Research Article
Research Article
Distribution and genetic diversity of the invasive pest Halyomorpha halys (Hemiptera, Pentatomidae) in Belgium
expand article infoOlivier Hendrik Berteloot, Alexandre Kuhn§, Gertie Peusens|, Tim Beliën|, Louis Hautier§, Thomas Van Leeuwen, Patrick De Clercq
‡ Ghent University, Ghent, Belgium
§ Crops and Forest Health Unit, Life Sciences Department, Walloon Agricultural Research Centre, Gembloux, Belgium
| Zoology Department, Research Centre for Fruit Cultivation, Sint-Truiden, Belgium
Open Access


The brown marmorated stink bug, Halyomorpha halys, native to East Asia, is an invasive pest of economic importance. It has invaded North America and many European countries and is further expanding its range. In Belgium, it was first observed in 2011. Halyomorpha halys is known to cause severe damage in commercial fruit orchards and vegetable crops. A dramatic and unmitigated expansion of H. halys in its adventive range could lead to significant economic implications for agricultural production. In this study, occurrence data of H. halys since its first observation in Belgium was analysed together with molecular information to map the populations and evaluate the genetic diversity of this pest. The genetic diversity of H. halys in Belgium was compared to data from other invaded and native countries reported in previous studies to identify possible invasion routes. The analysis of 1176-bp of mitochondrial DNA cytochrome c oxidase I and II genes (COI and COII) led to the discovery of two novel COI-COII haplotype combinations currently unique to Belgium. The invasion of H. halys in Belgium is likely the result of multiple and ongoing introductions from its native region and from already invaded countries in Europe, particularly Italy. The expansion of the brown marmorated stink bug populations in Belgium is recent and ongoing. Presently, it appears to thrive best in northern Belgium.


brown marmorated stink bug, haplotype diversity, Heteroptera, population genetics


Halyomorpha halys (Hemiptera: Pentatomidae) or the brown marmorated stink bug is a stink bug of economic importance, native to East Asia and an invasive pest species in Europe, North America, and other regions (Hoebeke and Carter 2003; Leskey et al. 2012; Lee et al. 2013; Haye et al. 2015; Zhu et al. 2016; Hamilton et al. 2018). In Europe, H. halys has already been detected as far north as The Netherlands (Aukema et al. 2019), Belgium (Claerebout et al. 2018) and the north of Germany (Hartung et al. 2022). Due to its polyphagous nature, H. halys can feed on virtually all primary fruit and vegetable crops in its invaded areas (Kuhar et al. 2012; Haye et al. 2015). For example, in northern Italy, it has become a key pest in fruit orchards, with an estimated economic impact of €588 million on the production of pear, apple, peach, and kiwi in 2019 (Bulgarini et al. 2020). Halyomorpha halys causes damage through its feeding activity. It inserts its stylets into the plant and injects saliva, pre-digesting the plant tissue before feeding on it (Rice et al. 2014). This feeding behaviour causes scarring, deformities, pitting, and discolouration of the product, rendering it unmarketable or even inedible (Rice et al. 2014; Bulgarini et al. 2020). Since its first record in Belgium in 2011, observations of H. halys on public citizen science databases (Observation International and local partners 2022) only appeared in 2017. Currently, it is assumed that H. halys has established univoltine overwintering breeding populations in Belgium (Claerebout et al. 2018). An observation of H. halys from the Haspengouw region in July 2021 indicated that H. halys is already present in commercial pip fruit orchards in Belgium. However, to date, no dramatic population increases, mass occurrences or damage has been reported in fruit production in Belgium (Berteloot et al. 2021). In 2022, in Belgium, 219.000 t of apples and 366.000 t of pears, some of the most vulnerable fruits to H. halys, were produced (European Commission 2022a, b). Apples and pears represent a combined revenue of more than € 148 million of which pear production is the most significant part with a revenue of € 119 million (Verbond van Belgische Tuinbouwcoöperaties 2022). An unmitigated expansion of H. halys in Belgium could therefore have a considerable impact on fruit production, especially in the Flanders region, which produces most of the apples, pears, and soft fruits in the country.

The increased accessibility and affordability of molecular technologies, as well as the expansion of databases containing publicly available DNA sequence data, have aided in the use of molecular tools to assess the genetic diversity and potential origin of invasive species (Cristescu 2016; Hamelin and Roe 2019). Due to its lack of recombination, relative neutrality and shorter coalescence time, mitochondrial DNA (mtDNA) is a highly popular molecular marker for examining genetic diversity and phylogeography of (invasive) animal species (Ficetola et al. 2008; Rollins et al. 2011; Bras et al. 2019; Ryan et al. 2019). Furthermore, for invasive species, the accumulation of easily reproducible genetic data in public databases facilitates the regular addition of new data from the invasion front to build a global pattern of invasion dynamics. For example, for H. halys, mtDNA sequences (portions of the mitochondrial gene cytochrome c oxidase subunits I and II – COI and COII, respectively) are already available for both native (China, Japan, Korea) and invaded countries (Gariepy et al. 2014; Xu et al. 2014; Cesari et al. 2015; Cesari et al. 2018; Lee et al. 2018; Yan et al. 2021).

In this study, we set out to fill one of the geographical knowledge gaps in Europe on the genetic diversity and distribution of H. halys. First, we investigated the genetic diversity of H. halys in Belgium by sequencing 99 specimens from 18 locations at two mitochondrial genes: COI and COII. Then, we compared those sequences to previously published H. halys sequences to infer the putative invasion routes to Belgium. Lastly, we used public citizen occurrence data to map the distribution of H. halys in Belgium from 2020 to 2022 and gain demographic insights into the Belgian populations.


Insect sampling

Halyomorpha halys specimens were collected from 18 locations in Belgium (Suppl. material 1) from agricultural sites and private gardens in 2021 and 2022 using baited traps (dual lure from Trécé Inc., Adair Oklahoma, USA) or by beating of the lower part of a tree trunk/shrub. The collected samples were stored dry or in 70% ethanol at -20 °C until used for molecular analysis.

DNA extraction & sequencing

DNA was extracted from two legs using a Chelex extraction method (Walsh et al. 1991). Briefly, the legs were crushed with a sterile pestle in 100 µl of 5% Chelex 100 (Bio-Rad, USA) solution. They were then incubated at 85 °C for 90 min, and the supernatant was collected after 3 min of centrifugation at 12,000 rpm. The cytochrome oxidase subunit I (COI) and II (COII) barcode regions of the mitochondrial DNA were amplified through PCR. For the COI region, the LCO 1490 (5’- GCTCAACAAATCATAAAGATATTGG-3’) and HCO 2198 (5’- TAAACTTCAGGGTGACCAAAAAATCA-3’) primers (Folmer et al. 1994) were used. For COII, the HhalysCO2F2 (5’-TAACCCAAGATGCAAATTCT-3’) and HhalysCO2R2 (5’- CCATATATAATTCCTGGACGA-3’) primers (Xu et al. 2014) were used. For both regions, the following PCR cycles were used: initial denaturation at 94 °C for 3 min, 38 cycles of denaturation at 94 °C for 30 sec, annealing at 48 °C for 30 sec and extension at 72 °C for 45 sec, followed by a final extension step at 72 °C for 7 min. The PCR product quality was checked on agarose gel. Both strands (forward and reverse) for each barcode region were sequenced (Eurofins, Germany GmbH) by Sanger sequencing.

Haplotype diversity analysis

Forward and reverse sequences were trimmed and assembled into a consensus sequence using CodonCode Aligner (version 10.0.2). COI and COII sequences obtained in this study were compared to COI and COII sequences from Yan et al. (2021) and Cesari et al. (2018), retrieved from GenBank and BOLD. Other previously conducted studies on the genetic diversity of H. halys only sequenced COI or COII fragments (or only reported unique haplotypes found without specifying which samples are associated with which haplotypes) (Gariepy et al. 2014; Xu et al. 2014; Valentin et al. 2017; Lee et al. 2018; Kapantaidaki et al. 2019). All individual COI and COII haplotypes found in this study have already been reported in other publications (see results) and were given the haplotype name used in those publications (Cesari et al. 2018; Yan et al. 2021). However, for COI, there were discrepancies between the sequences of haplotypes with the same name found in Cesari et al. (2018) and Yan et al. (2021). Haplotypes found in our study were named after the reference haplotypes of the study of Valentin et al. (2017) if a sequence match was found. Haplotype names from Cesari et al. (2018) were distinguished with the letter “c” (Table 1). The sequence of haplotype H41 from Yan et al. (2021) perfectly matched the H41 haplotype from Valentin et al. (2017) but corresponded to the sequence of H46 from Cesari et al. (2018). Therefore, the name of the sequence of this haplotype was retained in the present study as H41. Another sequence found in this study without a match in Valentin et al. (2017) or Yan et al. (2021) was already named H41 in Cesari et al. (2018) and was renamed “H41c” to distinguish it. For H40 and H43, the same haplotype names were given to different sequences by Cesari et al. (2018) and Yan et al. (2021). Again, those sequences were compared to the ones of Valentin et al. (2017). The H40 and H43 sequences from Yan et al. (2021) perfectly matched the identical name sequences from Valentin et al. (2017), and these names were retained in the present study. A letter “c” was added to the H40 and H43 sequences from Cesari et al. (2018) to distinguish them. Finally, the H42 and H49 sequences from Cesari et al. (2018) did not match the H42 and H49 haplotypes from Valentin et al. (2017) (no H42 and H49 haplotypes in Yan et al. (2021) for comparison). To be consistent, the letter “c” was added to the H42 and H49 sequences from Cesari et al. (2018).

Table 1.

Summary of the discrepancies between sequences of COI-haplotypes with the same name in different studies and the names used in the present study.

Valentin et al. (2017) Cesari et al. (2018) Yan et al. (2021) This study
H40 / H40 H40
/ H40 / H40c
H41 H46 H41 H41
/ H41 / H41c
/ H42 / H42c
H43 / H43 H43
/ H43 / H43c
/ H49 / H49c

Sequences were aligned and analysed in R v4.0.2 (R Core Team 2020), using packages msa (Bodenhofer et al. 2015), adegenet (Jombart 2008) and pegas (Paradis 2010). The relationships among haplotypes within Belgium and between haplotypes from Belgium and other countries were investigated through haplotype networks and genetic diversity indexes (haplotype, Hd, and nucleotide diversity, π). We tested for the presence of a genetic structure in Belgium by performing a Mantel test (Euclidean) on genetic and geographic distance matrices between collected specimens.

Occurrence data

Occurrences from January 1st, 2017, to December 31st, 2022 were obtained from the publicly available citizen science database (Observation International and local partners 2022). For H. halys, the recorded occurrences on the public citizen science database are quality-controlled, and the taxonomic accuracy of each observation is confirmed or rejected by a specialist through photos. The occurrence data was additionally examined to check the validity of all the occurrences. Only occurrences with a high confidence level in the taxonomic identification of H. halys and with spatial coordinates were used. Additionally, specimens collected during this research were identified through morphological identification using the H. halys identification key from Maistrello et al. (2016) and confirmed by our molecular analysis. The occurrence data was visualised with QGIS 3.30.1 (QGIS Development Team 2023).


DNA sequences

  • COI: 99 H. halys sequences were retrieved out of 99 specimens collected. All specimens yielded a 658-bp DNA sequence. The DNA sequence data and specimen collection information were made accessible on GenBank with accession numbers OR581617OR581715.
  • COII: 93 sequences with a length of 518-bp were retrieved from 99 H. halys specimens collected. The DNA sequence data and specimen collection information were made accessible on GenBank with accession numbers OR602454OR602546.

Haplotype diversity of H. halys

For the COI fragment individually, nine distinct haplotypes were found, consisting of 14 polymorphic sites (Fig. 1a). Three haplotypes were dominant (H01, H03 and H08) and were shared by roughly 80% of the individuals collected. Haplotype diversity was 0.77 ± 0.02 (mean ± SD). The obtained COI sequences from this study were compared with 609 COI sequences from other European countries, Chile, the USA, China, and Japan. H01 and H03 haplotypes are shared with those in invaded areas in Europe and America, as well as with those in the native area of China, but not with Japan. Haplotype H08 is shared only with some invaded areas in Europe (Austria and Italy). The remaining haplotypes are shared with Italy (H40c, H41, H41c, H42c and H49c), Japan (H23 and H41) and Hungary (H41).

Figure 1.

Haplotype network using A COI B COII and C COI-COII fragments of H. halys in Belgium. The circle size is proportional to the square root of the frequency of the haplotypes. The tick marks on each line represent a base pair difference.

For the COII fragment individually, five distinct haplotypes were found, consisting of 5 polymorphic sites (Fig. 1b). Haplotype diversity was 0.70 ± 0.01. Our COII sequences were compared with 651 COII sequences from other European countries, Chile, the USA, China, and Japan. Haplotypes h01, h03 and h11 accounted for 91 out of 95 haplotypes from Belgium. Haplotypes h01 and h03 are shared with invaded areas in Europe, the USA and China but not with Japan. Haplotypes h11 and h15 are only shared with some other European countries (Austria, Hungary, and Italy) and Japan. Haplotype h21 is shared only with Italy.

The resulting concatenated 1176-bp sequences rendered 12 distinct COI-COII haplotypes among 95 specimens consisting of 22 polymorphic sites in total (Fig. 1c). Two novel COI-COII haplotypes were identified (H03h11 and H08h21) in our samples; these haplotypes are unique to Belgium. The ten other haplotype combinations were previously reported in the literature. The comparison of COI-COII haplotypes from Belgium to previously published sequences confirm the pattern observed for individual loci. The most frequent haplotype H01h01 is shared with all native and invaded countries included in this study (Table 2). H03h03, the second most frequent haplotype, has been recorded in Austria, Chile, China, Italy, and Hungary. Some of the remaining haplotypes (H03h11, H03h21, H41ch03 and H49ch03) are only shared with Italy (and Austria for H08h11) and are close to haplotypes from China. Others (H23h11, H41h15 and H41ch11) are shared with Italy (and Hungary for H41h15) and/or with (or close to) Japan (H46h15, H42h11, H23h11 and H08h11). Finally, the H08h21 and the H03h11 haplotypes are unique to Belgium and are close to the haplotypes from Italy (within the group of haplotypes found in most invaded countries and China).

Table 2.

Summary table of mtDNA (COI-COII) diversity by country. With N: sample size, Hn: number of haplotypes, h: haplotype diversity and π: nucleotide diversity (only countries with available COI-COII sequences are listed).

Continent Country First record N Hn Hd ± SD π ± SD Study
Asia China Native 90 24 0.86 ± 0.02 0.0033 ± 0.0018 Yan et al. 2021
Japan Native 65 32 0.94 ± 0.01 0.0024 ± 0.0014 Yan et al. 2021
Turkey 2017 (Güncan and Gümüş 2019) 11 1 0 0 Yan et al. 2021
Europe Austria 2015 (Rabitsch and Friebe 2015) 15 4 0.69 ± 0.10 0.0021 ± 0.0013 Yan et al. 2021
Belgium 2011 (Claerebout et al. 2018) 95 12 0.79 ± 0.02 0.0031 ± 0.0018 This study
Georgia 2015 (Gapon 2016) 31 1 0 0 Yan et al. 2021
Greece 2011 (Milonas and Partsinevelos 2014) 8 3 0.61 ± 0.16 0.0025 ± 0.0017 Cesari et al. 2018
Hungary 2014 (Vétek et al. 2014) 90 3 0.11 ± 0.04 0.0003 ± 0.0003 Yan et al. 2021
Italy 2012 (Maistrello et al. 2014) 16 18 0.72 ± 0.03 0.0028 ± 0.0016 Cesari et al. 2018; Yan et al. 2021
Romania 2015 (Macavei et al. 2015) 30 1 0 0 Cesari et al. 2018
Serbia 2015 (Šeat 2015) 13 5 0.61 ± 0.07 0.0014 ± 0.0008 Yan et al. 2021
Slovenia 2017 (Rot et al. 2018) 15 3 0.51 ± 0.12 0.0012 ± 0.0008 Yan et al. 2021
North America United States 2001 (Hoebeke and Carter 2003) 24 1 0 0 Yan et al. 2021
South America Chile 2017 (Faúndez and Rider 2017) 31 2 0.06 ± 0.06 0.0001 ± 0.0002 Yan et al. 2021

The results of our Mantel test indicated a significant but weak correlation (r = 0.14, p = 0.001) between the genetic distance and the geographical distances for pairs of individuals. High haplotype diversity was observed in Belgium, Hd = 0.79 ± 0.02, with a nucleotide diversity value of π = 0.0031 ± 0.0018 (Table 2). This level of genetic diversity was lower than that of native regions Japan and China (Hd = 0.94 ± 0.014 and 0.86 ± 0.023, respectively) but similar to Italy (Hd = 0.72 ± 0.033) (Table 2). Other invaded areas of H. halys typically had lower haplotype diversity but their estimation may be approximate due to shallower sampling depth (low sample size and/or few sampling locations; Table 2). The genetic data analysis of this research is publicly available through the following link:

Distribution of H. halys in Belgium

The 740 observations from 6 years (2017–2022) were checked for accuracy and completeness. Since the first record in 2011, occurrences in subsequent years initially remained low, without any public citizen database records or specimens collected until 2017. Halyomorpha halys was recorded once in 2017 and 2018, 5 times in 2019 and 35 times in 2020. In recent years, the number of observations of H. halys has increased dramatically. In 2021, 183 observations were recorded, followed by a substantial increase to 515 in 2022. Up until November 2023, the Belgian public citizen database reported more than 2200 observations, a more than tenfold increase compared to 2021. From the occurrences of H. halys in 2020–2022, most of the observations were made in northern Belgium, mainly around the urban areas of the cities of Gent, Leuven, and Mechelen and the region of Haspengouw (Fig. 2a–c).

Figure 2.

Map of Belgium with recorded occurrences of H. halys in A 2020 B 2021, and C 2022. Each dot is an individual record, and density clouds indicate the level of density of occurrences in one area.


This study uncovered 9 COI, 5 COII and 12 COI-COII distinct haplotypes from 99 H. halys specimens collected in Belgium. Among these, two new COI-COII haplotype combinations (H03h11 and H08h21), currently unique to Belgium, were observed.

The principal COI haplotypes present in Belgium were H01 (33%), H08 (24%) and H03 (23%). H01 and H03 are the most frequent haplotypes in China and in most invaded countries (Gariepy et al. 2014; Valentin et al. 2017; Cesari et al. 2018; Lee et al. 2018; Yan et al. 2021; Gariepy et al. 2021). As such, their presence in Belgium is to be expected and therefore does not help to determine the origin of H. halys in Belgium. Interestingly, however, H08 is the second most abundant haplotype in Belgium. So far, this haplotype has been exclusively detected in certain European countries: Austria, France, Italy, Switzerland and Serbia (Valentin et al. 2017; Cesari et al. 2018; Gariepy et al. 2021; Yan et al. 2021). This suggests that at least part of the H. halys population in Belgium originates from previously invaded territories in Europe (i.e., bridgehead effect; Lombaert et al. 2010). Remarkably, eight out of the nine COI haplotypes found in Belgium are shared with Italy. Furthermore, half of these haplotypes were reported exclusively in these two countries (H40c, H41c, H42c and H49c) suggesting that Italy is a direct region of origin of H. halys in Belgium. The rare H23 haplotype was only found once in Belgium and has been reported in Japan and the Western USA (Oregon) (Valentin et al. 2017). It was also detected in a shipment in Australia originating from Italy, suggesting that the H23 haplotype is also present in Italy (Horwood et al. 2019; Gariepy et al. 2021). Introductions may thus have originated from Japan or the USA in addition to Italy.

For the COII fragment, h01, h03 and h11 each accounted for 32% of the abundance. The h01 and h03 haplotypes are native to China and Korea (but have not been reported in Japan yet) and are the most frequent COII haplotypes in invaded countries (Xu et al. 2014; Cesari et al. 2018; Yan et al. 2021). The distribution of the h11 COII haplotype is more restricted and has only been reported in Austria, Italy, Japan, and Korea (Xu et al. 2014; Cesari et al. 2018; Yan et al. 2021). Consistent with Italy as a source of H. halys for Belgium, the h21 haplotype was isolated from two specimens collected in Belgium and is only shared with Italy (Cesari et al. 2018).

In this study, the combination of COI and COII fragments did not result in a significantly better geographic resolution to reveal possible origins of the invasion. However, the presence of haplotype H03h21 provides some additional support for Italy as a source of the invasion since this combination is only shared with a sample from the Piedmont region of Italy (Cesari et al. 2018). Additionally, the inclusion of the COII fragment in this study revealed two novel haplotype combinations unique to Belgium: H08h21 and H03h11. The former is likely to originate from Italy since haplotype h21 has been exclusively reported there (Piedmont region, same sample as for H03h21), while H08 has been detected multiple times (Piedmont and Lombardy regions of Italy). H03h11 is more singular because it combines a COI haplotype native to China (H03) and a COII haplotype native to Korea or Japan (h11; see above). Such a combination could arise from recent COI or COII mutations. H03 is only two substitutions from the closest COI haplotype native to Japan (H27), and h11 is only one substitution from three COII haplotypes native to China (h03, h05 and h10). Alternatively, this combination could also exist in the regions of origin (China and/or Japan/Korea) but has not yet been sampled. Belgium’s dominant haplotypes generally overlap with those from previously invaded European countries, such as Italy, Switzerland, Austria, and Hungary. In contrast, rarer haplotypes are exclusively shared with Italy and its native region of Japan (H23).

The genetic diversity found in Belgium is surprisingly high (Hd = 0.79, π = 0.0018, N = 95) compared to other invaded countries previously studied (Table 2), several distinct haplotypes were isolated from single sampling sites (Suppl. material 1). A reduced genetic diversity is usually expected for introduced species because of a limited number of founders associated with early genetic drift. However, genetic bottlenecks associated with introductions can be counteracted if many individuals are introduced at the same time or if repeated introductions occur (Dlugosch and Parker 2008). Similarly, Schuler et al. (2020) found a high haplotype diversity (Hd = 0.68, π = 0.0046, N = 156) in the H. halys population of South Tyrol in Northern Italy. The population in Tyrol was established by a secondary introduction from Eastern USA into the Emilia Romagna region of Italy and the spread of the founder population in Switzerland to the neighbouring countries. In contrast, Valentin et al. (2017) concluded that most invasive populations in North America and Europe were established from a direct introduction of H. halys from China with separate introductions into Eastern and Western USA and Canada, as well as into Switzerland and Greece. The high genetic diversity of H. halys populations in Belgium and the overlap of haplotypes with previously invaded European countries, such as Italy, Switzerland, Austria, and Hungary but also with Japan indicates that the Belgian populations probably originated from multiple invasions from already invaded European countries, mainly Italy, but also directly from Japan through inadvertent human-mediated transportation (often due to global trade of goods) (Valentin et al. 2017). The weak genetic structure detected by our Mantel test could be related to the recent local expansion of these genetically diverse clusters.

Previous studies have shown that citizen science provides valuable data to characterise the spread of H. halys (Maistrello et al. 2016; Stoeckli et al. 2020; Streito et al. 2021). From our data in Belgium, more H. halys observations are recorded in the nosrthern part of Belgium compared to the southern part of Belgium, with more urban areas than agricultural, forested, and rural areas. However, on a national scale, spatial biases are commonly associated with human population density, settlements, and road infrastructure (Kelling et al. 2015; Geldmann et al. 2016; Girardello et al. 2019. The bias towards urban areas in citizen-collected occurrence data and rising popularity of tools to make observations (e.g., smartphones) represents a challenge to infer true spatio-temporal patterns from our occurrence data (Bowler et al. 2022). Nevertheless, it also provides natural experimental gradients to examine the impacts of future environmental scenarios including climate change (Lahr et al. 2018). Urban areas are often seen as heat islands, offering more suitable refugia to survive winters or more favourable conditions throughout the seasons to develop and reproduce. Therefore, these urbanised areas often comprise a larger population of insects (Kaiser et al. 2016; Frank and Backe 2023). According to Kistner (2017), the northern part of Belgium lies near the latitudinal border of the climate in Europe suitable for the winter survival and summer reproduction of H. halys. In contrast, the southern part of Belgium is currently modelled to be an unsuitable eco-climatic region for H. halys, with colder summer and winter temperatures and fewer refugia to survive winter due to the lower urbanisation (Kistner 2017). Niche modelling through climate suitability by Streito et al. (2021) essentially confirms this, with the northern part of Belgium having more suitable areas for H. halys while the southern part is more marginal to unsuitable for its survival and expansion. Despite the possibility of spatio-temporal bias in our occurrence data, some temporal trends can still be derived from citizen-collected occurrence data (Powney et al. 2019; Outhwaite et al. 2020; Sheard et al. 2021; Zattara and Aizen 2021; Bowler et al. 2022). Our observational data shows an almost fifteenfold increase in observations from 2020 to 2022. However, to date, no damage related to H. halys has been reported in agricultural production in Belgium (Berteloot et al. 2021). Based on the occurrence data, it is likely that the population expansion of H. halys in Belgium is very recent, as a relatively high number of observations were only made in 2021, 2022 and 2023. Streito et al. (2021) define three main phases in the invasion of H. halys: (1) the very beginning of the invasion, when populations of H. halys are low, and naturalists and official monitoring services who are excellent observers and expecting the emergence of H. halys can detect its presence, (2) when abundance increases, non-naturalist citizens are able to detect the species and start to provide information on the dynamics of the invasion and indirectly on the level of populations through citizen science platforms, and (3) when populations have expanded and become large enough, agricultural professionals take over and can predict and assess the population density and damages. From our occurrence data, the H. halys population in Belgium is seemingly under expansion, being numerously recorded in the citizen science databases.

Lastly, the univoltine H. halys population in Belgium likely expands in the summer and declines in the winter in current climatic conditions due to Belgium being situated at the northern latitudinal border of climatic suitability for H. halys, with winters cold enough to kill more individuals than winter temperatures in southern European countries like Italy, possibly delaying the fast expansion of its populations. However, both parts of Belgium are modelled to be suitable for the survival and development of H. halys by 2100 (Kistner 2017).


The results of this study provide haplotype information for H. halys from a newly invaded region. The haplotype diversity in Belgium is surprisingly high, with 9 COI, 5 COII and 12 COI-COII haplotypes found. The invasion of H. halys in Belgium likely occurred repeatedly and is assumed to be still ongoing through human-mediated transportation from other invaded European countries and directly from its native regions in Eastern Asia. A significant overlap between Belgian and Italian haplotypes points to Italy as the most probable source for a significant proportion of haplotypes currently present in Belgium. By combining the citizen-collected occurrence data with the molecular data, we assume the population expansion of H. halys is recent and ongoing.


This research was in part supported by funds from VLAIO (Flanders Innovation and Entrepreneurship) through LA-traject HBC.2018.2224 (“SOS Penta”) and by the DATAPESTFRU project (RI 2020-A340) funded by the Belgian Federal Public Service (FPS) Health, Food Chain Safety and Environment. We thank Stéphane Claerebout for providing us one sample collected in 2018 in Mouscron.


  • Aukema B, Bieman den K, Lommen G, Maat van de G, Troisfontaine L, Vossen P (2019) Nieuwe en interessante nederlandse Wantsen VI (Hemiptera: Heteroptera). Nederlandse Faunistische Mededelingen 46: 57–86.
  • Berteloot OH, Vervaet L, Huayan C, Talamas EJ, Van Leeuwen T, De Clercq P (2021) First record in Belgium of Trissolcus basalis (Hymenoptera, Scelionidae), an egg parasitoid of economically important stink bugs (Hemiptera, Pentatomidae). Belgian Journal of Zoology 151: 139–148.
  • Bowler DE, Callaghan CT, Bhandari N, Henle K, Barth MB, Koppitz C, Klenke R, Winter M, Bruelheide H, Bonn A (2022) Temporal trends in the spatial bias of species occurrence records. Ecography 8(8): e06219.
  • Bras A, Avtzis DN, Kenis M, Li H, Vétek G, Bernard A, Courtin C, Rousselet J, Roques A, Auger-Rozenberg M-A (2019) A complex invasion story underlies the fast spread of the invasive box tree moth (Cydalima perspectalis) across Europe. Journal of Pest Science 92(3): 1187–1202.
  • Bulgarini G, Badra Z, Leonardi S, Maistrello L (2020) The predatory ability of generalist predators on eggs, young nymphs and adults of the invasive Halyomorpha halys in southern Europe. BioControl 66(3): 355–366.
  • Cesari M, Maistrello L, Ganzerli F, Dioli P, Rebecchi L, Guidetti R (2015) A pest alien invasion in progress: Potential pathways of origin of the brown marmorated stink bug Halyomorpha halys populations in Italy. Journal of Pest Science 88(1): 1–7.
  • Cesari M, Maistrello L, Piemontese L, Bonini R, Dioli P, Lee W, Park C, Partsinevelos GK, Rebecchi L, Guidetti R (2018) Genetic diversity of the brown marmorated stink bug Halyomorpha halys in the invaded territories of Europe and its patterns of diffusion in Italy. Biological Invasions 20(4): 1073–1092.
  • Claerebout S, Haye T, Olafsson E, Pannier E, Bultot J (2018) Premières occurrences de Halyomorpha halys (Stål, 1855) pour la Belgique et actualisation de sa répartition en Europe (Hemiptera: Heteroptera: Pentatomidae). Bulletin de la Société Royale Belge d’Entomologie 154: 205–227.
  • Cristescu ME (2016) Genetic reconstructions of invasion history. In: Barret SCH, Colautti RI, Dlugosch KM, Rieseberg LH (Eds) Invasion Genetics. John Wiley & Sons, Ltd., Chichester, 267–282.
  • Faúndez EI, Rider DA (2017) The brown marmorated stink bug Halyomorpha halys (Stål, 1855) (Heteroptera: Pentatomidae) in Chile. Arquivos Entomolóxicos, 305–307.
  • Folmer O, Black M, Hoeh W, Vrijenhoek R (1994) DNA primers for amplification of mitochondrial cytochrome c oxidase subunit I from diverse metazoan invertebrates. Molecular Marine Biology and Biotechnology 3(5): 294–299.
  • Gapon DA (2016) First records of the brown marmorated stink bug Halyomorpha halys (Stål, 1855) (Heteroptera, Pentatomidae) in Russia, Abkhazia, and Georgia. Entomological Review 96(8): 1086–1088.
  • Gariepy TD, Haye T, Fraser H, Zhang J (2014) Occurrence, genetic diversity, and potential pathways of entry of Halyomorpha halys in newly invaded areas of Canada and Switzerland. Journal of Pest Science 87(1): 17–28.
  • Gariepy TD, Musolin DL, Konjević A, Karpun NN, Zakharchenko VY, Zhuravleva EN, Tavella L, Bruin A, Haye T (2021) Diversity and distribution of cytochrome oxidase I (COI) haplotypes of the brown marmorated stink bug, Halyomorpha halys Stål (Hemiptera, Pentatomidae), along the eastern front of its invasive range in Eurasia. NeoBiota 68: 53–77.
  • Geldmann J, Heilmann-Clausen J, Holm TE, Levinsky I, Markussen B, Olsen K, Rahbek C, Tøttrup AP (2016) What determines spatial bias in citizen science? Exploring four recording schemes with different proficiency requirements. Biodiversity Research 22(11): 1139–1149.
  • Güncan A, Gümüş E (2019) Brown marmorated stink bug, Halyomorpha halys (Stål, 1855) (Hemiptera: Heteroptera, Pentatomidae), a new and important pest in Turkey. Entomological News 128(2): 204–210.
  • Hamelin RC, Roe AD (2019) Genomic biosurveillance of forest invasive alien enemies: A story written in code. Evolutionary Applications 13(1): 95–115.
  • Hamilton GC, Ahn JJ, Bu W, Leskey TC, Nielsen AL, Park YL, Rabitsch W, Hoelmer KA (2018) Halyomorpha halys (Stål). In: McPherson JE (Ed.) Invasive Stink Bugs and Related Species (Pentatomoidea): Biology, Higher Systematics, Semiochemistry, and Management. CRC Press, Taylor & Francis, Boca Raton, 243–292.
  • Hartung V, Heller M, Husemann M (2022) First record of the invasive true bug (Heteroptera) Halyomorpha halys (Stål, 1855) from Hamburg with other records from Northern Germany and possible implications for its range expansion. Evolutionary Systematics 6(1): 57–64.
  • Haye T, Gariepy T, Hoelmer K, Rossi J-P, Streito J-C, Tassus X, Desneux N (2015) Range expansion of the invasive brown marmorated stinkbug, Halyomorpha halys: An increasing threat to field, fruit and vegetable crops worldwide. Journal of Pest Science 88(4): 665–673.
  • Hoebeke ER, Carter ME (2003) Halyomorpha halys (Stål) (Heteroptera: Pentatomidae): a polyphagous plant pest from Asia newly detected in North America. Proceedings of the Entomological Society of Washington 105: 225–237.
  • Horwood M, Milnes JM, Cooper WR (2019) Brown marmorated stink bug, Halyomorpha halys (Hemiptera: Pentatomidae), detections in Western Sidney, New South Wales, Australia. Austral Entomology 58(4): 857–865.
  • Kaiser A, Merckx T, Van Dyck H (2016) The Urban Heat Island and its special scale dependent impact on survival and development in butterflies of different thermal sensitivity. Ecology and Evolution 6(12): 4129–4140.
  • Kapantaidaki DE, Evangelou VI, Morrison WR III, Leskey TC, Brodeur J, Milonas P (2019) Halyomorpha halys (Hemiptera: Pentatomidae) Genetic diversity in North America and Europe. Insects 10(6): e174.
  • Kelling S, Fink D, La Sorte FA, Johnston A, Bruns NE, Hochachka WM (2015) Taking a ‘Big Data’ approach to data quality in a citizen science project. Ambio 44(S4): 601–611.
  • Kistner EJ (2017) Climate change impacts on the potential distribution and abundance of the brown marmorated stink bug (Hemiptera: Pentatomidae) with special reference to North America and Europe. Environmental Entomology 46(6): 1212–1224.
  • Kuhar TP, Kamminga KL, Whalen J, Dively GP, Brust G, Hooks CRR, Hamilton G, Herbert DA (2012) The pest potential of brown marmorated stink bug on vegetable crops. Plant Health Progress 13(1): 1–41.
  • Lahr EC, Dun RR, Frank SD (2018) Getting ahead of the curve: Cities as surrogates for global change. Proceedings of the Royal Society B, Biological Sciences 285(1882): e20180643.
  • Lee D-H, Short BD, Joseph SV, Bergh JC, Leskey TC (2013) Review of the biology, ecology, and management of Halyomorpha halys (Hemiptera: Pentatomidae) in China, Japan, and the Republic of Korea. Environmental Entomology 42(4): 627–641.
  • Lee W, Guidetti R, Cesari M, Gariepy TD, Park Y-L, Park C-G (2018) Genetic diversity of Halyomorpha halys (Hemiptera, Pentatomidae) in Korea and Comparison with COI sequence datasets from East Asia, Europe, and North America. The Florida Entomologist 101(1): 49–54.
  • Leskey TC, Hamilton GC, Nielsen AL, Polk DF, Rodriguez SC, Bergh JC, Herbert DA, Kuhar TP, Pfeiffer D, Dively GP, Hooks CRR, Raupp MJ, Shrewsbury PM, Krawczyk G, Shearer PW, Whalen J, Koplinka LC, Myers E, Inkley D, Hoelmer KA, Lee D-H, Wright SE (2012) Pest status of the brown marmorated stink bug, Halyomorpha halys in the USA. Outlooks on Pest Management 23(5): 218–226.
  • Lombaert E, Guillemaud T, Comuet J-M, Malausa T, Facon B, Estoup A (2010) Bridgehead effect in the worldwide invasion of the biocontrol harlequin ladybird. PLoS ONE 5(3): e9743.
  • Macavei LI, Baetan R, Oltean I, Florian T, Varga M, Costi E, Maistrello L (2015) First detection of Halyomorpha halys Stål, a new invasive species with a high potential of damage on agricultural crops in Romania. Lucrări Ştiinţifice 58: e2015.
  • Maistrello L, Dioli P, Vaccari G, Nannini R, Bortolotti P, Caruso S, Costi E, Montermini A, Casoli L, Bariselli M (2014) Primi rinvenimenti in Italia della cimice esotica Halyomorpha halys, una nuova minaccia per la frutticoltura. Giornate Fitopatologiche 1: 283–288.
  • Maistrello L, Dioli P, Bariselli M, Mazzoli GL, Giacalone-Forini L (2016) Citizen science and early detection of invasive species: Phenology of first occurrences of Halyomorpha halys in Southern Europe. Biological Invasions 18(11): 3109–3116.
  • Milonas PG, Partsinevelos GK (2014) First report of brown marmorated stink bug Halyomorpha halys Stål (Hemiptera: Pentatomidae) in Greece. Bulletin OEPP. EPPO Bulletin. European and Mediterranean Plant Protection Organisation 44(2): 183–186.
  • Observation International and local partners (2022) Observation International and local partners [ dataset Halyomorpha halys]. [retrieved June 5, 2023, from]
  • Outhwaite CL, Gregory RD, Chandler RE, Collen B, Isaac NJB (2020) Complex long-term biodiversity change among invertebrates, bryophytes and lichens. Nature Ecology & Evolution 4(3): 384–392.
  • Powney GD, Carvell C, Edwards M, Morris RKA, Roy HE, Woodcock BA, Isaac NJB (2019) Widespread losses of pollinating insects in Britain. Nature Communications 10(1): e1018.
  • QGIS Development Team (2023) QGIS Geographic Information System. Open Source Geospatial Foundation Project.
  • R Core Team (2020) R: A Language and Environment for statistical Computing. R Foundation for Statistical Computing, Vienna.
  • Rabitsch W, Friebe G (2015) From the west and from the east? First records of Halyomorpha halys (Stål, 1855) (Hemiptera: Heteroptera: Pentatomidae) in Vorarlberg and Vienna, Austria. Beiträge zur Entomofaunistik 16: 115–139.
  • Rice KB, Bergh CJ, Bergmann EJ, Biddinger DJ, Dieckhoff C, Dively G, Fraser H, Gariepy T, Hamilton G, Haye T, Herbert A, Hoelmer K, Hooks CR, Jones A, Krawczyk G, Kuhar T, Martinson H, Mitchell W, Nielsen AL, Pfeiffer DG, Raupp MJ, Rodriguez-Saona C, Shearer P, Shrewsbury P, Venugopal PD, Whalen J, Wiman NG, Leskey TC, Tooker JF (2014) Biology, ecology, and management of brown marmorated stink bug (Hemiptera: Pentatomidae). Journal of Integrated Pest Management 5(3): 1–13.
  • Rollins LA, Woolnough AP, Sinclair R, Mooney NJ, Sherwin WB (2011) Mitochondrial DNA offers unique insights into invasion history of the common starling: Mitochondrial DNA in invasive populations. Molecular Ecology 20(11): 2307–2317.
  • Rot M, Devetak M, Carlevaris B, Žežlina J, Žežlina I (2018) First record of brown marmorated stink bug (Halyomorpha halys Stål, 1855) (Hemiptera: Pentatomidae) in Slovenia. Acta Entomologica Slovenica 26: 5–12.
  • Ryan SF, Lombaert E, Espeset A, Vila R, Talavera G, Dincă V, Doellman MM, Renshaw MA, Eng MW, Hornett EA, Li Y, Pfrender ME, Shoemaker D (2019) Global invasion history of the agricultural pest butterfly Pieris rapae revealed with genomics and citizen science. Proceedings of the National Academy of Sciences of the United States of America 116(40): 20015–20024.
  • Schuler H, Elser D, Fischnaller S (2020) Population genetics of the brown marmorated stink bug Halyomorpha halys in the early phase of invasion in South Tyrol (Northen Italy). Bulletin of Entomological Research 111(4): 394–401.
  • Šeat J (2015) Halyomorpha halys (Stål, 1855) (Heteroptera: Pentatomidae) a new invasive species in Serbia. Acta Entomologica Serbica 20: 167–171.
  • Sheard JK, Rahbek C, Dunn RR, Sanders NJ, Isaac NJB (2021) Long-term trends in the occupancy of ants revealed through use of multi-sourced datasets. Biology Letters 17(10): e20210240.
  • Stoeckli S, Felber R, Haye T (2020) Current distribution and voltinism of the brown marmorated stink bug, Halyomorpha halys, in Switzerland and its response to climate change using a high-resolution CLIMEX model. International Journal of Biometeorology 64(12): 2019–2032.
  • Streito J-C, Chartois M, Pierre E, Dusoulier F, Armand J-M, Gaudin J, Rossi J-P (2021) Citizen science and niche modeling to track and forecast the expansion of the brown marmorated stinkbug Halyomorpha halys (Stål, 1855). Scientific Reports 11(1): e11421.
  • Valentin RE, Nielsen AL, Wiman NG, Lee D-H, Fonseca DM (2017) Global invasion network of the brown marmorated stink bug, Halyomorpha halys. Scientific Reports 7(1): e9866.
  • Vétek G, Papp V, Haltrich A, Rédei D (2014) First record of the brown marmorated stink bug, Halyomorpha halys (Hemiptera: Heteroptera: Pentatomidae), in Hungary, with description of the genitalia of both sexes. Zootaxa 3780: 194–200.
  • Walsh PS, Metzger DA, Higuchi R (1991) Chelex 100 as a medium for simple extraction of DNA for PCR-based typing from forensic material. BioTechniques 10: 506–513.
  • Xu J, Fonseca DM, Hamilton GC, Hoelmer KA, Nielsen AL (2014) Tracing the origin of US brown marmorated stink bugs, Halyomorpha halys. Biological Invasions 16(1): 153–166.
  • Yan J, Pal C, Anderson D, Vétek G, Farkas P, Burne A, Fan Q-H, Zhang J, Gunawardana DN, Balan RK, George S, Li D (2021) Genetic diversity analysis of brown marmorated stink bug, Halyomorpha halys based on mitochondrial COI and COII haplotypes. BMC Genomic Data 22(1): 1–7.
  • Zhu G-P, Ye Z, Du J, Zhang D-L, Zhen Y, Zheng C, Zhao L, Li M, Bu W-J (2016) Range wide molecular data and niche modeling revealed the Pleistocene history of a global invader (Halyomorpha halys). Scientific Reports 6(1): e23192.

Supplementary material

Supplementary material 1 

Metadata of all samples

Olivier Hendrik Berteloot, Alexandre Kuhn

Data type: csv

This dataset is made available under the Open Database License ( The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.
Download file (12.50 kb)
login to comment