Feeding preference and intraguild interactions between the parasitoid Trichogramma achaeae and the predator Macrolophus pygmaeus, two biological agents of Tuta absoluta

BACKGROUND

Tuta absoluta is an exotic species and a major pest of tomato crops in Europe. Macrolophus pygmaeus and Trichogramma achaeae are two biocontrol agents widely used in integrated pest management programs of the South American tomato pinworm Tuta absoluta. In this study, we evaluated under laboratory conditions the (i) voracity of M. pygmaeus females fed on single diets of Tuta absoluta eggs parasitized or unparasitized by Trichogramma achaeae, (ii) voracity and feeding preference of M. pygmaeus females provided with mixed diets of Tuta absoluta eggs unparasitized and parasitized by Trichogramma achaeae and (iii) effect of competitive and intraguild interactions between M. pygmaeus and Trichogramma achaeae on the number of Tuta absoluta eggs consumed and/or parasitized. Lastly, we assessed under field conditions the effect of interspecific and intraspecific interactions between natural enemies on the number of Tuta absoluta eggs consumed and/or parasitized.

RESULTS

Macrolophus pygmaeus consumed more unparasitized than parasitized eggs of Tuta absoluta. Under mixed diet regimes, Manly indices revealed a feeding preference for unparasitized eggs, and a decrease in the total number of eggs consumed, as the proportion of available parasitized eggs increased, whereas the unparasitized eggs were consumed in direct proportion to their availability. Conspecific interactions between M. pygmaeus, in contrast to Trichogramma achaeae, revealed the possible occurrence of intraspecific competition. For intraguild heterospecific interactions, the number of Tuta absoluta eggs consumed by M. pygmaeus and parasitized by Trichogramma achaeae was lower than that predicted for additive and non-interactive scenarios. Under field conditions, a significant difference between the conspecific treatment and heterospecific treatments revealed a slightly higher success rate in controlling Tuta absoluta when both M. pygmaeus and Trichogramma achaeae were used simultaneously.

CONCLUSION

Macrolophus pygmaeus prefers unparasitized eggs of Tuta absoluta but inflicts intraguild predation on Trichogramma achaeae. In conspecific experiments, mutual interference between M. pygmaeus predators intensifies as the number of individuals increases, but for Trichogramma achaeae, it occurs in an unpredictable manner. Adding Trichogramma achaeae could significantly increase the level of control of Tuta absoluta compared to what could be achieved when only M. pygmaeus is present in glasshouse tomatoes. © 2023 Society of Chemical Industry.

Monitoring Arthropods in maize and pasture fields in São Miguel and São Jorge Islands: IPM-Popillia Project

Background

The dataset presented here is an achievement of the H2020 European project "Integrated Pest Management of the Invasive Japanese Beetle, Popilliajaponica (IPM-Popillia)". This project addresses the challenge of a new risk to plant health in Europe, the invasion of the Japanese beetle, Popilliajaponica (Newman, 1838) (Coleoptera, Rutelidae) and provides an environmentally friendly IPM Toolbox to control the expanding pest populations across Europe. This study aims to present the records of terrestrial arthropod diversity with a special focus on four groups belonging to Carabids and Staphylinid beetles (Coleoptera), Opiliones and Anisolabididae (Dermaptera), collected with the potential to be used as biocontrol agents against P.japonica in future Integrated Pest Management programmes. A thorough sampling programme was conducted in maize and pasture fields in two Islands of the Azores (São Miguel and São Jorge) in the summer of 2022.

New information

We provided an inventory of the arthropods recorded in two Azorean agroecosystems (maize and pasture fields) from São Miguel and São Jorge Islands. A total of ten maize and ten pasture fields were sampled and a total of 360 pitfall traps were installed, 216 in São Miguel and 144 in São Jorge, for seven consecutive days in August and September of 2022.We collected 18559 specimens belonging to the phylum Arthropoda, four classes, twelve orders, twenty-six families and forty morphospecies (two identified at the family level as carabid and Staphylinid larvae and 38 identified at the species level). We identified 38 taxa at the species level (n = 18281). Of the 38 identified taxa, 18 species were predators, 15 were plant feeders and five were omnivores. The 18 predators belong to the following families: 10 species were Carabidae, two Staphylinidae, one Anisolabididae, one Chrysopidae, one Leiobunidae, one Nabidae, one Phalangiidae and one Scathophagidae. Concerning the origin of the predators, we recorded five native species: two Carabidae, one Leiobunidae, one Scathophagidae and one Nabidae. The other 13 predator species were introduced or indeterminate.

A roadmap for ladybird conservation and recovery

Ladybirds (Coleoptera: Coccinellidae) provide services that are critical to food production, and they fulfill an ecological role as a food source for predators. The richness, abundance, and distribution of ladybirds, however, are compromised by many anthropogenic threats. Meanwhile, a lack of knowledge of the conservation status of most species and the factors driving their population dynamics hinders the development and implementation of conservation strategies for ladybirds. We conducted a review of the literature on the ecology, diversity, and conservation of ladybirds to identify their key ecological threats. Ladybird populations are most affected by climate factors, landscape composition, and biological invasions. We suggest mitigating actions for ladybird conservation and recovery. Short-term actions include citizen science programs and education, protective measures for habitat recovery and threatened species, prevention of the introduction of non-native species, and the maintenance and restoration of natural areas and landscape heterogeneity. Mid-term actions involve the analysis of data from monitoring programs and insect collections to disentangle the effect of different threats to ladybird populations, understand habitat use by taxa on which there is limited knowledge, and quantify temporal trends of abundance, diversity, and biomass along a management-intensity gradient. Long-term actions include the development of a worldwide monitoring program based on standardized sampling to fill data gaps, increase explanatory power, streamline analyses, and facilitate global collaborations.

The failed invasion of Harmonia axyridis in the Azores, Portugal: Climatic restriction or wrong population origin?

We tested two questions: (i) whether the climatic conditions of the Azorean Islands in Portugal may have restricted the invasion of Harmonia axyridis across this archipelago and (ii) determine what population of this species could have a higher probability of invading the islands. We used MaxEnt to project the climate requirements of different H. axyridis populations from three regions of the world, and the potential global niche of the species in the Azorean islands. Then we assessed the suitability of the islands for each of the three H. axyridis populations and global potential niche through histograms analysis, Principal Component Analysis (PCA) of climate variables, and a variable-by-variable assessment of the suitability response curves compared with the climatic conditions of the Azores. Climatic conditions of the Azores are less suitable for the U.S. and native Asian populations of H. axyridis, and more suitable for European populations and the global potential niche. The PCA showed that the climatic conditions of the islands differed from the climatic requirements of H. axyridis. This difference is mainly explained by precipitation of the wettest month, isothermality, and the minimum temperature of the coldest month. We concluded that the climatic conditions of the Azores could have influenced the establishment and spread of H. axyridis on these islands from Europe. Our results showed that abiotic resistance represented by the climate of the potentially colonizable zones could hinder the establishment of invasive insects, but it could vary depending of the origin of the colonizing population.

Evaluation of Scymnus nubilus (Coleoptera: Coccinellidae) as a biological control agent against Aphis spiraecola and Cinara juniperi (Hemiptera: Aphididae)

BACKGROUND

Aphids are a major insect pest of forestry systems. In this study, we evaluate the potential of the ladybeetle Scymnus nubilus Mulsant (Coleoptera: Coccinellidae) as a biological control agent against Aphis spiraecola Patch and Cinara juniperi (De Geer) (Hemiptera: Aphididae) infesting Azorean endemic plants reared in forestry nurseries.

RESULTS

Aphis spiraecola, infesting Viburnum treleasei Gand. (Dipsacales: Adroxaceae), was the most abundant aphid; however, a higher proportion of Juniperus brevifolia (Seub.) Antoine (Pinales: Cupressaceae) was infested by C. juniperi. Scymnus nubilus fourth instar larvae were able to complete development on both aphid species. Voracity was significantly higher when S. nubilus was fed on A. spiraecola but biomass consumption was significantly lower. The relative growth rate and conversion efficiency of the fourth instar larvae were similar. Field experiments indicated that S. nubilus can contribute to the decrease in pest population densities. However, the fourth instar larvae proved to be more efficient when released onto A. spiraecola; this outcome can be attributed to the distribution patterns of the aphids on the host plant and to the aphid or host plant morphology. Predator density and sleeve cage effect are apparently critical factors in reaching an efficient control.

CONCLUSION

The obtained results provide the essential preliminary information required to establish future programs of biological control against aphids infesting Azorean endemic plants. Developmental and feeding performances, as well as the immediate impact of the predator when released onto A. spiraecola colonies, indicate that S. nubilus could be a useful candidate for reducing aphid populations. © 2019 Society of Chemical Industry.

Leucopis glyphinivora Tanasijtshuk (Diptera: Chamaemyiidae), a new aphidophagous biocontrol agent; development, survival and comparison with Aphidoletes aphidimyza Rondani (Diptera: Cecidomyiidae)

The silver fly Leucopis glyphinivora Tanasijtshuk (Diptera: Chamaemyiidae) is an aphidophagous predator during its larval stage. Our study describes the life cycle of L. glyphinivora and evaluates its potential as a biocontrol agent. The development, survival and longevity of L. glyphinivora were observed and compared with those of the aphid gall midge Aphidoletes aphidimyza Rondani (Diptera: Cecidomyiidae). Tests were conducted under laboratory conditions in Petri dishes with the green peach aphid Myzus persicae Sulzer (Hemiptera: Aphididae) on potato leaves. Leucopis glyphinivora has a 42% longer life cycle than A. aphidimyza. Larval development was 27% longer in L. glyphinivora than in A. aphidimyza. Egg hatch rate and pupal emergence rate were similar in both species, but larval survival was 20% lower for L. glyphinivora than for A. aphidimyza. Sex ratio was approximately 50% in both species. A longer development time for L. glyphinivora in the larval stage could be an advantage for biocontrol by providing more time to exert predation pressure against aphids. However, this may be offset by the lower survival rate found in the silver fly larvae.

Expedient metrics to describe plant community change across gradients of anthropogenic influence

Human influence associated with land use may cause considerable biodiversity losses, namely in oceanic islands such as the Azores. Our goal was to identify plant indicator species across two gradients of increasing anthropogenic influence and management (arborescent and herbaceous communities) and determine similarity between plant communities of uncategorized vegetation plots to those in reference gradients using metrics derived from R programming. We intend to test and provide an expedient way to determine the conservation value of a given uncategorized vegetation plot based on the number of native, endemic, introduced, and invasive indicator species present. Using the metric IndVal, plant taxa with a significant indicator value for each community type in the two anthropogenic gradients were determined. A new metric, ComVal, was developed to assess the similarity of an uncategorized vegetation plot toward a reference community type, based on (i) the percentage of pre-defined indicator species from reference communities present in the vegetation plots, and (ii) the percentage of indicator species, specific to a given reference community type, present in the vegetation plot. Using a data resampling approach, the communities were randomly used as training or validation sets to classify vegetation plots based on ComVal. The percentage match with reference community types ranged from 77 to 100 % and from 79 to 100 %, for herbaceous and arborescent vegetation plots, respectively. Both IndVal and ComVal are part of a suite of useful tools characterizing plant communities and plant community change along gradients of anthropogenic influence without a priori knowledge of their biology and ecology.

Using species spectra to evaluate plant community conservation value along a gradient of anthropogenic disturbance

The aim of this study was to assess the impact of anthropogenic disturbance on the partitioning of plant communities (species spectra) across a landcover gradient of community types, categorizing species on the basis of their biogeographic, ecological, and conservation status. We tested a multinomial model to generate species spectra and monitor changes in plant assemblages as anthropogenic disturbance rise, as well as the usefulness of this method to assess the conservation value of a given community. Herbaceous and arborescent communities were sampled in five Azorean islands. Margins were also sampled to account for edge effects. Different multinomial models were applied to a data set of 348 plant species accounting for differences in parameter estimates among communities and/or islands. Different levels of anthropogenic disturbance produced measurable changes on species spectra. Introduced species proliferated and indigenous species declined, as anthropogenic disturbance and management intensity increased. Species assemblages of relevance other than economic (i.e., native, endemic, threatened species) were enclosed not only in natural habitats, but also in human managed arborescent habitats, which can positively contribute for the preservation of indigenous species outside remnants of natural areas, depending on management strategies. A significant presence of invasive species in margin transects of most community types will contribute to an increase in edge effect that might facilitate invasion. The multinomial model developed in this study was found to be a novel and expedient tool to characterize the species spectra at a given community and its use could be extrapolated for other assemblages or organisms, in order to evaluate and forecast the conservation value of a site.

[Diagnosis of illiteracy in patients hospitalized at a nursing service. Prospective study]

When, at the end of a medical visit, a doctor prescribes medication, he may be unaware that writing is unknown to the patient. This fact compromises the patient's understanding of disease and therapeutics and thus the importance of diagnosing illiteracy. The A.A studied prospectively 200 consecutive patients admitted to a Medical Ward at Santa Maria Hospital in Lisbon, from 13/3/1997 to 8/7/1998. The study included age, gender, social environment, evaluation of the ability to read and write, years of scholarship and the principal diagnosis. The results were to chi 2 (Yates) and Student's T-tests.

RESULTS

94 patients were male and 106 female, aged between 18 and 95 years (mean 62.3), 106 from an urban environment, 54 from a rural environment and 37 had lived their adult life in a rural environment but were at present living in an urban environment. The percentage of illiteracy was 30.5%, being considerably higher in the females (43.4%) than in the males (15.96%), in patients above 65 years (49%) compared to patients from 15 to 64 years old (12%), in non-urban patients (55%) opposed to urban born patients (10.4%). Any of these variables, gender, age and social environments had statistical significance to P < 0.001 when associated to illiteracy.

CONCLUSIONS

The comparative analysis of the official results for the general Portuguese Population study, Census 91, shows an important analogy. In both studies illiteracy was worst in females and in those above 65 years of age. Today illiteracy is still days a serious National problem, with important medical implications, a troublesome obstacle to the understanding of the disease and compliance with therapy.

[A false incisional hernia during coumarin anticoagulation]

This short clinical report presents a case of giant pelvic hematoma with infiltration of the abdominal wall, initially misdiagnosed as incisional hernia by means of the old McBurney laparotomy. The patient, a 56-year-old female, was under chronic coumarin anticoagulation to prevent systemic embolism recurrence (rheumatic polyvalvular disease, atrial fibrillation, and previous brain embolism). On admission, the I.N.R. was 6.6. The risks versus benefits dilemma of chronic oral anticoagulation is briefly commented.