Host Plant Availability Research Articles

Environmental stress during larval development induces DNA methylation shifts in the migratory painted lady butterfly (Vanessa cardui).

Seasonal environmental fluctuations provide formidable challenges for living organisms, especially small ectotherms such as butterflies. A common strategy to cope with harsh environments is to enter diapause, but some species avoid unsuitable conditions by migrating. Despite a growing understanding of migration in the life cycles of some butterfly species, it remains unknown how individuals register and store environmental cues to determine whether and where to migrate. Here, we explored how competition and host plant availability during larval development affect patterns of DNA methylation in the migratory painted lady (Vanessa cardui) butterfly. We identify a set of potentially functional methylome shifts associated with differences in the environment, indicating that DNA methylation is involved in the response to different conditions during larval development. By analysing the transcriptome for the same samples used for methylation profiling, we also uncovered a non-monotonic relationship between gene body methylation and gene expression. Our results provide a starting point for understanding the interplay between DNA methylation and gene expression in butterflies in general and how differences in environmental conditions during development can trigger unique epigenetic marks that might be important for behavioural decisions in the adult stage.

Climate change, host plant availability, and irrigation shape future region-specific distributions of the Sitobion grain aphid complex.

Understanding where species occur using species distribution models has become fundamental to ecology. Although much attention has been paid to invasive species, questions about climate change related range shifts of widespread insect pests remain unanswered. Here, we incorporated bioclimatic factors and host plant availability into CLIMEX models to predict distributions under future climate scenarios of major cereal pests of the Sitobion grain aphid complex (Sitobion avenae, S. miscanthi, and S. akebiae). Additionally, we incorporated the application of irrigation in our models to explore the relevance of a frequently used management practice that may interact with effects of climate change of the pest distributions. Our models predicted that the area potentially at high risk of outbreaks of the Sitobion grain aphid complex would increase from 41.3% to 53.3% of the global land mass. This expansion was underlined by regional shifts in both directions: expansion of risk areas in North America, Europe, most of Asia, and Oceania, and contraction of risk areas in South America, Africa, and Australia. In addition, we found that host plant availability limited the potential distribution of pests, while the application of irrigation expanded it. Our study provides insights into potential risk areas of insect pests and how climate, host plant availability, and irrigation affect the occurrence of the Sitobion grain aphid complex. Our results thereby support agricultural policy makers, farmers, and other stakeholders in their development and application of management practices aimed at maximizing crop yields and minimizing economic losses. © 2023 Society of Chemical Industry.

Pest categorisation of Eotetranychus sexmaculatus

The EFSA Panel on Plant Health performed a pest categorisation of Eotetranychus sexmaculatus (Acari: Tetranychidae), the six-spotted spider mite, for the EU. The mite is native to North America and has spread to Asia and Oceania. It is not known to occur in the EU. The species is not listed in Annex II of Commission Implementing Regulation (EU) 2019/2072. E. sexmaculatus feeds on more than 50 hosts in 20 botanical families and can be a serious pest of important crops in the EU such as citrus (Citrus spp.), avocado (Persea americana), grapevine (Vitis spp.) and ornamentals such as Ficus spp. and Rosa spp. In California and New Zealand, the mite can breed continuously on evergreen hosts such as avocados and citrus, growing slowly during the winter and faster during the summer. Dry weather conditions hamper its development. Plants for planting, fruit, cut branches and cut flowers provide potential pathways for entry into the EU. Some host plants for planting are prohibited from entering the EU while others require a phytosanitary certificate, as do cut branches and cut flowers. In the warmer parts of southern EU Member States, climatic conditions and host plant availability are conducive for establishment and spread. The introduction of E. sexmaculatus is expected to have an economic impact in the EU through the reduction in yield, quality and commercial value of citrus and avocado production. Additional damage on other host plants, including ornamentals, under EU environmental conditions and cropping practices cannot be ruled out. Phytosanitary measures are available to reduce the likelihood of entry and spread. E. sexmaculatus satisfies with no key uncertainties the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

Pest categorisation of Pantoea ananatis.

The EFSA Plant Health Panel performed a pest categorisation of Pantoea ananatis, a Gram-negative bacterium belonging to the Erwiniaceae family. P.ananatis is a well-defined taxonomic unit; nonetheless, its pathogenic nature is not well defined and non-pathogenic populations are known to occupy several, very different environmental niches as saprophytes, or as plant growth promoting bacteria or biocontrol agents. It is also described as a clinical pathogen causing bacteraemia and sepsis or as a member of the gut microbiota of several insects. P.ananatis is the causal agent of different diseases affecting numerous crops: in particular, centre rot of onion, bacterial leaf blight and grain discoloration of rice, leaf spot disease of maize and eucalyptus blight/dieback. A few insect species have been described as vectors of P. ananatis, among them, Frankliniella fusca and Diabrotica virgifera virgifera. This bacterium is present in several countries in Europe, Africa, Asia, North and South America, and Oceania from tropical and subtropical regions to temperate areas worldwide. P.ananatis has been reported from the EU territory, both as pathogen on rice and maize and as an environmental, non-pathogenic bacterium in rice marshes and poplar rhizosoil. It is not included in EU Commission Implementing Regulation 2019/2072. The pathogen can be detected on its host plants using direct isolation, or PCR-based methods. The main pathway for the entry of the pathogen into the EU territory is host plants for planting, including seeds. In the EU, there is a large availability of host plants, with onion, maize, rice and strawberry being the most important ones. Therefore, disease outbreaks are possible almost at any latitude, except in the most northern regions. P.ananatis is not expected to have frequent or consistent impact on crop production and is not expected to have any environmental impact. Phytosanitary measures are available to mitigate the further introduction and spread of the pathogen into the EU on some hosts. The pest does not satisfy the criteria, which are within the remit for EFSA to evaluate whether the pest meets the definition of a Union quarantine pest. P.ananatis is probably widely distributed in different ecosystems in the EU. It may impact some specific hosts such as onions while on other hosts such as rice it has been reported as a seed microbiota without causing any impact and can even be beneficial to plant growth. Hence, the pathogenic nature of P. ananatis is not fully established.

The Effectiviness of Hormone Growth Promoting Fertilizers on Increasing The Production of Arbuscular Mycorrhizal Fungi Spores

Arbuscular Mycorrhizal Fungi (AMF) is one of the fungi that forms a mutualism symbiosis with plants where there is a mutually beneficial relationship between the two parties and acts as a biological fertilizer that needs to be reproduced.AMF propagation is strongly influenced by the availability of nutrients, growing media and host plants. The purpose of this study was to determine the application of hormone growth booster fertilizer to increase the production of arbuscular mycorrhizal fungi spores.This research was conducted at the Plastic House of the Indonesian Mycorrhizal Association (AMI) Southeast Sulawesi Branch and the Laboratory of the Department of Forestry, Faculty of Forestry and Environmental Sciences, Halu Oleo University, Kendari during September – November 2022.This study was arranged based on a Completely Randomized Factorial Design. which consists of 2 factors. The first factor: AMF type which consists of two levels, namely Glomus coronatum and Glomus claroideum. The second factor: Fertilizer application consisting of three levels, namely without fertilizer application (B0), 2, and 5 ml/pot fertilizer (B2) with 3 repetitions. So there are 18 treatment combinations. Each treatment unit contained 9 plants so that the total number of plants was 162 plants. The results of this study indicate that the interaction treatment of G. coronatum and G. claroideum without fertilizer application can give the best results in increasing the number of spores for 3 months and in the treatment of G. coronatum with a fertilizer dose of 2, 5 ml gave the best results for increasing the number of spores after drying. Treatment of G. claroideum with a dose of 5 ml of fertilizer gave the best results in increasing the number of spores after drying.

Pest categorisation of Milviscutulus mangiferae.

The EFSA Panel on Plant Health performed a pest categorisation of Milviscutulus mangiferae (Hemiptera: Sternorrhyncha: Coccidae), the mango shield scale, for the EU. The native range of M.mangiferae is uncertain. This species occurs widely in tropical and warmer subtropical regions throughout the world. Within the EU, the pest has been recorded in Italy in a greenhouse at the Botanical Garden of Padua on mango trees imported from Florida (USA); however, its establishment remains uncertain. It is not listed in Annex II of Commission Implementing Regulation (EU) 2019/2072. It is polyphagous, feeding on plant species belonging to more than 86 genera in more than 43 families including many crop and ornamental plants. It can be a serious pest of mango (Mangifera indica) and an occasional pest of a range of ornamental plants. Economically important crops in the EU such as citrus (Citrus spp.), avocado (Persea americana) and ornamentals such as hibiscus (Hibiscus spp.) and myrtle (Myrtus communis), are included in the host list of M. mangiferae. Reproduction of M.mangiferae is generally parthenogenetic and it completes two to three generations annually. Plants for planting, cut flowers and fruits provide potential pathways for entry into the EU. Climatic conditions in southern EU countries and host plant availability in those areas are conducive for establishment and spread. Establishment could also occur in heated greenhouses in cooler areas of the EU. The introduction of the mango shield scale is expected to have an economic impact in the EU through the reduction in yield, quality and commercial value of fruits and ornamental plants. Phytosanitary measures are available to reduce the likelihood of entry and further spread. M. mangiferae meets the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

Phenology of the black bean aphid, Aphis fabae, on organic crops and effect of parasitoid communities

The data that support the findings of this study is available in the Mendeley Data repository: https://DOI: 10.17632/wnvt4grz9d.1.

Interspecific differences in microhabitat use expose insects to contrasting thermal mortality

AbstractEcotones linking open and forested habitats contain multiple microhabitats with varying vegetal structures and microclimatic regimes. Ecotones host many insect species whose development is intimately linked to the microclimatic conditions where they grow (e.g., the leaves of their host plants and the surrounding air). Yet microclimatic heterogeneity at these fine scales and its effects on insects remain poorly quantified for most species. Here we studied how interspecific differences in the use of microhabitats across ecotones lead to contrasting thermal exposure and survival costs between two closely‐related butterflies (Pieris napiandP. rapae). We first assessed whether butterflies selected different microhabitats to oviposit and quantified the thermal conditions at the microhabitat and foliar scales. We also assessed concurrent changes in the quality and availability of host plants. Finally, we quantified larval time of death under different experimental temperatures (thermal death time [TDT] curves) to predict their thermal mortality considering both the intensity and the duration of the microclimatic heat challenges in the field. We identified six processes determining larval thermal exposure at fine scales associated with butterfly oviposition behavior, canopy shading, and heat and water fluxes at the soil and foliar levels. Leaves in open microhabitats could reach temperatures 3–10°C warmer than the surrounding air while more closed microhabitats presented more buffered and homogeneous temperatures. Interspecific differences in microhabitat use matched the TDT curves and the thermal mortality in the field. Open microhabitats posed acute heat challenges that were better withstood by the thermotolerant butterfly,P. rapae, where the species mainly laid their eggs. Despite being more thermosensitive,P. napiwas predicted to present higher survivals thanP. rapaedue to the thermal buffering provided by their selected microhabitats. However, its offspring could be more vulnerable to host‐plant scarcity during summer drought periods. Overall, the different interaction of the butterflies with microclimatic and host‐plant variation emerging at fine scales and their different thermal sensitivity posed them contrasting heat and resource challenges. Our results contribute to setting a new framework that predicts insect vulnerability to climate change based on their thermal sensitivity and the intensity, duration, and accumulation of their heat exposure.

Pest categorisation of Nipaecoccus viridis.

The EFSA Panelon Plant Health performed a pest categorisation of Nipaecoccus viridis (Hemiptera: Sternorrhyncha: Pseudococcidae), the spherical scale, for the EU. It is of Asian origin and occurs widely in southern Asia, Africa and tropical Australia. It has been introduced to a few countries in the Americas. In the Mediterranean basin it is found in Algeria, Egypt, Israel, Syria and Turkey, where it is limited to the Marmara region. It has not been reported within the EU. It is not listed in Annex II of Commission Implementing Regulation (EU) 2019/2072. It reproduces sexually, has three generations each year in citrus orchards in South Africa, and all stages can overwinter. First instar nymphs may move to neighbouring plants by crawling or be passively dispersed by wind or hitchhiking on clothing, equipment or animals. It is highly polyphagous, feeding on plants in 115 genera and 46 families. It is an important pest of citrus (Citrus spp.), cotton (Gossypium spp.), mango (Mangifera indica), avocado (Persea americana) and stored potatoes (Solanum tuberosum). It also feeds on a wide range of other fruit (apple Malus domestica, olive Olea europea, pear Pyrus communis and grape Vitis vinifera) and vegetable crops (tomato Solanum lycopersicum), and ornamental plants (roses, Rosa spp.) that are widely grown in the EU. Plants for planting, fruits, vegetables, and cut flowers are the main potential pathways for entry of N. viridis into the EU. Climatic conditions and availability of host plants in southern parts of the EU where there are few days of frost each year would likely allow this species to successfully establish and spread. Reductions in yield and quality of cultivated hosts including avocado, citrus, cotton and mango is anticipated if establishment occurs. Phytosanitary measures are available to reduce the likelihood of entry and spread. N. viridis meets the criteria that are within the remit of EFSA to assess for this species to be regarded as a potential Union quarantine pest.

Pest categorisation of Icerya aegyptiaca.

The EFSA Panelon Plant Health performed a pest categorisation of Icerya aegyptiaca (Hemiptera: Sternorrhyncha: Monophlebidae), the Egyptian fluted scale, for the EU. This insect is established in several countries in tropical and subtropical regions of the world. Within the EU, the pest has not been reported. It is not listed in Annex II of Commission Implementing Regulation (EU) 2019/2072. It is highly polyphagous, feeding on plants in 128 genera and 66 families, with some preference for avocado (Persea americana), banana (Musa sp.), citrus (Citrus spp.), coconut (Coccos nucifera), common pear (Pyrus communis), fig (Ficus spp.), guava (Psidium guajava), maize (Zea mays), mango (Mangifera indica), white mulberry (Morus alba), and grapevine (Vitis vinifera). It has also been recorded feeding on tomato (Solanum lycopersicum), as well as on ornamental plants. Plants for planting and fruits, vegetables and cut flowers are the main potential pathways for entry of I. aegyptiaca into the EU. Climatic conditions and availability of host plants in parts of the EU where there are very few days of frost each year would likely allow this species to successfully establish and spread. Economic impact in cultivated hosts including citrus, grapes, maize, peppers, sunflowers, tomatoes and ornamental crops is anticipated if establishment occurs. Phytosanitary measures are available to reduce the likelihood of entry and spread. I. aegyptiaca meets the criteria that are within the remit of EFSA to assess for this species to be regarded as a potential Union quarantine pest.

Assessing the Suitability of Chinese Cabbage as an Alternative Host for Spodoptera frugiperda (Lepidoptera: Noctuidae).

When the favored host of an herbivorous insect pest is absent, the availability of alternative host plants can maintain insect pest populations. Spodoptera frugiperda (Lepidoptera: Noctuidae) is a major invasive, polyphagous insect pest in China. To investigate the suitability of Chinese cabbage as an alternative host for S. frugiperda, oviposition preferences and life history traits were determined for S. frugiperda on Chinese cabbage, corn, and winter wheat over three generations. Results showed that S. frugiperda females preferred to lay their eggs on corn compared to winter wheat and Chinese cabbage. The survival rate of S. frugiperda decreased after switching from corn to Chinese cabbage, only 6% of individuals successfully pupated in the third generation. In addition, S. frugiperda reared on Chinese cabbage had lower pupal weight and fecundity. Winter wheat was a good host for S. frugiperda; although the survival rate decreased when S. frugiperda switched from corn to winter wheat in the parental generation, the survival rate increased over the next two generations to be as high as those reared on corn. Chinese cabbage is not a good long-term host for S. frugiperda, but it could maintain the pest population for at least two generations when more suitable host plants are unavailable. These results will inform management strategies for S. frugiperda.

Life‐stage‐related desiccation and starvation resistance in the biological control agent Neolema abbreviata

AbstractClimate variability in the tropics is partly associated with reduced and erratic precipitation, heat waves, and cold snaps thereby exerting abiotic environmental stressors to various arthropod species. For herbivorous insects, such extreme weather events may affect host plant quality and availability resulting in additional stressors such as desiccation and starvation. Neolema abbreviata Larcordaire (Coleoptera: Chrysomelidae) is a key biocontrol agent of Tradescantia fluminensis Vell. (Commelinaceae) and has recently been introduced in South Africa for management of its invasive host plant. However, it remains unknown how environmental stressors may influence its performance under anthropogenic climate change. Here, we investigated the effects of desiccation and starvation on performance of N. abbreviata larvae and adults and implications on biological control. Specifically, we measured desiccation and starvation resistance and critical thermal minima (CTmin) and maxima (CTmax) following stress. Desiccation and starvation pre‐treatment reduced both low (CTmin) and high (CTmax) temperature tolerance in both life stages albeit larvae were less cold tolerant and more heat tolerant than adults. In addition, resistance decreased with duration of exposure with desiccation resistance being higher in larvae than in adults, whereas the converse was true for starvation resistance. This indicates the challenges N. abbreviata may encounter when it faces environmental stressors in nature. Therefore, with projected climate change, this may potentially impact on its field establishment, spread, and effectiveness, thereby negatively influencing future classical biocontrol programs. Overall, the results provide valuable information in modelling potential distribution of N. abbreviata and developing sustainable management options of T. fluminensis under rapidly changing environments.

Archetype models upscale understanding of natural pest control response to land-use change.

Control of crop pests by shifting host plant availability and natural enemy activity at landscape scales has great potential to enhance the sustainability of agriculture. However, mainstreaming natural pest control requires improved understanding of how its benefits can be realized across a variety of agroecological contexts. Empirical studies suggest significant but highly variable responses of natural pest control to land-use change. Current ecological models are either too specific to provide insight across agroecosystems or too generic to guide management with actionable predictions. We suggest obtaining the full benefit of available empirical, theoretical, and methodological knowledge by combining trait-mediated understanding from correlative studies with the explicit representation of causal relationships achieved by mechanistic modeling. To link these frameworks, we adapt the concept of archetypes, or context-specific generalizations, from sustainability science. Similar responses of natural pest control to land-use gradients across cases that share key attributes, such as functional traits of focal organisms, indicate general processes that drive system behavior in a context-sensitive manner. Based on such observations of natural pest control, a systematic definition of archetypes can provide the basis for mechanistic models of intermediate generality that cover all major agroecosystems worldwide. Example applications demonstrate the potential for upscaling understanding and improving predictions of natural pest control, based on knowledge transfer and scientific synthesis. A broader application of this mechanistic archetype approach promises to enhance ecology's contribution to natural resource management across diverse regions and social-ecological contexts.

Pest categorisation of Pulvinaria psidii.

The EFSA Panel on Plant Health performed a pest categorisation of Pulvinaria psidii (Hemiptera: Coccidae), the green shield scale, for the EU. P. psidii was originally described from Hawaii on Psidium sp. and it is now established in many countries in tropical and subtropical regions of the world. Within the EU, the pest has been reported from mainland Spain and the Canary Islands. P. psidii is not listed in Annex II of Commission Implementing Regulation (EU) 2019/2072. It is highly polyphagous, feeding on 230 plant species belonging to more than 70 botanical families with preference for avocado (Persea americana), citrus (Citrus spp.), coffee (Coffea sp.), guava (Psidium guajava), litchi (Litchi chinensis), mango (Mangifera indica), mulberry (Morus sp.) and pomegranate (Punica granatum). It has also been recorded feeding on some solanaceous plants: tomato (Solanum lycopersicum) and pepper (Capsicum annuum), as well as on ornamental plants. Climatic conditions and availability of host plants in southern EU countries would most probably allow this species to successfully establish and spread. Economic impact in cultivated hosts including citrus, mangoes, mulberries, as well as vegetable and ornamental crops is anticipated if establishment occurs. Indeed, P. psidii has already been reported causing damage to Melia azedarach, a widely used ornamental tree that lines streets in Valencia. There is contradictory information regarding impact in mangoes in Spain. This could be due to the relatively recent establishment of the pest. Phytosanitary measures are available to reduce the likelihood of entry and further spread. P. psidii meets the criteria that are within the remit of EFSA to assess for this species to be regarded as a potential Union quarantine pest.

Pest categorisation of Tetraleurodes perseae.

The EFSA Panel on Plant Health performed a pest categorisation of Tetraleurodes perseae (Hemiptera: Aleyrodidae), the red‐banded whitefly, for the territory of the EU. T. perseae is a tropical and subtropical species that originated in the Neotropical region and has now spread and established in the USA (California and Florida), Israel and Lebanon. T. perseae is not listed in Commission Implementing Regulation (EU) 2019/2072. It is oligophagous on Lauraceae and most frequently reported on avocado (Persea americana), on which it is considered a minor or secondary pest. No evidence was found indicating damage to other plants. T. perseae larvae develop on the foliage and don’t attack the fruit. The number of generations per year varies between one and ten. High populations may promote the growth of black sooty moulds on the foliage and fruit, and adults feeding on the buds can lead to deformed immature leaves and premature leaf drop. However, T. perseae populations are usually effectively controlled by hymenopteran parasitoids, at least one of which (Cales noacki) is widespread in the EU. The producers of organic avocados in the EU could encourage the use of C. noacki, although occasional outbreaks of T. perseae could temporarily impact the fruit quality. Adults disperse naturally by flying and all stages can be moved over long distances by the trade of infested plant material. Plants for planting provide potential pathways for entry and spread in the EU. Climatic conditions and availability of host plants in southern EU countries are conducive for establishment. Phytosanitary measures are available to reduce the risk. T. perseae satisfies all of the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest. However, this conclusion has a high uncertainty regarding magnitude of potential impact as the insect is a minor and sporadic pest in its current area of distribution.

Pest categorisation of Oligonychus perseae.

The EFSA Panel on Plant Health performed a pest categorisation of Oligonychus perseae (Acari: Prostigmata: Tetranychidae), the persea mite, for the EU. O. perseae is a tropical species that originated in Mesoamerica and has now spread and established in California, Florida, Hawaii, Morocco, southern Europe and Israel. Within the EU, it is established in Italy, Portugal and Spain. O. perseae is not listed in Commission Implementing Regulation (EU) 2019/2072. It is polyphagous, feeding on plants in 20 genera in 17 families. It is most frequently reported on avocado (Persea americana), where it is considered a key pest. No evidence was found indicating damage to other crops. O. perseae live on leaves and do not attack the fruit. Populations usually grow exponentially at the beginning of summer and decline at the end of this season. High population densities can cause severe defoliation, resulting in downgrading of fruit through sunburn. However, this type of damage is common only if trees additionally suffer from water stress. The lack of additional avocado pests in the EU, which facilitates the production of organic avocados, is jeopardised by the occurrence of this mite, as it may require pesticide applications. This is why O. perseae is considered an important pest of avocados in Spain, where more than 80% of EU avocado production occurs. Natural dispersal is restricted to neighbouring trees. However, human‐assisted movement can result in long‐distance spread. Plants for planting provide potential pathways for further entry and spread, including O. perseae‐free EU MS where avocados are grown (i.e. Cyprus, France, Greece). Climatic conditions and availability of host plants in southern EU countries are conducive for establishment. Phytosanitary measures are available to reduce the likelihood of further entry and spread. O. perseae satisfies with no key uncertainties the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

Pest categorisation of Aulacaspis tubercularis.

The EFSA Panel on Plant Health performed a pest categorisation of Aulacaspis tubercularis (Hemiptera: Diaspididae), the white mango scale, for the EU. A. tubercularis is a tropical species that originates from Asia but is now established in several tropical and subtropical regions throughout the world. It also occurs within the EU and is established in Italy, Portugal and Spain. A. tubercularis is not listed in Commission Implementing Regulation (EU) 2019/2072. It is polyphagous, feeding on plants in more than 37 genera in 23 families and is most frequently reported on mango (Mangifera indica). Indeed, it is considered one of the key pests of mango crops around the world. No evidence was found indicating damage to crops other than mango. A. tubercularis is established in southern Spain (Andalusia) with four overlapping generations and two population peaks, one in summer and another in autumn. Andalusia is the main mango producing area of the EU and A. tubercularis can cause losses through downgrading of fruit. The main natural dispersal stage is the first instar, which crawls over the host plant or may be dispersed further by wind and animals. Plants for planting and fruits provide potential pathways for further entry and spread. Climatic conditions and availability of host plants in southern EU countries are conducive for establishment. Phytosanitary measures are available to reduce the likelihood of further entry and further spread. A. tubercularis satisfies the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

Larval parasitism in a specialist herbivore is explained by phenological synchrony and host plant availability.

Parasitism is a key factor in the population dynamics of many herbivorous insects, although its impact on host populations varies widely, for instance, along latitudinal and altitudinal gradients. Understanding the sources of geographical variation in host-parasitoid interactions is crucial for reliably predicting the future success of the interacting species under a context of global change. Here, we examine larval parasitism in the butterfly Aglais urticae in south-west Europe, where it is a mountain specialist. Larval nests were sampled over 2years along altitudinal gradients in three Iberian mountain ranges, including the Sierra Nevada, home to its southernmost European population. Additional data on nettle condition and adult butterflies were obtained in the study areas. These data sources were used to investigate whether or not differences in parasitism rates are related to the geographical position and phenology of the host, and to the availability of the host plants. Phenological differences in the host populations between regions were related to the severity of summer drought and the corresponding differences in host plant availability. At the trailing-edge of its distribution, the butterfly's breeding season was restricted to the end of winter and spring, while in its northern Iberian range the season was prolonged until mid-summer. Although parasitism was an important source of mortality in all regions, parasitism rates and parasitoid richness were highest in the north and lowest in the south. Moreover, within a region, there was a notable increase in parasitism rates over time, which probably led to selection against an additional late summer host generation in northern regions. Conversely, the shorter breeding season in Sierra Nevada resulted in a loss of synchrony between the host and one important late season parasitoid, Sturmia bella, which may partly explain the high density of this butterfly species at the trailing-edge of its range. Our results support the key role of host phenology in accounting for differences in parasitism rates between populations. They also provide insights into how climate through host plant availability affects host phenology and, ultimately, the impact of parasitism on host populations.

Roles of Heterogeneous Habitat for Conservation of Nymphalidae in Sarawak (East Malaysia)

Species diversity characterises an area or a targeted habitat and provides information on the species assemblages, which is a primary reflection of habitat diversity. It incorporates both species richness and abundance and may rely on factors, such as host-plant availability and food resources. Kubah National Park is a lowland mixed dipterocarp forest, and uniquely offers various vegetation types, which includes heath and submontane forests. In the present study, four contrasting forest habitats were selected along forest trails, namely, primary forests, secondary forests, heath forests and forest edges. Forty baited traps were used within a six-months of sampling period. The highest abundance was recorded at the heath forest while the least was at the secondary forest. However, there was no significant difference in terms of species abundance between forest habitats for subfamilies, as well as for the 15 most abundant nymphalid species sampled, except for Mycalesis mnasicles. This satyrine was regarded as being able to differentiate habitat, apart from sensitive to canopy openings. Secondary forest provides a heterogeneous habitat for nymphalids, and thus highest diversity was observed here. This study implies that habitat association of the family is crucial, as it will provide information for both species inventory as well as the fluctuation patterns of the nymphalids diversity. Similar study is suggested to be carried out in the future, which incorporates more than one habitat types and in a more extensive period.

Pest categorisation of Zaprionus indianus.

The EFSA Panel on Plant Health performed a pest categorisation of Zaprionus indianus (Diptera: Drosophilidae), the African fig fly for the territory of the EU. This species successfully colonised the Indian subcontinent more than four decades ago, and more recently South and North America. Within the EU, the pest occurs in Cyprus, Malta, Portugal (Madeira) and Spain (Canary Islands and Andalusia). Z. indianus is not listed in Annex II of Commission Implementing Regulation (EU) 2019/2072. The larvae of this fly feed on more than 80 plant species both cultivated and non‐cultivated. Females produce around 60–70 eggs. Egg laying mostly occurs in decaying fruit or fruit with injuries or mechanical damage. However, Z. indianus can oviposit on undamaged healthy fruit such as figs, strawberries and guavas which provide a potential pathway for entry into the EU. Lower temperature thresholds are around 9–10°C. Optimum development occurs at 28°C. The number of generations per year varies from 12 to 16. Climatic conditions in many EU member states and host plant availability in those areas are conducive for establishment. The introduction of Z. indianus is expected to have an economic impact in the EU especially on fig and strawberry production. Damage caused by other fruit flies (Drosophilidae and Tephritidae) could be increased by mixed infestations. Phytosanitary measures are available to reduce the likelihood of entry and further spread. Z. indianus satisfies all of the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.