Citizen science and niche modeling to track and forecast the expansion of the brown marmorated stinkbug Halyomorpha halys (Stål, 1855)

An update for Halyomorphahalys (Stål, 1855) (Hemiptera, Pentatomidae) distribution in Belgium

The brown marmorated stink bug, Halyomorphahalys, represents an important insect pest and subsequently an important agricultural threat due to its polyphagous feeding habits and adaptability to diverse climates. Native from East Asia, its recent establishment in various regions, including North America and Europe, has led to substantial yield losses and economic impacts, which highlight the need for comprehensive research efforts, based on data occurrence by combining those from expert entomologists and citizen scientists. We reported here 14 new occurrences of this insect pest in the three regions of Belgium. Then, these data were merged with data occurrences from other studies and GBIF datasets of Belgium. The combined dataset showed a peak of presence of Halyomorphahalys in October and a dominance of field observations from citizen scientists especially in the nothern part of Belgium, Flanders. Crowd-sourced data have provided valuable insights into the presence and distribution of Halyomorphahalys in Belgium. Given the importance of the generated dataset, it could be asserted that this pest is uniformly distributed across the entire country, which necessitates additional research to evaluate its impact on various crops.

Ecological forecasts of insect range dynamics: a broad range of taxa includes winners and losers under future climate

Species distribution models are the primary tools to project future species' distributions, but this complex task is influenced by data limitations and evolving best practices. The majority of the 53 studies we examined utilized correlative models and did not follow current best practices for validating retrospective or future environmental data layers. Despite this, a summary of results is largely unsurprising: shifts toward cooler regions, but otherwise mixed dynamics emphasizing winners and losers. Harmful insects were more likely to show positive outcomes compared with beneficial species. Our restricted ability to consider mechanisms complicates interpretation of any single study. To improve this area of modeling, more classic field and lab studies to uncover basic ecology and physiology are crucial.

Incursion Preparedness, Citizen Science and Early Detection of Invasive Insects: The Case of Aleurocanthus spiniferus (Hemiptera, Aleyrodidae) in France

We describe the process by which the quarantine whitefly, Aleurocanthus spiniferus (Hemiptera, Aleyrodidae), was detected in France. The initial observation was made by a volunteer who reported a picture of an adult in the Inventaire National du Patrimoine Naturel (INPN Espèces), a citizen science resource developed by l'Office Français de la Biodiversité and the French Muséum National d'Histoire Naturelle. The specimen was suspected to be A. spiniferus from this picture by one of the expert entomologists in charge of the Hemiptera group validation. Once the species was identified, it was mounted on a slide and the information was officially passed on to the ministry in charge of agriculture via a communication channel set up in advance for this type of situation. The ministry then triggered the regulatory actions planned in the event of the suspected detection of quarantine organisms. Sampling was quickly carried out and the specimens collected on this occasion were formally identified as belonging to the species A. spiniferus. This led to the formalization of an outbreak in France. This sequence of decisions took just two months from the first observation to the implementation of a management plan. This case presents how incursion preparedness contributes to a rapid response. Furthermore, this case exemplifies how citizen science can contribute to the early detection of invasive species and highlights the importance of informing both the general public and professionals about major environmental issues.

Climate change and the potential distribution of the glassy-winged sharpshooter (Homalodisca vitripennis), an insect vector of Xylella fastidiosa

Biological invasions represent a major threat for biodiversity and agriculture. Despite efforts to restrict the spread of alien species, preventing their introduction remains the best strategy for an efficient control. In that context preparedness of phytosanitary authorities is very important and estimating the geographical range of alien species becomes a key information. The present study investigates the potential geographical range of the glassy-winged sharpshooter (Homalodisca vitripennis), a very efficient insect vector of Xylella fastidiosa, one of the most dangerous plant-pathogenic bacteria worldwide. We use species distribution modeling (SDM) to analyse the climate factors driving the insect distribution and we evaluate its potential distribution in its native range (USA) and in Europe according to current climate and different scenarios of climate change: 6 General Circulation Models (GCM), 4 shared socioeconomic pathways of gas emission and 4 time periods (2030, 2050, 2070, 2090). The first result is that the climate conditions of the European continent are suitable to the glassy-winged sharpshooter, in particular around the Mediterranean basin where X. fastidiosa is present. Projections according to future climate conditions indicate displacement of climatically suitable areas towards the north in both North America and Europe. Globally, suitable areas will decrease in North America and increase in Europe in the coming decades. SDM outputs vary according to the GCM considered and this variability indicated areas of uncertainty in the species potential range. Both potential distribution and its uncertainty associated to future climate projections are important information for improved preparedness of phytosanitary authorities.

Advances in understanding and predicting the spread of invading insect populations

Understanding and predicting the spread of invading insects is a critical challenge in management programs that aim to minimize ecological and economic harm to native ecosystems. Although efforts to quantify spread rates have been well studied over the past several decades, opportunities to improve our ability to estimate rates of spread, and identify the factors, such as habitat suitability and climate, that influence spread, remain. We review emerging sources of data that can be used to delineate distributional boundaries through time and thus serve as a basis for quantifying spread rates. We then address advances in modeling methods that facilitate our understanding of factors that drive invasive insect spread. We conclude by highlighting some remaining challenges in understanding and predicting invasive insect spread, such as the role of climate change and biotic similarity between the native and introduced ranges, particularly as it applies to decision-making in management programs.

Vectors as Sentinels: Rising Temperatures Increase the Risk of Xylella fastidiosa Outbreaks

Global change is expected to modify the threat posed by pathogens to plants. However, little is known regarding how a changing climate will influence the epidemiology of generalist vector-borne diseases. We developed a high-throughput screening method to test for the presence of a deadly plant pathogen, Xylella fastidiosa, in its insect vectors. Then, using data from a four-year survey in climatically distinct areas of Corsica (France), we demonstrated a positive correlation between the proportion of vectors positive to X. fastidiosa and temperature. Notably, a higher prevalence corresponded with milder winters. Our projections up to 2100 indicate an increased risk of outbreaks. While the proportion of vectors that carry the pathogen should increase, the climate conditions will remain suitable for the bacterium and its main vector, with possible range shifts towards a higher elevation. Besides calling for research efforts to limit the incidence of plant diseases in the temperate zone, this work reveals that recent molecular technologies could and should be used for massive screening of pathogens in vectors to scale-up surveillance and management efforts.

The King's Lace Bug Recaredus rex Distant, 1909 (Hemiptera: Heteroptera: Tingidae): Systematic Position, First Palaearctic and Afrotropical Records, and Ecological Niche Modelling

Simple Summary

Lace bugs (Tingidae) are known for their spectacular bodily appearance; the pronotum and hemelytra of the adult specimens are lacelike, with a delicate network of areolae that resemble lace. The species are phytophagous and always feed on a specific plant or groups of closely related plants. Therefore, they are recognised as mono- or oligophagous bugs, whose feeding activities may cause significant injury to plant pods and leaves. Lace bugs are distributed worldwide and reported in all continents except Antarctica. Although most of the lace bug species are distributed in a particular zoogeographical region, some genera are widely known from the Holarctic region. However, species with a Palaeotropical distribution are scarce. In this study, based on new records and ecological niche modelling, we indicate that Recaredus rex, one of the most enigmatic lace bugs, has a possible Palaeotropical distribution. Moreover, we hypothesise that R. rex is an oligo- or polyphagous species. In addition, the systematic position of the genus Recaredus is discussed.

Abstract

The systematic position and actual distribution of Recaredus rex, for a long time one of the most enigmatic lace bug genus and species, is very obscure because only the type specimen and three other individuals from India are known to date. In the present paper, we report the first records of R. rex from the Palaearctic region (Iran) and tropical Africa (Ghana). Based on the occurrence localities and climatic variables, we predict potentially useful ecological niches for this species using Maxent software. The areas with the best environmental conditions for R. rex indicated in our studies suggest its possible Palaeotropical distribution. Moreover, we regard these results as a good starting point for further searches for specimens of this species. This might help verify the hypothesis of the broad Palaeotropical distribution of R. rex and its oligo- or polyphagy. In addition, the lace bug genus Recaredus, based on the diagnostic characteristics provided for the tribe Acalyptaini, and the structure of aedeagus, is transferred from the tribe Ypsotingini to the Acalyptaini. A key to all genera currently included in the latter tribe is also provided.

Flying over Eurasia: Geographic Variation of Photoperiodic Control of Nymphal Development and Adult Diapause Induction in Native and Invasive Populations of the Brown Marmorated Stink Bug, Halyomorpha halys (Hemiptera: Heteroptera: Pentatomidae)

Simple Summary

The brown marmorated stink bug is an invasive true bug that originates in eastern Asia and is considered now one of the most harmful invasive insect pests in North America and Europe. Similar to the many species that produce more than one generation per year, this bug responds to day length: under short-day conditions (which predict the approaching of autumn), adults form a special overwintering (diapause) physiological state, whereas, under long-day conditions (typical for summer), they reproduce. Critical day length is the condition that induces diapause in 50% of adults. This critical day length is usually strongly correlated with the latitude of the population origin. In this study, we compared the critical day lengths of one native (Andong, South Korea) and three invasive (Torino, Italy; Basel, Switzerland; and Sochi, Russia) populations. The critical day lengths of both sexes fell between 14.5 and 15.0 h in the Korean population, and between 15.0 and 15.5 h in the three European populations. The results demonstrate that microevolution was possibly ‘too slow to keep up’ with the rapid spread of the invader across Eurasia. It is expected that in the near future, the critical day length of invasive H. halys populations will gradually change to adapt better to the local conditions.

Abstract

Facultative winter adult diapause in Halyomorpha halys is regulated by a long-day photoperiodic response. Day length also influences nymphal development, which slows down at the critical (near-threshold) day lengths. We compared the photoperiodic responses of one native (Andong, South Korea) and three invasive (Torino, Italy; Basel, Switzerland; and Sochi, Russia) populations in a laboratory common-garden experiment. Nymphs developed and emerging adults were reared at 24 °C in a range of photoperiods with day lengths of 14.0, 14.5, 15.0, 15.5, and 16.0 h. The critical day lengths of the photoperiodic responses of both sexes fell between 14.5 and 15.0 h in the native Korean population and between 15.0 and 15.5 h in three invasive European populations. The differences between the three invasive populations were not significant, despite their distant origins. Moreover, the difference between the Korean and European populations was much smaller than was expected. The microevolution was possibly ‘too slow to keep up’ with the rapid spread of the invader across Eurasia. It is expected that soon the critical day length of the invasive H. halys populations will gradually change to adapt better to local conditions. At present, the critical day length for diapause induction of 15 h 15 min can be used to model the phenology, further spread, and response to climate change for all European populations of the pest.

Improving invasive species management using predictive phenology models: an example from brown marmorated stink bug (Halyomorpha halys) in Japan

BACKGROUND

In order to better understand the population dynamics of invasive species in their native range, we developed two predictive phenological models using the ubiquitous invasive insect pest, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), as the model organism. Our work establishes a zero-inflated negative binomial regression (ZINB) model, and a general additive mixed model (GAMM) based on 11 years of black light trap monitoring of H. halys at three locations in Japan.

RESULTS

The ZINB model indicated that degree days (DD) have a significant effect on the trap catch of adult H. halys, and that precipitation has no effect. A dataset generated by 1000 simulations from the ZINB suggested that higher predicted trap catches equated to a lower probability of encountering a zero-count. The GAMM produced a cubic regression smooth curve which forecasts the seasonal phenology of H. halys as following a bell-shaped trend in Japan. Critical DD points during the field season in Japan included 261 DD for first H. halys adult detection and 1091 DD for peak activity.

CONCLUSIONS

This study establishes the first models capable of forecasting native H. halys population dynamics based on DD. These robust models practically improve population forecasting of H. halys in the future and help fill gaps in knowledge pertaining to its native phenology, thus ultimately contributing to the progression of efficient management of this globally invasive species. © 2021 Society of Chemical Industry.