Reassessment of molecular and morphological variation within the Anagrus atomus species complex (Hymenoptera: Mymaridae): egg parasitoids of leafhoppers (Hemiptera: Cicadellidae) in Europe and North America

Influence of Vineyard Inter-Row Management on Grapevine Leafhoppers and Their Natural Enemies

Inter-row management in vineyards can influence the abundance of grapevine pests and their natural enemies. In 2013-2015, in a vineyard in northeastern Italy, the influence of two vineyard inter-row management strategies (i.e., alternate mowing, AM, and periodical tillage, PT) on the population dynamics of grapevine leafhoppers Hebata vitis and Zygina rhamni and their natural enemies, the mymarid Anagrus atomus and spiders (Araneae), and other hymenopteran parasitoids, were studied with different survey approaches. The infestations of both leafhoppers were lower in AM than PT due to the reduced leafhopper oviposition and higher nymph mortality in AM. This occurred although leafhopper egg parasitization by A. atomus was greater in PT than AM according to a density-dependent relationship with the leafhopper egg amount. Hymenopteran parasitoids other than A. atomus were the most abundant in AM, probably due to the higher availability of nectar and pollen than in PM. The significantly higher population densities of hunting spiders in AM than PT can be associated with the higher predation of leafhopper nymphs. Therefore, the study demonstrated that the alternate mowing of vineyard inter-rows enhances the abundance of natural enemies, such as spiders and hymenopteran parasitoids, and can contribute to grapevine leafhopper pest control.

Chinese Species of the Genus Pseudanaphes Noyes & Valentine (Hymenoptera: Mymaridae) with Description of a New Species

The fairyfly Mymaridae (Hymenoptera: Chalcidoidea) are widely distributed worldwide, but species of this family have rarely been collected and recorded from the Qinghai-Tibet Plateau. In this study, mymarids collected in Tibet, China, are identified based on morphology and molecular data. Two species of the genus Pseudanaphes Noyes & Valentine are treated and illustrated here, including a known species, P. zhaoi Lin, and a new species, P. yadongicus Aishan & Cao sp. nov. In addition, a key to the world species of Pseudanaphes (females) and DNA barcodes for P. yadongicus and P. zhaoi are provided.

Differences in Gall Induction of Flower-like Galls on Haloxylon by Psyllids (Hemiptera: Aphalaridae), and the Emergence of Corresponding Parasitoids

Simple Summary

Haloxylon spp. have been infested by various gall inducers, and natural enemies that impact pest populations must be understood to build integrated pest control strategies affecting pest dynamics. However, limited studies report on the gall inducers and parasitoids of flower-like galls on Haloxylon, as well as the parasitic efficacy of the parasitoids. This study aimed to determine the main gall inducers that induced flower-like galls on Haloxylon ammodendron and H. persicum, and the parasitoid complex associated with them. In total, five species of gall inducers and three species of parasitoids were obtained from three types of flower-like galls on Haloxylon. Further, the parasitization indexes, emergence, and lifespan of parasitoids were also discussed. The present study may serve as a basis for understanding the importance of biological investigations of parasitoids in the gall inducers living in flower-like galls, which is important for pest control and the conservation of the ecological environment in the Haloxylon forest.

Abstract

Saxaul is a kind of dominant perennial psammophyte that widely distributes in arid and semi-arid desert areas, and it has multiple functions in preventing desertification, especially in windbreak and sand fixation. Various gall inducers induce galls on the saxaul, including the flower-like gall. Parasitoids have great potentiality in controlling gall inducers. However, studies about gall inducers and parasitoids of flower-like galls on Haloxylon, as well as the parasitic efficacy of the parasitoids, are rarely reported. In this study, the flower-like galls were observed on Haloxylon ammodendron and H. persicum in Fukang, Xinjiang, China. Two types of flower-like galls were found on H. ammodendron, while only one type was found on H. persicum. In total, five species of gall inducers and three species of parasitoids were obtained from the galls mentioned above. All the galls were induced by Caillardia (Hemiptera: Aphalaridae), which were mostly bivoltine in Fukang. Besides, their parasitoids Psyllaephaguscaillardiae and P. longiventris could be observed on all the types of galls. Additionally, correlative studies on the parasitization indexes demonstrated that all the dominant parasitoids of diverse flower-like galls were P. caillardiae, which were slightly more in number than the P. ogazae discovered in the flower bud-like galls. In addition, the relevance between the emergence or lifespan of parasitoids and temperature was also investigated. The results showed that the number of parasitoids emerging decreased rapidly after a period of enhancement with the increase of temperature, including an optimum temperature, while the lifespan of wasps gradually shortened with the temperature rising. Our results highlight the importance of the biological investigation of parasitoids in the gall inducers lived in closed galls, which may provide critical evidence for us to understand its potential application in biological control.

Review of the species of Pediobius (Hymenoptera, Eulophidae) having extreme dorsal setation and description of a new species from East Africa

The Afrotropical species of the genus Pediobius (Hymenoptera, Eulophidae) characterized by extreme setation on the dorsal mesosoma are reviewed and grouped into a newly proposed setigerus group. This group is characterized by the broad attachment of the third funicular and first claval segments, so that the funicle is functionally 2-segmented with a 3-segmented clava. Four species are recognized for the group: P. setigerus Kerrich (from Ghana, Ivory Coast, Republic of Guinea, the Democratic Republic of the Congo, Uganda), P. multisetis Bouek (from Ivory Coast), P. sp. indet. aff. multisetis (from Uganda), and P. erinaceus Gumovsky sp. n. (from Uganda). This last species is associated with a leaf miner, and is easily recognizable in having numerous strong bristles on the lateral areas of the mesoscutum, along the notauli, and anterior margin of the mesoscutum, a smooth mesoscutellum with only one pair of thin setae, and the pronotal collar with only 6 thin setae. By contrast, in P. setigerus and P. multisetis the mesoscutellum is sculptured and bears a row of about 20 strong bristles on each side, and the pronotal collar also bears about 20 strong bristles. The differences between P. setigerus and P. multisetis, as well as issues on their biology and type material, are discussed.

Behavioural Evidence and Chemical Identification of a Female Sex Pheromone in Anagrus atomus (Hymenoptera: Mymaridae)

Anagrus atomus (L.) is an egg parasitoid involved in the biological control of Empoasca vitis (Göthe) in vineyards. Sex pheromones play a crucial role in mate finding for several parasitoid species and could be used for monitoring under field conditions. We carried out laboratory and field studies aimed at assessing the existence and identity of a possible A. atomus sex pheromone. We found that males were significantly attracted by virgin females independent of age. Males were not attracted to individuals of the same sex, but they were attracted by a crude extract from an unmated female and its polar fraction. Eugenol (4-allyl-2-methoxyphenol) was identified as the attractive substance and proved to be attractive not only in the olfactometer but also in another laboratory bioassay and under field conditions. Attraction of males, but not females, confirms that this is not an aggregation pheromone. This is the first sex-pheromone component identified in Mymaridae, however more compounds could be involved in the mating behaviour of A. atomus. The utility of a sex pheromone in A. atomus is discussed in the context of fitness returns.