Telchin licus insularis ( Houlbert 1918 )

González, Jorge M. & Cock, Matthew J. W., 2004, A synopsis of the Castniidae (Lepidoptera) of Trinidad and Tobago, Zootaxa 762, pp. 1-19 : 8-12

Telchin licus insularis ( Houlbert 1918) (Fig. 9)

Castnia licus Drury 1773 : Potter (1893); Kaye (1901); Ballou (1905); Urich (1909, 1915); Wolcott (1913); Skinner (1930); Vesey­Fitzgerald (1936); Graf (1942).

Castnia licus insularis Houlbert 1918 : Houlbert (1918); Kaye & Lamont (1927).

Castnia licoides Boisduval 1874 : Myers (1931, 1935, 1938); Box (1954); Cock (1985); Des Vignes (1987).

Castnia licoides insularis Houlbert 1918 : Lathy (1922, 1925); Rothschild (1919).

Castnia licoides ab. licoidella Houlbert 1918: Lathy (1922, 1925).

Leucocastnia licus insularis (Houlbert) : Cock (2003).

Telchin licus is a widespread and variable species in South and Central America. The taxonomic status of the associated subspecies and forms are confusing, and as Miller (1995) points out “far too many specific epithets and/or forms have been described”. Several recent works have made changes (González 2003; Lamas 1995; Miller 1995) without establishing a clear unambiguous taxonomy. Our treatment here, therefore, must be considered provisional pending a detailed study based on good dated series, genitalia dissections, and ideally DNA analysis. Telchin licus was described from Surinam, but the nominate subspecies may be restricted to east Brazil (G. Lamas pers. comm.). It has been suggested that T. licus and Castniomera atymnius may be conspecific (see discussion above under the later species), but the most recent treatment ( Lamas 1995) retains them as separate species, and we follow that here.

Based on five males and one female from Trinidad with no specific locality, Houlbert (1918) recognized an “intermediate variety” compared to those from the “Guyanes” and named it “form insularis”, which characteristically “never had more than four reddishorange spots in the external margin of the hind wings”. We follow current usage and treat this form as a valid subspecies ( Lamas 1995; Miller 1986, 1995), but we doubt that it will prove to be distinct from nominate T. licus when the species is fully researched. Similar populations occur in Colombia and Venezuela (G. Lamas pers. comm.).

Castnia licoides Boisduval , was described from Brazil (Santa Catharina), and is now considered a synonym of T. licus (e.g. Miller 1995), but the name has been used in the Trinidad literature for T. licus insularis (e.g. des Vignes 1987). Houlbert (1918) and Lathy (1922) report “ Castnia licoides ab. licoidella Strand” (Fig. 10) “from St. Ann’s”, Trinidad. The form licoidella is thought to have been described from Peru ( Lamas 1995) and is usually treated as a synonym of T. licus based on a comparison of the genitalia ( Miller 1986), although G. Lamas (pers. comm.) suggests it may be a valid species. In our opinion, Trinidad specimens associated with this name are color pattern varieties of T. licus insularis .

This is the most common and widespread castniid in Trinidad and as indicated above, it has been mentioned in the Trinidad literature under several synonyms. Perhaps surprisingly, it is not known from Tobago. It is locally known as the giant moth borer or large moth borer of sugar cane, Saccharum officinarum (Poaceae) (des Vignes 1987). It can be a significant pest; individually the larvae are the most damaging pest of sugar cane ( Myers 1931). Early in the twentieth century, large­scale netting of adults was a control measure – more than 100,000 could be caught on one estate in one season ( Urich 1912; Wolcott 1913). Cock (1985) summarizes efforts towards its biological control, which thus far have been unsuccessful.

Skinner (1930) presents a detailed life cycle of the moth, including color illustrations in which two adult “forms” can be seen, and discusses control measures in sugar cane. We summarize Skinner’s observations here and note that they are similar to the brief descriptions in Ballou (1905, 1912) and Graf (1942). Eggs are typically laid singly at the base of the cane between the dry trash and the stem. Eggs are 4 mm in length, spindle shaped, and with five longitudinal keels. They are rosy­lavender when first laid and hatch in 7–14 days. The newly hatched larvae (5 mm in length) make their way down between the leaf sheath and the cane to ground level, where they make a small cavity and then tunnel into the heart of the cane. The larva tunnels upwards and downwards, and creates a shelter in the rootstock where it normally rests. Larvae mature after about eight weeks, often longer, and are about 100 mm long. Pupation takes place in the rootstock or at the base of the cane, and lasts 4–6 weeks. The larva makes an emergence window 76–100 mm above ground level before pupation.

Sugar cane is an exotic crop in the Americas ( Purseglove 1968), so T. licus must have native host plants that were used before sugar cane became available. Ballou (1905) and Myers (1931) suggest that T. licus became a significant pest of sugar cane in the first years of the 20th century, perhaps two centuries after sugar cane was first grown in the region. In order to locate possible sources for effective parasitoids and predators for use in the biological control of T. licus in sugar cane, Myers (1931, 1932) studied the question of its original food plants. He considered T. licus to be primarily a forest species and found that Heliconia bihai (Heliconiaceae) , a common species of disturbed and secondary forests, frequently is used as a food plant in Trinidad up to 610 m ( Myers 1932). According to Myers (1935), the young larva begins boring high up into the stalk, probably where the egg is laid. Initially it ascends the stem, but then descends; all large larvae are found at or below the ground surface, before passing up the stem 1–2 m to pupate. Mature leaves commonly show a transverse row of regularly spaced holes across their width. These holes are made as the young larva bores its way into the growing spike when the young leaf is still wrapped within the spike.

Although T. licus commonly attacks H. bihai in Trinidad, it has several other hosts. Ballou (1912) mentions Bromeliaceae and Orchidaceae as “its original food plants”, but this has not been confirmed and probably reflects confusion with another castniid. Graf (1942) repeats this information without attributing a source. Skinner (1930) mentions banana, coconut, and canna as food plants, but does not provide the source of this information. However, T. licus is widely known to use bananas at different localities throughout its range from Costa Rica to Brazil ( Dyar 1905; González & Fernández Yépez 1993; Lara 1964; Matta 1921; Salt 1929). Myers (1932) notes finding larvae commonly in pseudostems of plantains ( Musaceae ) in Guyana, and the species has been reported from banana in Trinidad (Potter 1892). Myers (1935) notes that the larvae, even when mature, are found higher up in the pseudostem of plantains, up to 2 m above soil level, where they pupate. He further suggests that H. humilis is likely to be a host plant, and he searched unsuccessfully for larvae in Trinidad on H. psittacorum , which he considered a savannah plant. Myers (1932) also twice found larvae in Paspalum virgatum (Poaceae) in Trinidad, but he did not state whether he reared adults from this host. Vesey­Fitzgerald (1936) quotes Myers (1932) as recording T. licus from Cyperaceae , but this seems to be a misquote. Myers (1935) reported second hand records from Guyana in “ginger” and “razor grass”.

Vesey­Fitzgerald (1936) continued Myers’ studies on the natural hosts, and found that H. bihai and H. humilis are the most frequent host plants, but that H. pulverulenta , which is associated with well­developed shady forest, is rarely attacked. In contrast to Myers’ (1935) observations, Vesey­Fitzgerald (1936) found that H. psittacorum is regularly attacked whether in wet savannah, open secondary forest, or coconut plantations. He also found that incidence is sometimes high on Renealmia bracteosa (Zingiberaceae) , which is associated with sheltered forest clearings or light shade of secondary forest growth. Finally, Vesey­Fitzgerald lists two further species that are rarely used: Costus sp. ( Costaceae ) and Ischnosiphon arouma (Marantaceae) , noting that the former is associated with stream sides and the latter with dense shady forest. He concludes that the preferred hosts are typical of unstable communities with only moderate shade, and that to a degree this description also can be applied to sugar cane. Vesey­Fitzgerald does not explicitly state that larvae were reared to adults from these hosts. However, his comment “experiments have shown that larvae found in the wild plants considered can be transferred to cane and vice versa, without any harmful effects”, indicates a rather detailed study from which the host records can be trusted.

One of the more puzzling records is that of coconut, Cocos nucifera . This food plant has been reported at least once from Venezuela; Genty et al. (1978) in their review of the oil palm pests of Latin America state that T. licus (as C. licus ) has been found on coconut palm in Venezuela, but we have found no confirmation of this statement. We have traced the original Trinidad record back to Urich’s (1909) account of the 'Cane Sucker' (as C. licus ) in which he states that "Mr. Ottier has found caterpillars of this moth attacking young coconut palms at Laventille and Mr. Collens discovered a caterpillar feeding on the soft internal leaf tissue of a palm ( Oreodoxa oleracea [i.e. palmiste, Roystonea oleracea ]) from the Cascade Valley". Urich (1909) goes on to repeat observations presumably, although not explicitly, based on Kappler (1887) relating to Eupalamides cyparissias (as C. dedalus ) in Surinam: “Mr August Kappler, a Surinam planter, refers to Castnia daedalus (an allied species) as being conspicuous by the damage its caterpillar does to the coconut palm. … the caterpillar bores through the bark and penetrates into the soft tissues; after a time the lower leaves turn yellow and hang down perpendicularly without dropping off. The caterpillar is removed from its burrow with a pair of pointed forceps and if the wound so caused is treated with tar the tree will recover, but the fruit for that year will be lost. When, however the growing point turns yellow, Kappler says that there is no recovery possible and the tree generally dies.” In a later publication, Urich (1915) seems to confuse the observations he quoted from Surinam with the situation for T. licus in Trinidad, stating “the caterpillar attacks young coconut plants by eating the soft tissues of the developing fronds and if left too long destroys the bud. The leaves of the frond attacked generally burns yellow and the caterpillar which will usually be found at the base of the frond and be cut out and the wound tarred, or treated with crude oil.”

Subsequent reports, many of which refer to palms rather than young palms, are probably derived from those of Urich (1909, 1915), rather than based on new observations (e.g.

Giblin­Davis 2001; Lever 1969, Skinner 1930; Vesey­Fitzgerald 1936; Wolcott 1933). We note that Urich did not state whether the records which he quoted were based on larvae or reared adults, and we have some doubts about the accuracy of this report; as it has not been confirmed, and confusion with E. cyparissias is not impossible (see comments under that species). However, we also note that T. licus has a relatively wide host range, and that, furthermore, Urich (1915) specifically refers to young palms, i.e. with host plant architecture broadly similar to that of several other hosts. Possibly this behavior is rare, and given the subsequent observations of Myers (1932) and Vesey­Fitzgerald (1936) regarding habitat preference, this behavior may well be restricted to partially shady situations. Furthermore, bearing in mind that replanting of coconuts has not been very extensively practiced in Trinidad as the industry declined during the twentieth century, it may well be that this damage to young palms has been overlooked.

Material examined: ST. GEORGE: 1ɗ, 6 mi. N of Arima, Jul 3 1962, T.E. Pliske (AME); 1ɗ, 5½ mi. WNW Arima, Arima Pass, Andrew’s Trace, 1800–2000 ft., 22 Dec 1969 (AMNH); 1ɗ 2mi. ENE Arima, Hts. of Guanapo Rd., Guanape Plot, 8­XII­70, Ehrlich & Gilbert, leg. (AMNH); 1Ψ, 3 ½ mi. N. Arima, Simla 600 ft., 12 Dec 1969, Ehrlich & Gilbert (AMNH); 1ɗ, Arima Valley, Asa Wright Nature Centre, 23 Jul 1978, R.A. Mendez (AMNH); 1Ψ, Arima Valley, 100 m, 10°41’N, 61°17’W, 5 Dec 1993, W.M. Neukirchen (UMSM)**; 1ɗ, Fondes Amandes, 3 Feb 1963, B. Heineman (AMNH); 1Ψ, Guanapo Rd., 20 Jan 1963, B. Heineman (AMNH); 1Ψ, Lalaja South Road, milestone 1, 8 Nov 1978, M.J.W. Cock (MJWC); 1? Maracas, 12 May [19]17. N. Lamont (NMS)*; 1ɗ, Mt. Pleasant, 100 m, 30 Nov 1993, W.M. Neukirchen (UMSM)**; 1ɗ, Port of Spain, Botanical Gardens, 3 Feb 1933 (AMNH); 1ɗ, 1Ψ, Port of Spain, Emperor Valley, 100 – 500 ft., St. A. Rogers (HEC); 3ɗɗ, 1Ψ, <15 miles of Port of Spain, <1000 ft., Dec 1913 – Apr 1914, F.W. Jackson (HEC); 1?, St. Ann’s, 20 Nov 1915, N. Lamont (NMS)*; 10ɗɗ, St. Anne’s, R. Dick (BMNH); 1ɗ, St. Ann’s Valley, 400 ft., Jan 1922, F.W. Jackson (HEC); 1ɗ, St. Ann’s, Port of Spain, on plants by roadside, 7 Sep [19]75, E. Fuhr (AME); ST. PATRICK: 1 ɗ, Parrylands Oilfield, 21 Aug 1980, M.J.W. Cock (MJWC); VICTORIA: 1Ψ, San Fernando, 18 Oct 1917, R.W. Farmborough (HEC); ST. PATRICK/VICTORIA: 1?, R[ock] P[enal] Road, 10 Feb [19]36. N. Lamont (NMS)*; TRINIDAD: 1ɗ, F. Johnson (AMNH); 1ɗ Lowsley (BMNH); 1ɗ, 1Ψ, c. 1874, presented by R. Meldola (HEC); 1ɗ, 1919, F.W. Jackson (HEC); 1ɗ Dec 1922, W.J. Kaye (AME); 1ɗ, 1926, F.W. Jackson (HEC); 1Ψ, E.A. Smith Coll. (NMNH); 2ɗɗ (HEC); 3 ɗɗ (AME). There are several specimens in UWI, in Sir Norman Lamont’s collection, but we do not have details of these.

*Specimens reported to us by K. Bland (pers. comm.) which the authors have not examined.

** Specimens reported to us by G. Lamas (pers. comm.) which the authors have not examined.