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Ecological effects and management of invasive alien Vespidae
Abstract and Figures
Insect species associated with human goods continue to be accidentally introduced into new locations. A small proportion of these introduced species become invasive, causing a range of impacts in the receiving community. It is therefore important to evaluate the patterns of which species become invasive and which strategies are most successful in managing them. This review assesses the distribution, abundance, impact and management of the invasive Vespidae worldwide. We identified 34 vespid species known to be introduced around the world, but the seven most invasive species are all eusocial. Most introduced Vespidae only occur in one or two countries, but some areas have become geographic hotspots of invasion: Hawaii (15 species), North America (eight species), New Zealand (five species), Australia (four species) and South America (four species). Two invasive species, Vespula vulgaris and V. germanica have become particularly widespread and abundant with a range of impacts on biodiversity and ecosystem function. Other successful invasive species include several Polistes spp., which affect local biodiversity through direct predation or competition for food or space. Toxic baiting has been the most successful control strategy against invasive vespids to date, although this has mostly been small scale experimental management as it has proved difficult to develop commercial control products. Development of shelf-stable lures or baits combined with suitable toxins or pathogens could overcome some of the commercial impediments. Several attempts at biological control using parasitoids have not successfully reduced invasive wasp populations, although the biocontrol agent has only established in one case. The social structure of colonies and their high reproductive efficiency have facilitated invasion by these species, but it also means management at the population level will be difficult. This emphasises the need to prevent such invasions from occurring in the first place.
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... Even when resources are not limited, invasive and native species may be adversely affected if either exploits key resources at a greater efficiency, such as through monopolization of food by behavioral mechanisms during foraging (Masciocchi et al., 2010). Vespula wasps are eusocial wasps that have rapidly spread to several regions of the world over the past century (Beggs et al., 2011;Lester & Beggs, 2019). Vespula germanica (Fabricius) and Vespula vulgaris (Linnaeus), two species of this genus, represent major problems for economic and human activities due to their dangerous stings, detrimental effects on ecological and productive systems, rapid population growth and generalist diets (MacIntyre & Hellstrom, 2015). ...
... Vespula germanica (Fabricius) and Vespula vulgaris (Linnaeus), two species of this genus, represent major problems for economic and human activities due to their dangerous stings, detrimental effects on ecological and productive systems, rapid population growth and generalist diets (MacIntyre & Hellstrom, 2015). These species exhibit complex behavioral patterns and social mechanisms associated with foraging, which are directly related to colony triumph and possibly to their successful invasions in several countries around the world (Beggs et al., 2011;Lozada & D'Adamo, 2014). ...
... V. germanica and V. vulgaris are native to the Holartic region, and sympatric also in invaded area such as New Zealand, Australia, South Africa, North America, Chile, and Argentina (Clapperton et al., 1989;Masciocchi et al., 2010;Beggs et al., 2011;Barrera Medina & Muñoz, 2013;Lester & Beggs, 2019). These wasps exhibit temporal overlap, as well as a high degree of dietary overlap. ...
Foraging behavior is a key factor associated with the success of social insect invasions. Vespula wasps show complex behavioral patterns and social mechanisms associated with foraging, which are directly related to their invasive success in several countries worldwide. Vespula vulgaris (Linnaeus) and Vespula germanica (Fabricius) are invasive wasps, coexisting in Patagonia, showing temporal and dietary overlap. As generalist, opportunistic predators and scavengers with broad diets, these sympatric wasps share similar niches and foraging habits. We analyzed their foraging strategies and interaction, observing the behavior of each species in the presence of workers of the same species, and the other species at a given resource, directly and indirectly. Directly, from a continuous visual record, we observed and recorded the frequency of wasp's behavior at a feeder for 30 min. Indirectly, we conducted pairwise choice tests to compare wasp preference for treated and untreated feeders with visual and olfactory cues simulating the presence of wasps of the same or different species. We found consistent differences between species in aggressiveness. V. vulgaris showed a greater degree of intraspecific agonistic behavior than toward V. germanica , while V. germanica was less aggressive, and intraspecific and interspecific interactions were similar. Also, V. vulgaris preferred landing on baits without visual and olfactory cues simulating wasps presence, while V. germanica preferred baits with cues simulating its own species over baits with cues representing V. vulgaris . Our results suggest that V. germanica prioritize social facilitation as foraging strategy, while for V. vulgaris aggression is the predominant strategy.
... First worker-based record of Vespula flaviceps flaviceps (Smith, 1870) (Hymenoptera, Vespidae) from Okinawa Prefecture, Japan (Edwards, 1980;Akre, 1982;Donovan, 1984;Beggs et al., 2011)．これらの種では，侵入後に多年 性や多女王制に生態が大きく変化し，コロニーサ イズが巨大化するとともに攻撃性が増加している (Donovan et al., 1992;Beggs et al., 2011;Hanna et al., 2014a;Schmack et al., 2019) ．そして，果実等への農 業被害や刺傷被害が生じ，侵入先の生態系に大きな 負の影響を与えている (Edwards, 1980;Akre, 1982;Beggs, 2001;Wilson et al., 2009;Wilson & Holway, 2010;Beggs et al., 2011;Hanna et al., 2011Hanna et al., , 2014b ...
... First worker-based record of Vespula flaviceps flaviceps (Smith, 1870) (Hymenoptera, Vespidae) from Okinawa Prefecture, Japan (Edwards, 1980;Akre, 1982;Donovan, 1984;Beggs et al., 2011)．これらの種では，侵入後に多年 性や多女王制に生態が大きく変化し，コロニーサ イズが巨大化するとともに攻撃性が増加している (Donovan et al., 1992;Beggs et al., 2011;Hanna et al., 2014a;Schmack et al., 2019) ．そして，果実等への農 業被害や刺傷被害が生じ，侵入先の生態系に大きな 負の影響を与えている (Edwards, 1980;Akre, 1982;Beggs, 2001;Wilson et al., 2009;Wilson & Holway, 2010;Beggs et al., 2011;Hanna et al., 2011Hanna et al., , 2014b ...
... First worker-based record of Vespula flaviceps flaviceps (Smith, 1870) (Hymenoptera, Vespidae) from Okinawa Prefecture, Japan (Edwards, 1980;Akre, 1982;Donovan, 1984;Beggs et al., 2011)．これらの種では，侵入後に多年 性や多女王制に生態が大きく変化し，コロニーサ イズが巨大化するとともに攻撃性が増加している (Donovan et al., 1992;Beggs et al., 2011;Hanna et al., 2014a;Schmack et al., 2019) ．そして，果実等への農 業被害や刺傷被害が生じ，侵入先の生態系に大きな 負の影響を与えている (Edwards, 1980;Akre, 1982;Beggs, 2001;Wilson et al., 2009;Wilson & Holway, 2010;Beggs et al., 2011;Hanna et al., 2011Hanna et al., , 2014b ...
... In invaded regions, various control efforts have been implemented to suppress hornet populations, reduce api-ary damage, and mitigate broader ecological impacts (Beggs et al., 2011;Turchi & Derijard, 2018). However, most field-based control measures rely on direct collection using nets or hornet attractant traps, which are labor-intensive and offer short-term effectiveness (Beggs et al., 2011;Hsu et al., 2021;Lioy et al., 2020). ...
... In invaded regions, various control efforts have been implemented to suppress hornet populations, reduce api-ary damage, and mitigate broader ecological impacts (Beggs et al., 2011;Turchi & Derijard, 2018). However, most field-based control measures rely on direct collection using nets or hornet attractant traps, which are labor-intensive and offer short-term effectiveness (Beggs et al., 2011;Hsu et al., 2021;Lioy et al., 2020). Developing more sustainable and effective strategies requires a deeper understanding of Vespa biology, colony development, and foraging behavior; however, such ecological insights remain scarce for many species (Matsuura, 1984;Monceau et al., 2014). ...
This study investigated the seasonal occurrence patterns of overwintered queens and hornet workers (Vespa spp.) collected over two years (2022 and 2024) at an apiary in Daegu, South Korea. Using hornet attractant traps, 744 individuals representing eight Vespa species were collected, of which Vespa velutina Lepeletier, 1836 and Vespa crabro Linnaeus, 1758 were the most frequently observed. The timing of the emergence of overwintered queens varied by species: Vespa mandarinia Smith, 1852 and V. velutina were the earliest to appear in early April, followed by V. crabro, Vespa analis Fabricius, 1775, and Vespa ducalis Smith, 1852. Workers began to emerge predominantly in mid-July, with populations peaking in August and September and declining sharply in October. Notably, following the application of a control method using an insecticide (clothianidin) in late July 2024, a marked decrease in the number of V. velutina workers was observed. This study highlights interspecific differences in the timing of colony development and provides foundational data for the effective management of hornets in apiary environments.
... The global economic effects of IAS are estimated to reach at least US$ 1.288 trillion (2017 US dollars) in approximately 50 years [71], with invasive insects alone accounting for at least US$ 70.0 billion annually [7]. Among IAS, social wasps pose unique challenges, causing significant ecological disturbance and economic losses, particularly in the beekeeping industry [1,4,33]. Moreover, unlike invasive agricultural pests, social wasps present serious public health risks due to their venom, which can be lethal [11,19,20], leading to a rise in stinging incidents, especially in urban areas [35,50]. ...
... Unfortunately, colony collapse by parasites or parasitoids in social wasps is rare; therefore, the effectiveness of biological control against invasive social wasps is minimal. For example, the control effects of the parasitoid Sphecophaga vesparum Curtis against the invasive Vespula species, and the endoparasitoid nematodes Pheromermis vesparum and Conops vesicularis against V. velutina were insignificant [4,16,69]. Xenos species are the most common parasitoids of social wasps and their parasitic mechanisms on wasps are unique. Xenos species mainly stylopize workers, males, and new queens, except for the foundress. ...
The invasive hornet Vespa velutina Lepeletier, which first invaded South Korea in 2003, has spread throughout the country, significantly affecting apiaries, ecosystems, and human health. Xenos spp. (Xenidae, Strepsiptera) are primarily parasitic to social wasps, with V. analis being the only known host in Korea. Until recently, no parasites or parasitoids on V. velutina had been discovered. In 2020, strepsipteran parasites were discovered on 11 hornet workers in Andong City, South Korea. These parasites, comprising four larvae and seven pupae, were all male, except for one individual of an undetermined sex. Molecular analysis and morphological examination identified the parasites as Xenos moutoni (du Buysson, 1903) and X. oxyodontes Nakase & Kato, 2013. This marks the first recorded instance of strepsipteran parasites on V. velutina in regions invaded by this hornet. Although the exact infection rate of these parasites could not be determined, it appears that native strepsipteran parasites have adapted to a non-native Vespa species. Stylopization, the condition caused by these parasites, is known to negatively affect hornet colonies: infected workers do not contribute to nest activities, hindering nest development, and infected reproductive individuals (males and new queens) do not mate, which impedes the establishment of new colonies. However, due to the hornet’s high reproductive rate and compensatory mechanisms, the overall control effect of the parasites is likely to be minor.
... Other social insects could benefit from climate warming, enhancing their potential for expansion and presenting challenges within the context of climate change (Bertelsmeier et al., 2016;Menzel and Feldmeyer, 2021). Alien social hymenopterans have exhibited remarkable success in invading new environments globally (Monceau et al., 2015) due to their proficient dispersal abilities, swift reproductive rates, versatile diets, and robust competitive abilities against native biota (Beggs et al., 2011;Chapman and Bourke, 2001;Holway et al., 2002). ...
... From an application perspective, our findings could be useful in the management V. crabro in vulnerable insular ecosystems by providing insights into the direction and magnitude of its response under various future climate and socio-economic scenarios. Although social Vespidae like V. crabro are notoriously difficult to eradicate due to their high fertility (Beggs et al., 2011;Pusceddu et al., 2019), predictive modeling combined with local knowledge can offer valuable tools for policymakers and managers. These tools can help identify future vulnerable areas and prioritize them for monitoring and intervention. ...
Climate change poses unprecedented challenges to ecosystems and species, particularly in biodiversity hotspots like the European-Mediterranean regions. The ecological consequences are not easily discernible. Although the influence of climate on plants and vertebrates has been extensively studied, its impact on alien insects, especially social wasps, remains underexplored. To address this gap, this study identifies climatically suitable habitats for Vespa crabro under current conditions, projects its potential future distribution, and assesses potential range shifts driven by climate change to guide monitoring programs and management measures. We focused on Sardinia, a Mediterranean island with a heterogeneous morphological, geological, and climatic pattern, where V. crabro was accidentally introduced.
We used 316 verified citizen science occurrences, high-resolution bioclimatic variables (40x40 m) specifically developed for the island, and two future climate and socio-economic scenarios for two temporal horizons (2040 and 2060) to model climatic suitability using an ensemble framework with three machine learning algorithms: Artificial Neural Networks (ANN), Generalized Boosting Model (GBM), and Random Forest (RF). To ensure reliable predictions, we addressed several technical challenges, including correcting for sampling biases and spatial autocorrelation. The individual models were weighted based on spatial cross-validation performance and combined to obtain the ensemble model.
Performance varied among 150 individual models (3 algorithms × 10 replicates × 5 folds), depending on the algorithms, replicates, and subsets selected for training and testing. RF demonstrated the highest predictive performance, outperforming ANN and GBM. The ensemble model achieved even higher predictive accuracy with Receiver Operating Characteristics (ROC) = 0.95 ± 0.02 and True Skill Statistic (TSS) = 0.78 ± 0.06.
Key factors influencing V. crabro distribution included Annual Mean Temperature, Maximum Temperature of Warmest Month, Temperature Annual Range, Precipitation of Driest Month, and Precipitation Seasonality. Currently, climatically suitable habitats are predominantly in the northern part of the island, in most coastal areas, and in specific inland regions, especially those near or inside mountainous areas. Future projections indicate a distribution range contraction by the 2040s and 2060s, primarily driven by extreme variability in precipitation and rising temperatures approaching the species' thermal tolerance limits.
Our study demonstrates the value of integrating citizen science data, high-resolution climate data, and advanced modeling techniques to understand and manage alien species in the context of climate change. It highlights the importance of fine-scale studies to complement broader analyses, providing deeper insight into the impacts of climate change on species distribution, especially in heterogeneous areas like those in the Mediterranean.
... Commonly known as yellowjackets, Vespula germanica (F.) and Vespula vulgaris (L.) (Hymenoptera: Vespidae) are sympatric haplodiploid eusocial wasps native to Eurasia, which in the last decades have invaded many parts of the globe, becoming significant pests in many countries 18 . The first detection of V. germanica in Argentina date from 1980 in north-western Patagonia 19 while V. vulgaris was first detected in 2010 in the same region 20 . ...
During the mating season, reproductive individuals of numerous insect species gather in rendezvous areas, which increases mating opportunities. Male hymenopterans often have to move considerable distances during a particular season, searching or waiting for receptive females. Such behavior is likely driven by a complex combination of individual and species-specific traits, environmental influence, and landscape cues. Our field study aimed to determine factors affecting the occurrence of Vespula spp. drones, focusing on the influence of vegetation traits, atmospheric factors and diel effects, and the species occurrence proportion in an invaded area in Patagonia. Our results indicate that the probability of drone presence over different types of vegetation is affected both by plant species and height. Also, weather and time of day influence the number of individuals simultaneously gathering, as higher abundances of flying drones are found in early hours, warmer days and at low cloud cover. Lastly, through mid-flight drone captures, we determined that both V. germanica and V. vulgaris drones are found concurrently in the same rendezvous areas. This constitutes the first exploratory field study reporting the heterospecific occurrence of Vespula spp. drones and overall, our results contribute to the understanding of yellowjackets mating systems.
Supplementary Information
The online version contains supplementary material available at 10.1038/s41598-025-85851-0.
... 10 (Jung et al., 2008;Choi et al., 2012). 63.2% (Abrol, 1994;Choi, 2016), (Apis mellifera) (Beggs et al., 2011;Daniela et al., 2020). ...
Plants function within complex ecological communities, relying on chemical signals to mediate interactions with other organisms. The foraging behaviour of insects, such as the invasive hornet Vespa velutina nigrithorax , introduced into northwestern Spain over a decade ago, may be influenced by floral volatiles. This hornet detects plant secondary metabolites, including semiochemicals, which aid in locating nectar, carbohydrates, prey, mating sites, and other resources. Understanding the volatile organic compounds (VOCs) emitted by plants visited by V. velutina may help to develop targeted control strategies. The aim of this study was to identify and analyse the volatile compounds emitted by 18 plant species frequented by V. velutina nigrithorax in the province of Ourense, northwest Spain. Solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS) was used in this study. A total of 110 VOCs were identified, of which 21 compounds were abundant in the samples, with terpenes being the most abundant. Furthermore, a PLS-DA analysis selected 33 volatile compounds with variable importance scores (VIPs) greater than 1, in particular methylanthranilate with a value of 1.81. Eleven of these compounds were found to be abundant in the analysed samples, including ( Z )-β-ocimene; 1-octen-3-ol; 3-hexen-1-ol, acetate, ( Z )-; 3-octanone; eugenol; linalool; methyl salicylate; o -cymene; α-farnesene; α-terpineol and β-farnesene. The selection of these compounds provides valuable insights into plant-insect interactions, highlighting their diverse roles as plant volatiles in mediating insect behaviour and underlining their potential as targets for environmentally friendly pest management strategies.
The present checklist is the product of a critical taxonomic review of the Canadian/Alaskan fauna during the previous two decades. As of December 2024, 531 described species in 84 genera of apoid wasps (Ammoplanidae, Ampulicidae, Astatidae, Bembicidae, Crabronidae, Mellinidae, Pemphredonidae, Philanthidae, Psenidae, Sphecidae) are recorded from Canada and Alaska. Seventy species and two genera (Psammaletes Pate and Larra Fabricius) are newly recorded from the area, including eight accidentally introduced species and three naturally Holarctic species. Compared to the previous Catalog of Hymenoptera in America north of Mexico (Krombein 1979) the number of recorded species in Canada and Alaska has increased by 124% and the number of genera by 42%. The genera Foxia Ashmead and Pluto Pate are also recorded for the first time, but they are not included in the checklist because their species remain either unidentified or undescribed. A total of 23 species are non-native and have been introduced accidentally from other biogeographic regions. Crabro dietrichi R. Bohart is newly recognized as the only species endemic to the area of the checklist (restricted to Prince Edward Island, Canada). A total of 2109 provincial, territorial and Alaskan records are included, 705 of which (33.4%) are new. Records are based on verified material from 22 different collections, only 1.6% rely exclusively on data in the literature. The Alaskan fauna consists of 63 species (31 new records) in 24 genera (eight new records) and seven families, all of which are also known from Canada. No apoid wasps have been found in Greenland. The regions with the most diverse faunas are Alberta (326 species, 64 genera), Ontario (294 spp., 71 genera), British Columbia (292 spp., 64 genera) and Saskatchewan (248 spp., 58 genera). The highest number of new records are from Alberta (124 spp.), Saskatchewan (117 spp.), Manitoba (113 spp.) and New Brunswick (60 spp.). The greatest numbers of species exclusive to one political area within Canada and Alaska are recorded from British Columbia (63 spp.) and Ontario (44 spp.). In order to clarify species concepts, type material or images of types of 57 nominal species were examined. This led to 25 taxonomic changes. Eight synonyms are reinstated as valid species: Gorytes decorus Fox, sp. restit., Nysson freyigessneri Handlirsch, sp. restit., Lindenius errans (Fox), sp. restit., Oxybelus pacificus (Rohwer), sp. restit., Diodontus antennatus (Mickel), sp. restit. (extralimital to the area of the checklist), D. nigritus Fox, sp. restit. and Pemphredon bipartior Fox, sp. restit. Diodontus beulahensis (Rohwer), sp. restit. (extralimital to the area of the checklist) is a suspected synonym of D. americanus Packard. Fourteen new or revised synonymies are proposed: Crabro canningsi Finnamore, syn. nov. = C. maeklini Morawitz, Crossocerus eriogoni (Rohwer), syn. nov. = C. minimus (Packard), Solierella foxii (Viereck, 1906; nec 1902) (preoccupied), syn. rev. = S. mammillata Buck, nom. nov.; Diodontus gillettei Fox, syn. nov., D. rugosus Fox, syn. nov., D. florissantensis Rohwer, syn. rev., D. bidentatus Rohwer, syn. nov., D. siouxensis (Mickel), syn. nov., and D. striatus (Mickel), syn. nov. are all = D. americanus; D. vallicolae Rohwer, syn. nov., D. vallicolae salicis Rohwer, syn. rev., D. maestus (Mickel), syn. rev. and D. ater (Mickel), syn. rev. are all = D. nigritus Fox; Mimesa gregaria (Fox), syn. nov. = M. unicincta Cresson. Two new replacement names are proposed for preoccupied names: Solierella mammillata Buck, nom. nov. (for Niteliopsis foxii Viereck, 1906) and Mimesa curta Pulawski & Buck, nom. nov. (for Psen simplex Malloch, 1933). In an appendix, taxonomic changes and revised species concepts of 33 species or species complexes are briefly explained in order to clarify their status and avoid confusion. The biogeography of Canadian and Alaskan species is discussed, including Holarctic species and species shared with other biogeographic regions, distribution patterns within the Nearctic region, endemism, remarkable new records, geographic prevalence of nesting habits, distribution patterns and introduction timelines of introduced species, as well as faunal change. Diodontus minutus (Fabricius) is newly recognized as an introduced species from the Palearctic region despite first being discovered in North America in 1934. Based on literature data and observations on the internet platform iNaturalist.org, we document recent, rapid range expansions in ten native species of Sphecidae, Philanthidae and Bembicidae. These trends are likely caused by climate change and are projected to further increase apoid wasp diversity in Canada in the future. Lastly, we discuss the important contribution citizen science is making to faunistic wasp research through iNaturalist and other collaborative websites.
Social wasps (Hymenoptera: Vespidae) constitute an important group of predatory insects that are particularly well-suited for transportation beyond their native habitats into new environments through commercial trade, a phenomenon that is strongly influenced by climate change. As they are predominantly predators dominating numerous natural food chains of insects, these alien species can exert serious and devastating impacts on the native entomological fauna of the new habitats they invade. Additionally, because species belonging to the subfamilies Polistinae and Vespinae possess potent stings for defending their colonies, invasive social wasps represent a public health concern due to the wide range of allergic reactions they can elicit in humans. In this paper, we review the principal invasions of social wasps into novel habitats around the world and highlight the need for efficient immunotherapies to address the allergological risks posed by alien species. We detail the recent invasion of the Asian Vespa velutina nigrithorax in Europe, where the native Vespa crabro is found, as well as the increasing presence of Vespa orientalis in northern Tuscany, Italy. We discuss the optimal immunotherapy required in cases of human stinging incidents and describe how this relates to the phylogenetic distance between the three species.
The yellow paper wasp, Polistes versicolor (Olivier) was first recorded in the Galapagos archipelago in 1988. Its life cycle and ecological impacts were studied on two islands 11 yr after it was first discovered. This invasive wasp adapted quickly and was found in most environments. Colony counts and adult wasp monitoring showed a strong preference for drier habitats. Nest activities were seasonally synchronized, nest building followed the rains in the hot season (typically January–May), when insect prey increases, and peaked as temperature and rains started to decline. Next, the number of adult wasps peaked during the cool season when there is barely any rain in the drier zones. In Galapagos, almost half of the prey loads of P. versicolor were lepidopteran larvae, but wasps also carried spiders, beetles, and flies back to the colonies. An estimated average of 329 mg of fresh insect prey was consumed per day for an average colony of 120–150 wasp larvae. The wasps preyed upon native and introduced insects, but likely also affect insectivorous vertebrates as competitors for food. Wasps may also compete with native pollinators as they regularly visited flowers to collect nectar, and have been recorded visiting at least 93 plant species in Galapagos, including 66 endemic and native plants. Colonies were attacked by a predatory moth, Taygete sphecophila (Meyrick) (Lepidoptera: Autostichidae), but colony development was not arrested. High wasp numbers also affect the activities of residents and tourists. A management program for this invasive species in the archipelago is essential.
Le 1er novembre 2005, l'un de nous (JPB) récoltait un Hyménoptère de grande taille dans son jardin (lieu-dit "le Long de Haut", Nérac, Lot-et-Garonne) sur un fruit de Plaqueminier (Diospyros kaki L., Ebe-baceae), arbre plus connu localement sous le nom de Kaki et dont les fruits pourrissants sont connus pour attirer en automne de nombreux Hyménoptères et en particulier des Frelons (Vespa crabro L., 1758). Sans être spécialiste des Hyménoptères, les deux premiers auteurs furent tout de suite intrigués par la coloration singulière de l’insecte et convaincus que cet insecte insolite était nouveau pour la faune de France. Une rapide recherche sur Internet devait fournir une première détermination : notre guêpe géante était une Vespa velutina, Lepeletier, 1836, à vaste aire de distribution couvrant le sud de l’Inde, la Thailande, la Chine (incluant Hong-Kong), le Laos, le Vietnam, la Malaisie, l’Indonésie (Java, Lombok). Elle n'a jamais été récoltée dans les régions plus occidentales. L’espèce est signalée comme redoutable prédateur de l’abeille domestique (Apis melifera L.). Il est impossible de la confondre avec le moindre Hyménoptère de nos contrées. Cette détermination fut confirmée par notre collègue et ami Jean-Yves Rasplus (INRA, Montpellier) qui insista sur l’aspect inquiétant de cette découverte.
Because invasive species threaten the integrity of natural ecosystems, a major goal in ecology is to develop predictive models to determine which species may become widespread and where they may invade. Indeed, considerable progress has been made in understanding the factors that influence the local pattern of spread for specific invaders and the factors that are correlated with the number of introduced species that have become established in a given region. However, few studies have examined the relative importance of multiple drivers of invasion success for widespread species at global scales. Here, we use a dataset of >5,000 presence/absence records to examine the interplay between climatic suitability, biotic resistance by native taxa, human-aided dispersal, and human modification of habitats, in shaping the distribution of one of the world's most notorious invasive species, the Argentine ant (Linepithema humile). Climatic suitability and the extent of human modification of habitats are primarily responsible for the distribution of this global invader. However, we also found some evidence for biotic resistance by native communities. Somewhat surprisingly, and despite the often cited importance of propagule pressure as a crucial driver of invasions, metrics of the magnitude of international traded commodities among countries were not related to global distribution patterns. Together, our analyses on the global-scale distribution of this invasive species provide strong evidence for the interplay of biotic and abiotic determinants of spread and also highlight the challenges of limiting the spread and subsequent impact of highly invasive species.
Aggregations of diapausing Polistes versicolor were observed and sampled at three sites in the Venezuelan Northern Cordillera (ca 2,400 m) during the dry season (November to April). During the wet season (May–October), Polistes versicolor occupies lowland areas where food supply appears to be abundant year round. Here it coexists with P. canadensis which does not move to the mountains during the dry season so there seems to be no basis for a seasonal diapause in P. versicolor. The phenomenon is compared with a conspecific population in Brazil that also has been reported to aggregate. Energy savings, escape from predators, and the presence of a pronounced dry season at lower elevations are some of the possible reasons for this behavior. Resumen.—Agregaciones de Polistes versicolor en diapausa fueron observadas y colectadas dur-ante la e ´poca seca (Noviembre a Abril), en tres lugares diferentes de la Cordillera de la Costa Venezolana (ca 2.400 m). Durante la e ´poca hú meda (Mayo–Octubre), P. versicolor ocupa a ´reas en Venezuela donde el suministro de alimentos es abundante todo el añ o. Aquí coexiste con P. canadensis, la cual no se mueve hasta las montañ as durante la e ´poca seca, de manera que no pareciera existir una base para que tenga una diapausa estacional. El fenó meno es comparado con una población coespecífica estudiada en Brasil, la cual ha sido reportada en agregaciones. Ahorro energético, escape de depredadores o que la presencia de la e ´poca seca demanda la apari-ción de una diapausa, se mencionan como algunas de las razones para exhibir este comporta-miento.
Arthropods were collected from the crowns of mountain beech trees Nothofagus solandri var. cliffortioides. Data based on one "non-honeydew' tree suggest that arthropod abundance, species dominance patterns and community structure vary markedly between beech trees with a complement of sooty beech scale Ultracoelostoma spp. and those without. It is implied that scale honeydew secretions provide an essential rseource base for arthropods in beech forests and that this is an important factor determining the abundance and composition of the arthropod fauna. Changes in tree morphology brought about by associated fungal mould growth may influence the abundance (and perhaps composition) of certain bark and epiphyte dwelling arthropods. -from Author