Karyotypes of parasitic Hymenoptera： Diversity, evolution and taxonomic significance

Haploid chromosome numbers （n） of parasitic Hymenoptera （= traditional Parasitica ＋ Chrysidoidea） vary from 2 to 23. However, this range can be subdivided into three intervals with n = 14-23 （less derived parasitic wasps, e.g., some Ichneumonidae and Braconidae as well as Gasteruptiidae）, 8-13 （many other parasitic Hymenoptera） and 2-7 （Dryinidae, the majority of Chalcidoidea and some advanced Braconidae, e.g. Aphidiinae）. The symmetric karyotype with a relatively high chromosome number （n -- 14-17） and the prevalence of biarmed chromosomes must be considered as a groundplan feature of parasitic Hymenoptera. Independent reductions of chromosome numbers （n ≤ 10-11） occurred in some groups of the superfamily Ichneumonoidea as well as in the common ancestor of the Proctotrupoidea sensu lato, Ceraphronoidea, Cynipoidea and Chalcidoidea. Further mul- tiple decreases in chromosome numbers （n ≤ 4-6） took place in some Braconidae, various lineages of the superfamily Chalcidoidea as well as in the family Dryinidae. Two main trends prevailed in the karyotype evolution of parasitic wasps： the reduction of chromosome numbers （mainly due to tandem fusions and less frequently due to centric ones） and karyotypic dissymmetrization （through an increase in size differentiation of chromosomes and/or in the share of acrocentrics in a chromosome set）. Although karyotypic features of parasitic Hymenoptera can be used for solving taxonomic problems at various levels, this method is the most effective at the species level.

Singing on the wings! Male wing fanning performances affect female willingness to copulate in the aphid parasitoid Lysiphlebus testaceipes （Hymenoptera： Braconidae： Aphidiinae）

Lysiphlebus testaceipes （Hymenoptera： Braconidae： Aphidiinae） is a generalist endoparasitoid attacking more than 100 aphid species. In L. testaceipes, wing fanning is a main male courtship display evoked by a female-borne sex pheromone. However, no information is available on the characteristics and behavioral role of male fanning during courtship in this parasitoid. Here, the courtship behavior of a wild strain ofL. testaceipes was quantified and the male wing fanning performances were analyzed through high-speed video recordings and examined in relation to mating success. Courtship sequence of wild L. testaceipes did not substantially differ from that previously reported for other populations mass reared on aphids. We observed that the male courtship duration did not affect mating success. However, video analysis revealed that the males producing high-frequency fanning signals achieved higher mating success over those that display low-frequency fanning. Wing fanning before successful and unsuccessful courtship differed in amplitude of wing movements and alignment toward the mate, highlighting that frontal courtship positively influence the female mating decisions. This study increases knowledge on sexual behavior in a key parasitoid of aphids, highlighting the importance of wing fanning among the range of sensory modalities used in the sexual communication ofL. testaceipes. From a practical point of view, this information is useful in L. testaceipes-based biocontrol strategies, since it can help to establish parameters for quality checking of mass-reared wasps over time.