Parasitism is one of the most successful and ancient strategies. Due to the specialized lifestyle of parasites, they are usually affected by reductions and changes in their body plan in comparison with nonparasitic sister groups. Extreme environmental conditions may impose restraints on behavioural or physiological adaptations to a specific host and limit morphological changes associated with speciation. Such morphological homogeneity has led to the diversity of parasites being underestimated in morphological studies. By contrast, the species concept has dramatically changed in many parasitic groups during recent decades of study using DNA sequence data. Here we tested the phenomenon of cryptic species diversity in the twisted‐wing parasite family Xenidae (Strepsiptera) using nuclear and mitochondrial DNA sequence data for a broad sample of Xenidae. We used three quantitative methods of species delimitation from the molecular phylogenetic data – one distance‐based (ABGD) and two tree‐based (GMYC, bPTP). We found 77–96 putative species in our data and suggested the number of Xenidae species to be more diverse than expected. We identified 67 hosts to species level and almost half of them were not previously known as hosts of Xenidae. The mean number of host species per putative species varied between 1.39 and 1.55. The constant rate in net diversification can be explained by the flexibility of this parasitic group, represented by their ability to colonize new host lineages combined with passive long‐range dispersal by hosts.

No abstract

Host specialization is an important ecological characteristic of parasitic species. The identification of the parasitic strategy of the genus Stylops (Strepsiptera; Stylopidae) is, however, ambiguous. According to the number of recognized species based on existing taxonomy, highly specialized and supergeneralistic species exist in this genus. Our research aims to clarify the concept of host specialization in the genus Stylops, in which all of the members are parasites of Andrena bees. Based on the phylogenetic analysis of the parasites (mostly females) and the mapping of hosts onto the phylogenetic tree, we tested three hypotheses of host specialization: (1) each species of the genus Stylops is associated with a single host species; (2) Stylops species are specialized to a group of closely related hosts; and (3) a single Stylops species is a generalist, parasitizing all host Andrena species in this particular region. Our evidence clearly shows a close relationship between the parasite and the host: one species of Stylops attacks one or a few host species of Andrena bees, usually from a single subgenus. Moreover, a moderate generalistic strategy is also likely in a few Stylops species. According to our results, the species diversity of the strepsipteran parasites of bees must be reconsidered. A single European species of Stylops should be divided into a higher number of valid species.

Xenos is a strepsipteran genus whose members are parasitic to eusocial wasps, including the hornet genus Vespa. We undertook an extensive sampling of strepsipterans in Xenos from hornets collected in East Asia and performed molecular phylogenetic analyses based on mitochondrial cytochrome c oxidase subunit I gene sequences (652 bp) to investigate the cryptic diversity among 21 individuals of strepsipterans. The analyses, accompanied by morphological examination, revealed that these strepsipterans represent two distinct species, X. moutoni du Buysson, 1903 and X. oxyodontes sp. nov. The two species differed in their host-utilization pattern: the latter was almost specific to Vespa analis and V. simillima, whereas the former was associated with other species in Vespa.

Recent developments in video monitoring and time-lapse photography techniques have increased the efficiency of observing floral visitors. However, such approaches still require a great investment of time and effort to extract the relevant information from the large quantity of data produced. In an attempt to shorten this time-consuming process and make it more efficient, we have developed a system to automatically detect moving objects. This new system involves the comparison of consecutive frames to detect differences between the images and highlights those frames that are likely to contain insect visitors. The specifications of the system and the results from a pilot study using the data of the orchid species Platanthera ussuriensis are described below.

The blissine bug Macropes obnubilus, which lives aggregately under leaf sheaths of the evergreen dwarf bamboo, is infected by the strepsipteran parasite Blissoxenos esakii. To determine the ecological properties of the bug-strepsipteran system, we conducted field surveys of natural populations of Macropes bugs and Blissoxenos parasites. The parasitism rate of strepsipterans was high throughout the year and was significantly higher in female than in male bugs. Blissoxenos adult males emerged mainly in May, and neotenic adult females released triungulins in August. The triungulins invaded host nymphs, but subsequent larval development did not occur before the bugs matured. At most, two strepsipterans could mature in a host because of spatial limitations. The mortality of triply or more parasitized bugs was significantly higher than that of singly or doubly parasitized bugs, which survived longer than uninfected ones. The heavy strepsipteran infection profoundly affected the host population by causing host reproductive failure.

BackgroundGeographic differences in flower size sometimes reflect geographic differences in pollinator size. However, we know little about whether this flower size specialization to the regional pollinator size occurred independently at many places or occurred once and then spread across the distribution range of the flower species. ResultsWe investigated the relationship between the local corolla tube length of flowers and morphological traits of local pollinators in 12 populations of Lamium album var. barbatum on two different mountains in the Japan Alps. Then, using 10 microsatellite markers, we analyzed genetic differentiation among the 12 populations. The results showed that local corolla tube length was correlated with the average size of relevant morphological traits of the local pollinators: corolla tube length was greater in populations visited frequently by the largest flower visitors, Bombus consobrinus queens, than it was in other populations. We also found that the degree of genetic similarity between populations more closely reflected interpopulation geographic proximity than interpopulation similarity in corolla tube length.ConclusionsAlthough genetic similarity of populations was highly associated with geographic proximity, corolla tube length varied independently of geographic proximity and was associated with local pollinator size. These results suggest that in L. album var. barbatum, long corolla tube length evolved independently in populations on different mountains as a convergent adaptation to locally abundant large bumblebee species.

BackgroundGeographic differences in floral size sometimes reflect geographic differences in pollinator size. However, we know little about whether this floral size specialization to the regional pollinator size occurred independently at many places or occurred once and then spread across the distribution range of the plant species.ResultsWe investigated the relationship between the local floral size of flowers and local pollinator size in 12 populations ofLamium albumvar.barbatumon two different mountains in the Japan Alps. Then, using 10 microsatellite markers, we analyzed genetic differentiation among the 12 populations. The results showed that local floral size was correlated with the average size of relevant morphological traits of the local pollinators: floral size was greater in populations visited frequently by the largest flower visitors,Bombus consobrinusqueens, than it was in other populations. We also found that the degree of genetic similarity between populations more closely reflected interpopulation geographic proximity than interpopulation similarity in floral size.ConclusionsAlthough genetic similarity of populations was highly associated with geographic proximity, floral size varied independently of geographic proximity and was associated with local pollinator size. These results suggest that inL. albumvar.barbatum, large floral size evolved independently in populations on different mountains as a convergent adaptation to locally abundant large bumblebee species.