Nettle Caterpillar Research Articles

Phylogeny, envenomation syndrome, and membrane permeabilising venom produced by Australia’s electric caterpillar Comana monomorpha

Zygaenoidea is a superfamily of lepidopterans containing many venomous species, including the Limacodidae (nettle caterpillars) and Megalopygidae (asp caterpillars). Venom proteomes have been recently documented for several species from each of these families, but further data are required to understand the evolution of venom in Zygaenoidea. In this study, we examined the ‘electric’ caterpillar from North-Eastern Australia, a limacodid caterpillar densely covered in venomous spines. We used DNA barcoding to identify this caterpillar as the larva of the moth Comana monomorpha (Turner, 1904). We report the clinical symptoms of C. monomorpha envenomation, which include acute pain, and erythema and oedema lasting for more than a week. Combining transcriptomics of venom spines with proteomics of venom harvested from the spine tips revealed a venom markedly different in composition from previously examined limacodid venoms that are rich in peptides. In contrast, the venom of C. monomorpha is rich in aerolysin-like proteins similar to those found in venoms of asp caterpillars (Megalopygidae). Consistent with this composition, the venom potently permeabilises sensory neurons and human neuroblastoma cells. This study highlights the diversity of venom composition in Limacodidae.

Dynamic analysis and optimal control strategies of a predator–prey mathematical model for the pest eradication in oil palm plantation

Oil palm cultivation stands as a crucial industry in Indonesia, significantly contributing to the nation’s economy by generating employment opportunities and fostering social welfare for communities residing near plantations. Despite its economic importance, oil palm plantations face various challenges, with one prominent issue being the infestation of nettle caterpillar pests. These pests cause leaf skeletonization, resulting in a staggering 36% reduction in oil palm productivity over a two-year period. This paper explores diverse strategies for pest management in oil palm plantations, encompassing biological control through the stimulation of natural predators, mechanical control involving the collection and incineration of cocoons, and chemical control through pesticide application. The research introduces a predator–prey mathematical model for oil palm plantation pests, where the leaf area serves as the primary food source for caterpillars, acting as prey. Through dynamic model analysis, four equilibrium points are identified, with interconnected conditions dictating their existence and stability. These conditions are visually represented in a bifurcation plane, providing concise information. The study further includes bifurcation diagrams of equilibrium points to elucidate the influence of each parameter on pests, predators, and the leaf area of oil palm plants. Additionally, sensitivity analysis of the stable interior equilibrium point is conducted to understand the impact of individual parameters. The paper extends its investigation to optimal control strategies, evaluating six scenarios categorized into two population conditions: with predators and without predators. Within each population condition, three control strategies are considered—chemical control only, mechanical control only, and a combination of chemical and mechanical control. Simulation results from the optimal control study reveal that the presence of natural predators emerges as a pivotal strategy in effectively managing nettle caterpillars. Notably, the control of resistant pests through pupa incineration has a substantial impact on reducing the caterpillar population in subsequent life cycles.

Aroplectrus dimerus (Hymenoptera: Eulophidae), Ectoparasitoid of the Nettle Caterpillar, Oxyplax pallivitta (Lepidoptera: Limacodidae): Evaluation in the Hawaiian Islands.

The stinging nettle caterpillar, Oxyplax (syn. Darna) pallivitta (Lepidoptera: Limacodidae), is a serious invasive pest of agricultural products and a health hazard on the Hawaiian Islands first discovered in 2001. Nursery workers and homeowners have been stung by the caterpillars while handling their plants, especially rhapis palms (Rhapis sp.). Throughout its invaded range, it causes widespread damage, including the many cultivated and native palm species that have grown in Hawaii. Larvae contain urticating hairs that secrete a toxin, causing painful skin swelling and irritation on contact. Horticulture and nursery products impacted by the limacodid pest are estimated at $84.3 million (2018 value). Suppression efforts with pesticides and lure traps were ineffective, and the moth population continued to spread to major Hawaiian Islands (Hawaii, Kauai, Maui, Oahu). The introduction of specific biological control agents from the native region was thought to be the long-term solution for this invasive pest. Initial exploration in Indonesia and Thailand resulted in the introduction of a pupal ectoparasitoid, Nesolynx sp. (Hymenoptera: Eulophidae: Tetrastichinae), that was not specific. The oriental wasp, Aroplectrus dimerus Lin (Hymenoptera: Eulophidae: Eulophinae), idiobiont gregarious ectoparasitoid of the stinging nettle caterpillar, was introduced from Taiwan in 2004 for host specificity studies and biocontrol in Hawaii. Host range testing showed the parasitoid attacked only limacodid species, and it was approved for field release in 2010. The parasitoid identity, host specificity under containment facility conditions, reproductive performance, and colonization on the major infested sites were assessed. A total of 13,379 parasitoids were colonized on 162 release sites on four Hawaiian Islands. Evaluations were conducted using field surveys of larvae, pupal counts, and male lure traps. Field parasitism was thoroughly investigated on Oahu Island, averaging 18.9 ± 5.6% of 3923 collected larvae during 2010-2023. The numbers of male moths caught/trap/month were significantly reduced on Oahu Island (p < 0.05). Recently, the hyperparasitoid, Pediobius imbreus Walker (Hymenoptera: Eulophidae: Entedoninae), was detected, reducing the efficiency of A. dimerus in the field. The mean hyperparasitism of A. dimerus pupae was 27.3 ± 7.6% on Oahu Island. There was no detailed biological assessment for A. dimerus or its field evaluation available in scientific literature. Results were discussed regarding the potential use of A. dimerus in biocontrol elsewhere if the stinging nettle caterpillar was invaded in the future.

The sublethal doses effect on controlling of the nettle caterpillar Setothosea asigna (Lepidoptera: Limacodidae) on oil palm plantation

The nettle caterpillar, Setothosea asigna, is a major pest in an oil palm plantation in North Sumatra, which causes severe defoliation and reduces productivity. Controlling this pest commonly uses Pyrethroids insecticides, but dimehypo was also used when controlling bagworms and nettle caterpillars in the exact location. The sublethal doses were reported to decrease pest mortality. The study aimed to determine the effect of dimehypo sublethal doses on mortality and pupae acceleration of Setothosea asigna. This study used five doses of treatments using the fogging technique, i.e., 50, 100, 150, 200, and 250 ml/ha, and untreated were tested following a completely randomized design (CRD) with five replications. The results showed that the sublethal doses (50, 100, 150, and 200 ml/ha) had low mortality reached 58.33-62.50%, and the efficacy value reached 52.38-57.14% in seven days after application. The lethal dose (250 ml/ha) has 100% mortality seven days after application, and the efficacy value reaches 80.95% in five days. The sublethal doses of 50, 100, and 150 ml/ha showed an acceleration in the Setothosea asigna pupation on three days and doses of 200 ml/ha on five days from the untreated treatment. This founding could be the reason for Setothosea asigna’s overlapping populations and prolonged the pest outbreak.

Characteristic Observation of Cordyceps Militaris (L) Wild Type Strain from Five Oil Palm Plantation in Muara Wahau East Borneo

Cordycep militaris (L) is known in oil palm plantations as a natural enemy of nettle caterpillars. This fungus infects the caterpillars that descend down to become pupae around the palm circle, so that the pupae do not develop into imago and the pest's life cycle will be interrupted. This fungus is one of the 3 main entomopathogenic fungi used as bioinsecticides to control pests in oil palm plantations. In this study, the characteristics of C. militaris were observed from 5 oil palm plantations cultured in vitro using two types of media and two incubation methods. The results showed that there were mycelium pigmentation in nutrient-rich media Sabouraud Dextrose Agar plus Yeast extract (SDAY) when incubated with lighting. Only one of five mycelium cultures using SDAY media showed pigmentation on the no-light incubation method. Pigmentation did not occur in nutrient-poor media such as agar (WA), either incubated with lighting or with no-light. The growth of isolates was generally higher on SDAY media than on WA media. This study showed that C. militaris is a facultative phagotrophic fungus. The highest growth of isolates cultured on SDAY media incubated with lighting was found in isolates A and C, with colony diameter 90 mm, high mycelium density (+++) and hairy texture like cotton at the end of the 3rd week after inoculation. In the no-light incubation method, the highest growth was found in isolates B and C with colony diameter 90 mm, high mycelium density (+++) and hairy texture like cotton at the end of the 3rd week after inoculation. Isolates A and C showed high virulence potential to be used as bioinsecticides.

Knowledge Level on Bagworm in Oil Palm and its Control Using Integrated Pest Management (IPM) Practices Among Independent Oil Palm Smallholders in Johor

Bagworm (Psychidae) and nettle caterpillars (Limacodidae) are among the major insect pests of oil palm in Malaysia. Bagworm from the species Metisa plana is the most destructive insect pests compared to nettle caterpillar in oil palm plantations. Outbreaks of bagworms were frequently occurred in various areas own by independent oil palm smallholders in Johor. At present, no scientific study has been conducted to indicate the level of knowledge among the independent oil palm smallholders on bagworm and its control, especially using the Integrated Pest Management (IPM) practices. Therefore, this study was conducted to determine knowledge level on bagworm and its control using IPM among 313 independent smallholders in three infestation areas in Johor, which are Mukim Chaah Bahru, Mukim Chaah, Mukim Paloh and Mukim Chamek. Data were collected by interview guided with a questionnaire consisting 23 questions regarding bagworm and its IPM practices. Most of the respondents are more than 51 years (61.1%), with 77.7% males and 22.3% females. They are mostly having primary (47.1%) and secondary (47.5%) school qualifications. This study found that most of the respondents have a basic understanding of bagworm in oil palm and its control measures using IPM practices, but their knowledge is still at a low level. Correlation analysis showed a significant relationship between the level of knowledge on bagworm and its control methods with race, education level and field management experience among the respondents. Therefore, more focus should be given by extension agents to enhance smallholder knowledge on bagworm management, especially in the potential and affected areas in Johor.

Identification of Novel Toxin Genes from the Stinging Nettle Caterpillar Parasa lepida (Cramer, 1799): Insights into the Evolution of Lepidoptera Toxins.

Simple SummaryMany caterpillar species can produce toxins that cause harmful reactions to humans, varying from mild irritation to death. Currently, there is very limited knowledge about caterpillar toxin diversity, because only a few species have been investigated. We used the transcriptome technique to identify candidate toxin genes from the nettle caterpillar Parasa lepida (Cramer, 1799). It is a common pest of oil palm, coconut, and mango in South and South-East Asia, which can cause severe pain and allergic responses to those in contact with them. We reported 168 candidate toxin genes. Most of them are members of the toxin genes families commonly recruited in animal venoms such as serine protease and serine protease inhibitors. However, we identified 21 novel genes encoding knottin-like peptides expressed at a high level in the transcriptome. Their predicted 3D structures are similar to neurotoxins in scorpion and tarantula. Our study suggests that P. lepida venom contains diverse toxin proteins that potentially cause allergic reactions and pain. This study sheds light on the hidden diversity of toxin proteins in caterpillar lineage, which could be future fruitful new drug sources.Many animal species can produce venom for defense, predation, and competition. The venom usually contains diverse peptide and protein toxins, including neurotoxins, proteolytic enzymes, protease inhibitors, and allergens. Some drugs for cancer, neurological disorders, and analgesics were developed based on animal toxin structures and functions. Several caterpillar species possess venoms that cause varying effects on humans both locally and systemically. However, toxins from only a few species have been investigated, limiting the full understanding of the Lepidoptera toxin diversity and evolution. We used the RNA-seq technique to identify toxin genes from the stinging nettle caterpillar, Parasa lepida (Cramer, 1799). We constructed a transcriptome from caterpillar urticating hairs and reported 34,968 unique transcripts. Using our toxin gene annotation pipeline, we identified 168 candidate toxin genes, including protease inhibitors, proteolytic enzymes, and allergens. The 21 P. lepida novel Knottin-like peptides, which do not show sequence similarity to any known peptide, have predicted 3D structures similar to tarantula, scorpion, and cone snail neurotoxins. We highlighted the importance of convergent evolution in the Lepidoptera toxin evolution and the possible mechanisms. This study opens a new path to understanding the hidden diversity of Lepidoptera toxins, which could be a fruitful source for developing new drugs.

Parasitoid Diversity and Host-Parasitoid Interaction in Oil Palm Plantations with Different Management System

Parasitoids play an important role in controlling pests, including pests of oil palm. To maximize biological control technique using parasitoids, interactions between pests and parasitoids need to be studied. This research aimed to study parasitoid diversity and host-parasitoid interaction in oil palm plantation with the different management system. The field research was conducted in oil palm plantation own by smallholder and company (PT Humusindo) in Jambi. Sampling insects was conducted by collecting pests (parasitoid host) on oil palm trees with age of four years old. Eggs, larvae, and pupae of the pests were taken directly by hand then reared in the laboratory to know their parasitoids. Pests and parasitoids emerged were identified up to morphospecies or species level. A total of 176 lepidopteran pests consisting of 15 morphospecies and 6 families, and 650 parasitoids consisting of 21 morphospecies and 12 families have been collected. Nine morphospecies of pests from 25 individuals were found in smallholder plantation and 14 morphospecies of pests from 151 individuals in company plantation. Eight morphospecies of 26 parasitoids were found in smallholder plantations and 8 morphospecies of 624 parasitoids in the company plantation. The interaction structure between pests and parasitoids is more complex in the company plantation than in smallholder plantations. Family Braconidae and Ichneumonidae are the most parasitoids found and associated with nettle caterpillars. The different of the management system of oil palm plantation did not affect the diversity and abundance of pests as well as their parasitoids in oil palm plantations.

Study on Surfactant-Solvent Mixture Formulation and Its Application on Pesticide Emulsion Product

Nettle caterpillars (Setothosea asigna) are one of the common insects found in palm tree plantation which significantly reduce palm oil production by eating palm tree leaves. Surfactant is commonly used as an emulsifier and stabilizer in the pesticide mixture to refrain the mixture from separating. Commercial surfactants that are being used by the farmers holds the emulsion for approximately 2 hours. The performance of Diethanolamide (DEA) as surfactant for the insecticide mixture was investigated in this research. The various concentration of DEA in pesticide mixture showed the increasing mixture stability up to 24 hours before separating. Commercial surfactant used by the farmers is at 7-10% of the mixture. Meanwhile, DEA lowers the percentage of usage to 5%. The reduction of percentage of surfactant usage leads to the reduction of surfactant cost. Sample A5B5 found to be the best among other surfactants. Sample A5B5 has the density of 0.878 g/cm3, viscosity of 19.72 cP, surface tension of 24.311 dyne/cm, and contact angle of 31.7830.

Origin of the hungry caterpillar: Evolution of fasting in slug moths (Insecta: Lepidoptera: Limacodidae).

Studies of caterpillar defense strategy evolution typically focus on aposematic coloration, gregarious behavior, and/or chemical defense. In the slug moth family Limacodidae, the evolution of chemical defense is coupled to the life history trait of first instar feeding behaviors. In nettle caterpillars, the first instars fast and molt into a second instar that feeds. In contrast, gelatines and monkey slug larval forms feed in the first instar. This study focused on whether the evolution of fasting associated with the nettle morphology was a derived trait of single or multiple origins. Twenty-nine species of Limacodidae (including one Chrysopolominae) representing 27 genera and four outgroup species with known first and final instar morphologies and behaviors were included. Four out-group species representing Megalopygidae (1 sp), Dalceridae (1 sp) and Aididae (2 sp) were included. These were sequenced for three molecular markers for a total of 4073 bp, mitochondrial COI (∼1500 bp), 18S (∼1900 bp) and the D2 region of 28S (approximately 670 bp). Maximum likelihood and Bayesian analyses were conducted. The resulting phylogeny and comparative analysis of feeding strategy revealed that the nettle caterpillar morphology and behavior of larval fasting may have a single origin.

Serial Dilution of Nettle Caterpillar Viruses Applied as Bioinsecticide against Setothosea Asigna van Eecke (Lepidoptera:Limacodidae) the Important Pest of Oil Palm

Serial Dilution of Nettle Caterpillar Viruses Applied as Bioinsecticide against Setothosea Asigna van Eecke (Lepidoptera:Limacodidae) the Important Pest of Oil Palm

Parachuting Behavior and Predation by Ants in the Nettle Caterpillar,Scopelodescontracta

This paper documents the bizarre descending behavior from the tree crown to the ground of the larvae of the moth, Scopelodes contracta Walker (Lepidoptera: Limacodidae) and the interaction of the larva with predatory ants. S. contracta larvae infest leaves of many tree species in urban areas and orchards in Japan. Mature larvae and leaves without basal leaf parts were found under trees of four species infested with S. contracta larvae in Osaka, Japan. Individual larvae riding on leaves were observed falling from tree crowns to the ground. Many S. contracta cocoons were found in the soil below the trees two weeks after the observed parachuting. These observations indicate that S. contracta larvae parachuted to the ground where they spin their cocoons in the soil. When a larva that had just parachuted down was returned to an arboreal twig, the larva repeated the parachuting behavior. This parachuting behavior appears to be adaptive, because larvae can descend to the ground safely and with low energy cost. Worker ants of Tetramorium tsushimae Emery (Hymenoptera: Formicidae) and Pristomyrmex punctatus Mayr (Hymenoptera: Formicidae) occasionally attacked larvae on the ground before they had a chance to burrow in the soil.

Phenology and population radiation of the nettle caterpillar, Darna pallivitta (Moore) (Lepidoptera: Limacodidae) in Hawai’i

The nettle caterpillar, Darna pallivitta (Moore) (Lepidoptera: Limacodidae), is an invasive pest with established populations on three Hawai’ian islands. Indigenous to Southeast Asia, D. pallivitta caterpillars cause defoliation of ornamental nursery stock and pose a human health hazard due to their urticating hairs that can cause painful skin reactions. Identification of the pheromone component n-butyl (E)-7,9-decadienoate (E7,9-10:COOnBu) from D. pallivitta has made it possible to investigate the phenology and population dynamics using baited traps. Male captures in Jackson traps baited with E7,9-10:COOnBu showed a vegetation preference for tall-grass fields and forest/grass interfaces over forest areas. Microlocation preferences were also found for trap height, with over 65% of males being caught in traps suspended at 1 m, compared with the traps at 3 and 5 m. Captures of male moths in traps baited with live females, and direct observations of female calling behavior, showed peak activities 6–7 h after the onset of scotophase. This is a much later communication period than for D. bradleyi and D. trima and may provide a mechanism by which D. pallivitta maintains reproductive isolation in areas where all three species are present. Coastal and inland transects established in eastern Hawai’i measured aspects of population fluctuations and radiation into new areas with relation to elevation and microclimate. Population expansion was measured by comparing moth population means and 80% population boundaries over time. Both population measures showed a higher expansion for the coastal transect. Differences in population expansion may be attributed in part to temperature and elevation, while precipitation does not seem to have a strong effect. Both the behavioral and ecological data collected can be used to optimize deployment of detection/control strategies and to predict population expansion/risk assessment for establishing quarantine protocols for the nettle caterpillar.

Status of Common Oil Palm Insect Pests in Relation to Technology Adoption

A survey was conducted by the Malaysian Palm Oil Board (MPOB) in 2005 on the status of insect pest infestation, distribution and the industry's perception and adoptions of insect pest control technologies. Sabah and Perak had recorded the most occurrence of bagworms (30%), while other states individually had less than 15 per cent bagworm occurrence. Metisa plana and Pteroma pendula were mainly concentrated in Perak, Sabah and Johor, while Mahasena corbetti was more prevalent in Sabah and Perak. A similar trend was also observed in the distribution of nettle caterpillars, however, Melaka and Terengganu have no records of nettle caterpillar infestation during the period 2000-2005. In adopting the beneficial plants for bagworm and nettle caterpillar control, at least three oil palm agencies have fully adopted (100%) the technology while four agencies have still not implemented the technology in 2005. The planting of beneficial plants was widely practiced in Sabah, followed by Perak, Selangor, Sarawak, Negeri Sembilan, Melaka and Johor. In Selangor, Negeri Sembilan and Melaka it seems to be planted as a preventive measure. There was a one-fold reduction in bagworm infestation in estates which planted the beneficial plants compared to those which did not. This clearly suggests the contribution and role of beneficial plants in enhancing population of natural enemies for controlling the bagworms in plantations. The rhinoceros beetle, Oryctes rhinoceros was mainly concentrated in Johor, Sabah, Perak and Pahang. Compared to the previous years, there was almost a one-third reduction in the infestation in 2005, likely due to the adoption of technologies on better replanting techniques or the use of chemicals/pheromone trapping for control of the pest. A majority felt that the use of chemical pesticides may have reduced the infestation of the pest, while others thought that single-layer trunk chips laid during the zero-burning method has possibly reduced breeding and infestation. Some estates that responded also felt that biocontrol agents such as Bacillus thuringiensis, Metarhizium and Oryctes virus will gain more importance in the coming years. Keywords: Survey, insect pests, oil palm, bagworms, nettle caterpillars, rhinoceros beetle, technologies.

Decadienoates : Sex pheromone components of nettle caterpillars Darna trima and D. bradleyi

This study was undertaken to identify sex pheromone components of nettle caterpillars Darna trima and Darna bradleyi (Lepidoptera: Limacodidae) whose larvae defoliate oil palm, Elaeis guineensis, in southeast Asia. Coupled gas chromatographic–electroantennographic detection (GCEAD) analyses of pheromone gland extracts revealed two antennally active compounds produced by female D. trima and two by female D. bradleyi. Molecular structures of these candidate pheromone components were identified by electron-impact and chemical-ionization mass spectrometry; retention-index calculations on DB-5, DB-23, and DB-210 columns; microanalytical treatments, as well as syntheses of "auxilliary" compounds that facilitated identification of the compounds. The compounds from D. trima were 2-methylbutyl (E)-7,9-decadienoate (A) and (E)-2-hexenyl (E)-7,9decadienoate (B); from D. bradleyi we identified methyl (E)-7,9-decadienoate (C), and isobutyl (E)-7,9-decadienoate (D). In field experiments in Malaysia, (S)-2-methylbutyl (E)-7,9-decadienoate (SA) in combination with B proved to be essential and synergistic pheromone components for attraction of male D. trima. (R)-2-Methylbutyl (E)-7,9-decadienoate (RA) had no behavioral activity. Compound D singly attracted male D. bradleyi, but addition of C to D at a 1 : 10 ratio significantly enhanced attractiveness of the bait. Synthetic pheromone blends were more effective trap baits than unmated female moths and could be developed for monitoring populations of D. trima and D. bradleyi in Asian oil palm plantations.

Sex Pheromone Components of Nettle Caterpillar, Setora nitens

Gas chromatographic–electroantennographic detection (GC-EAD) analyses of pheromone gland extracts of female nettle caterpillars, Setora nitens, revealed four compounds that consistently elicited responses from male moth antennae. Retention indices on three fused silia columns (DB-5, DB-23, and DB-210) of two EAD-active compounds were almost identical to those of (E)-9-dodecenal (E9–12 : Ald) and (E)-9,11-dodecadienal (E9,11–12 : Ald), two pheromone components previously identified in congeneric Setothosea asigna. However, comparative GC, GC-EAD, and GC-mass spectrometry of extracted S. nitens compounds and authentic standards revealed that the candidate pheromone components were (Z)-9-dodecenal (Z9–12 : Ald) and (Z)-9,11-dodecadienal (Z9,11–12 : Ald). The two other EAD-active compounds in pheromone gland extracts proved to be the corresponding alcohols to these aldehydes. In field-trapping experiments in Tawau, Malaysia, synthetic Z9–12 : Ald and Z9,11–12 : Ald at a 1 : 1 ratio, but not singly, attracted male S. nitens. Attractiveness of these two aldehydes could not be enhanced through the addition of their corresponding alcohols. Whether these differences in pheromone biology and chemistry between S. nitens and S. asigna are sufficient to prevent cross-attraction of heterospecific males or whether nonpheromonal mechanisms are required to maintain reproductive isolation is currently being studied.

Slug and Nettle Caterpillars

Slug and Nettle Caterpillars

Book Notices

SLUG AND NETTLE CATERPILLARS. THE BIOLOGY, TAXONOMY AND CONTROL OF THE LIMACODIDAE OF ECONOMIC IMPORTANCE ON PALMS IN SOUTH‐EAST ASIA. Edited by M. J. W. Cock, H. C. J. Godfray and J. D. HollowayZOOGEOGRAPHY OF CARIBBEAN INSECTS. Edited by James K. LiebherrTHE NATURAL HISTORY AND BEHAVIOR OF NORTH AMERICAN BEEWOLVES. By Howard E. Evans and Kevin M. O'Neill

Book Review

Slug and Nettle Caterpillars. The Biology, Taxonomy and Control of the Limacodidae of Economic Importance on Palms in South‐East Asia. M. J. W. Cock, H. C. J. Godfray and J. D. Holloway (Eds)