian Jaya before 1983 as it appeared by the border in north-western mainland PNG in 1983, and then spread rapidly through http://www.cabi.org/cabreviews Matthew J. W. Cock 17 [47] extrapolated from several studies on defoliation and fruit loss indicating that more than 16% defoliation will cause loss of yield, and 50% defoliation will cause 28% yield loss. As the banana skipper spread, it destroyed an average of some 60% of banana leaves, leading to both a serious delay in fruit maturation and reduced weight of banana bunches. After C. erionotae was introduced and established, there was a reduction in the estimated average leaf damage from 60 to 5%. The losses due to E. thrax each year were calculated at 30% of crop, of which 95% was saved by the biological control introduction. Using a discount rate of 5% per year over the 30 year period, the net present value of lost production due to E. thrax amounts to approximately A$301.8 million. The value of damage prevented by biological control is estimated at A$201.6 million. The reduction of banana skipper abundance by 90% in Southern PNG has correspondingly reduced the chance of adults invading not only Australian islands in the Torres Strait but also the Australian mainland. The successful biological control programme in PNG has therefore provided significant benefits to banana production in Australia. Assuming similar levels of damage in Australia as in PNG, these benefits were estimated to be A$223 million to the year 2020. The assessment of benefits did not consider the social and cultural uses of banana leaves, nor the possible benefits in Irian Jaya, to which the parasitoid almost certainly spread. Bauer et al. [190] considered the impact of the PNG biological control programme on poverty. Poverty through income deprivation is a significant problem in PNG. Estimates from a 1996 household income survey suggested that around 30% of the PNG population have household incomes below the poverty line (i.e. income is not sufficient to sustain 2200 calories per day of food consumption and cover the cost of essential non-food items). The biological control of E. thrax has had a significant beneficial impact on the effective incomes of most PNG households by improving the supply of bananas and by lowering the price of bananas to purchasers. The improvement in income due to biological control measures against the banana skipper would put between 6000 and 15 000 rural farmers (depending on assumptions) above the poverty line who would otherwise have been below it. The successful implementation of the project has also contributed to lower urban banana prices,
Bascombe et al. illustrates male genitalia and female venation of E. torus from Hong Kong REF .Molecular level identification by DNA barcoding is needed to confirm the early stages of the pest to plan effective management strategies .
A critical review of the literature on the pest Erionota spp. (Lepidoptera, Hesperiidae): taxonomy, distribution, food plants, early stages, natural enemies and biological control.
CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources
CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources
Biology