Parasitoid Assemblages Research Articles

Parasitoids (Hymenoptera, Eulophidae, Braconidae) as a mortality factor for the lime leaf miner (<i>Phyllonorycter issikii</i>, Lepidoptera, Gracillariidae) in the Cis-Urals

The assemblage of hymenopteran parasitoids associated with the invasive lime leaf miner, Phyllonorycter issikii (Lepidoptera, Gracillariidae) developing on the lime (Tilia cordata) was studied in the Perm Region and in the Republic of Bashkortostan during 2019. Sixteen species of parasitoids of Ph. issikii were recognized: Diglyphus isaea, Elachertus fenestratus, Hyssopus geniculatus, Pnigalio agraules, P. mediterraneus, Sympiesis dolichogaster, S. gordius, S. sericeicornis, Chrysocharis laomedon, Ch. nephereus, Ch. pentheus, Ch. pubens, Ch. pubicornis, Ch. submutica, Minotetrastichus frontalis (Eulophidae) and Pholetesor circumscriptus (Braconidae). Three species, Diglyphus isaea, Chrysocharis pubens and Ch. submutica (Eulophidae), were reported as parasitoids of the lime leaf miner for the first time. The roles the complex of parasitoids played in the mortality of the miner were negligible. The mortality ranged from 1.3±0.3 (Perm) to 23.7±3.3% (Tolbazy village).

Response of parasitoid communities to insecticide application during a Lymantria dispar outbreak in mixed oak forests

Abstract In the temperate mixed oak forests of Central Europe, outbreaks of insects such as the spongy moth, Lymantria dispar, can cause severe defoliation and insecticide is sometimes applied for their control. Parasitoids, mainly Hymenoptera and Diptera, are among the most diverse and important natural enemies of caterpillars in these forests. However, due to their cryptic lifestyle and taxonomic difficulties, we lack knowledge on the impact of insecticide applications on complex host‐parasitoid networks. In a large‐scale field experiment, we tested the effect of spraying the lepidopteran‐specific insecticide Mimic (tebufenozide) on the abundance and community composition of both adult and larval parasitoids. We combined morphological identification, DNA barcoding and metabarcoding to identify parasitoids adult or inside caterpillars, both sampled by canopy fogging during an outbreak and two subsequent years. We analysed the abundance of parasitoids, community composition and network specialisation using statistical methods that account for sample incompleteness in host‐parasitoid data. For adult parasitoid assemblages, we found strong annual effects on abundance, with highest numbers of adult parasitoids occurring in the outbreak year, as well as on annual changes in community composition, but no effect linked to insecticide application. However, the abundance and species number of immature parasitoids revealed negative effects of insecticide application, while community composition was only affected by annual variation. Coverage‐based network analyses showed a reduction of taxonomic network diversity and network specialisation associated with insecticide application in the first 2 years. Synthesis and applications: This real‐world experiment shows that parasitoid populations respond immediately to large‐scale outbreaks but only limited to local disturbances. Results indicate that this group of natural enemies exhibits high mobility, enabling them to track host populations across large spatial scales. However, our observation of reduced network specialisation after insecticide application is a warning signal that ecosystem function, and consequently natural pest control services, may be impaired by human interference at the local stand scale.

The relative influence of agricultural abandonment and semi-natural habitats on parasitoid diversity and community composition.

Wild biodiversity is usually larger in semi-natural habitats than in croplands, but this pattern is not ubiquitous because it varies among taxa and geographic regions. Knowing how the diversity of natural enemies is structured at the landscape level is important to better understand when semi-natural habitats promote the conservation of natural enemies and ultimately enhance biocontrol. We explore the relative influence of agricultural abandonment and the proportion of semi-natural habitats at the landscape level on the diversity and abundance of parasitoid wasps in the Ichneumonidae family. We studied changes in parasitoid diversity both at local and regional scales (i.e. alpha vs beta diversity), and both at the taxonomic and functional level (i.e. species vs guild identities). We extracted landscape features in circular buffers of varying radii to perform a multi-scale analysis, and to assess at which scale landscape-level effects influenced parasitoid assemblages. We found that parasitoid alpha and beta diversity decreased with an increasing proportion of semi-natural habitats. The multi-scale analysis revealed that for this group of natural enemies, landscape-level effects occur at mid to low distances (i.e. less than 500m). Our results provide insights into the origin of pest natural enemies, their spillover to croplands, and may help to understand under which circumstances semi-natural habitats fail at promoting biocontrol services.

Network structure and taxonomic composition of tritrophic communities of Fagaceae, cynipid gallwasps and parasitoids in Sichuan, China

Abstract A key question in insect community ecology is whether parasitoid assemblages are structured by the food plants of their herbivore hosts. Tritrophic communities centred on oak‐feeding cynipid gallwasps are one of the best‐studied tritrophic insect communities. Previous work suggests that host plant identity is a much stronger predictor of oak–cynipid interactions than of cynipid–parasitoid interactions. However, these relationships have not been formally quantified. We reason that the potential for ‘bottom‐up’ effects should increase with host plant phylogenetic diversity. We, therefore, generated quantified interaction network data for previously unstudied tritrophic cynipid communities in Sichuan, China, where, in addition to Quercus, cynipid host plants include Castanea, Castanopsis and Lithocarpus. We characterise these communities taxonomically and compare the extent to which host plant taxonomy predicts plant–herbivore and plant–parasitoid associations. We sampled 42,620 cynipid galls of 176 morphotypes from 23 host plant species, yielding over 4500 specimens of 64 parasitoid morphospecies. Many parasitoids were identifiable to chalcidoid taxa present in other Holarctic oak cynipid communities, with the addition of Cynipencyrtus (Cynipencyrtidae). As elsewhere, Sichuan parasitoid assemblages were dominated by generalists. Gallwasp–plant interaction networks were significantly more modular than parasitoid–plant association networks. Gallwasps were significantly more specialised to host plants (i.e. had higher mean d' values) than parasitoids. Parasitoid assemblages nevertheless showed significant plant‐associated beta diversity, with a dominant turnover component. We summarise parallels between our study and other Fagaceae‐associated cynipid communities and discuss our findings in light of the processes thought to structure tritrophic interactions centred on endophytic insect herbivores.

Temporal changes in the composition of parasitoid assemblages associated with the invasive chestnut gall wasp

Abstract Invasive alien species pose a challenge to ecosystem stability and crop production, so understanding their interactions with the natural communities they invade is crucial to mitigate negative effects. The oriental chestnut gall wasp, Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae), is an invasive insect that attacks chestnut trees. It was first recorded in Spain in 2012 and is now presumably present in the majority of chestnut stands in the country. We assessed variation in the abundance of D. kuriphilus galls and the composition of their associated parasitoid community (Hymenoptera: Chalcidoidea) during a 4‐year period (2014–2017) in 12 sampling sites in Catalonia (Spain, northeastern Iberian Peninsula), and identified which species contributed most significantly to the control of D. kuriphilus. The results show that the abundance of individual parasitoid species varied during the study period and that the number of species increased year after year. There was also a transition in the parasitoid community composition across the years. Our data suggest that the joint action of the non‐native parasitoid Torymus sinensis Kamijo and the native T. notatus (Walker) (Hymenoptera: Chalcidoidea: Torymidae) led to the decline of D. kuriphilus until it was no longer considered a pest. Also, the observed pool of parasitoid species ended up being relatively homogeneous across sites over the years, which may be due to the high natural dispersal of these parasitoids (both by active flight and passive wind dispersal).

Egg parasitoid assemblages and their effectiveness against the Lepidoptera soybean defoliators in Argentina's subtropical production region

AbstractSoybean, Glycine max (L.) Merr. (Fabaceae), is one of the most important crops worldwide, but caterpillars of various species (Lepidoptera) may greatly reduce its annual yield. Nowadays, the main method of controlling these pest species is based on the use of broad‐spectrum insecticides, which are harmful to human health and increase environmental contamination. Therefore, other sustainable methods of control, such as biological control, are in increasing demand. The present study aimed to identify the egg parasitoid species that attack lepidopterans defoliating soybeans in South America's subtropical regions, as well as evaluate their effectiveness at various stages of soybean development. The research was conducted in a commercial soybean field (80 ha) located in Tucumán, Argentina, which was surrounded by wild vegetation as a way to promote biological control. Every week, throughout three consecutive soybean seasons, 20 soybean plants were randomly selected and brought to the laboratory in search of lepidopteran eggs. Over the course of the three crop seasons, the soybean plants were attacked by Anticarsia gemmatalis Hübner (Erebidae), Rachiplusia nu (Guenée), and Chrysodeixis includens (Walker) (both Noctuidae). Six egg parasitoid species were identified, but only three of them were frequently found during the current study. Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) was the most predominant species attacking all lepidopteran pests across all soybean phenological stages. Encarsia porteri (Mercet) (Hymenoptera: Aphelinidae) preferred to attack R. nu eggs, whereas Telenomus cyamophylax Polaszek (Hymenoptera: Scelionidae) parasitized only A. gemmatalis and R. nu eggs. Despite the use of insecticides in the soybean field, the parasitism rates recorded were high. This suggests that using conservation tactics such as native vegetation patches and surrounding alternative crops may result in higher rates of natural control.

Parazytoidy z podrodzin Pimplinae (Hymenoptera, Ichneumonidae)i Aphidiinae (Hymenoptera, Braconidae) występujące w zieleni miejskiej miasta Poznania

The study aimed to determine the species composition and abundance of parasitoids from the subfamilies Pimplinae (Hymenoptera, Ichneumonidae) and Aphidiinae (Hymenoptera, Braconidae) found in various habitats in urban greenery and to demonstrate the rela¬tionship between plant species diversity and the species structure of parasitoid assemblages. It was found that only for the subfamily Aphidiinae was there a significant effect of habitats on the abundance of individual assemblages and the effect of years on the total abundance of assemblages. A positive relationship was observed between vegetation diversity and the abundance and species diversity of parasitoids of the subfamily Aphidiinae, as well as similarity in the qualitative-quantitative structure of Pimplinae assemblages present in a given habitat. Positive effects of trees: Betula pendula, Tilia tomentosa, Salix alba and Salix caprea, shrubs: Berberis julianae, Ber¬beris vulgaris and Spiraea japonica, and herbaceous plants: Elymus repens, Festuca rubra and Hypochoeris radicata on the qualitative¬-quantitative structure of parasitoid assemblages of the subfamily Pimplinae by creating a suitable food base for these entomophagous imagines were noted.

Hymenopteran parasitoids of black soldier fly Hermetia illucens (L.) (Diptera: Stratiomyidae) in chicken farms with two new species from India

Hymenopteran parasitoids of the black soldier fly (BSF) Hermetia illucens (Linnaeus, 1758) (Diptera, Stratiomyidae), are recorded from southern India. Two new species, Calyoza hermetiae Binoy, & Colombo sp. nov. (Bethylidae, Epyrinae) and Eniacomorpha bouceki Binoy sp. nov. (Chalcididae, Dirhininae) are described and illustrated. Spalangia cameroni Perkins, S. obscura Bouček and S. simplex Perkins (Spalangiidae, Spalangiinae) and Dirhinus anthracia Walker (Chalcididae, Dirhininae) are also reported from BSF and are diagnosed and illustrated. A key to the hymenopteran parasitoids of BSF respectively belonging to Bethylidae (1 sp.), Chalcididae (4 spp.), Diapriidae (1 sp.), Spalangiidae (3 spp.), is provided. This study forms the first record of a host for Calyoza. Finally, the negative impact of these parasitoid assemblages on BSL is discussed.

Host–enemy interactions provide limited biotic resistance for a range‐expanding species via reduced apparent competition

AbstractAimAs species' ranges shift poleward in response to anthropogenic change, they may lose antagonistic interactions if they move into less diverse communities, fail to interact with novel populations or species effectively, or if ancestral interacting populations or species fail to shift synchronously. We leveraged a poleward range expansion in a tractable insect host–enemy community to uncover mechanisms by which altered antagonistic interactions between native and recipient communities contributed to ‘high niche opportunities’ (limited biotic resistance) for a range‐expanding insect.LocationNorth America, Pacific Northwest.MethodsWe created quantitative insect host–enemy interaction networks by sampling oak gall wasps on 400 trees of a dominant oak species in the native and expanded range of a range‐expanding gall wasp species. We compared host–enemy network structure between regions. We measured traits (phenology, morphology) of galls and interacting parasitoids, predicting greater trait divergence in the expanded range. We measured function relating to host control and explored if altered interactions and traits contributed to reduced function, or biotic resistance.ResultsInteraction networks had fewer species in the expanded range and lower complementarity of parasitoid assemblages among host species. While networks were more generalized, interactions with the range‐expanding species were more specialized in the expanded range. Specialist enemies effectively tracked the range‐expanding host, and there was reduced apparent competition with co‐occurring hosts by shared generalist enemies. Phenological divergence of enemy assemblages interacting with the range‐expanding and co‐occurring hosts was greater in the expanded range, potentially contributing to weak apparent competition. Biotic resistance was lower in the expanded range, where fewer parasitoids emerged from galls of the range‐expanding host.Main ConclusionsChanges in interactions with generalist enemies created high niche opportunities, and limited biotic resistance, suggesting weak apparent competition may be a mechanism of enemy release for range‐expanding insects embedded within generalist enemy networks.

PARASITIODS (HYMENOPTERA, EULOPHIDAE, BRACONIDAE) AS A MORTALITY FACTOR FOR THE LIME LEAF MINER (<i>PHYLLONORYCTER ISSIKII</i>, LEPIDOPTERA, GRACILLARIIDAE) IN TRANS-URALIA AND WESTERN SIBERIA

The assemblage of hymenopteran parasitoids associated with the invasive lime leaf miner, Phyllonorycter issikii (Lepidoptera, Gracillariidae) developing on the lime (Tilia cordata) was studied in the Kurgan Province (Madvezh’ye Lake), and in the cities of Tobolsk, Omsk, and Novosibirsk during 2018−2019. Twenty-one species of parasitoids of Ph. issikii were recognized: Pteromalus sp. (Pteromalidae), Cirrospilus diallus, Elachertus sp., Hyssopus geniculatus, H. nigritulus, Pnigalio mediterraneus, Pnigalio sp., Sympiesis dolichogaster, S. gordius, S. sericeicornis, Chrysocharis laomedon, Ch. pentheus, Ch. pubicornis, Ch. viridis, Chrysocharis sp., Neochrysocharis formosus, Minotetrastichus frontalis (Eulophidae), Colastes braconius, Apanteles sp., Pholetesor circumscriptus and Cotesia sp., (Braconidae). Chrysocharis viridis has been reported as a parasitoid of lime leaf miner for the first time. The role of the complex of parasitoids in the mortality of the miner is negligible, the mortality rate ranging from 1.9 ± 0.4 (Novosibirsk) to 23.7 ± 3.3% (Omsk).

Response of the rice stem borer Chilo suppressalis (Walker) and its parasitoid assemblage to landscape composition

The rice stem borer (RSB), Chilo suppressalis (Walker), is an economically important pest of rice in subtropical Asia. Up till present, it remains unknown how pest abundance and parasitoid-mediated biological control are modulated by landscape composition. In this study, 20 rice fields with varying proportion of non-crop habitat in (2000 m radius) landscape sectors were selected in China’s Jiangxi province. RSB infestation levels were highest in agriculture-dominated landscapes. Meanwhile, parasitism rate increased with pest pressure but was not related to landscape-level non-crop habitat cover. Landscape-level responses of parasitoids were species-specific and likely modulated by functional traits. The specialist parasitoid Cotesia chilonis (Munakata) responded negatively to non-crop habitat, while positive responses were recorded for the generalists Eriborus sinicus (Holmgren) and Microgaster russata (Haliday). Our work unveils the occurrence of a bottom-up cascade in which spatiotemporal rice cropping patterns shape pest pressure and parasitism dynamics, with more diverse landscapes experiencing lower RSB infestation levels. Non-crop habitats within the landscape matrix equally retained parasitoid species with varying feeding modes and attack strategies. Hence, despite its (globally) inconsistent impacts on biological control, agricultural landscape diversification can directly benefit pest suppression and thus remains a valuable component of the ecological intensification toolbox.

Aphid‐parasitoids trophic relationship in a cereal crop succession system: Population oscillation and food webs

Abstract In the 1970s, cereal aphids populations (specially Metopolophium dirhodum) were out of balance in the subtropical region of South America and a successful biological control program with the introduction of parasitoids restored equilibrium. After that, changes in crop systems may have affected aphid‐parasitoid communities. The objective of this work was to evaluate the current assemblage of cereal aphid parasitoids, describing their oscillations, parasitism level, and trophic relationships in food webs in a cereal succession system (wheat‐corn‐oat) currently adopted in this region. Over a year, the associated parasitoid/hyperparasitoid species were inventoried by field‐exposed Rhopalosiphum padi, Schizaphis graminum, M. dirhodum, and Sitobion avenae (recruitment method) and by Moericke traps. Six species of primary parasitoids were sampled in both aphids and traps with the same abundance sequence: A. platensis, A. rhopalosiphi, L. testaceipes, D. rapae, A. uzbekistanicus, and A. ervi. Parasitism and complexity of food webs were higher during the wheat season (winter–spring), decreasing in corn (summer) and increasing again in oat (autumn). In the current assemblage of cereal aphid parasitoids in the subtropical region of South America, three species of parasitoids that were already present before the biological control program and three that were introduced oscillate in abundance throughout the year, resulting in an alternation of the complexity of the food webs and in the levels of parasitism in the crop seasons. A. platensis and A. rhopalosiphi are the most abundant species and A. rhopalosiphi remains fundamental in the control of M. dirhodum and S. avenae.

Parasitoids of Lobesia botrana (Lepidoptera: Tortricidae) in the Douro Demarcated Region vineyards and the prospects for enhancing conservation biological control.

The more restrictive regulations of pesticides in Europe have led to an increase in conservation biological control (CBC) research. However, little attention has been paid to the main determinants of Lobesia botrana parasitism. The Douro Demarcated Region landscape offers scope for the use of CBC. The study was conducted between 2002 and 2015 aiming at: (i) identifying parasitoids associated with L. botrana and evaluating their impact as biological control agents in each generation of the pest, and (ii) evaluating the effect of both the proportion of ecological infrastructures (EI) near the vineyards, and the impact of management practices (chemical treatments and ground cover) on the parasitism of L. botrana. A total of 3226 larvae/pupae of L. botrana were collected (15% were parasitized and 485 parasitoids emerged). A complex of 16 taxa of parasitoids was identified, the majority belonging to Hymenoptera. The most abundant were Elachertus sp. (Eulophidae), Campoplex capitator Aubert (Ichneumonidae), and Brachymeria tibialis (Walker) (Chalcididae), which represented 62.5, 12.6, and 12.0% of the total assemblage of parasitoids which emerged, respectively. The percentage of parasitism ranged from 0.0 to 61.5% (first generation), from 0.0 to 36.8% (second generation), and from 0.0 to 12.1% (third generation). Importantly, it was found that the parasitism rate was higher in vineyards with ground cover. In addition, EI in the area surrounding the vineyards produced a significant increase in parasitism. These results suggest potential for CBC of L. botrana if EI around vineyards, and ground cover with native perennial plants within vineyards, are encouraged.

Artificial temporary non-crop habitats support parasitoids on arable land

Non-crop habitats are important to support biodiversity and ecosystem services in agricultural landscapes. Whereas perennial and managed non-crop habitats have known benefits, temporary non-crop patches within arable fields (field defects) have been poorly studied. We created artificial field defects (unsown patches) in oilseed rape (Brassica napus L.) fields and evaluated their effects on parasitoid assemblages at two crop growth stages. Moreover, we compared unmanaged patches with those sown with flowering plants (Onobrychis vicifolia) and crop controls and analyzed the influence of position within the field (edge or interior), and total flower availability. Altogether, we found almost 200 morphospecies of hymenopteran parasitoids (140 in unsown patches, 147 in Onobrychis patches, and 81 in controls), including important enemies of crop pests. Species richness and abundance were higher on both types of unsown patches than in controls but were not affected by Onobrychis sowing. The differences between unsown patches and controls were larger during oilseed ripening, suggesting that these temporary habitats can offer important resources during crop senescence. Parasitoid species composition differed between controls and unsown patches, indicating that species not linked to the crop could also benefit from these habitats. Finally, unsown patches with higher flower availability supported higher species richness, total abundance, and abundance of three key species during OSR flowering. Thus, newly created unmanaged habitats have the potential to increase biodiversity despite their small size, although increasing flower resources can boost their benefits. Unsown patches can be easily created by switching-off sowing, facilitating their adoption by farmers. Future studies on pest control levels and comparisons with other agri-enviromental schemes would help to elucidate the cost-benefit of unsown patches.

Co-occurrence in ant primary parasitoids: a Camponotus rectangularis colony as host of two eucharitid wasp genera.

Different assemblages of parasitoids may attack a given host species and non-random distribution patterns in parasitoid species assemblages have been reported on various occasions, resulting in co-occurrence at the population, colony, or even individual host levels. This is the case for different closely related species of eucharitid wasps (a family of specialized ant parasitoids) sharing similar niches and co-occurring on the same host at different levels. Here we reviewed all known associations between eucharitid wasps and the ant host genus Camponotus Mayr, 1861 and reported new ant-parasitoid associations. In addition, we report a new case of co-occurrence in eucharitid wasps, at the host colony level, involving a new undescribed species of Pseudochalcura Ashmead, 1904 and an unidentified species of Obeza Heraty, 1985, which attack the common but very poorly known neotropical arboreal ant Camponotus rectangularis Emery, 1890. Most attacks were solitary, but various cocoons were parasitized by two (16%) or three (8%) parasitoids. Globally, parasitism prevalence was very low (3.7%) but showed an important variability among samples. Low parasitism prevalence along with host exposure to parasitoid attack on host plants and overlapping reproductive periods of both parasitoid species may have allowed the evolution of co-occurrence. We also provided some additional data regarding the host ant nesting habits, the colony composition and new symbiotic associations with membracids and pseudococcids. The seemingly polydomous nesting habits of C. rectangularis could play a part in the reduction of parasitism pressure at the population level and, combined with occasionally important local parasitism rates, could also contribute to some parts of the colonies escaping from parasites, polydomy possibly representing an effective parasitism avoidance trait.

Importance of interaction rewiring in determining spatial and temporal turnover of tritrophic (Piper‐caterpillar‐parasitoid) metanetworks in the Yucatán Península, México

AbstractNatural history studies documenting spatial and temporal variation of species assemblages and their interactions are critical for understanding biodiversity and community ecology. We characterized caterpillar–parasitoid assemblages on shrubs in the genus Piper across remnants of semi‐evergreen forest in the Yucatán Península during the rainy and rainy–dry seasons. We collected caterpillars feeding on Piper leaves and reared them to adults or parasitoids to: (i) describe tritrophic interactions between Piper, caterpillars, and parasitoids, (ii) compare empirical metanetworks among sites and seasons, and (iii) investigate patterns in species and interaction turnover across spatial and temporal scales to understand the contribution of species composition and interaction rewiring to overall interaction turnover. We found six Piper species supporting 79 species of caterpillars, which in turn hosted 20 species of parasitoids. In total, there were 116 realized trophic interactions. Species and interactions exhibited substantial turnover at temporal and spatial scales. Total interaction turnover was more pronounced across seasons in all sites (>93%), than it was between sites (<91%). We also found that interaction rewiring contributed more to overall interaction turnover than species turnover. The spatial and temporal variation in metanetworks documented here contribute to understanding fine‐scale temporal and spatial turnover in tropical species and interactions and raise important questions about the lability of consumer specialization and the short‐term effects of interaction rewiring on the stability of biotic communities. Our results highlight the importance of tropical food web studies that are based on natural history using consistent field methods to document bi‐ and tripartite interactions.Abstract in Spanish is available with online material.

Tritrophic web structure in montane Andean forests undergoing ecological restoration

Parasitism represents an important ecosystem service, reducing pest abundance. Since most hosts of parasitoids are herbivores, plant diversity likely shapes both herbivore and parasitoid assemblages. While restoration efforts are being adopted worldwide, mitigating habitat degradation, little is known about how tritrophic webs are organized among plant species in recovering ecosystems. Here we collected exposed herbivores (Coleoptera and Lepidoptera larvae) during four sampling months from five plant species in two restoration areas in Andean forests in southern Ecuador. Larvae were kept in the laboratory until the emergence of the adults or parasitoids. Herbivore and parasitoid diversity and parasitism rates were compared among plants. A total of 82 immature individuals (56 Lepidoptera and 26 Coleoptera—23 predatory and 3 herbivorous) were collected and 102 parasitoids emerged (all Hymenoptera except one tachinid fly). Herbivore and parasitoid assemblages showed a high species turnover between plant species. The mean parasitism rate was 35.14% and 46.67% in the two restoration sites, respectively, with no significant differences found within forests or plants. Long-term food web monitoring should be carried out to improve our understanding of how ecosystems under ecological restoration programs functionally recover.

Potential for biological control of the vegetable leafminer, Liriomyza sativae (Diptera: Agromyzidae), in Australia with parasitoid wasps

AbstractThe vegetable leafminer, Liriomyza sativae Blanchard, poses a risk to vegetable and nursery production in mainland Australia since established in Cape York in 2015. Effective control overseas depends on maximising the impact of natural enemies. Problems with polyphagous Liriomyza pest species typically result from the destruction of their parasitoids by excessive use of non‐selective insecticides. Field studies are reviewed to identify parasitoid species involved in the biological control of L. sativae in open‐air and glasshouse production internationally and to assess the current knowledge of parasitoids of agromyzids in Australia. Overseas, invading Liriomyza populations have frequently been exploited by endemic parasitoids (often found on non‐pest agromyzid species), and non‐crop hosts have played a role as reservoirs of these parasitoids. The few published Australian field studies on the occurrence of agromyzid flies and their parasitoids show a large community of wasps attacking agromyzids, with species mainly from the Eulophidae, Pteromalidae and Braconidae. The most abundant recorded species are two cosmopolitan eulophid species, Hemiptarsenus varicornis (Girault) and Diglyphus isaea (Walker), and four Australian species: two eulophid species, Zagrammosoma latilineatum Ubaidillah and Closterocerus mirabilis Edwards & La Salle, one pteromalid species, Trigonogastrella sp., and one braconid species, Opius cinerariae Fischer, for which there is little biological information. One deficiency in the known assemblage in Australia is the absence of parasitoids from the Eucoilinae (Hymenoptera: Figitidae), a subfamily with several abundant species attacking agromyzids overseas. The composition and impact of the endemic parasitoid assemblage in Australia on populations of L. sativae needs to be assessed adequately in the field before the importation of additional exotic parasitoid species is contemplated. Overseas, two species, D. isaea and Dacnusa sibirica Telenga, are reared commercially for augmentative biological control, although the relatively high cost of production has restricted their release to protected cropping situations. Knowledge gaps remain locally about the taxonomy, distribution, host range and life cycle of parasitoids, and their potential impact on L. sativae.

Caterpillar-parasitoid food webs and biological control in two extensive crops

Food webs offer a useful approach to the study of complex communities interacting across trophic levels, potentially linking community structure and ecosystem services such as biological control. Herbivore-parasitoid food webs are relevant for agricultural production, in terms of pests and their control. Here, we compare caterpillar-parasitoid food webs in a perennial (alfalfa) and an annual (soybean) crop in Central Argentina, by analyzing their diversity, food web structure and parasitism rates using four years of data. Caterpillar – parasitoid communities in extensive agricultural systems have barely been addressed in a food web context. We found the same eleven defoliating Lepidoptera species in both crops, with similar annual richness values. However, alfalfa sustained larger caterpillar populations and richer parasitoid assemblages than soybean, even when only summer data (when both crops coexisted) were considered. Parasitism rates were also higher on alfalfa (only for yearlong data), suggesting bottom-up effects on the third trophic level, and may reflect the resource continuity offered by this crop. A discriminant analysis separated alfalfa from soybean food webs, mainly on the basis of vulnerability (an indicator of the mean number of parasitoid species per host), which was in turn unrelated to parasitism rates, thus suggesting a breach between two functional approaches, i.e. food webs and ecological processes such as biological control.

First record of <i> Anselmella malacia </i> Xiao & Huang, 2006 (Hymenoptera: Eulophidae), a new insect pest of water apple <i>(Syzygium samarangense) </i> and its associated parasitoid in Dong Thap Province, Vietnam

The eulophid wasp, Anselmella malacia Xiao & Huang, 2006 (Hymenoptera: Eulophidae), is reared from fruits of the water apple, Syzygium samarangense, and is reported as an important phytophagous developing as seed-eaters of Syzygium species in Malaysia. Analysing specimens of pest insects infested inside of pear-shaped fruits of the cultivated water apple, S. samarangense, in Dong Thap Province, South Vietnam, a total of four insect species were recorded as the important pests for fruits of six varieties of the cultivated water apples. The hymenoteran wasp, A. malacia, is recorded for the first time from Vietnam. Further evidence is needed to prove A. malacia being an invasive pest in Vietnam. The associated hymenopteran parasitoid assemblage with the fruit infested insect pests is also provided.