Host Plant Availability Research Articles

Pest categorisation of Pseudococcus cryptus.

The EFSA Panel on Plant Health performed a pest categorisation of Pseudococcus cryptus Hempel (Hemiptera: Pseudococcidae), the citriculus mealybug, for the EU. P. cryptus originates from Southeast Asia but is now established in East Africa, the Middle East and South America. The pest is not currently known to occur in the EU (there was a record once, in 2006, in a zoo/botanical garden from southern Spain). P. cryptus is not listed in Commission Implementing Regulation (EU) 2019/2072. It is polyphagous, feeding on plants in more than 90 genera in 51 families, and exhibits a preference for citrus (Citrus spp.) and palms (especially Cocos nucifera, Elaeis guineensis and Areca catechu). It is an important pest of citrus in Japan and parts of the Middle East, although in Israel, it is controlled by natural enemies. It is sexually reproductive, has six overlapping generations each year in Israel, and each female lays up to approximately 150 eggs, depending on temperature and host species. 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, fruits, vegetables and cut flowers provide potential pathways for entry into the EU. Climatic conditions in EU member states around the Mediterranean Sea where there is host plant availability, especially citrus, are conducive for establishment. The introduction of P. cryptus is expected to have an economic impact in the EU through reduction in yield and quality of important crops (mainly citrus) and damage to various ornamental plants. Phytosanitary measures are available to reduce the likelihood of entry and further spread. P. cryptus 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 Sirex nitobei.

The EFSA Panel on Plant Health performed a pest categorisation of Sirex nitobei (Hymenoptera: Siricidae), the nitobe horntail, for the territory of the EU. S. nitobei is not listed in Annex II of Commission Implementing Regulation (EU) 2019/2072 but was identified as a potential regulated pest in a commodity risk assessment of Pinus thunbergii artificially dwarfed plants from Japan. This species is present in Japan (except Hokkaidō), the Republic of Korea and 13 Chinese provinces. S. nitobei attacks several Pinus species and has been reported less frequently on Abies firma and Larix spp., including L. leptolepis. The females oviposit into the sapwood. Eggs are deposited together with a phytotoxic mucus and a symbiotic fungus, Amylostereum areolatum or A. chailletii. The combined action of the venom and the fungus results in the death of the host trees. The fungus degrades the lignocellulosic components of the wood, and the larvae feed on the liquid fraction of the digested residues left by the fungus. All immature stages live in the hosts sapwood. The lifecycle of the pest lasts 1 year. S. nitobei can travel with conifer wood, wood packaging material or plants for planting, but these pathways from third countries are closed by prohibition. However, a derogation exists for artificially dwarfed Japanese black pine (Pinus thunbergii) from Japan, which therefore provides a potential pathway. Climatic conditions in several EU member states and host plant availability in those areas are conducive for establishment. The introduction of S. nitobei is potentially damaging for pines. Phytosanitary measures are available to reduce the likelihood of entry and further spread, and there is a potential for biological control. S. nitobei satisfies all the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

Butterfly diversity in the village Banihari, District Dakshin Dinajpur, West Bengal, India

The aim of the present investigation was determine the butterfly diversity in a village Banihari, West Bengal, India and calculate the diversity indices. Pollard transect line method with minor changes was adopted for study. Survey was done at early morning with monthly interval. Butterflies were photographed with digital camera. Number of butterflies within the transect line were counted and then calculated the diversity indices with PAST 3.0 software. A total 48 butterfly species under four families were recorded during the study period. Most dominant family was Nymphalidae then followed by Pieridae, Lycaenidae and Papilionidae. Number of taxa, Shannon diversity index and Margalef species richness index were maximum at site1 and minimum at site 4. Most common butterflies were Common Mormon, Psyche, Blue Tiger, Plain Tiger, Striped Tiger, Grey Pansy, Small branded swift and Angled Castor. Moderate numbers of Butterflywere reported at the study site. Butterfly diversity depends on availability of host plants. Butterfly diversity decreased day by day due to many anthropogenic activities such as habitat loss, loss of host plant and use of pesticides.

Pest categorisation of Maconellicoccus hirsutus.

The EFSA Panel on Plant Health performed a pest categorisation of Maconellicoccus hirsutus (Hemiptera: Pseudococcidae), the pink hibiscus mealybug, for the EU. M. hirsutus is native to Southern Asia and has established in many countries in tropical and subtropical regions throughout the world. Within the EU, the pest has been reported from Cyprus and Greece (Rhodes). M. hirsutus is not listed in Annex II of Commission Implementing Regulation (EU) 2019/2072. It is highly polyphagous, feeding on plants assigned to 229 genera in 78 plant families, and shows some preference for hosts in the families Malvaceae, Fabaceae and Moraceae. Economically important crops in the EU such as cotton (Gossypium spp.), citrus (Citrus spp.), ornamentals (Hibiscus spp.), grapes (Vitis vinifera), soybean (Glycinae max), avocado (Persea americana) and mulberry trees (Morus alba) may be significantly affected by M. hirsutus. The lower and upper developmental temperature threshold of M. hirsutus on Hibiscus rosa‐sinensis are 14.5 and 35.0°C, respectively, with optimal female development estimated to be at 29.0°C. There are about 10 generations a year in the subtropics but as many as 15 may occur under optimal conditions. Plants for planting, fruits, vegetables and cut flowers provide potential pathways for entry into the EU. Climatic conditions in EU member states around the Mediterranean Sea and host plant availability in those areas are conducive for establishment. The introduction of M. hirsutus is expected to have an economic impact in the EU through damage to various ornamental plants, as already observed in Cyprus and Greece, and reduction in yield and quality of many significant crops. Phytosanitary measures are available to reduce the likelihood of entry and further spread. Some uncertainties include the area of establishment, whether it could become a greenhouse pest, impact, and the influence of natural enemies. M. hirsutus meets the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

Host Plant Availability and Nest-Site Selection of the Social Spider Stegodyphus dumicola Pocock, 1898 (Eresidae).

An animals' habitat defines the resources that are available for its use, such as host plants or food sources, and the use of these resources are critical for optimizing fitness. Spiders are abundant in all terrestrial habitats and are often associated with vegetation, which may provide structure for anchoring capture webs, attract insect prey, or provide protective function. Social spiders construct sedentary communal silk nests on host plants, but we know little about whether and how they make nest-site decisions. We examined host plant use in relation to host plant availability in the social spider Stegodyphus dumicola Pocock, 1898 (Eresidae) across different arid biomes in Namibia and analysed the role of host plant characteristics (height, spines, scent, sturdiness) on nest occurrence. Host plant communities and densities differed between locations. Spider nests were relatively more abundant on Acacia spp., Boscia foetida, Combretum spp., Dichrostachys cinerea, Parkinsonia africana, Tarchonanthus camphoratus, and Ziziphus mucronatus, and nests survived longer on preferred plant genera Acacia, Boscia and Combretum. Spider nests were relatively more abundant on plants higher than 2 m, and on plants with thorns and with a rigid structure. Our results suggest that spiders display differential use of host plant species, and that characteristics such as rigidity and thorns confer benefits such as protection from browsing animals.

Pest categorisation of Xanthomonas citri pv. viticola.

The EFSA Plant Health Panel performed a pest categorisation of Xanthomonas citri pv. viticola (Nayudu) Dye, a Gram‐negative bacterium belonging to the Xanthomonadaceae family. The pathogen is a well‐defined taxonomic unit and is the causal agent of the leaf spot and bacterial canker of Vitis vinifera. This bacterium is present in India and Brazil, where it affects table grape cultivation; the same pathogen is able to cause a disease on Azadirachta indica and on some weed species. Reports indicate that the bacterium is present in Thailand as well. The pathogen has never been reported from the EU territory and it is not included in EU Commission Implementing Regulation 2019/2072. The pathogen can be detected on its host plants using direct isolation, serological or PCR‐based methods. Its identification is achieved using biochemical and nutritional assays, together with a multilocus sequence analysis based on seven housekeeping genes. The main pathway for the entry of the pathogen into the EU territory is plant propagation material. In the EU, there is large availability of host plants, with grapevine being one of the most important crops in Europe and more specifically in its Mediterranean areas. Since X. citri pv. viticola is only reported in tropical and subtropical areas (BSh and Aw climatic zones according to the Köppen–Geiger classification), there is uncertainty whether the climatic conditions in the EU territory are suitable for its establishment. Nevertheless, due to the great importance of grapevine for the EU agriculture, any disease outbreak may have a high‐economic impact. Phytosanitary measures are available to prevent the introduction of the pathogen into the EU. X. citri pv. viticola satisfies the criteria that are within the remit of EFSA to assess for this species to be regarded as a potential Union quarantine pest.

Diversity of Lepidoptera: Rhopalocera at Selorejo Waterfall Area, Ponorogo District, East Java, Indonesia

Selorejo Waterfall is a natural tourist area that is directly adjacent to the Sigogor Mountain Nature Reserve and has a beautiful and natural environment. This makes the Selorejo Waterfall area has a good environment for the sustainability of various species of butterflies. This research aimed to find out the diversity and abundance of butterflies in the Selorejo Waterfall area. This research was conducted using the Visual Day Flaying method by following the trail in the Selorejo Waterfall area. This study found 26 species belongs 4 families with 109 individuals in total. The value of the species diversity index at the location of H'= 2.81 moderate category. The diversity of butterflies in the Selorejo Waterfall area was influenced by the availability of host plants and feed as well as abiotic factors.

Effects of geographic variation in host plant resources for a specialist herbivore's contemporary and future distribution

AbstractSpecies distributions are driven by abiotic and biotic factors, but the importance of variation in the availability and quality of critical resources is poorly understood. Disentangling the relative importance of these factors—abiotic environment, availability of critical resources, and resource quality—will be important to modeling species current distributions and responses to projected climate change. We address these questions using species distribution models (SDMs) for the western monarch butterfly population (Danaus plexippus), whose larvae feed exclusively on Asclepias species known for their heterogeneous distribution and variation in host quality. We modeled the distribution of 24 Asclepias species to compare three monarch distribution models with increasing levels of complexity: (1) a null model using only environmental factors (climate envelope model), (2) a model using environmental factors and Asclepias availability estimated as species richness, (3) and a model using environmental factors and Asclepias’ availability weighted by host plant quality as assessed through a greenhouse bioassay of larval performance. Asclepias models predicted that half of the Asclepias species will expand their ranges and shift toward higher latitudes, while half will contract. These patterns were uncorrelated with host plant quality. Among the three monarch models, the climate envelope model was the poorest performing. Models accounting for host plant availability performed best, while accounting for host plant quality did not improve model performance. The climate envelope model estimated more restrictive contemporary and future monarch ranges compared to both host plant models. Although all three models predicted future monarch range expansions, the projected future distributions varied among models. The climate envelope model predicted range expansions along the Pacific coast and contractions inland. In contrast, the host plant availability and quality models predicted range expansions in both of these regions and, as a result, 14% and 19% increases in distribution (respectively) relative to the climate envelope model. These models do not include other factors affecting monarch persistence. Nevertheless, our findings suggest that accounting for information on host plant availability and response to climate change is necessary to predict future species distributions, but that variation in the quality of those critical resources may be of secondary importance.

Diversity Study of the Buterfly Species in Kallar, Kunjapanai and Kottagiri in Tamil Nadu

The present investigation has been carried out to enumerate the butterfly diversity that greatly depends on the availability of host plants. The study has been carried from Jan 2018 - December 2019 in three different regions such as Kallar, Kunjapanai and Kottagiriin Tamilnadu, India. During this study a total of 16396 butterflies representing 135 species and five families were identified. Larval host plants were identified for 135 butterfly species. Diversity indices such as Dominance species, Shannon index, Simpson index, Evenness and Fisher alpha Index were calculated seasonal wise. The butterfly species belonging to the nymphalidae family was found dominant in the three study areas. The butterfly diversity was maximum in the monsoon season when compared with pre monsoon, post monsoon and summer season.

Occurrence of an endangered grassland butterfly is mainly driven by habitat heterogeneity, food availability, and microclimate.

The Marsh Fritillary (Euphydryas aurinia) was once widespread in large parts of Central Europe. However, in the course of the last century, populations of the butterfly largely collapsed. Here, we surveyed patch and microhabitat occupancy and its drivers in one of the last vital populations in calcareous grasslands. Our study revealed that environmental conditions at the landscape and habitat level determined the occurrence of E.aurinia in a montane agricultural landscape with low land-use intensity. Patch occupancy increased with the cover of Devil's-bit Scabious (Succisa pratensis) grasslands in the surroundings of the patches, habitat heterogeneity and host-plant cover. Microhabitat occupancy was driven by a warm microclimate and high availability of host plants. In the well-connected landscape of nutrient-poor grasslands, patch occupancy of E. aurinia was driven by parameters defining a high habitat quality. Habitat heterogeneity very likely buffers E. aurinia populations against environmental stochasticity and, hence, enhances long-term viability. For the gregariously feeding caterpillars of E. aurinia, host-plant biomass is essential. Due to their more luxuriant growth, S. pratensis plants were clearly preferred, although the Glossy Scabious (Scabiosa lucida) was also widespread. Additionally, the growth of large Succisa plants was favored by soil humidity and grassland abandonment. To cope with the adverse macro- and mesoclimatic conditions of the study area, females of the butterfly selected host plants growing in extraordinarily warm microhabitats for oviposition. To secure long-term viability of E. aurinia populations, we recommend creating mosaics of traditionally managed grasslands and early stages of abandonment within the patches.

Predicting the Invasion Risk by Anastrepha sororcula (Diptera: Tephritidae) in Distinct Geographic Regions.

The movement of endemic fruit flies to new habitats represents a major biological and economic threat. Anastrepha sororcula Zucchi, 1979 is widely distributed in Brazil and also in Colombia, Ecuador, and Paraguay. Here, we present the potential distribution of A. sororcula in endemic areas and project this model into other regions such as part of sub-Saharan Africa, Central America, and Asia to show areas around the world that this species can potentially establish. We combined geographic coordinates with climate data. The models were built using the maximum entropy (MaxEnt) algorithm. Many mango- and guava-producing countries exhibited climatic suitability for A. sororcula in the regions studied including the nine largest world producers: India, Brazil, Malawi, Kenya, Haiti, Cuba, Colombia, Madagascar, and the Democratic Republic of the Congo. Many of these countries showed ideal host plant availability and climatic conditions for the entry and establishment of A. sororcula. This study is a pioneer in the identification of representative areas in the world with climatic suitability for A. sororcula, which shows the importance of predicting areas at risk of invasion to monitor the movement and establishment of fruit fly species in new regions, which is fundamental to area-wide integrated pest management programs.

Non-overlapping climatic niches and biogeographic barriers explain disjunct distributions of continental Urania moths

Larvae of Urania moths feed exclusively on Omphalea plants, which are widely distributed in the Neotropics. However, the distributions of the two Urania species in this region are disjunct. This distributional pattern could derive from the presence of the Andes, but it could also be related to differences in ecological niches, the presence of negative interactions, or the absence of conditions that can only be observed at a habitat level. We tested whether differences in the ecological niches of continental Urania moths play a role in their disjunct distribution. Using species records and climatic variables, we characterized the ecological niches of Urania moths and their host plants and analyzed the overlap of the moths' niches. Using ecoregions as a proxy of habitat-level environmental conditions, we explored the role of host plant availability on the moth distributions. Suitable conditions for the species were widespread, with a lack of suitability mostly restricted to the Andean highlands. The two moth distributions were closely related to that of their host plants. There was medium-high overlap of niche models when available conditions were considered; however, niche overlap was not found to be statistically significant. Our results corroborate the barrier effect of the Andes on the dispersal of these moths, but they also show that niche differences contribute to the disjunct distributions of U. fulgens and U. leilus. Furthermore, other non-climatic factors appear to play a crucial role in the disjunction of the species ranges in areas where overlapping suitable conditions are continuous. Our findings support speciation in Urania moths as allopatric and indicate that their disjunct distributions can be attributed to multiple factors. Other studies exploring the causes of similar distributional patterns should consider that a single factor may not be enough to explain such patterns.

Preliminary Assessment of Lepidoptera Biodiversity on Isla Guadalupe, Mexico, a Critically Threatened Ecosystem Currently Recovering from Extensive Habitat Degradation

Little is known of insect biodiversity on Isla Guadalupe, a large (c. 250 km2) Pacific island located off the west coast of Baja California, Mexico, which has undergone more than 150 years of extensive habitat degradation owing to grazing by feral goats. Goats were successfully eradicated in 2007, and thus Isla Guadalupe provides a rare opportunity to study changes in biodiversity in the flora and fauna as the habitat in this isolated geographic region begins to recover. We conducted a preliminary survey of Lepidoptera biodiversity by collecting and observing mainly adult individuals during July–August, 2019. We also included previous observations from 2003–2016, and two historical records dating back to 1874 and 1922. Our annotated inventory includes 31 species of Lepidoptera (10 species of butterflies from four families, and 21 species of moths from seven families), and includes one butterfly species recorded 100 years ago that we did not find and which may be extirpated. Although life history stages were not recorded (except for the cosmopolitan Vanessa cardui), we also comment on the availability of potential larval host plants based on literature records from other regions. Most of the Lepidoptera species in our inventory (n = 22) have also been recorded from at least one of the comprehensively studied Channel Islands in southern California, USA, and all 31 species are also present on the California mainland. Thus, the Lepidoptera fauna on Isla Guadalupe recorded here corresponds to that associated with Californian Biogeographic Province.

Assessing the Role of Developmental and Environmental Factors in Chemical Defence Variation in Heliconiini Butterflies

Chemical defences in animals are both incredibly widespread and highly diverse. Yet despite the important role they play in mediating interactions between predators and prey, extensive differences in the amounts and types of chemical compounds can exist between individuals, even within species and populations. Here we investigate the potential role of environment and development on the chemical defences of warningly coloured butterfly species from the tribe Heliconiini, which can both synthesize and sequester cyanogenic glycosides (CGs). We reared 5 Heliconiini species in captivity, each on a single species-specific host plant as larvae, and compared them to individuals collected in the wild to ascertain whether the variation in CG content observed in the field might be the result of differences in host plant availability. Three of these species were reared as larvae on the same host plant, Passiflora riparia, to further test how species, sex, and age affected the type and amount of different defensive CGs, and how they affected the ratio of synthesized to sequestered compounds. Then, focusing on the generalist species Heliconius numata, we specifically explored variation in chemical profiles as a result of the host plant consumed by caterpillars and their brood line, using rearing experiments carried out on two naturally co-occurring host plants with differing CG profiles. Our results show significant differences in both the amount of synthesized and sequestered compounds between butterflies reared in captivity and those collected in the field. We also found a significant effect of species and an effect of sex in some, but not all, species. We show that chemical defences in H. numata continue to increase throughout their life, likely because of continued biosynthesis, and we suggest that variation in the amount of synthesized CGs in this species does not appear to stem from larval host plants, although this warrants further study. Interestingly, we detected a significant effect of brood lines, consistent with heritability influencing CG concentrations in H. numata. Altogether, our results point to multiple factors resulting in chemical defence variation in Heliconiini butterflies and highlight the overlooked effect of synthesis capabilities, which may be genetically determined to some extent.

Noctuid and geometrid moth assemblages show divergent elevational gradients in body size and color lightness

Previous macroecological studies have suggested that larger and darker insects are favored in cold environments and that the importance of body size and color for the absorption of solar radiation is not limited to diurnal insects. However, whether these effects hold true for local communities and are consistent across taxonomic groups and sampling years remains unexplored. This study examined the variations in body size and color lightness of the two major families of nocturnal moths, Geometridae and Noctuidae, along an elevational gradient of 700 m in Southern Germany. An assemblage‐based analysis was performed using community‐weighted means and a fourth‐corner analysis to test for variations in color and body size among communities as a function of elevation. This was followed by a species‐level analysis to test whether species occurrence and abundance along an elevation gradient were related to these traits, after controlling for host plant availability. In both 2007 and 2016, noctuid moth assemblages became larger and darker with increasing elevation, whereas geometrids showed an opposite trend in terms of color lightness and no clear trend in body size. In single species models, the abundance of geometrids, but not of noctuids, was driven by habitat availability. In turn, the abundance of dark‐colored noctuids, but not geometrids increased with elevation. While body size and color lightness affect insect physiology and the ability to cope with harsh conditions, divergent trait–environment relationships between both families underline that findings of coarse‐scale studies are not necessarily transferable to finer scales. Local abundance and occurrence of noctuids are shaped by morphological traits, whereas that of geometrids are rather shaped by local habitat availability, which can modify their trait–environment‐relationship. We discuss potential explanations such as taxon‐specific flight characteristics and the effect of microclimatic conditions.

Invasion and expansion of exotic whiteflies (Hemiptera: Aleyrodidae) in India and their economic importance

Exotic invasive whiteflies (Hemiptera: Aleyrodidae) in India cause direct and indirect yield losses in agriculture, horticulture and forestry crop plants. Around 25 years ago, the spiralling whitefly, Aleurodicus dispersus Russell invaded and established on many host plants including economically important crops in India. Recently, within a span of five years, seven whiteflies invaded India viz., solanum whitefly, Aleurothrixus trachoides (Back) reported to breed on 37 plant species; rugose spiraling whitefly (RSW), Aleurodicus rugioperculatus Martin found breeding on 40 host plants; nesting whiteflies, Paraleyrodes bondari Peracchi on 34 host plants and P. minei Ιaccarino infest about 25 host plants; legume feeding whitefly, Tetraleurodes acaciae (Quaintance) infesting 5 host plants; palm infesting whitefly, Aleurotrachelus atratus Hempel on 4 host plants and woolly whitefly, Aleurothrixus floccosus (Maskell) infesting guava. These invasive species are native to the Neotropical region, mostly from Central America and the Caribbean. Extensive spread along the coastal regions and gardens near the backwater of India is predicted owing to the favorable weather factors and availability of host plants. Species of exotic whiteflies with similar habits co-exist in more or less the same niche and have a similar pattern of growth and development. The intensity of infestation of RSW on coconut, banana and oil palm, the woolly whitefly on guava and the palm infesting whitefly and nesting whiteflies on coconut was severe. The exotic aphelinid parasitoid, Encarsia guadeloupae Viggiani (Hymenoptera: Aphelinidae), a predator Pseudomallada astur (Banks) (Neuroptera: Chrysopidae) and the entomopathogenic fungus, Isaria fumosorosea Wize (Hypocreales: Clavicipitaceae) play a major role in reducing the population of these invasives. The most insidious spread of these species in India is likely mediated by humans through the movement of infested seedlings and plant materials. Extensive surveys revealed that these species spread rapidly in the large geographical region of India mostly through transportation of infested seedlings. This study reports a major expansion of the geographic and host range and the patterns of co-occurrence, damage and economic impact of these exotic species in India and their natural enemies.

Isolation protocol trials for grapevine bacteriosis (Pierce's disease) agent <i>Xylella fastidiosa</i> Wells et al. during research monitoring of the Republic of Crimea

Xylella fastidiosa Wells et al. causes grapevine bacteriosis and is among most hazardous malicious bacterial phytopathogens affecting a wide variety of important crops and ornamental plants. The agent colonises plant xylem and transmits with insects feeding on xylem sap. The insect vectors of X. fastidiosa belong to the order Hemiptera, suborder Auchenorrhyncha, families Cicadellidae, Cercopidae, Aphrophoridae and Cicadidae. A phytosanitary control survey conducted by the All-Russian Research Institute for Plant Quarantine in 2014 identified a high risk of X. fastidiosa introduction and adaptation in the Russian Federation. The Crimean Peninsula is a potential introduction area of the Pierce’s disease agent due to suitable climatic conditions, the ample availability of major host plants, as well as insect vectors. During a research monitoring in 2018-2020, the Institute assessed the phytosanitary status of the Crimean territory. The survey sampled vegetative parts of grapevines, stone fruits (peach, cherry, plum, merry, almond), selected essential-oil and ornamental shrubs and trees. Diagnostic procedures were performed in accordance with the international standards. A three-year phytosanitary survey of the Crimean plantations revealed no presence of X. fastidiosa. Two protocols of sample preparation and DNA extraction from various substrates have been tested. A real-time PCR-based protocol was proved highly specific for zero false positive and nonspecific rates.

Pest categorisation of Diaphorina citri.

The EFSA Panel on Plant Health performed a pest categorisation of Diaphorina citri (Hemiptera: Liviidae) (Asian citrus psyllid) for the EU. D. citri is a key pest of citrus in several countries as it is a vector of serious bacterial pathogens, the putative causal agents of Huanglongbing (HLB) also known as citrus greening. Eggs are laid on tips of growing shoots on and between unfurling leaves. Females may lay more than 800 eggs during their lives. Nymphs pass through five instars. The life cycle requires from 14 to 49 days, depending upon the season. There is no diapause, but populations are low in winter. It overwinters as an adult which may live for several months. The species completes 9–10 generations/year; however, under protected conditions, up to 16 generations have been recorded. Commission Implementing Regulation (EU) 2019/2072 (Annex IIA) regulates D. citri, as a quarantine pest not known to occur in the EU territory. Fruits and plants for planting provide potential pathways for entry into the EU. Climatic conditions and the availability of host plants provide conditions to support establishment in the EU. The introduction of D. citri would have an economic impact in the EU through direct but mainly indirect effects due to potential transmission of HLB. Phytosanitary measures are available to reduce the likelihood of entry. D. citri satisfies the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest. D. citri does not meet the criteria of occurring in the EU, nor plants for planting being the principal means of spread, for it to be regarded as a potential Union regulated non‐quarantine pest.

Genetic and Ecological Relationships of Anastrepha ludens (Diptera: Tephritidae) Populations in Southern Mexico.

Simple SummaryThe Mexican fruit fly, Anastrepha ludens, causes extensive damage to important agricultural commodities wherever it is found. Any effort to control or limit the damage caused by this pest requires a thorough understanding of the genetic makeup of the populations found in a particular area. Our study focused on flies found in the Soconusco region of southern Mexico. Flies in this region are typically found infesting different types of fruit trees that are either cultivated or naturally occurring. For our study, we collected male and female flies from four different types of fruit trees in several specific localities in the Mexican state of Chiapas. We analyzed the genetic makeup of a total of 725 flies in an attempt to look for differences that might be associated with the sex of the flies, the specific plants they were found on, or specific localities within the study area. We found a lot of genetic differences in flies from the various collections, but these were not strongly associated with different types of fruit trees or the specific collection site. From this, we concluded that the populations of flies from this entire region were largely similar.Knowledge of the influence of evolutionary factors that promote either the differentiation or cohesion of pest insect populations is critical for the improvement of control strategies. Here, we explore the extent to which genetic differentiation occurs between populations of the Mexican fruit fly, Anastrepha ludens, in association with four plant hosts (Citrus sinensis, C. paradisi, Mangifera indica and Casimiroa edulis) in the Soconusco region of Chiapas (Mexico). Using variants from six enzymatic loci, we obtained measures of genetic diversity for three sample arrangements: (1) by sex per locality, (2) by locality and (3) by host. The extent of genetic differentiation in populations was assessed using the Analyses of Molecular Variance (AMOVA) method for each array of samples, and moderate to high levels of genetic variation were observed between the sexes, as well as among localities and host plants. A Bayesian approach was then used to assess any population structure underlying the genetic data we obtained, but this analysis showed no significant structuring due to locality or host plant. We also considered whether the observed genotypic frequencies in male and females matched those expected under a hypothesis of random mating. Here we found significant deviations from expected genotypic frequencies, suggesting that sexual selection is acting on these populations. Overall, our results indicate that sexual selection, along with the presence of some heterogeneity in environments provided by both geographical factors and availability of host plants, has influenced the evolution of pest populations in this region of Mexico. Implications for area-wide pest management strategies are discussed.

Clonal versus non-clonal milkweeds (Asclepias spp.) respond differently to stem damage, affecting oviposition by monarch butterflies.

BackgroundOviposition decisions are critical to the fitness of herbivorous insects and are often impacted by the availability and condition of host plants. Monarch butterflies (Danaus plexippus) rely on milkweeds (Asclepias spp.) for egg-laying and as food for larvae. Previous work has shown that monarchs prefer to oviposit on recently regrown plant tissues (after removal of above-ground biomass) while larvae grow poorly on plants previously damaged by insects. We hypothesized that these effects may depend on the life-history strategy of plants, as clonal and non-clonal milkweed species differ in resource allocation and defense strategies.Methodology/Principal FindingsWe first confirmed butterfly preference for regrown tissue in a field survey of paired mowed and unmowed plots of the common milkweed A. syriaca. We then experimentally studied the effects of plant damage (comparing undamaged controls to plants clipped and regrown, or damaged by insects) on oviposition choice, larval performance, and leaf quality of two closely related clonal and non-clonal species pairs: (1) A. syriaca and A. tuberosa, and (2) A. verticillata and A. incarnata. Clonal and non-clonal species displayed different responses to plant damage, impacting the proportions of eggs laid on plants. Clonal species had similar mean proportions of eggs on regrown and control plants (≈35–40% each), but fewer on insect-damaged plants (≈20%). Meanwhile non-clonal species had similar oviposition on insect-damaged and control plants (20–30% each) but more eggs on regrown plants (40–60%). Trait analyses showed reduced defenses in regrown plants and we found some evidence, although variable, for negative effects of insect damage on subsequent larval performance.Conclusions/SignificanceOverall, non-clonal species are more susceptible and preferred by monarch butterflies following clipping, while clonal species show tolerance to clipping and induced defense to insect herbivory. These results have implications for monarch conservation strategies that involve milkweed habitat management by mowing. More generally, plant life-history may mediate growth and defense strategies, explaining species-level variation in responses to different types of damage.