Abstract. 1. Previous studies have found the parasitoid wasp family Ichneumonidae (Hymenoptera) to have an exceptional latitudinal species richness gradient that peaks at mid-latitudes instead of the tropics; however, insufficient tropical sampling and species description may have biased the conclusions. It has been unclear which subfamilies might be species rich in tropical lowland rain forests.2. This study reports the subfamily abundance composition of a large ichneumonid data set (>30 000 individuals in 20 subfamilies) collected by Malaise traps and insecticidal canopy fogging in Amazonian Ecuador and Peru and suggests which subfamilies would be important for future study.3. Relative abundance data from one Peruvian site are compared to similar lowland samples from Costa Rica and Georgia (USA).4. Contrary to a common assumption, a number of ichneumonid subfamilies are very abundant and presumably species rich in western Amazonia. Cryptinae and Orthocentrinae are noticeably the two most abundant subfamilies, and a number of koinobiont lepidopteran parasitoids, which are generally thought to be scarce in the tropics, are also surprisingly abundant (e.g. Anomaloninae, Banchinae and Cremastinae). However, the subfamilies whose primary hosts are rare in the tropics (e.g. Ctenopelmatinae, Tryphoninae) can still be expected to be more diverse in the temperate than in tropical zone.5. Further research on the latitudinal species richness gradient within different ichneumonid subfamilies is encouraged to help understand what factors determine macroecological species richness patterns and what is the total number of ichneumonid species on earth.

The old idea that parasitoid wasps (Ichneumonidae) show an inverse latitudinal diversity gradient has recently been challenged, but how ichneumonid species richness varies across the globe is still not well understood. We carried out field inventories in 21 sites on three continents to clarify this question, focusing on the subfamilies Pimplinae and Rhyssinae. Our total sampling effort was 628 Malaise trap months and the total catch exceeded 65 000 individuals. Our main focus was in two intensively inventoried areas in Amazonia, together yielding 257 Malaise trap months and 26 390 ichneumonid individuals. To expand the scope and assess global species diversity patterns of the Pimplinae and Rhyssinae, we compiled published species lists from a total of 97 study localities around the world. The highest observed species richness in any locality, 105 species, was found in one of our field sites in Peruvian Amazonia. None of the other localities reported more than 70 species, even the ones with a sampling effort comparable to ours. Despite the local thoroughness of our field inventories in Amazonia, data analyses indicated that a substantial proportion of the parasitoid wasp species occurring in each site remained unobserved. The highest local species richness values were reported from the tropics. Nevertheless parasitoid wasps are still too sparsely sampled to draw solid conclusions about whether or not their species richness follows a particular latitudinal trend, and if so, where their richness peaks.

Xanthopimpla Saussure, 1892 is one of the largest genera of the family Ichneumonidae. Th e genus is very species rich in Indo-Australia but poorly represented in the Neotropical region. In this paper two morphologically very distinctive species of the genus, X. amazonica sp. n. Gómez, Sääksjärvi & Veijalainen, and X. jussilai sp. n. Veijalainen, Sääksjärvi & Broad, are described and illustrated. Th e new species have been collected in the Peruvian and Ecuadorean Amazonia. A revised key to the Neotropical species of the genus is provided. Xanthopimpla aurita Krieger is recorded for the fi rst time from Peru.

Lepidopteran larvae encounter a variety of phenolic compounds while consuming their host plants. Some phenolics may oxidize under alkaline conditions prevailing in the larval guts, and the oxidation products may cause oxidative stress to the larvae. In this study, we aimed to find new ways to predict how phenolic compounds may be modified in the guts of herbivorous larvae. To do so, we studied the ease of oxidation of phenolic compounds from 12 tropical tree species. The leaf extracts were incubated in vitro in alkaline conditions, and the loss of total phenolics during incubation was used to estimate the oxidizability of extracts. The phenolic profiles of the leaf extracts before and after incubation were compared, revealing that some phenolic compounds were depleted during incubation. The leaves of the 12 tree species were each fed to 12 species of lepidopteran larvae that naturally feed on these trees. The phenolic profiles of larval frass were compared to those of in vitro incubated leaf extracts. These comparisons showed that the phenolic profiles of alkali-treated samples and frass samples were similar in many cases. This suggested that certain phenolics, such as ellagitannins, proanthocyanidins, and galloylquinic acid derivatives were modified by the alkaline pH of the larval gut. In other cases, the chromatographic profiles of frass and in vitro incubated leaf extracts were not similar, and new modifications of phenolics were detected in the frass. We conclude that the actual fates of phenolics in vivo are often more complicated than can be predicted by a simple in vitro method.

Six new species of Hymenoepimecis Viereck are described from Brazilian Amazonian tropical forest: H. amazonensis sp. n., H. duckensis sp. n., H. kleini sp. n., H. manauara sp. n., H. ribeiroi sp. n. and H. uberensis sp. n., and male genitalia is described for the first time for the genus. In addition, we provide an identification key, diagnosis and distributional records for Brazilian Amazonian species of Hymenoepimecis. By describing these new species we aim to draw further attention to the considerable species richness of the genus in Amazonia.

Epirhyssa Cresson 1865 is a large tropical genus of the family Ichneumonidae. It is the most diverse genus of the subfamily Rhyssinae with about 118 species worldwide. In this study we conducted four long-term field inventories to review the Peruvian Amazonian species of the genus. We provide illustrations, diagnosis and an identification key to the species currently known to occur in the region, including descriptions of 10 new species. In addition, we describe the female of E. wisei Porter and the male of E. pertenuis Porter, discuss the biogeographical patterns of species richness of the genus and provide new faunistic records for Brazil, Colombia, Ecuador, French Guiana, Paraguay and Peru. The Peruvian Amazonia is, according to our results, among the most species-rich areas in the world for this genus. Some of the new species described in this work were named by the public in Finland and Peru during two innovative competitions to name these beautiful species. The aims of these competitions were to draw attention to the plethora of unknown species lurking in the shades of tropical forests and the necessity to protect these highly diverse areas.

Xanthopimpla Saussure, 1892 is one of the largest and best studied genera of the family Ichneumonidae. It is most species rich in the Oriental and Afrotropical regions with only a few species occurring in Central and South America. The present study reviews the Neotropical species of the genus including descriptions of four new species from Amazonia and Northeast South America. We define a new species group: the amazonica species-group, to accommodate the following five species: X. amazonica Gómez, Sääksjärvi & Veijalainen, X. guianensis Gómez & Sääksjärvi sp. n., X. jussilai Veijalainen, Sääksjärvi & Broad, X. pucallpensis Gómez & Sääksjärvi sp. n. and X. vidali Gómez sp. n. The aurita species-group, which had hitherto been regarded as the only species-group in the Neotropical region, is currently represented by five species: X. allpahuaya Gómez & Sääksjärvi sp. n., X. aurita Krieger, X. craspedoptera Krieger, X. rhabdomera Townes and X. spiloptera Krieger. The Andean species X. peruana Krieger is established as an unplaced species outside of the amazonica and aurita species-groups. A key to Neotropical species-groups and species of Xanthopimpla is provided. Xanthopimpla aurita is recorded for the first time from Ecuador and Colombia and its extensive distribution is discussed. Xanthopimpla amazonica, X. craspedoptera and X. jussilai are recorded for the first time from Brazil; X. amazonica is recorded for the first time from French Guiana; X. spiloptera is recorded for the first time from French Guiana and Peru, and X. rhabdomera is recorded for the first time from Peru.

In this work we describe and illustrate two new species of Scambus from the Peruvian Andes and the Andean-Amazonian interface: S. amazonicus Gómez sp. n., and S. incanus Gómez sp. n. These are the first Scambus species described from Peru. In addition, we provide an identification key to the Neotropical species of the genus.