Species richness estimation of the Afrotropical Darwin wasps (Hymenoptera, Ichneumonidae).

Species richness is one of the fundamental metrics of biodiversity. Estimating species richness helps spotlight taxonomic groups that are particularly under-studied, such as the highly diverse Darwin wasps. The only available estimate of the number of Darwin wasps in the Afrotropics proposed almost 11,000 species, compared to the 2,322 recorded species. However, it relied exclusively on the ratio of morphospecies to described species in Henry Townes' personal collection. We provide an updated estimate of the Afrotropical Darwin wasp species, using empirical data from multiple sources, including the increase in species numbers following generic revisions, morphospecies sorting in natural history collections, and diversity patterns of better-studied insects (butterflies) for extrapolation. Our analyses suggest that our knowledge of Darwin wasps is highly incomplete, with only 13-22% of species known in the five most extensively studied countries in the Afrotropics. We estimate 9,206-15,577 species of Darwin wasps within the entire Afrotropics, with the highest concentration expected in the Equatorial Afrotropics and Madagascar. Due to data constraints, our approach tends to underestimate diversity at each step, rendering the upper estimate (15,577 species) more realistic. We highlight reasons contributing to the gap between recorded and estimated species richness, including logistical and financial factors, as well as post-colonial influences.

Do changes in Lactuca sativa metabolic performance, induced by mycorrhizal symbionts and leaf UV-B irradiation, play a role towards tolerance to a polyphagous insect pest?

The increased ultraviolet radiation (UV) due to the altered stratospheric ozone leads to multiple plant physiological and biochemical adaptations, likely affecting their interaction with other organisms, such as pests and pathogens. Arbuscular mycorrhizal fungi (AMF) and UV-B treatment can be used as eco-friendly techniques to protect crops from pests by activating plant mechanisms of resistance. In this study, we investigated plant (Lactuca sativa) response to UV-B exposure and Funneliformis mosseae (IMA1) inoculation as well as the role of a major insect pest, Spodoptera littoralis. Lettuce plants exposed to UV-B were heavier and taller than non-irradiated ones. A considerable enrichment in phenolic, flavonoid, anthocyanin, and carotenoid contents and antioxidant capacity, along with redder and more homogenous leaf color, were also observed in UV-B-treated but not in AMF-inoculated plants. Biometric and biochemical data did not differ between AMF and non-AMF plants. AMF-inoculated plants showed hyphae, arbuscules, vesicles, and spores in their roots. AMF colonization levels were not affected by UV-B irradiation. No changes in S. littoralis-feeding behavior towards treated and untreated plants were observed, suggesting the ability of this generalist herbivore to overcome the plant chemical defenses boosted by UV-B exposure. The results of this multi-factorial study shed light on how polyphagous insect pests can cope with multiple plant physiological and biochemical adaptations following biotic and abiotic preconditioning.

Back to the Wild: The Parasitoid Community of Lobesia botrana (Lepidoptera: Tortricidae) in a Grapevine-Free Natural Environment.

The European grapevine moth (EGVM), Lobesia botrana (Lepidoptera: Tortricidae), is one of the major concerns for vineyard managers in the Mediterranean area. It is a polyphagous moth, which develops on a wide variety of host plants, among which the spurge flax, Daphne gnidium (Thymelaeaceae), very likely represents its originary wild host plant. In this study, we investigated the parasitoid complex of L. botrana feeding on D. gnidium during a three-year sampling in a natural reserve in Tuscany, Italy, where this plant is extremely abundant while the grapevine is absent. A total of 24 species of parasitoids were obtained from eggs, larvae, and pupae of EGVM, belonging to 6 families of Hymenoptera and a family of Diptera. The ichneumonid wasp Campoplex capitator was the most abundant larval parasitoid. Four species of the genus Trichogramma were obtained from parasitized eggs during the first year of sampling, with a peak in the parasitisation during the EGVM 3rd generation. Some of the main EGVM parasitoids on spurge flax were also observed in vineyards, although a certain degree of redundancy was observed in the wild, due to several less frequent "satellite" species exploiting the same host. Overall, this research sheds light on the parasitoid community and dynamics of this important moth pest in a grapevine-free natural ecosystem, discussing the possible role of natural areas as ecological reservoirs of pest natural enemies.

A world review of the bristle fly parasitoids of webspinners.

BACKGROUND: Dipteran parasitoids of Embioptera (webspinners) are few and extremely rare but known from all biogeographical regions except Australasia/Oceania. All belong to the fly family Tachinidae, a hyperdiverse and widespread clade of parasitoids attacking a variety of arthropod orders. RESULTS: The webspinner-parasitizing Diptera are reviewed based mostly on records from the collecting and rearing by Edward S. Ross. A new genus is erected to accommodate a new Afrotropical species, Embiophoneus rossi gen. et sp. nov. The genus Perumyia Arnaud is reviewed and a new species, Perumyia arnaudi sp. nov., is described from Central America while P. embiaphaga Arnaud is redescribed and new host records are given. A new species of Phytomyptera Rondani, P. woodi sp. nov., is described from Myanmar, representing the first report of a member of this genus obtained from webspinners. The genus Rossimyiops Mesnil is reviewed, R. longicornis (Kugler) is redescribed and R. aeratus sp. nov., R. fuscus sp. nov. and R. rutilans sp. nov. are newly described from the Oriental Region, and an updated key to species is given. CONCLUSIONS: Webspinners were probably colonized independently at least four times by tachinids shifting from other hosts, most likely Lepidoptera.

Leaf UV-B Irradiation and Mycorrhizal Symbionts Affect Lettuce VOC Emissions and Defence Mechanisms, but Not Aphid Feeding Preferences.

Arbuscular mycorrhizal fungi (AMF) and ultraviolet-B radiation (UV-B) play important roles in plant-insect interactions by altering plant physiology and histology. We hypothesized that UV-B-induced oxidative stress was mitigated by AMF symbiosis. In this study, we conducted a multifactorial experiment to explore lettuce plant response to AMF inoculation and UV-B exposure (0.4 W m-2; 16 h d-1; 2 weeks), either together or individually, as well as the interaction with the polyphagous insect pest Myzus persicae (Sulzer). Lettuce plants subjected to UV-B radiation showed an increase in callose and oxidative stress indicators, as well as a decrease in stomatal density. Mycorrhizal colonization cancelled out the effect of UV-B on stomatal density, while the symbiosis was not affected by UV-B treatment. The plant volatile emission was significantly altered by UV-B treatment. Specifically, the non-terpene 1-undecene abundance (+M/+UVB: 48.0 ± 7.78%; -M/+UVB: 56.6 ± 14.90%) was increased, whereas the content of the non-terpene aldehydes decanal (+M/+UVB: 8.50 ± 3.90%; -M/+UVB: 8.0 ± 4.87%) and undecanal (+M/+UVB: 2.1 ± 0.65%; -M/+UVB: 1.20 ± 1.18%) and the sesquiterpene hydrocarbons (+M/+UVB: 18.0 ± 9.62 %; -M/+UVB: 19.2 ± 5.90%) was decreased. Mycorrhization, on the other hand, had no significant effect on the plant volatilome, regardless of UV-B treatment. Aphid population was unaffected by any of the treatments, implying a neutral plant response. Overall, this study provides new insights about the interactions among plants, UV-B, and AMF, outlining their limited impact on a polyphagous insect pest.

A striking new species of Dolichomitus Smith, 1877 (Hymenoptera: Ichneumonidae; Pimplinae) from South America.

BACKGROUND: Dolichomitus Smith, 1877 is a genus of Darwin wasps characterised by their large bodies and long ovipositors, that includes more than 75 species worldwide, 20 of which occur in the Neotropical Region. Due to recent efforts, the number of species of this genus continues to increase in South America. NEW INFORMATION: A new iridescent species of Pimplinae, Dolichomitus meii sp. nov., is described and illustrated. It was discovered from the biological station of Yanayacu located in the north-eastern slopes of the tropical Andes. It may be separated from all other species of Dolichomitus Smith by the striking colour pattern and apically strongly decurved ovipositor.

Mating Disruption for Managing the Honeydew Moth, Cryptoblabes gnidiella (Millière), in Mediterranean Vineyards.

The demand for a reduced use of pesticides in agriculture requires the development of specific strategies for managing arthropod pests. Among eco-friendly pest control tools, pheromone-based mating disruption (MD) is promising for controlling several key insect pests of economic importance, including many lepidopteran species. In our study, we evaluated an MD approach for managing the honeydew moth (HM), Cryptoblabes gnidiella, an emerging threat for the grapevine in the Mediterranean basin. The trials were carried out in two study sites, located in Tuscany (central Italy, years 2017-2019) and Apulia (southern Italy, years 2016 and 2018-2019), and by applying MD dispensers only in April, in April and July, and only in July. To evaluate the effects of MD, infested bunches (%), damaged area (%) per bunch, and number of living larvae per bunch were compared among plots covered with MD dispensers, insecticide-treated plots (Apulia only), and untreated control plots. Male flights were monitored using pheromone-baited sticky traps. Except for the sampling carried out in Tuscany in 2018, where HM infestation level was very low, a significant difference was recorded between MD and control plots, both in terms of HM damage caused to ripening grapes and/or number of living larvae per bunch. Overall, our study highlighted that MD, irrespective of the application timing, significantly reduced HM damage; the levels of control achieved here were similar to those obtained with the application of insecticides (no MD). However, MD used as stand-alone strategy was not able to provide complete pest control, which may instead be pursued by growers with an IPM approach.

Old Parasitoids for New Mealybugs: Host Location Behavior and Parasitization Efficacy of Anagyrus vladimiri on Pseudococcus comstocki.

The Comstock mealybug, Pseudococcus comstocki (Hemiptera: Pseudococcidae) is a primary pest of orchards in the North and Northwest of China. This pest appeared recently in Europe, including Italy, where it is infesting mainly vineyards as well as apple and pear orchards. The present study investigated the efficacy of Anagyrus vladimiri, a known biological control agent (BCA) of Planococcus ficus, on P. comstocki to evaluate a potential use for the management of this new pest. No-choice tests were conducted to quantify the parasitoid behavior against P. ficus and P. comstocki. The parasitoid successfully parasitized both species (parasitization rate: 51% and 67% on P. comstocki and P. ficus, respectively). The A.vladimiri developmental time (19.67 ± 1.12 vs. 19.70 ± 1.07 days), sex ratio (1.16 ± 1.12 vs. 1.58 ± 1.07) and hind tibia length of the progeny showed no differences when P. comstocki and P. ficus, respectively, were exploited as hosts. Two-choice tests, conducted by providing the parasitoid with a mixed population of P. ficus and P. comstocki, showed no host preference for either of the two mealybug species (23 vs. 27 first choices on P. comstocki and P. ficus, respectively). The parasitization rate (61.5% and 64.5% in P. comstocki and P. ficus, respectively) did not differ between the two hosts. Overall, our study adds basic knowledge on parasitoid behavior and host preferences and confirms the use of this economically important encyrtid species as an effective BCA against the invasive Comstock mealybug.

Tachinid (Diptera, Tachinidae) parasitoids of Lobesia botrana (Denis & Schiffermüller, 1775) (Lepidoptera, Tortricidae) and other moths.

The present paper reports data on the biology of eleven species of tachinid flies collected in Italy and Spain on different host plants and emerged from different host larvae. An annotated list of the eleven species emerged from the collected lepidopterans is provided; information about distribution and biology are given as well as the description of their puparia. Two new parasitoid species of the European Grapevine Moth (EGVM) Lobesia botrana were recorded: Clemelis massilia, whose host preferences were unknown so far, and Neoplectops pomonellae. A list of lepidopteran pest species with their associated plants and tachinid parasitoids is then given in order to highlight the relationships among the three components of the biocenosis (plant, herbivore and parasitoid). Eventually, due to the great economic importance of L. botrana in viticulture, a preliminary identification key to the puparia of its tachinid parasitoids is provided.

New records of Ichneumonidae (Hymenoptera) for the Italian fauna.

New distributional records on 55 ichneumonids (Hymenoptera, Ichneumonidae) from Italy are provided. Of these, 47 species are new for Italy, including representatives of the subfamily Diacritinae and of the tribes Zimmeriini (Ichneumoninae) and Pseudorhyssini (Poemeniinae); six species are new for Sardinia, one for Sicily and one for the Italian mainland. The hitherto unknown female of Baranisobashibericus Heinrich, 1972 (Ichneumoninae) is described.

Vertical stratification of ichneumonid wasp communities: the effects of forest structure and life-history traits.

Parasitoid wasp communities of the canopy of temperate forests are still largely unexplored. Very little is known about the community composition of parasitoids between canopy and understory and how much of this difference is related to forest structure or parasitoid biological strategies. In this study we investigated upon the difference in the community composition of the parasitic wasps Ichneumonidae between canopy and understory in a lowland temperate forest in northern Italy. We used general linear models to test whether parasitic strategy modifies species vertical stratification and the effect of forest structure. We also tested differences in ß-diversity between canopy and understory traps and over time within single forest layers. We found that stand basal area was positively related to species richness, suggesting that the presence of mature trees can influence local wasp diversity, providing a higher number of microhabitats and hosts. The ichneumonid community of the canopy was different from that of the understory, and the ß-diversity analysis showed higher values for the canopy, due to a higher degree of species turnover between traps. In our analyses, the vertical stratification was different between groups of ichneumonids sharing different parasitic strategies. Idiobiont parasitoids of weakly or deeply concealed hosts were more diverse in the understory than in the canopy while parasitoids of spiders were equally distributed between the two layers. Even though the ichneumonid community was not particularly species-rich in the canopy of the temperate forests, the extension of sampling to that habitat significantly increased the number of species recorded.