We use an integrative taxonomic approach to revise the genus Anisopteromalus . In particular, we apply multivariate ratio analysis ( MRA ), a rather new statistical method based on principal component analysis ( PCA ) and linear discriminant analysis ( LDA ), to numerous body measurements and combine the data with those from our molecular analysis of Cytb and ITS2 genetic markers (on a subset of species) and all available published data on morphology, karyology, behaviour, host associations and geographic distribution. We demonstrate that the analysis of quantitative characters using MRA plays a major role for the integration of name‐bearing types and thus for the association of taxa with names. Six species are recognized, of which two are new: A. cornis B aur sp.n. and A. quinarius G okhman & B aur sp.n. For Anisopteromalus calandrae ( H oward), a well‐known, cosmopolitan parasitoid of stored‐product pests, we have selected a neotype to foster continuity and stability in the application of this important name. The species was sometimes confused with the related A. quinarius sp.n. , another cosmopolitan species that is frequently encountered in similar environments. We also show that several species originally described or later put under Anisopteromalus actually belong to different genera: Cyrtoptyx camerunus ( R isbec) comb.n. ; Meraporus glaber ( S zelényi) comb.n. ; Dinarmus schwenkei ( R oomi, K han & K han) comb.n. Neocatolaccus indicus A yyar & M ani is confirmed as a junior synonym of Oxysychus sphenopterae ( F errière) syn.n. and Anisopteromalus calandrae brasiliensis ( D omenichini) stat.rev. must be considered as a valid but doubtful taxon. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:BDFE96D3‐D0F4‐4012‐90F5‐9A087F7F5864 .

Extraordinarily high rates of recombination have been observed in some eusocial species. The most popular explanation is that increased recombination increases genetic variation among workers, which in turn increases colony performance, for example by increasing parasite resistance. However, support for the generality of higher recombination rates among eusocial organisms remains weak, due to low sample size and a lack of phylogenetic independence of observations. Recombination rate, although difficult to measure directly, is correlated with chromosome number. As predicted, several authors have noted that chromosome numbers are higher among the eusocial species of Hymenoptera (ants, bees and wasps). Here, we present a formal comparative analysis of karyotype data from 1567 species of Hymenoptera. Contrary to earlier studies, we find no evidence for an absolute difference between chromosome number in eusocial and solitary species of Hymenoptera. However, we find support for an increased rate of chromosome number change in eusocial taxa. We show that among eusocial taxa colony size is able to explain some of the variation in chromosome number: intermediate‐sized colonies have more chromosomes than those that are either very small or very large. However, we were unable to detect effects of a number of other colony characteristics predicted to affect recombination rate – including colony relatedness and caste number. Taken together, our results support the view that a eusocial lifestyle has led to variable selection pressure for increased recombination rates, but that identifying the factors contributing to this variable selection will require further theoretical and empirical effort.

The current state of the comparative insect karyology and the main applications of chromosomal analysis of insects are reviewed. The most important characteristics of insect karyotypes in mitosis and meiosis are considered. Karyological studies provide important information on the genetic structure, life cycles and ecological characteristics, evolution, taxonomy, and phylogeny of insects. Insects have two principal mechanisms of sex determination: more common mechanism is based on the presence of sex chromosomes, and another, on haplodiploidy. Karyotypic analysis allows a number of linkage groups as well as the primary sex ratio to be determined. Chromosomal rearrangement can be used for the ecological monitoring of various insect populations and for pest control. Although a full-scale use of karyotypic details for constructing phylogenies of large insect taxa (except for Diptera which have polygene chromosomes) is possible only in combination with other features, chromosomal characters are still very important for phylogenetic purposes because their evolution is more or less independent of the environment. Chromosomal analysis can be used to reveal and identify sibling species, as well as to identify immature phases of insects. Studies of insect chromosomes may reveal cases of hybridization between forms with different karyotypes. At present, squashed and air-dried preparations are used for studying insect chromosomes. Together with morphometric analysis, differential chromosome staining methods, such as C-and AgNOR-banding, fluorochrome staining, in situ hybridization (including chromosome painting), restriction banding, etc. are being used to detect and document karyotypic differences. An outline of trends and prospects of the comparative insect karyology is given.