Eublemmistis chlorozonea Hampson 1902
Creators: name: Swart, Rudi C.
name: Bradley, Suncana
name: Staude, Hermann S.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Lepidoptera
Noctuidae
Eublemmistis
Eublemmistis chlorozonea

description: RESULTS
Early Stages: There were no discernible patterns with regard to season and phenology. Larval forms were observed from late-May to mid-October, whereas cocoons were observed in February, May, July and September (Table 1). Eublemmistis chlorozonea seems to primarily utilise indigenous forest but RCS found a cocoon ca. 120 meters from the indigenous forest edge, in transformed forest vegetation with mature trees of the invasive alien Acacia mearnsii. Observations were made on a variety of host tree species, mostly Afrocarpus falcatus and Pterocelastrus tricuspidatus. Rather than species of tree, it appears as if the presence of several types of lichen determines larval presence (Fig. 3).
The larva of E. chlorozonea is a semi-looper with only two sets of prolegs, apart from the anal claspers. It covers itself with lichen fragments (Fig. 4) and forms a cocoon, that hangs on a thin thread from the tree bark, and which is covered in white lichen (Fig. 5). After an undetermined period of time, the adult emerges from an orange-brown pupa (Fig. 6). Often, post-emergence, the remaining cocoon is seen pressed up against the bark, not hanging in the air as it does pre-emergence, still containing the split open pupa.
The colour of the lichen covering the larvae depends on the colour of lichen the individual larva is observed on. These colours include white, off-white, dull green-white, and dull peach-white. In captivity, larvae accepted and fed on all colours and types of lichen presented. For example, on the 7 th of October 2022, a larva was collected from the Saasveld forest and placed in a glass tank with pieces of bark containing white lichen and kept moist via lightly misting with water once a week. A pupa was formed on the 31 st of October 2022, and the cocoon was found dangling vertically on the side of a flowerpot that was placed in the tank. On the 24 th of November 2022, an adult emerged.
The same lichen that the larva feeds on is used as camouflage. This enables it to blend in perfectly within its habitat, as there is no difference in colour or texture with their surroundings. Often the only giveaway is movement, which resembles a bit of lichen in the breeze unless they’re feeding or building their disguise. The process of covering themselves in lichen, as observed by the second author (SB), is slow and meticulous. They use their mandibles to scrape off bits of lichen and transfer it in chunks onto their bodies. As silk is used in attaching their cocoons to bark, we presume that silk is also mixed with lichen to make it adhere to their bodies. By bending their bodies backwards, they can easily reach and cover their whole length.
Adult: The forewing measures 8–10 mm in length, and the sexes are similar in size. The wings are white ground colour and variable mustard to green shading, with zigzag lines on the forewings with two distinct black cell spots, which are merged into one in some specimens (Fig. 7). Adults have a characteristic resting posture with wings folded over the body and substrate while resting (Fig. 7). They are nocturnal and attracted to light sources but can be seen resting in the undergrowth of the forest by day where they are easily disturbed.
DISCUSSION
The use of lichen in larval camouflage is not unique to E. chlorozonea. A similar strategy is employed by Enispa prolectus (Erebidae) and other members of the Enispa genus, a widely occurring genus in the Indo-Australian tropics and subtropics (Sugi et al. 1987; Pellinen 2017). Wilson & Methven (1997) noted a lichen camouflage strategy similar to E. chlorozonea by the neuropteran Leucochrysa pavida from southern Illinois, United States. In this species, the lichen fragments, collected from tree surfaces, form a packet of debris, which are also used to form the cocoon during pupation (Wilson & Methven 1997). The larvae of L. pavida has dorsal setae on which the lichen fragments are placed. Leucochrysa pavida uses its pincered jaws to break off small pieces of lichen and rolls these into small balls (Wilson & Methven 1997). Research suggests preference for certain species of lichen (Wilson & Methven 1997). Of interest is that L. pavida is predatory during its larval phase, whereas E. chlorozonea was observed actively feeding on lichen.
The species of lichen harvested and utilized by L. pavida include Lecanora strobilina, Myelochroa aurulenta, and a species of Lepraria. In Afrotemperate forests, lichen research is still in its infancy for the most part, making it extremely difficult to identify local lichens to species. For example, the genus Lecanora has received little attention and needs revision (Fryday 2015); although it is certainly present in the southern Cape forests. A species of Lepraria was observed as a common lichen host on which E. chlorozonea was found. It seems likely, based on our experiments, that E. chlorozonea does not specialise on a particular species of lichen but will feed on several lichen species. Its distribution, rather than restricted by host species, seems to be restricted to Afromontane forest habitats because these remain moist for most of the year. Lichens in other southern African habitats are dormant (dry) for long periods and it is probable that the larvae of E. chlorozonea are not able to survive such extended periods of desiccation. Platt (1920) listed the tree Albizia adianthifolia as a larval host plant of E. chlorozonea, but it seems likely that this larva (or pupa) was found on the trunk of the tree where it fed on lichens found on that tree rather than on the foliage of the tree itself.
description: Published as part of Swart, Rudi C., Bradley, Suncana & Staude, Hermann S., 2024, A first ecological description of the lichen-clad larva of Eublemmistis chlorozonea Hampson, 1902 (Lepidoptera: Erebidae) from a southern Afrotemperate forest, pp. 11-15 in Metamorphosis 35 (1) on pages 106-107, DOI: 10.4314/met.v35i1.3, http://zenodo.org/record/14119562