Unequal Reproduction Early in a Social Transition: Insights from Invasive Wasps.

AbstractIn eusocial insects, nestmate queens can differ in their reproductive output, causing asymmetries in the distribution of mutual benefits. However, little is known about how reproductive success is partitioned in incipiently polygynous species, which would provide clues about the evolutionary forces shaping the emergence of polygyny. Here, we leverage a recent transition from predominantly single-queen (monogyne) to multiple-queen (polygyne) colonies in an invasive yellowjacket species to investigate whether queens in incipiently polygyne colonies invest equally in reproductive effort or vary in their relative investment in each caste. We excavated nine polygyne Vespula pensylvanica colonies in Hawaii and used restriction site-associated DNA sequencing to infer the parentage of worker, male, and gyne (daughter queen) pupae from each nest comb. In four colonies with at least eight gyne pupae, a single queen produced most or all gynes. These queens had no male offspring and few worker offspring, suggesting that a subset of nestmate queens might exploit the collective benefits of newly polygyne societies. In contrast to most queens, gyne producers had offspring distributed nonrandomly across nest combs. Nestmate queens generally exhibited low relatedness levels. Our results suggest that rapid, ecologically driven transitions to polygyny among unrelated queens may, at their onset, be vulnerable to reproductive asymmetries that are likely evolutionarily unstable. More broadly, this study contributes to the understanding of social evolution by uncovering asymmetric partitioning of reproduction in a population with newly evolved polygyny and raises questions about the future trajectories of introduced populations.

DNA barcodes and new primers for nature's pest controllers: the social wasps.

Globally, biodiversity is declining because of anthropogenic pressures, and this could lead to extinction of some species before they are discovered. The loss of insect taxa is of prime concern, given recent reports of significant declines in the populations of many taxa across the globe. Efforts to document biodiversity have met with several challenges, amongst which are the difficulties in using morphological features to discriminate species, especially in insects. DNA barcoding is a rapid and reliable method for species identification and discovery but choosing appropriate primers to amplify the barcode region without co-amplifying contaminants remains a key challenge. We developed and tested a set of primers for PCR amplification of the DNA barcode region of the COI gene in polistine wasps. We tested their efficacy in 36 species of vespid wasps, and the solitary wasp Zethus miniatus Saussure. Samples were obtained from Africa, Americas, Asia, and Europe. The polistine-specific primers successfully amplified the barcode region for all polistines tested, without amplifying any Wolbachia present; they also worked with many species from the other Vespidae wasp subfamilies. The new primers are valuable for the discovery and accurate documentation of polistine wasps in the four continents.

Wasp Waist and Flight: Convergent Evolution in Wasps Reveals a Link between Wings and Body Shapes.

Insect flight is made possible by different morphological structures: wings produce the lift, the thorax drives the wings' movements, and the abdomen serves as a secondary control device. As such, the covariation of these structures could reflect functional constraints related to flight performances. This study examines evolutionary convergences in wasp body shapes to provide the first evidence for morphological integration among insect wings, thorax, and abdomen. The shapes of the forewings and hind wings, thorax, and petiole (connecting abdomen and thorax) of 22 Vespidae species were analyzed using computerized tomography and geometric morphometrics. Results show a clear relationship between petiole and wings or thorax shapes but not between wings and thorax. Wasps with elongated bodies have pointed wings, both features thought to improve flight maneuverability. In contrast, stouter species have rounded wings, which may allow for higher flight speeds. These integration patterns suggest that multiple selective regimes on flight performance, some of them biased toward maneuverability or maximal speed, drove the morphological diversity in Vespidae. The results also suggest that wing shapes evolved under constraints related to the body type they have to lift. The abdomen morphology is thus another factor to take into account to understand the flight performance of insects.

Phylogenomics indicates Amazonia as the major source of Neotropical swarm-founding social wasp diversity.

The Neotropical realm harbours unparalleled species richness and hence has challenged biologists to explain the cause of its high biotic diversity. Empirical studies to shed light on the processes underlying biological diversification in the Neotropics are focused mainly on vertebrates and plants, with little attention to the hyperdiverse insect fauna. Here, we use phylogenomic data from ultraconserved element (UCE) loci to reconstruct for the first time the evolutionary history of Neotropical swarm-founding social wasps (Hymenoptera, Vespidae, Epiponini). Using maximum likelihood, Bayesian, and species tree approaches we recovered a highly resolved phylogeny for epiponine wasps. Additionally, we estimated divergence dates, diversification rates, and the biogeographic history for these insects in order to test whether the group followed a 'museum' (speciation events occurred gradually over many millions of years) or 'cradle' (lineages evolved rapidly over a short time period) model of diversification. The origin of many genera and all sampled extant Epiponini species occurred during the Miocene and Plio-Pleistocene. Moreover, we detected no major shifts in the estimated diversification rate during the evolutionary history of Epiponini, suggesting a relatively gradual accumulation of lineages with low extinction rates. Several lines of evidence suggest that the Amazonian region played a major role in the evolution of Epiponini wasps. This spatio-temporal diversification pattern, most likely concurrent with climatic and landscape changes in the Neotropics during the Miocene and Pliocene, establishes the Amazonian region as the major source of Neotropical swarm-founding social wasp diversity.

Phylogenomic Evidence Overturns Current Conceptions of Social Evolution in Wasps (Vespidae).

The hypothesis that eusociality originated once in Vespidae has shaped interpretation of social evolution for decades and has driven the supposition that preimaginal morphophysiological differences between castes were absent at the outset of eusociality. Many researchers also consider casteless nest-sharing an antecedent to eusociality. Together, these ideas endorse a stepwise progression of social evolution in wasps (solitary → casteless nest-sharing → eusociality with rudimentary behavioral castes → eusociality with preimaginal caste-biasing (PCB) → morphologically differentiated castes). Here, we infer the phylogeny of Vespidae using sequence data generated via anchored hybrid enrichment from 378 loci across 136 vespid species and perform ancestral state reconstructions to test whether rudimentary and monomorphic castes characterized the initial stages of eusocial evolution. Our results reject the single origin of eusociality hypothesis, contest the supposition that eusociality emerged from a casteless nest-sharing ancestor, and suggest that eusociality in Polistinae + Vespinae began with castes having morphological differences. An abrupt appearance of castes with ontogenetically established morphophysiological differences conflicts with the current conception of stepwise social evolution and suggests that the climb up the ladder of sociality does not occur through sequential mutation. Phenotypic plasticity and standing genetic variation could explain how cooperative brood care evolved in concert with nest-sharing and how morphologically dissimilar castes arose without a rudimentary intermediate. Furthermore, PCB at the outset of eusociality implicates a subsocial route to eusociality in Polistinae + Vespinae, emphasizing the role of mother-daughter interactions and subfertility (i.e. the cost component of kin selection) in the origin of workers.

The Behavior and Reproductive Physiology of a Solitary Progressive Provisioning Vespid Wasp: Evidence for a Solitary-Cycle Origin of Reproductive Castes.

The emergence of queens and workers from solitary antecedents mark a major evolutionary transition in the history of life. The solitary progressive provisioning wasp Synagris cornuta, a member of the subfamily Eumeninae (basal to eusocial vespid wasps), alternates between behavioral states characterized as queenlike and worker-like. Akin to a queen in eusocial wasps, a S. cornuta female initiates construction of a cell into which she oviposits and then, similar to a worker, cares for the brood as it develops. The ovarian groundplan (OGP) hypothesis for caste origins predicts that these behavioral states are associated with cyclical changes in ovarian status, where females performing queenlike tasks have eggs and those performing worker-like tasks possess only small oocytes. Our findings show strong support for the OGP hypothesis: the ovaries of S. cornuta females undergo differential oogenesis depending on the behavioral phase: the largest oocyte in the ovaries of females building a cell progresses faster compared to that of females attending brood. Yet contrary to the OGP hypothesis, neither juvenile hormone nor ecdysteroids is associated with the reproductive cycle. Finally, the cuticular hydrocarbon profile showed no link with ovarian status, suggesting that fertility signals evolved subsequent to the emergence of group living.

Caste-fate determination primarily occurs after adult emergence in a primitively eusocial paper wasp: significance of the photoperiod during the adult stage.

Independent-founding paper wasps constitute a major group of primitively eusocial insects, and when caste-fate determination occurs in temperate species of these wasps, particularly regarding whether it occurs before or after emergence, remains unclear. No critical morphological differences occur between potential queens of the next generation (often called gynes) and workers in primitively eusocial insects. The gynes of temperate species are characterized by diapausing, and the nutrients available during the larval stage have often been believed to determine caste fate. Short days usually induce diapause in temperate nonsocial insects, although few investigations of the effects of day length on caste-fate determination in paper wasps have been conducted. By exposing individuals to different combinations of short and long days during the immature and adult stages, we show for the first time that short days during the adult stage (but not during the immature stage) facilitated caste-fate determination toward gynes in a paper wasp. Moreover, the decision to diapause partly depended on changes in the photoperiod during the pupal and adult stages. The size of the adult also affected caste-fate determination, with diapause more likely to occur in large adults, but this size effect did not occur when individuals were exposed to many short days during the pupal stage. In addition, all adults except for a small proportion of smaller individuals prepared for diapause under short days. These findings suggest that the photoperiod is a higher priority cue than adult size.

Convergent Reversion to Single Mating in a Wasp Social Parasite.

While eusociality arose in species with single-mating females, multiple mating by queens has evolved repeatedly across the social ants, bees, and wasps. Understanding the benefits and costs of multiple mating of queens is important because polyandry results in reduced relatedness between siblings, reducing kin-selected benefits of helping while also selecting for secondary social traits that reduce intracolony conflict. The leading hypothesis for the benefits of polyandry in social insects emphasizes advantages of a genetically diverse workforce. Workerless social parasite species (inquilines) provide a unique opportunity to test this hypothesis, since they are derived from social ancestors but do not produce workers of their own. Such parasites are thus predicted to evolve single mating because they would experience the costs of multiple mating but not the benefits if such benefits accrue through the production of a genetically diverse group of workers. Here we show that the workerless social parasite Dolichovespula arctica, a derived parasite of wasps, has reverted to obligate single mating from a facultatively polyandrous ancestor, mirroring a similar reversion from obligate polyandry to approximate monandry in a social parasite of fungus-farming ants. This finding and a comparison with two other cases where inquilinism did not induce reversal to monandry support the hypothesis that facultative polyandry can be costly and may be maintained by benefits of a genetically diverse workforce.

Death eaters respond to the dark mark of decomposition day and night: observations of initial insect activity on piglet carcasses.

Some insect taxa can be of critical importance for criminal investigations because they can be used to assist with a time since death determination. Blow flies (Diptera: Calliphoridae) often are the initial colonizers of a carcass, usually arriving within minutes to hours after carcass exposure during the day. Other insects, such as coleopterans and hymenopterans, can arrive to a carcass during early colonization and affect blow fly development. However, the extent of these interactions remains unclear. This study analyzed the initial 6 h after a piglet carcass was placed out in two locations (rural and urban) in diurnal and nocturnal conditions with continuous video recording and hourly observations. Four piglets were placed out every 2 weeks over the summer of 2014. Initial blow fly arrivals to the carcasses were only recorded during diurnal conditions, and a checklist of orders associated with each environment (time and location) was created. During diurnal conditions, initial blow fly arrival times in rural environments were significantly faster than those in urban, arriving as quickly as 23 s after exposure. These observations also included a novel interaction with Vespidae, which to the best of our knowledge has not been seen in the literature before. This experiment provides baseline data on early insect colonization in two environments in New Jersey, and lends insight into insect interactions that could affect initial colonization.

Evidence for a Nest Defense Pheromone in Bald-Faced Hornets, Dolichovespula Maculata, and Identification of Components.

In eusocial insects like Bald-faced hornets, Dolichovespula maculata, nest defense is essential because nests contain a large number of protein-rich larvae and pupae, and thus are attractive to nest predators. Our objectives were to investigate whether D. maculata exhibit pheromone-mediated nest defense, and to identify and field test any pheromone components. We tested for pheromone-mediated nest defense behavior of D. maculata by placing a paired box-apparatus near the entrance of D. maculata nests, and treating both boxes with a solvent control, or one of the two boxes with a solvent control and the other with either venom sac extract, the putative source of nest defense pheromone, or synthetic pheromone. The sound impulses caused by nest mates attempting to sting or strike the boxes were recorded for 3 min. Compared to the double-control treatment, the number of strikes increased 27-fold when one of the two boxes was treated with venom sac extract, providing evidence for an alarm response. The box treated with venom sac extract also induced a significantly greater proportion of strikes than the corresponding control box, providing evidence for a target-oriented response. Analyzing venom sac extract by gas chromatographic-electroantennographic detection (GC-EAD) and GC-mass spectrometry resulted in the identification of seven candidate pheromone components: (a) dimethylaminoethanol, (b) dimethylamino ethyl acetate, (c) 2,5-dimethylpyrazine, (d) N-3-methylbutylacetamide, (e) 2-heptadecanone, (f) (Z)-8-heptadecen-2-one, and (g) (Z)-10-nonadecen-2-one. Testing in paired-box bioassays blends of the nitrogen-containing volatile components a-d, the less volatile ketones e-g, or both (a-g), indicated that a-d primarily have an alarm function. The ketones e-g, in contrast, induced target-oriented responses, possibly marking the box, or potential nest predators, for guided and concerted attacks, or enhancing the alarm-inducing effect of the volatile pheromone components, as shown in honey bees. Comparing the behavioral effects of venom sac extract, blends a-d, e-g, and a-g, venom sac extract was most effective in triggering the full complement of alarm and target-oriented responses. These comparisons further suggested that a component is missing in the group of components that triggers the alarm rather than the target-oriented response.

Discovery and Development of Chemical Attractants Used to Trap Pestiferous Social Wasps (Hymenoptera: Vespidae).

Chemical attractants for trapping temperate social wasps have been discovered during the screening of chemicals as attractants for flies, the study of pentatomid bug pheromones, and the testing of volatiles of fermented sweet baits. Wasp attraction to these chemicals seems to be related to either food-finding or prey-finding behavior. Of these attractive chemicals, commercial lures marketed in North America for trapping wasps generally contain heptyl butyrate, or the combination of acetic acid and 2-methyl-1-butanol. Heptyl butyrate is a very good attractant for two major pest wasp species in North America and minor wasp pests in the Vespula rufa species group. The combination of acetic acid with isobutanol attracted nearly all North American pest species of social wasps, including yellowjackets (Vespula and Dolichovespula), a hornet (Vespa crabro), and several paper wasps (Polistes spp.). The testing of wasp chemical attractants in different geographic areas demonstrated responses of many wasp taxa and showed a broad potential scope for the marketing of trap lures. Comparisons of compounds structurally similar to isobutanol revealed similar activity with 2-methyl-1-butanol, which is now used commercially because of a vapor pressure that is more favorable than isobutanol for formulations and dispensers. Doses and concentrations needed for good wasp catches were determined for heptyl butyrate, acetic acid, isobutanol, and 2-methyl-1-butanol, either formulated in water or dispensed from a controlled release device. Trap designs were developed based on consumer considerations; visual appeal, ease and safety of use, and low environmental impact. The resultant lures and traps are marketed in numerous physical and on-line retail outlets throughout the United States and southern Canada.

Foraging Behavior Interactions Between Two non-Native Social Wasps, Vespula germanica and V. vulgaris (Hymenoptera: Vespidae): Implications for Invasion Success?

Vespula vulgaris is an invasive scavenging social wasp that has very recently arrived in Patagonia (Argentina), a territory previously invaded - 35 yrs earlier - by another wasp, Vespula germanica Although V. vulgaris wasps possess features that could be instrumental in overcoming obstacles through several invasion stages, the presence of preestablished populations of V. germanica could affect their success. We studied the potential role played by V. germanica on the subsequent invasion process of V. vulgaris wasps in Patagonia by focusing on the foraging interaction between both species. This is because food searching and exploitation are likely to overlap strongly among Vespula wasps. We carried out choice tests where two types of baits were presented in a pairwise manner. We found experimental evidence supporting the hypothesis that V. germanica and V. vulgaris have an asymmetrical response to baits with stimuli simulating the presence of each other. V. germanica avoided baits with either visual or olfactory cues indicating the V. vulgaris presence. However, V. vulgaris showed no preference between baits with or lacking V. germanica stimuli. These results suggest that the presence of an established population of V. germanica may not contribute to added biotic resistance to V. vulgaris invasion.

Chemical Strategies of the Beetle Metoecus Paradoxus, Social Parasite of the Wasp Vespula Vulgaris.

The parasitoid beetle Metoecus paradoxus frequently parasitizes colonies of the common wasp, Vespula vulgaris. It penetrates a host colony as a larva that attaches itself onto a foraging wasp's body and, once inside the nest, it feeds on a wasp larva inside a brood cell and then pupates. Avoiding detection by the wasp host is crucial when the beetle emerges. Here, we tested whether adult M. paradoxus beetles avoid detection by mimicking the cuticular hydrocarbon profile of their host. The beetles appear to be chemically adapted to their main host species, the common wasp, because they share more hydrocarbon compounds with it than they do with the related German wasp, V. germanica. In addition, aggression tests showed that adult beetles were attacked less by common wasp workers than by German wasp workers. Our results further indicated that the host-specific compounds were, at least partially, produced through recycling of the prey's hydrocarbons, and were not acquired through contact with the adult host. Moreover, the chemical profile of the beetles shows overproduction of the wasp queen pheromone, nonacosane (n-C29), suggesting that beetles might mimic the queen's pheromonal bouquet.

COMPARISON OF CHITIN STRUCTURES DERIVED FROM THREE COMMON WASP SPECIES (Vespa crabro LINNAEUS, 1758, Vespa orientalis LINNAEUS, 1771 and Vespula germanica (FABRICIUS, 1793)).

There has been no study on the chitin structure of wasp species. Here, we selected the three most common wasp species belonging to the family Vespidae for chitin extraction and characterization. Chitin was isolated from each wasp species and characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffractometry (XRD), elemental analysis (EA), and scanning electron microscopy (SEM). The chitin contents of Vespa crabro, Vespa orientalis, and Vespula germanica were 8.3, 6.4, and 11.9%, respectively. The crystalline index (CrI) values for the chitin extracted from each species were 69.88, 53.92, and 50%, respectively. The most important finding of the study is that although the same method was used to extract chitin from each of the three wasp species, the degree of acetylation was different: for V. crabro and V. orientalis it was 96.85 and 99.82% (the chitin was extremely pure), respectively, whereas that for V. germanica the chitin was 79.83%.

The mitochondrial genome of a social wasp, Vespula rufa (Linnaeus, 1758) (Hymenoptera: Vespidae).

For an ongoing systematic study of Korean Vespidae, we analyzed the complete mitochondrial genome of a social wasp, Vespula rufa (Linnaeus 1758), from the South Korea. The mitogenome is 17,521 bp in length, comprising 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, and two ribosomal RNA (rRNA) genes. The nucleotide composition is 40.5% adenines, 43.0% thymines, 6.0% guanines, and 10.5% cytosines. The GC content is 16.5%. A maximum-likelihood analysis was conducted to understand phylogenetic relationships, based on 13 complete mitogenome sequences of Vespinae species. We recognized that V. rufa is being placed basal within the genus Vespula. The complete mitochondrial genome of V. rufa provides useful genetic information for further studies.

Molecular Characterization and Phylogenetic Analysis of Flightin Gene in Vespa basalis (Hymenoptera, Vespidae).

Flight is a complex physiological process requiring precise coordination of muscular contraction. A key protein in insect flight is flightin, which plays an integral role in the flight muscles. This research sought to evaluate the flight competence of the social wasp V. basalis by characterizing the molecular components involved. Our study focused on Vespa basalis, one of the most dangerous hornet species, utilizing PCR to obtain a partial cDNA sequence of the flightin protein. We then employed phylogenetic and sequence analysis to gain insights into this protein in flight-related adaptations. The cDNA has an 1189-base pair sequence including an open reading frame (453 bp) encoding 150 amino acids. Analyzing the deduced amino acid sequence using an online tool revealed a molecular weight of 18.05 kDa, an isoelectric point of 5.84, four functional site patterns, and no transmembrane topology. We constructed a phylogenetic tree of flightin based on 38 species. Our analysis indicated that V. basalis is most closely related to V. mandarinia; this alignment is consistent with their similar aggressive behavior, but their evolutionary relationship, based on mitochondrial sequences, presents a contrast. These initial findings on the flightin gene in V. basalis lay the groundwork for future functional studies to elucidate its specific role in flight adaptations and explore its potential as a target for pest management strategies.

Ecological integration of Vespa velutina Lepeletier, 1836 in South Korea: a comprehensive study of co-occurrence and interaction patterns with native social wasps.

BACKGROUND: The spread of Vespa velutina Lepeletier, 1836 (Asian hornet) in South Korea poses a threat to biodiversity and agriculture. Traditional species interaction models often fail to capture the complexity of invasive species dynamics. This study used association rule learning (ARL) and clustering analyses to explore the interactions of V. velutina with native Vespidae species in South Korea, with the aim of uncovering patterns of coexistence and competition. RESULTS: Over 4 years (2020-2023), 304 traps were strategically placed across South Korea to collect data on Vespidae species. Our findings showed that Vespula flaviceps, Vespa crabro, and Vespula koreensis were the most frequently encountered species. V. velutina was also widespread, suggesting its successful integration into local ecosystems. The ARL analysis, using the 'apriori' algorithm, identified significant co-occurrence patterns and potential interactions. The rules generated indicated both competitive and coexistent relationships with varying levels of association strength across different regions. Clustering analyses, including hierarchical and k-means clustering, grouped species based on their occurrence similarities. The distinct clusters formed in the analysis highlighted the unique ecological roles and interactions of V. velutina and other Vespidae species in South Korean ecosystems. CONCLUSION: This study confirms the successful establishment of V. velutina in diverse South Korean ecosystems and highlights its complex interactions with native species. These findings support the need for nuanced management strategies that consider the intricate ecological relationships of V. velutina. This approach is crucial for the effective management of invasive species and ecosystem conservation. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Confirmation of the valid specific status of Dolichovespulakuami Kim & Yoon, 1996 (Hymenoptera, Vespidae) based on molecular and morphological evidence.

The taxonomic validity of Dolichovespulakuami, especially in relation to D.flora, has been the subject of a long-term debate. Herein, the valid specific status of the former was supported through an integrated analysis of morphological characters and DNA barcodes. The pronotal rugae and male genitalia of the two species are different, and partial mitochondrial genes (cytochrome oxidase subunit I, COI) indicate that they form significantly distinct lineages. The hitherto unknown male of D.kuami is described for the first time, and a brief discussion of the D.maculata species group is provided.

Outcomes of wasp and bee stings in Taiwan.

BACKGROUND: The families of Hymenoptera causing commonly poisonous animal stings in Taiwan include Apoidea (bee) and Vespidae (wasp). This study aimed to investigate the epidemiologic, clinical characteristics, and outcomes of the severity of envenomation following wasp or bee stings in Taiwan. METHODS: We conducted a retrospective study by identifying all wasp and bee sting-related envenomation reported to the Taiwan National Poison Control Center between January 2001 and November 2021. Data were reviewed and abstracted by two independent reviewers. We then used ordinal logistic regression analysis to find potential predictors of severe wasp and bee sting-related envenomation. RESULTS: In Taiwan, bee or wasp stings mainly occur in late summer and autumn. A total of 611 patients were reported to the Taiwan National Poison Control Center with 7.5% resulting in severe or fatal envenomation. Four-hundred and forty-one patients were eligible for the final analysis of the predictors of severity. Logistic regression analysis showed that a greater number of stings, being stung by wasps, older age, and stings over the body were significant predictors for greater severity. The systemic effects following wasp and bee sting included anaphylactic reaction, prolongation of activated partial thromboplastin time, rhabdomyolysis, acute kidney injury, and elevated liver enzymes. CONCLUSIONS: Wasps generally inflicted more severe envenomation than bees. Only 7.5% of patients had severe or fatal outcomes. Patients with older age, multiple stings, and/or multiple sites of stings were more likely to have severe outcomes.

Online citizen sciences reveal natural enemies and new occurrence data of Meteorusstellatus Fujie, Shimizu & Maeto, 2021 (Hymenoptera, Braconidae, Euphorinae).

Background: Citizen science is a research approach that involves collaboration between professional scientists and non-professional volunteers. The utilisation of recent online citizen-science platforms (e.g. social networking services) has greatly revolutionised the accessibility of biodiversity data by providing opportunities for connecting professional and citizen scientists worldwide. Meteorusstellatus Fujie, Shimizu & Maeto, 2021 (Hymenoptera, Braconidae, Euphorinae) has been recorded from the Oriental Islands of Japan and known to be a gregarious endoparasitoid of two macro-sized sphingid moths of Macroglossum, Ma.passalus (Drury) and Ma.pyrrhosticta Butler. It constructs characteristic star-shaped communal cocoons, suspended by a long cable. Although M.stellatus has been reported only from the Oriental Islands of Japan, the authors recognise its occurrence and ecological data from Taiwan and the Palaearctic Island of Japan through posts on online citizen-science groups about Taiwanese Insects on Facebook and an article on a Japanese citizen-scientist's website. New information: Through collaboration between professional and citizen scientists via social media (Facebook groups) and websites, the following new biodiversity and ecological data associated with M.stellatus are provided: Meteorusstellatus is recorded for the first time from Taiwan and the Palaearctic Region (Yakushima Is., Japan).Cechetraminor (Butler, 1875), Hippotioncelerio (Linnaeus, 1758) and Macroglossumsitiene (Walker, 1856) (Lepidoptera, Sphingidae) are recorded for the first time as hosts of M.stellatus and two of which (C.minor and H.celerio) represent the first genus-level host records for M.stellatus.Mesochorus sp. (Hymenoptera, Ichneumonidae), indeterminate species of Pteromalidae and Trichogrammatidae (Hymenoptera), are recognised as hyperparasitoid wasps of M.stellatus.Parapolybiavaria (Fabricius, 1787) (Hymenoptera, Vespidae) is reported as a predator of pendulous communal cocoons of M.stellatus. The nature of suspended large-sized communal cocoons of M.stellatus and the importance and limitations of digital occurrence data and online citizen science are briefly discussed.