Invasive and Taxonomically Messy – The First Record of Olepa schleini (Lepidoptera: Noctuoidea: Erebidae: Arctiinae) in the Afrotropics

INTRODUCTION

Olepa Watson, 1980 is a genus of tiger moths (Lepidoptera: Noctuoidea: Erebidae: Arctiinae) belonging to the tribe Arctiini. Disregarding controversies regarding the taxonomic identity of some of the described forms, the most recent review lists 14 valid species and 2 subspecies within the genus (Kalawate et al. 2024). Most of the Olepa species are distributed in South-East Asia, and the majority of them are known only from India. Surprisingly, a single species, O. schleini Witt et al., 2005, was described relatively recently from Israel. Its peculiar distribution prompted discussion on the biogeographic relationships of the new taxon. In the original description, it was referred to as “an old relic species” associated with “the Mediterranean coastal marshes”. However, after more detailed study of the host plants, Rittner et al. (2012) suggested that O. schleini might not be a native species, but rather a new incomer from another region. They came to such a conclusion based on the larvae not being recorded from any indigenous plant, but observed only on six non-native host plants, with Ricinus communis L. (Euphorbiaceae) being the major one. Finally, they suggested that the species originated from the Indian subcontinent, although it had not been known there at the time. This hypothesis found its positive verification when Kalawate et al. (2020a) published results of their genetic barcoding studies, confirming the presence of O. schleini populations in western India (Maharashtra). Following this discovery, Kalawate and Dinesh (2021) published a thorough study aiming to clarify and confirm that the species is indeed an indigenous Indian taxon artificially introduced to Israel, where it became an invasive pest of castor. However, not only do the biogeographic relationships of O. schleini remain obscured. The same refers to its taxonomic status, which was questioned by Zhang et al. (2022), who synonymised O. schleini with O. ricini (Fabricius, 1775) based on their morphogenetic similarity. Finally, Kalawate et al. (2024) reanalysed all available genetic sequences (new and previously published) and, using additional comparative morphological data, argued that O. ricini and O. schleini are well-supported, separate taxa and formally resurrected the latter from synonymy. As for now, O. schleini is regarded as a morphologically variable species distributed in India, China and Israel.

The Union of the Comoros is situated in the Mozambican Channel in the Indian Ocean, between the African continent and Madagascar (11°23′-13°00′S 43°13′-45°18′E). It is an archipelagic country occupying three (Grande-Comore, Anjouan, Mohéli) of the four large islands of the Comoro Islands archipelago. The fourth, Mayotte, is an overseas department of France. These tropical islands, thanks to their volcanic origin, topography and the heterogeneity of ecological conditions, harbour a unique biotic diversity of global importance, composed of both marine and terrestrial fauna and flora (Louette et al. 2004). They are characterised not only by exceptional biodiversity but also by a high number of endemic species (Caldecott 1996), combined with rapidly growing pressures on the local environment (Maéva 2015).

Due to the rapid development of agriculture and the growing market of food products, invasions of alien phytophagous insects in the Comoros are increasing (Guillemaud et al. 2011). Unintentionally introduced pest insects cause growing problems of alimentary security for this developing country, where economic means and human resources are limited. In 2000, the Comoros experienced an invasion of coconut whiteflies, Aleurotrachelus atratus Hempel, 1922 and Paraleyrodes bondari Peracchi, 1971 (Streito et al. 2004). The oriental fruit fly, Bactrocera dorsalis (Hendel, 1912), was first reported in the country, specifically in Grande Comore, in 2005 (DeMeyer et al. 2012). In 2018, the Comoros recorded an invasion of Drosophila suzukii (Matsumura, 1931) (Hassani et al. 2020). The recent Lepidoptera invasions are those of fall armyworm Spodoptera frugiperda (Smith, 1797) and African armyworm Spodoptera exempta (Walker, 1857), well-known pests belonging to the family Noctuidae. The first one was reported in the Comoros in 2018 and the second in 2012 on Mayotte (Germain et al. 2014, Nagoshi et al. 2022).

This study aims to report the first case of introduction of Olepa schleini to the Comoros, and the entire Afrotropical region. Based on morphological and genetic data, we discuss the taxonomic position of the specimens from the Comoros, critically analysing all sequences of Olepa available in the public databases. We describe in detail the damages caused by the caterpillars and discuss the putative ways of introduction of the species to the Comoros. Finally, we discuss the potential risks of establishing the new population for the castor crops in continental Africa.

MATERIAL AND METHODS

Studied material. Live larvae of the last instar have been collected by HM in Moroni (Ngazidja Island) on 25 November 2023, and reared in laboratory conditions until pupation. The details of the collecting localities are provided in Results and on the map (Fig. 1). After hatching, the fresh specimens were killed in the freezer. Eight dead specimens were transferred to glassine envelopes and sent to Poland (ISEA PAS, Kraków) for further examination. Morphologicalstudies. Upon delivery in Poland, but prior to remoistening, a single foreleg of each individual was sampled for molecular study. All specimens were subsequently prepared, dried and labelled following the standard methods used in Lepidoptera studies (Schauff 1986), and photographed using a Canon 70D digital camera with a macro lens EF 50 mm. All eight voucher specimens are incorporated into the scientific collection of the ISEA PAS. To examine the morphology of internal reproductive organs, two males and two females were dissected. For photography, the preparations were mounted in glycerine on microscope slides. Finally, they were transferred into Euparal and mounted under cover slips as permanent slides. Pictures were taken using a stereoscope microscope (Leica S9i system), and edited with the Adobe Photoshop CC program. The morphological terminology of genitalia follows Volynkin (2024).

Molecular studies. For the molecular identification of the specimens, the barcode region of the cytochrome c oxidase subunit I gene (COI) was selected. Genomic DNA extraction from legs was conducted with NucleoSpin Tissue kit (Machery-Nagel, Germany), following the manufacturer's protocol. The first part of the COI gene was amplified with HCO/LCO primers (Wahlberg and Wheat 2008), according to the PCR protocol described by Zenker et al. (2017). Obtained products were sequenced with BrilliantDye Terminator v.3.1 kit (NimagGen, the Netherlands) and read with a ABI Prism 3130xl sequencing machine at ISEA PAS, Kraków. The sequences and the respective chromatograms were checked manually in BioEdit (Hall 1999), and ambiguous sites were encoded according to IUPAC nucleotide codes. Final sequences were uploaded to the VoSeq database (Peña and Malm 2012) and subsequently deposited in GenBank as accession numbers PV872405-PV872411.

To verify the taxonomic status of the Comoro specimens, we included all Olepa COI sequences available in GenBank as the primary resource, supplemented with BOLD records (Table 1). To visualise their position within Olepa, we conducted a phylogenetic analysis within the Maximum Likelihood framework, using IQ-TREE (Nguyen et al. 2015) on the web server (Trifinopoulos et al. 2016), with automatic substitution model selection. Ultrafast Bootstrap (Hoang et al. 2017) and SH-like approximate likelihood test (Guindon et al. 2010) were used to verify nodal support, both with 1000 replicates.

After verification of publicly available sequence codes, authors, specimen collecting dates, and localities, we found most of the BOLD records to be uploaded to GenBank, but in some cases not crossreferenced, and also some records to be duplicated in BOLD (Table 1).

In total, our initial dataset consisted of 57 unique Olepa barcode sequences, with an Arctia caja KF533444 sample used as an outgroup. In the tree inferred with this dataset, we found the O. ghatmatha sample MT318099 (Kalawate et al. 2020b) and five identical O. ricini samples AM050280-AM050284 (Witt et al. 2005) forming long branches (Fig. 2). In manual checking, the sequence MT318099 appeared relatively short (351 bp) compared to the other samples, with ‘messy’ beginning and ending, and differing in 15 amino acids when codons were translated (although without stop codons, not shown). Further, a BLAST query of the sequence AM050280 showed its closest similarity to a few different Geometridae species, suggesting that samples AM050280-AM050284 are mismatched or contaminated. Thus, we excluded the above-mentioned samples and repeated the analysis on a dataset of 51 sequences.

Abbreviations. INRAPE – Institut National de Recherche pour l'Agriculture, la Pêche et l'Environnement, Moroni, Union des Comores; ISEA PAS – Institute of Systematics and Evolution of Animals Polish Academy of Sciences, Kraków, Poland; ŁP – Łukasz Przybyłowicz, Kraków, Poland; BAK – Boinahadji Ahamada Karihila, Moroni, Union des Comores; HM – Hakimou Mahamoudou, Moroni, Union des Comores; MW – Marcin Wiorek, Kraków, Poland.

Figure 1.

Distribution of Olepa schleini in Comoros, Ngazidja Island.

RESULTS

Identity of the species

Olepa schleini Witt, Müller, Kravchenko, Miller, Hausmann & Speidel, 2005

Materialexaminedmorphologically and genetically (1♀was not sequenced): 5♀♀, 3♂♂ Comoros, Moroni, Graphica Imprimerie, 11°43′27.96″S 43°14′49.37″E, 25 XI 2023 (larvae ex situ), 22 I 2024 (imagines ex cult.).

Morphological determination. Due to the lack of a modern, extensive revision of the genus and an identification key to species, for the morphological determination of the Comoro specimens we followed the descriptions and illustrations of the morphological characters available in the published papers on Olepa. The examination of the variability of the forewing pattern and the hindwing background colouration (which are intensively pink-red in Comoros specimens, Fig. 3A–B) of all available illustrations of Olepa specimens did not provide a base for useful discrimination between taxa. These characters are rather uniform across the genus and express high intraspecific variability. The examination of the male genitalia turned out to be much more informative. Within Olepa, two main types of uncus and valva can be distinguished. The uncus can be either elongate and narrow or broad and triangular, whilst the valva can gradually narrow towards the tip or be equipped in the terminal portion with more or less extensive, blunt or more pointed protrusions.

The genitalia of the two examined male specimens are characterised by a clearly narrow, elongate uncus and valva directed inwards, narrowing and devoid of any marginal protrusions (Fig. 3C1–C2). This combination undoubtedly indicates them to represent the nominotypical subgenus (Singh and Singh 2013). Within this group of 10 species, such an arrangement is typical for only three taxa: O. ricini, O. schleini and O. neumuthi Orhant, 2012. Thus, further examination was narrowed down to the published data for these three species. The examination of all available illustrations of the male genitalia published in Orhant (1986, 2012), Witt et al. (2005), Singh and Singh (2013), Zhang et al. (2022), Kalawate et al. (2020a), and the summarising review of Kalawate et al. (2024) did not result in the convincing ascription of the Comoros specimens to any of the taxa. The valva, albeit more similar to the morphotype referred to as schleini, can also be well matched with some illustrations determined as ricini. It should be noted that the genitalia of O. neumuthi, known from a single male, taking into account the morphological similarity combined with intraspecific variation of ricini and schleini, cannot serve as a significant determinant of the taxonomic affiliation to this taxon. For the purpose of this study, which is not aimed at revision of the ricini group of species, the Comoros invasive population is tentatively determined by morphology as belonging to O. schleini. Additionally, the genitalia of a single dissected female are depicted (Fig. 3D) to illustrate the morphological details of the Comoros specimens.

Molecular determination. In our final phylogenetic tree (Fig. 4), the Olepa samples from the Comoros are placed in the large terminal clade, together with 13 samples identified as O. schleini in Kalawate et al. (2020a), Rönkä et al. (2016) and Witt et al. (2005), four samples of O. ricini from the paper by Zhang et al. (2020), the holotype of O. neumuthi (LEPGO009-14), and a few further, unpublished sequences assigned to O. ricini and O. schleini in GenBank. In the clade, there are seven Comoros samples, 17 O. schleini samples, seven O. ricini samples, and one O. neumuthi sample in total.

All samples assigned to O. schleini are grouped in the terminal clade, whilst six further samples of O. ricini are scattered in other places in the tree.

Considering the obtained topology, we interpret the samples from Comoros as belonging to O. schleini. Distribution in Comoros. In December 2023, an invasion of O. schleini caterpillars was observed in the south of Moroni (Graphica cartier). In February 2024, the same species invaded the neighbourhoods around Graphica and later in early March, the Zilmadjou district, a few kilometres from Graphica. In total, the species has been recorded in 10 localities within an area of a few square kilometres (Fig. 1).

Host plants in Comoros. Caterpillars of O. schleini in the Comoros were recorded predominantly on Castor Bean (R. communis), which is the species' main hostplant (Fig. 5A, E). The caterpillars were observed to be able to destroy castor leaves completely, which is congruent with the observations from Israel (Müller et al. 2005). In the Comoros, other plants growing in the vicinity of infested castor individuals were also observed to be attacked, including the economically significant Musa x paradisiaca L. (Fig. 5B), Artocarpus altilis (Parkinson) Fosberg, Persea americana Mill., Passiflora edulis Sims, and Carica papaya L. (Fig. 5C), and further Achyranthes aspera L., Tragia benthamii Baker, Paederia foetida L., Morinda citrifolia L., Calanchoe pinnata Pers., Plectranthus sp., Ficus sp., Dracaena sp., Xanthosoma sp., Acalypha wilkesiana Müll. Arg., Jatropha curcas L., Epipremnum pinnatum L. (Engl.), Ipomoea obscura L. (Ker) Gawl., Solanum torvum Sw. (Fig. 5D), Urena lobate L., Cordyline fruticose L. (A) Chev., and Achyranthes aspera L. The full list of observed host plants is provided in Table 2. It should be stressed that except for plants from the genera Ipomoea, Musa, Ricinus and Solanum, all remaining 23 recorded plants represent new host genera for Olepa. They belong to various orders of monocotyledon and eudicotyledon plants, highlighting the polyphagous nature of O. schleini.

Table 1.

Accession numbers of samples used in the final phylogenetic analysis (see text).

Figure 2.

Maximum Likelihood phylogenetic tree of Olepa based on the initial dataset of COI gene sequences (see text). Support values at nodes represent SH-like/Ultrafast Bootstrap, respectively.

Figure 3.

Olepa schleini from the Comoros. (A) female; (B) male; (C) male genitalia (Genital Slide No S555); (D) female genitalia (Genital Slide No S556).

Figure 4.

Maximum Likelihood phylogenetic tree of Olepa based on the final dataset of COI gene sequences (see text). Support values at nodes represent SH-like/Ultrafast Bootstrap, respectively.

DISCUSSION

Members of Arctiinae are rarely reported as alien invasive species, and Erebidae generally are not very successful invaders, compared to some other families of Lepidoptera (Mally et al. 2022). Furthermore, at least three out of seven Arctiinae invasive species listed in Mally et al. (2022) are known to have been intentionally released, and the origins of the others are uncertain, with Tyria jacobeae (Linnaeus, 1758) as a biological control of Ragwort being one of the most striking cases. One of the best examples of unintentional introductions within tiger moths is the North American Fall Webworm Hyphantria cunea (Drury, 1773). This was first reported in Europe in 1949, and subsequently it has successfully colonised the entire temperate area of Asia, reaching Japan. The species is regarded as one of the most polyphagous of all insects, with 636 species recorded as food plants (Warren and Tadic 1970).

Figure 5.

Selected plants attacked by Olepa schleini in Comoros. (A) Ricinus communis; (B) Musa x paradisiaca; (C) Carica papaya; (D) Solanum torvum; (E) many larvae on a Castor stem.

Table 2.

Details of the infestation of different plants in Comoros by larvae of O. schleini.

Table 2.

Details of the infestation of different plants in Comoros by larvae of O. schleini. Continued

Molecular data on the genus Olepa. Molecular data on the genus Olepa published so far are preliminary, consisting predominantly of the COI (DNA barcode) sequences published by Kalawate et al. (2020a, 2020b), Witt et al. (2005), and Zhang et al. (2022), with only six nuclear gene sequences available for O. schleini (Rönkä et al. 2016). The most comprehensive and up-to-date Olepa phylogeny was published by Kalawate et al. (2024), but unfortunately, based exclusively on the COI gene. Analysis of the trees obtained by Kalawate et al. (2024) and by us leads to the conclusion that the taxonomic status and relationship of O. ricini and O. schleini cannot be inferred with the available data, and much less the evolutionary history of the entire genus, or the genetic variability of the extant taxa and populations. However, the much-needed taxonomic revision of the genus Olepa is beyond the aim of this paper. Since the Comoro specimens unequivocally fall within the O. schleini clade, which is supported by the morphological analyses, we hypothesise that they belong to this taxon. The analyses conducted in our paper cannot answer the questions about the geographic origin of the newly detected Comoro population either. The samples from Israel, India, China and Thailand are mixed within the O. schleini clade, and none of them can be indicated with certainty as the most probable source of introduction.

Nevertheless, following our finding of erroneous sequences AM050280-AM050284 and the low quality of the MT318099 sequence, we can argue that the alleged polyphyletic character of Olepa, suggested in Kalawate et al. (2024), results solely from the data structure and is incorrect. This is also supported by the data available on BOLD, where the samples cluster together with some European geometrids (BIN, BOLD:AAE1311).

The samples identified as O. ricini are scattered in three different lineages across the tree, making the species appear paraphyletic. It raises substantial doubts about the accuracy of the specimens' determination and the taxonomic status of some other taxa included in the dataset. The molecular and morphological data obtained so far support the presence of diverse lineages within Olepa, some of them being recognised as species or subspecies (Kalawate et al. 2024). Currently (September 2025) on BOLD, the majority of Olepa individuals, identified as O. schleini, O. neumuthi, and O. ricini, represent the same DNA barcode cluster (BIN, BOLD:AAC3385), with up to 1% variability. By contrast, O. zedesi (BIN, BOLD: AAK3571) and O. suryamal (BIN, BOLD: ACH0336) are over 4% distinct. Nevertheless, the overall diversity of the genus appears tangled, with more complex research required to address these issues. Considering the unclear and recently changed status of some species (Kalawate et al. 2024), O. ricini could have been used as the ‘default’ identification of ambiguous individuals, which cannot be verified without access to these specimens and their genitalia slides. This leads to an even more important question: whether the actual O. ricini is present in our dataset at all, which could be fully answered only by sequencing the type specimens of this species that are deposited at the Zoological Museum, University of Copenhagen (see Orhant 1986).

The most unequivocal result concerning the remaining Olepa species is the question about the taxonomic distinctiveness of O. neumuthi Orhant, 2012, synonymised with O. ricini by Singh and Singh (2013), and subsequently resurrected as a valid species by Kalawate et al. (2024). According to our molecular results, the single specimen of O. neumuthi does not belong to a separate evolutionary lineage but is arranged together with the Comoro samples of O. schleini. As illustrated in the original description (Orhant 2012: figs 9–11), eggs and caterpillars of O. neumuthi were found in a Castor Bean plantation, suggesting it to be an introduced pest rather than a Ricinus herbivore native to Thailand. With the overall morphological similarity to the other members of the “ricini-schleini complex”, it is plausible that the specimen does not represent a separate, previously unknown taxon but rather an alien, likely invasive species of Olepa introduced to Thailand, similar to the case reported here from the Comoros.

Parasites or parasitoids. Müller et al. (2005) did not mention any parasitoids reared within four years of their study. Instead, they report numerous lethal infections caused by microsporidial fungi. There is no other published data on the natural enemies, especially parasitoids of Olepa species.

Olepa as a pest. Host plants of 10 out of 14 species of Olepa remain unknown (Kalawate and Dinesh 2021). Ricinus communis is utilised by O. koslandana Orhant, 1986, O. neumuthi, O. ricini and O. schleini. In the case of the first two species, it is the only known food plant (Orhant 2012, Farooqui et al. 2022), and in both cases, larvae were collected in a single locality. Thus, there is no information about the severity of infestation of the castor plants in the studied areas in India and Thailand.

Almost all information related to the importance of the Olepa species in agriculture is based on observations of O. ricini. The genus is frequently reported in India as the pest on aubergine, banana, castor, cotton, lablab, maize, sunflower and sesame. Depending on the plant species and source it is regarded as a minor or major pest (David and Ananthakrishnan 2004, Singh and Gandhi 2012). The caterpillars were also collected, probably incidentally, on leaves of vanilla (Vanitha et al. 2011).

The first reports of the potentially calamitous impact of O. schleini caterpillars on castor plantations were in Müller et al. (2005). These authors, who described the taxon some months earlier from Israel, noted that the larvae occurring in larger numbers were able to completely defoliate castor individuals. Additionally, instead of searching for new plants (by dispersing on the ground), they utilised all remaining edible parts of the infested individual, such as green twigs, green seeds and the bark of small branches. They reported a single case in which the small castor tree was “killed […] within a few days”.

Based on the study of Rittner et al. (2012), O. schleini seems to be a highly polyphagous species whose larvae were reported to utilise nine plant species from eight different families. He was also the first to suggest that this moth can be “a potential pest species in agriculture and horticulture” and considered Brassica oleracea L. as the vegetable potentially most susceptible to the loss.

The published data, as well as the field observations gathered in the course of the present study, indicate that regardless of the true taxonomic status of the O. ricini/schleini complex, this pest can constitute a significant threat to commercial castor plantations in Africa. In the Comoros, Olepa apparently has adapted very quickly to the local climatic and ecological conditions and has become a locally abundant taxon. Although the islands lie on the opposite side of the Equator from India, they both belong to the tropical climate zone. The distance from the Equator is similar in case of both Africa and the Comoros, which are about 1300 km distant, which is equal to the location of Bengaluru in the southern portion of the Indian Peninsula, from where O. cf. ricini was recorded (Kalawate et al. 2024). The concerns about a population establishment on the African continent seem to be justified, the more that the existence of the population of O. schleini in Israel proves that the species can easily adapt to relatively dry conditions.

The discovery of so numerous larvae of O. schleini defoliating R. communis in many localities across Moroni may herald a serious threat to the local population of this plant. It may potentially have a significant socioeconomic influence. Castor, which is thought to have an original origin in East Africa (Kenya and Ethiopia), was introduced to the Comoros and Madagascar by colonists more than a century ago as a source of income that could attract major investors (Anziz 2021, Xu et al. 2021). Soon after its introduction, castor oil was adopted in traditional Comorian medicine (Matthew et al. 2020). Although this plant, growing in many dry, tropical and subtropical regions as well as in temperate regions with hot summers, is currently not cultivated in the Comoros (Ghnimi 2015), it has become a widespread weed present in various habitats. Castor grain is used in the Comoros as the source of multi-purpose oil with many potential applications, thanks to the reactivity of its main fatty acid, ricinoleic acid (Mutlu and Meier 2010, Kunduru et al. 2015, Patel et al. 2016, Mubofu 2016). Thus, the plant is of increasing importance on the domestic market, with the emergence of new, small cosmetic companies, which produce and sell castor oil made in the Comoros, making it an increasingly important part of the local economy. Threats to castor oil production in Africa. According to official data published by TRIDGE ( https://www.tridge.com/intelligences/castor-beancastor-seed/production), the largest castor oil producer as of 2022 was India with 1.6 million tonnes, significantly exceeding all other producers from the top 10 list. Among them, there are two East African countries, Mozambique and Ethiopia, and the former is the second largest producer of castor oil in the world. However, virtually all East African countries are significant producers and exporters of castor oil ( https://www.helgilibrary.com/charts/which-countryproduces-the-most-castor-oil/). In this light, the discovery of a potential pest of R. communis close to the African mainland raises the question of the potential impact of O. schleini on Castor Bean plantations in those countries. If the moth was able to colonise – certainly in the case of human involvement – a land located about 5000 km from the known range of the species, the risk of its unintentional transportation to the African mainland, only 300–415 km away from the Comoros, is very high. The observation data retrieved from iNaturalist confirm the presence of wild Castor Bean plants in different locations along the eastern coast of Africa, with numerous coastal records from Kenya and Tanzania. The records also confirm the presence of the host plants in Mombasa and Dar es Salaam (iNaturalist), which are the largest seaports of these countries, respectively. Records of castor along the sea coast of Mozambique are also frequent.

Origins and means of transport of O. schleini to the Comoros. The first record of the originally Asian O. schleini in the Afrotropics raises questions about its possible origins and routes of its introduction to the Comoros. The species is present in both India and Israel, and could have been introduced to the Comoros from the former country, as many of the products used in the Comoros come from India. For example, the rice consumed in the Comoros comes from India and Thailand. According to the unpublished report of INRAPE from 2023, approximately 2,880 tons of luxury rice, distributed across 114 containers, were imported from India and Thailand to the Comoros. Of these 2,880 tons, 97.74% (2,815 tons) originated from India. Also, according to the unpublished rapport of INRAPE from 2024, the quantity decreased to 2,780 tons in 109 containers, with 2,715 tons (97.66%) coming from India.

Without prior studies, it is difficult to explain how exactly the species was transported to the Comoros, but one can consider two major routes: via air or sea. The latter one seems more likely, by transportation with goods such as containers of rice or other plant products, since the main cargo associated with unintentional alien insect species introductions is plant and wood products (Fenn-Moltu et al. 2022). This scenario is also supported by the localisation of transport infrastructure objects in Grand Comoro. The main airport on the island, Prince Said Ibrahim International Airport, is located 19 km in a straight line from the collecting localities. In contrast, the Moroni Sea Port borders the north margin of the area where the species has been recorded. Shipping cargo from the Comoros to India typically takes around 2 to 3 weeks, depending on the route and port of destination. Sea freight transit time from India to Mombasa is estimated at 3–5 weeks by the online calculators of the largest shipping companies, such as Maersk or Hapag-Lloyd ( https://www.maersk.com/schedules/pointToPoint, https://www.hapag-lloyd.com/solutions/schedule/#/). Such a period is short enough to transport any developmental stage of a moth, perhaps except for the imago, which needs regular feeding and is generally the shortest living stage. The transported individual(s) can potentially also continue to develop in any of the four stages (egg, larva, pupa, imago). It should be emphasised that not just an adult female is required to effectively establish a new population. It can be easily initiated by pupae, which, after disembarking of transported goods in the destination port, quickly turn into much more mobile imagines.

CONCLUSIONS

In conclusion, despite the still unclear taxonomic status of the population of discovered Olepa in the Comoros, this observation is very important from an economic perspective. It is the first record of this potentially severe pest of Castor in the Afrotropics and serves as a warning for the quarantine services in continental Africa. The study undertaken highlights the importance of proper curation and allocation of genetic data submitted to publicly available databases, as well as their critical evaluation before application in more general studies.

Finally, the morphological and genetic study conducted shows how superficial our knowledge of the biological variability of the described entities ascribed to the genus Olepa is. Clarification of this intriguing issue will benefit not only basic science but is vital for more applied aspects related to agriculture or pest control. We are convinced that regular monitoring of the Comorian population of O. schleini is needed. Taking into account the apparently aggressive nature of both Israeli and Comoros populations of Olepa, active eradication of the species from the Comoros territory should also be considered.

AUTHOR CONTRIBUTIONS

All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by LP, HM and MW. The first draft of the manuscript was written by LP, and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

STATEMENTS AND DECLARATIONS

The authors declare that no funds, grants, or other support were received during the preparation of this manuscript.

COMPETING INTERESTS

The authors have no relevant financial or nonfinancial interests to disclose.