New record of larval-pupal endoparasitoid Exorista deligata parasitising Indian Tea looper Hyposidra talaca from India

This is the �rst record of Exorista deligata (Pandellé, 1896) (Diptera: Tachinidae) as a parasitoid of Hyposidra talaca (Walker, 1860) (Lepidoptera: Geometridae) from India. H. talaca is a major and new emerging defoliator of the Tea plant Camellia sinensis (L) Kuntze (Theaceae). It completes multiple generations per year without diapause on C. sinensis, resulting in heavy crop loss. The eld-collected larvae/pupa of H. talaca were checked for parasitoid infestations and reared until either the host or parasitoid emerged. The parasitoid was identi�ed as E. deligata with morphological characteristics and con�rmed by the mitochondrial cytochrome oxidase subunit-I (COX-CO1) gene sequencing technique. The parasitoid is infrequent with unexplored parasitic biology. It parasitises the larva and completes its lifecycle inside the developing H. talaca by entirely devouring the host. The mean percent parasitisation caused by E. deligata studied herein was 25.4% (range 5.88%-57.69%). Based on its parasitisation ability, we suggest the species could be a potential biological control agent to address the damage mitigation caused by the tea looper pest, H. talaca.


Introduction
The tea plant, Camellia sinensis (L) Kuntze, is an important agro-commercial crop, most widely consumed (processed leaves) as a hot beverage worldwide (Li et al., 2019), and contributing to the economy of many countries.China, India, Kenya and Sri Lanka are the leading tea-producing countries in the world (Smith, 2016), followed by Vietnam, Turkey, Indonesia, Armenia, Japan, Bangladesh, Malawi, Uganda, and Tanzania (Roy et al., 2017).India is the world's secondlargest producer of tea and one of the top tea-consuming countries, with about 80% of tea produced in the country consumed by the domestic population (IBEF, 2022).Tea cultivation is an important income source for local tea cultivators/farmers.India's total tea production in 2020 was 1,257.52 million kg, and from January to September 2022, it was about 984.67 million kg (IBEF, 2022).However, the black inchworm, Hyposidra talaca (Walker, 1860) (Lepidoptera: Geometridae), causes heavy loss by defoliating the tea (C.sinensis) plantations in North-East India (Das et al., 2010a;Sinu et al., 2011;Prasad andMukhopadhyay, 2013, 2015).Besides India and Indochina, H. talaca is found in Thailand, Taiwan, Sri Lanka, Sundaland, Sulawesi, Philippines, Solomon Islands, New Guinea, Australia, and Queensland (GBIF, 2022).The neonates of H. talaca disperse by their salivary strands, and the fth larval instar is the most damaging (Das et al., 2010b;Sinu et al., 2015;Roy et al., 2017).Female moths in tea plantations prefer to conceal their eggs under the scaly bark of trees, with fewer chances of being attacked by other natural enemies (Sinu et al., 2011).H. talaca with 6 to 8 generations/year, a short lifespan, and subsequently interchanging habitats from wild plants to Tea plantations (Das et al., 2010a;Sinu et al., 2011;Roy et al., 2017).As a result, its apparent persistence in C. sinensis plantations (Prasad andMukhopadhyay, 2013, 2015;Roy et al., 2017) with a lack of adequate natural enemies is a severe threat to tea plantations (Das et al., 2010a;Roy et al., 2017).Despite having few natural enemies (Das et al., 2010b), more than 100 host plants have been identi ed for H. talaca (Sinu et al., 2011;Roy et al., 2017).Moreover, it is more aggressively invasive on C. sinensis than on alternative host plants.It has developed a high tolerance for certain insecticides (Roy et al., 2017).
Various pest control techniques include chemical pesticides, pheromones, entomopathogenic and synthetic insecticides (Ye et al., 2014).Also, integrated management has been promoted, with consideration given to mechanical, physical, biological, and chemical techniques (Roy et al., 2017) along with habitat management strategies (Li et al., 2019).However, the excessive use of pesticides affects the environment, causing ecological harm, biodiversity, and food safety and may pose health hazards (Chen et al., 2017).Thus, biological pest control is highly encouraged to manage the pest problems of tea plantations.
Interestingly, Exorista deligata (Pandellé, 1896) (Diptera: Tachinidae: Exoristinae: Exoristini) is associated with the tea looper pest, H. talaca, as a parasitoid from Northeast India.The parasitoid completes its lifecycle by parasitising the larvae of H. talaca and emerges from its later/pupal stages.Tachinidae, with about 8,600 known species worldwide, is one of Diptera's most diverse and species-rich families with ecological importance as parasitoids (O'Hara et al., 2019) next to the parasitic Hymenoptera (Stireman, 2016).Most tachinid species (about 70%) prefer to parasitise lepidopteran larvae, and some of them are utilised in biological control programmes against agricultural and forest pests (Jiang et al., 2016;Dai et al., 2022).The plant-feeding larvae are the most common hosts for Tachinids, for instance, E. sorbillans (Wied) has more than ten hosts, including silkworms (Jin, 2001), and Tachinids affecting the silkworms are often known as the uzi ies (Singh et al., 1993;Gathalkar & Barsagade, 2016).However, hosts of numerous tachinid species are still unknown (Kara et al., 2020).
In this study, we record E. deligata from India for the rst time, parasitising H. talaca in the tea-cultivating states of India.This study provides illustrative documentation on E. deligata, encompassing morphological and molecular diagnosis for species identi cation, geographical distribution and data statistics to explore its occurrence and parasitic potentials.This work will aid the fundamental knowledge about this species in existing databases.It may help in developing sustainable integrated pest control strategies.The study also encourages future explorations based on the possibility of E.deligata y as a biological pest control agent against the tea lopper pest, H. talaca.

Study area and Sample processing
The sample collection was conducted from September 2021 -October 2022 from Soraipani Tea Estate, Titabor (26°32 '44.196 1"E) located at the adjoining premises of Tocklai Tea Research Institute, Assam (Fig. 1), (temperature range ~25-33°C/RH 30-55%); and brought to the laboratory of Entomology, CSIR-National Chemical Laboratory, Pune, India, and were reared/maintained at temperature ranges between 25 o -30 o C and relative humidity 55%-80%.A cotton ball soaked with water and sucrose solution was provided on adult (host/parasitoid) emergence.Subsequently, the pupae were dissected under a binocular microscope (Motic SMZ-168 Series) to check the parasitoid infestations.The adult parasitoids that emerged from host H. talaca pupae were processed for identi cation.

Morphological identi cation
Morphological studies were performed on at least 30 randomly selected adults and a few maggots/larvae and pupal stages, examined under the Meiji Biological Microscopes MT4300H (Meiji et al., Japan) and photographed.Based on morphological characteristics (Pandellé, 1896;Crosskey, 1976;Tschorsnig and Herting, 1994;Cumming and Wood, 2017) and identi cation of the parasitoid upto species level (as per Pandellé, 1896;Tschorsnig and Herting, 1994), including male and female differentiation was made.The species have been deposited to the Zoological Survey of India (ZSI), Western Regional Centre, Pune, and Voucher No. Ent-10/254 is obtained).
Molecular identi cation and phylogenetic analysis DNA isolation and PCR analysis: Insect legs were used for DNA isolation using an MN NucleoSpin ® kit per manufacturers' instructions.DNA was eluted in 20.0μL of elution buffer.2.0μL of DNA was checked on the gel, and 2.0uL was used for PCR.Cytochrome oxidase I gene-speci c primers, including forward and reverse primers, were used to amplify the mtDNA COI gene.DNA-PCR was accomplished using two primers for each sample, viz., 1) LCO -2198: 5'-GGTCAACAAATCATAAAGATATTGG-3' and 2) HCO -1490: 5'-TAAACTTCAGGGTGACCAAAAAATCA -3' with the help of Applied Biosystems BigDye Terminator V3.1 Cycle sequencing kit.The nal volume of each reaction was 25.0μL; the reaction mix was prepared and added to 200μL PCR tubes for each sample.The reaction mix was processed with an initial denaturation at 95°C/5 min; denaturation at 94°C/1 min; annealing at 45°C/1 min; extension at 72°C/1.30min, with 40 cycles; and extended for 7 min at 72°C; hold at 4°C until use.Subsequently, agarose gel electrophoresis of the PCR products and the standard DNA marker 100-1000bp size was performed using 2% (w/v) agarose gel using standard 0.5X TBE gel electrophoresis buffer for 30 minutes at 5v/cm.The remaining wells are PCR products loaded for the samples ampli ed using LCO and HCO primers.The size of the amplicons was ~700bp.Ampli ed products were puri ed by removing unused dNTPs and primers.The ExoSAP-IT™ clean-up reagent (Thermo Fisher) was used for the enzymatic clean-up of ampli ed PCR product.
DNA sequencing of PCR products and analysis: The sequencing products were loaded on an automated DNA sequencing instrument, Applied Biosystems 3130 Genetic Analyzer.Sequencing Analysis 5.1 software was used to analyse sequences. .ChromasProV3.1 sequence assembly software was used to assemble COI region sequences acquired from the test sample.The assembled sequences were used for BLAST analysis using multiple sequence analysis tools in the NCBI database.The genus and species of insect under study were identi ed based on the rst ten hits obtained in the BLAST search.
Phylogenetic analysis: To further con rm the origin of the identi ed species, the evolutionary history was inferred using the Maximum Parsimony (MP) method.The MP tree was obtained using the Subtree-Pruning-Regrafting (SPR) algorithm with search level 1, in which the initial trees were obtained by the random addition of sequences (10 replicates).This analysis involved 36 nucleotide sequences.The coding data was translated assuming a Standard genetic code table.There were a total of 180 positions in the nal dataset.Evolutionary analyses were conducted in MEGA11 (Tamura et al., 2021).The evolutionary distances, measured in terms of the number of base substitutions per site, were calculated using the Maximum Composite Likelihood technique (Tamura et al., 2004).

Data collections and Statistical Analysis
The rate of infestation (based on host/parasitoid emergence/observed) was calculated, and graphical presentations were performed using Microsoft ® Excel (2019).The statistical analysis was performed (with a small data set generated in the study) using OriginPro 2023, OriginLab Corporation, Northampton, MA, USA.Data were evaluated using a correlation coe cient and a Pearson pairwise comparison test at p < 0.05 signi cance level, and the parasitisation rate was calculated.

Results
The parasitoid Exorista deligata (Pandellé, 1896) (identi ed in this study Voucher No. Ent-10/254) emerged from the pupae of eld-collected H. talaca pupae by making holes mainly at the abdominal segments (Fig. 2a).As per our observations, there was no damage or sign of parasitisation on H. talaca pupae until the emergence (host/parasitoid); however, black spots or scars on the larval integument were noticed.The pupae of H. talaca were dissected (after the incubation period was over), where we observed the immature stages of the parasitoid (maggot to pupal stages) inside the host pupa (Fig. 2c-e and Sup.Info.1).The complete devastation of the host pupa due to parasitoid feeding followed by parasitoid (larva/adult) emergence.

Morphological characteristics of the parasitoid (Exorista deligata)
The identi cation of the parasitoid (E.deligata) was made based on morphological characteristics (Sup.Info.2), also revisited and highlighted below (to ascertain the parasitoid's strain possibility if any, as this is the new distribution record from India) as per the literature and catalogue available.
Male and female differentiation: The female is larger than the male, male with more hairs and bristles at the abdomen and head.The orbital area is slightly smaller in males than in females.The outer orbital bristles are absent in males (Fig. 3a-e), whereas the 4 proclinate orbital bristles and outer vertical bristle are present on the orbital area, between the frontal bristles and the eye rim present only in females (Fig. 3f-j).
Head and appendages: The head is spherical to oval; the facial ridge is straight to slightly convex in lateral angle, with a row of setae over most of its length.3 ocelli present.Eyes hairy or practically bare but tiny hair can be seen under high magni cation; ocular orbital margin with tiny hairs; palps are dark orange to reddish yellow.Antennae: 3 segmented and aristate, scape with (5-6) small hairs dorsally; pedicel/2 nd antennal segment with dispersal black bud-like marks with few sensillae besides arranged in an irregular line at half height (species-speci c characteristics) Fig. 3c&h; distal agellum with an elongated postpedical; the arista at frontal agellum.The face has silvery white pruinosity; the front-orbital plate and upper parafacial are thin golden pruinosity; the anterior reclinate orbital seta is situated posterior to the middle of the front-orbital plate; the parafacial is bare.Mouthparts: are hypognathous, and the proboscis, composed of the labrum, mandibles, hypopharynx, and maxillae, are enclosed in a grooved labium, and the vibrissa arising at a level of lower facial margin or slightly above.
Prosternum has 3 presutural and 4 post sutural dorsocentral setae, and at least 2 setulae laterally.Scutum divided by suture; scutellum black-grey patched with 2 pairs of marginal bristles, 1 subapical, 1 apical, 3 humeral bristles present, and pro-episternum with few hairs.The three basal setae on the postpronotum are aligned in a line.With only a few setulae or no setulae on the anterior fourth, the katepisternal has 3 setae.
Wing and venation: The wing is transparent and membranous; at the front edge is divided into 6 sections, cs1 to cs6 with costal hairs, vein M with obtuse or almost right-angled bend lies between cross-veins dm-cu and r-m.The 4 th costal sector is equal to or longer than CS6.The r4+5 wing cell slightly opens and closes at the wing margin or shortly petiolate.Vein R4+5 only has a few (5) setulae at the base; the anal vein is less noticeable at the wing end, and a halter is present.Legs: legs covered with hairs and robust bristles.Coxa is black-brown, femur and trochanter are grey on the ventral side and black on the dorsal side.The femur has long bristles and hairs; the tibia is black with tiny straight hairs.Fore tibia is with 4 to 6 anterodorsal, 2 posterior, and 1 ventral setae; while midtibia has 2 anterodorsal, 2 posterodorsal and 1 ventral setae.The posterior tibia has 5 to 6 anterodorsal, 4 to 6 posterodorsal, and 3 ventral setae/bristles of variable lengths.
Abdomen: The abdomen is slightly bent and has ve tergite-long structures with black-and-grey marginal strips.In contrast to the other tergites, the 5 th tergite's lateral border has long and wide setae.The 3 rd and 4 th terga lack median discal setae; the 4 th tergum has a row of strong and erect marginal setae; the 5 th tergum has rows of discal and marginal setae; the 3 rd to 5 th terga have thick greyish yellow pruinosity on the anterior half.Syntergum 1+2 has two short median marginal setae; dorsal-marginal bristles are present; post-scutellum, latromarginal bristles are present; and there is one discal bristle (Fig. 3

d&i).
The male genitalia: Male terminalia is covered by more setae than females, with a wider opening at the ventral side with male organs.A large section on the asymmetrical 6 th sternite connects to the left hemitergite of the 6 th tergite, tapering in the middle and ending just after the 5 th sternite.It does not link to the right hemitergite of the 6 th tergite.Syntergite 7+8 has half bearing pair of spiracles at the anterior, while the posterior half is setulose with ne setae at the marginal row.With nearly half of the dorsal surface, the epandrum is setulose.In lateral view, the posterior border forms a ventral surface length with a long, rounded lobe at the lower end and a pointed, projecting lobe at the middle.In posterior view, the surstylus, epandrium, and the apex of the cercus are straight, tapering, and curved toward the apex, with inner and exterior surfaces with short, upright setulae.While, in lateral view, all these with apex of the cercus are slightly curved towards the anterior region, the cerci are fully setose, not fused, with a pointed apex extending to the surstyli level.They are also gently curved inward at the posterior and uniformly curved toward the anterior area (Fig. 3d-e).
Female genitalia: Female terminal region is oval to v-shaped, with a small ventral opening covered by fewer setae than males.The ovipositor is membranous, short and narrow in setulate areas between sclerites.Tergites 6+7 have the broader posterior setose margin and are modi ed into two hemitergites than the anterior margin.Sternites 6 th and 7 th are subtriangular, having a setose, with a more considerable posterior margin than an anterior margin.The 6 th pair of spiracles are located in the membrane before the hemitergites of the 6 th tergite; the 7 th pair are at the anterolateral margin of the hemitergites of the 6 th tergite.Tergite 8 th is exceptionally tiny, reduced to two lateral, thin sclerites at the hypoproct.Cerci are not fused (Fig. 3i-j); by matching the above morphological characteristics with existing cotalogue/literature, the identi cation of this species was done (see Sup. Info.2: Taxonomic Key).
Morphology of immature stages: The third instar larvae of E. deligata is 11-segmented, off-white to beige-coloured, with tiny bud-like structures at anterior and posterior ends.At the anterior end, these are 2 black-coloured, supposed to be mouth hooks, having 2 spiracular discs.At the posterior end, 2-spiracles are present.It shrinks and darkens with time; the spiracular plates become more prominent in further pre-pupal to the pupal stage afterwards (Fig. 3k-m).Puparia: The pupa is smooth dark brown-red, and oval-to-cylindrical in shape with 2 small anterior spiracles with two conspicuous and darkened posterior spiracles discs (for respiration).The spiracle discs are fused into one and 3 spiracle slits on the upper surface of each spiracle disc.Posterior spiracular plates are barely raised above.Each posterior spiracular plate has three linear openings (Fig. 3n-p).

Molecular identi cation and phylogenetic analysis
Agarose Gel Electrophoresis of PCR product: Agarose gel electrophoresis of the genomic DNA and the PCR products (Fig. 4a-b) the rst lane is the DNA marker 100-1000bp size standard, along with PCR products loaded for the samples ampli ed with LCO and HCO primers.The sequence of mitochondrial cytochrome oxidase gene (COI region) obtained was used for molecular identi cation of the species.For instance, out of ~700 bp sequence obtained, 610 bp was trimmed based on the chromatogram peaks and quality of the DNA sequence.The BLAST analysis of the sequence showed maximum identity scores with Exorista deligata ( rst two hits), followed by Exorista xanthaspis and Exorista japonica (Table 1).Based on the BLAST hits and identity scores, the parasitoid y was identi ed as Exorista deligata and the resultant sequence was deposited in NCBI GenBank under the accession number OQ373004.However, since the overall identity scores in BLAST analysis were less than 98%, indicated that a parasitoid strain of Exorista deligata reported in the present paper is novel and/or its COI region sequence is not deposited yet in NCBI GenBank.
To understand the phylogenetic origin of parasitoid y Exorista deligata OQ373004, based on COI region sequences of thirty-four species, a rooted phylogenetic tree of length 456 was constructed as described under materials and methods.A resultant tree showed a consistency index of 0.622807 (0.544974), a retention index of 0.691203 (0.691203), and a composite index of 0.430486 (0.376687) for all sites.The gures in parentheses indicate the respective values for parsimony-informative sites.As shown in Fig. 4c, a tree was rooted with Chetogena parvipalpis, which was diverged into two main branches, which were further diverged into three subbranches and ve sub-sub branches.The parasitoid y E. deligata IND1 (OQ373004) identi ed in the present study was grouped with the other strains of E. deligata.Moreover, within the subgroup of E. deligata, IND1 y showed slight diversion and formed a separate branch, indicating its novelty from other reported E. deligata strains.The other species, E. xanthaspis and E. japonica formed sub-sub-branches with the E. deligata, further con rmed con rming its evolutionary origin and identity.Overall, based on BLAST sequence hits and phylogeny constructed based on the cytochrome oxidase gene (COI region), the parasitoid y is reported as a novel strain of Exorista deligata.The extent of parasitism caused by Exorista deligata The eld survey conducted from 2021 to 2022 revealed the occurrence of E. deligata on the pupae of Hyposidra talaca.We have calculated the host and parasitoid emergence along with pupae with parasitoid infestation (dead pupa without any parasitic sign were not included in the parasitism rate calculations).The total parasitoids (n=66) were collected from the total H. talaca collections (n=730) throughout the study (n=11 batches) from the tea cultivating elds.The graph (Fig. 5) shows the rate of parasitism calculated as the ratio of the number of E. deligata (emerged + inside host) to the total combined number of both the H. talaca and E. deligata adults that emerged/observed.The statistical analysis (Supl.Info.3) concluded that the rate of parasitism of H. talaca caused by Tachinid parasitoid varied from 0% (min) to 57.69% (max).The overall mean % parasitism was 25.4% (SD = 18.16783) for the collection done in 11 batches.There was no signi cant correlation between the rate of parasitism and the number of samples collected during the study (r = -0.16079;p = 0.63671 > 0.05); thus, the different number of samples collected during the study did not affect the rate of parasitism.Similarly, no signi cant correlation between batches and parasitoids emerged/was observed (r = -0.00983;p = 0.97712 > 0.05).In contrast, each collection correlates signi cantly with host emergence (r = 0.79844*; p = 0.00321 < 0.05).However, the host emergence showed a weak negative correlation with the parasitoid observed (r = -0.07185;p = 0.83372 > 0.05).

Discussion
For the identi cation of parasitoid, and species-speci c key characteristics we followed Pandellé (1896); Tschorsnig and Herting (1994), and for other morphological terminologies of Tachinids, we referred the available catalogues and literature (Crosskey, 1976;; Cumming and Wood, 2017;).The species was identi ed as Exorista deligata (Voucher No. Ent-10/254 /Accession No. OQ373004) and it was also con rmed by molecular technique, i.e., mitochondrial cytochrome c oxidase subunit I gene sequencing followed by BLAST and its position in a phylogenetic analysis with reference to its closest homologues (Saitou & Nei 1987;Mao et al., 2007;Pohjoismäki et al., 2016).
As per the literature, E. deligata is uncommon, with a few occurrences in Finland and other countries (Pohjoismäki & Kahanpää, 2014;Kara et al., 2020;FinBIF, 2022).Moreover, the oviposition, larval-pupal development and parasitic potential of this species were unexplored except for its occurrence on Acanthopsyche atra (Lin), Pachythelia villosella (Ochs), Psyche constancella (Bru), Sterrhopteryx hirsutella (Hue) (all Psychidae: Lepidoptera) as hosts, from Southern Europe, Southern Sweden and Finland (Tschorsnig and Herting, 1994).The present study explores the occurrence and its parasitic potential on H. talaca as a host from India for the rst time.The polyphagous larval parasitoids, e.g., E. larvarum (L), lay their eggs on the lepidopteran and tenthredinid larvae and penetrate through larval integument on hatching (Valigurová et

Conclusion
This is the rst con rmed report of E. deligata parasitising a major defoliator H. talaca, of the tea plant C. sinensis.The morphological and molecular studies corroborate the parasitoid species as E. deligata.It is rare in its abundance around the globe; nevertheless, the study also records its existence from India for the rst time.E. deligata parasitises (larva) and kills (pupae) H. talaca and does not allow the pupa to develop further or survive, indicating its idiobiont nature of endoparasitism.The mean percent mortality/parasitism caused by E. deligata was 25.4%, while the maximum percent mortality was 57.69%, and the lowest was 0 -5.88% during the study period from September 2021 to October 2022.The parasitisation rate ascertains the possibility of E. deligata as a natural enemy of H. talaca.Therefore, regular monitoring, including its bio-ecology, host range, seasonal patterns, and ecological to economic effects by this parasitoid, is encouraged to develop biological pest management strategies against the tea looper pest, H. talaca.
COI gene sequence of parasitoid y: Following are the assembled gene sequences of parasitoid: > Exorista deligata IND1 {Accession No. OQ373004} TTGGTACCTCATTAAGTATTTTAATTCGAGCTGAATTAGGACACCCTGGATCACTAATTGGAGATGATCAAATTTATAATGTAATTGTTACAGCCCATGCATTTATTATAATT BLAST Results and Phylogenetic Tree: collections and tea cultivation sites of Northeast India, Asia.(modi ed from source: ©Maphill & Google maps).

Figure 4 Agarose
Figure 4 Agarose gel electrophoresis of (a) genomic DNA and (b) Agarose gel electrophoresis of the PCR products; (c)Phylogenetic analysis based on cytochrome oxidase subunit 1 (COI) partial gene fragment isolated from parasitoid y Exorista deligata IND1 with its closest homologues.The evolutionary history was inferred using the Maximum Parsimony (MP) method using MEGA11.E. deligata IND1 was grouped with the other reported Exorista deligata strains based on COI gene sequences.The black bold arrow indicates the position of the E. deligata IND1 strain in phylogeny

Table 1 .
The closest homologue of parasitoid fly Exorista deligata IND1 identified in the present study based on the cytochrome oxidase subunit 1 (COI) gene partial sequence ((Accession No. OQ373004; Length-610 bp).
(Dindo et al., 2019;Dai et al., 2022)022) species, the third instar can migrate freely within the host haemocoel(Dindo & Nakamura, 2018;Dai et al., 2022).The pupation occurs within a puparium or at the tough shell of the third instar.Typically, it happens by either the third instar i) crawls away from the host (mostly the last instar) and pupates in the soil or ground or ii) pupariation occurs within the host (O'Hara, 2008).Similarly, we observed that E. deligata pupates both in i) soil/ground by escaping from the host pupa H. talaca (pupates mostly in soil); or inside the host pupa (pupal shell), where they get double (self and host pupal shell) protection like other hymenopteran species(Gathalkar et al., 2017).The multiple tachinid larvae (e.g., E. japonica) can live within a single host and develop further(Dindo et al., 2019;Dai et al., 2022); however, we observed a solitary mode of development in E. deligata.
(Dindo & Grenier, 2014);Sow et al., 2019)al enemies (e.g., parasitoids) is a successful approach to reducing crop yield(DeBach and Rosen, 1991;Fisher, 1999)that serves as a sustainable alternative to insecticide use(Hladik et al., 2014).Tachinids are utilised in biological pest management as effective natural enemies for various insect pests(Grenier, 1988;Dindo & Nakamura, 2018).Identifying parasitoid species is obligatory to understand host-parasitoid interactions, and the parasitism rate must be estimated accurately(Greenwood et al., 2016;Sow et al., 2019).Tachinid hosts primarily include insects that graze on plants.It has two critical consequences on communities: it reduces the number of hosts and, indirectly, the amount of feeding damage to plants that hosts utilise (O'Hara, 2008).Depending on variables, together with the size of the host, parasitoid population, and environmental circumstances, the level of parasitism can range widely, from less than 1% to close to 100% (O'Hara, 2008).Tachinids are unique in their capacity to attack hosts concealed in plants or soil(Dindo & Grenier, 2014).Similarly, parasitism caused by E. deligata on H. talaca larvae, including the concealed host, emerges from the host pupa or sometimes larvae crawl away and pupate, suggesting that the pupa is the most favourable stage for developing this parasitoid.