Background:Brachycyrtinae is a small, but distinctive subfamily of Darwin wasps (Hymenoptera, Ichneumonidae) with one widespead species in Europe: Brachycyrtusornatus Kriechbaumer, 1880. We recently collected the species during the faunistic survey of the Urban Biodiversity Parks project in Skanssi, Turku, south-western Finland. New information:We report the Darwin wasp Brachycyrtusornatus as the first record of the subfamily for Finland. We collected a single female specimen with a Malaise trap in Skanssi Biodiversity Park during a period from August to September 2024. This is the northernmost record of B.ornatus and the subfamily Brachycyrtinae as a whole. Notes on the species' distribution and morphological variation are included.

ABSTRACT Spiders utilize an indirect method of sperm transfer via specialized male palpal structures. In entelegyne spiders, these structures exhibit a remarkable complexity, comprising various sclerites that interlock with the female genitalia to provide stability and facilitate sperm transfer. Among the four primary coupling mechanisms recognized in entelegyne spiders, one, termed self‐bracing, involves interactions between structures stabilizing the expanded copulatory organ during mating. Such interactions can involve elements that are not part of the copulatory organ. The retrolateral tibial apophysis (RTA), a characteristic of the largest group of spiders (RTA clade), is the most prominent structure for this purpose. However, recent research has demonstrated that in spiders that have lost the RTA, other parts of the palp, specifically femoral apophyses, can be involved in self‐bracing. The presence of a femoral palpal fapophysis is uncommon in spiders, and only a few taxa possess apophyses on multiple palpal articles, i.e., tibia and femur, the interaction and evolution of which remain to be elucidated. This study investigated the function and interaction of apophyses on different palpal structures for the first time using the funnel weaver Anatextrix monstrabilis (Agelenidae). We specifically examined the hypothesis that the various prominent femoral apophyses are involved in self‐bracing despite the presence of an RTA. Micro‐computed tomography data of a cryofixed mating pair revealed that at least one of these apophyses functions in self‐bracing by fitting into the groove of the embolic base, representing the second documented case of this unique self‐bracing mechanism in entelegyne spiders. Furthermore, scanning electron microscopy revealed previously undocumented features in the female genitalia of Anatextrix, including an epigynal fovea, an anterior hood, and well‐developed epigynal lateral margins, which potentially play a role in interlocking with male palpal sclerites during copulation. In contrast to ghost spiders (Anyphaenidae), the only other known group of entelegyne spiders exhibiting self‐bracing with femoral apophyses, Anatextrix species demonstrate notable differences with regard to the size and shape of these apophyses. Thus, our study indicates that male palpal femoral structures, which do not contact female genitalia during genital coupling, can be subject to strong selection pressures similar to somatic structures that function beyond basic sperm transfer.

Factors such as host species, phylogeny, diet, and both timing and location of sampling are thought to influence the composition of gut-associated bacteria in insects. In this study, we compared the faecal-associated bacterial taxa for three Coenagrion and one Enallagma damselfly species. We expected high overlap in representation of bacterial taxa due to the shared ecology and diet of these species. Using metabarcoding based on the 16S rRNA gene, we identified 1513 sequence variants, representing distinct bacterial ‘taxa’. Intriguingly, the damselfly species showed somewhat different magnitudes of richness of ZOTUs, ranging from 480 to 914 ZOTUs. In total, 921 (or 60.8% of the 1513) distinct ZOTUs were non-shared, each found only in one species, and then most often in only a single individual. There was a surfeit of these non-shared incidental ZOTUs in the Enallagma species accounting for it showing the highest bacterial richness and accounting for a sample-wide pattern of more single-species ZOTUs than expected, based on comparisons to the null model. Future studies should address the extent to which faecal bacteria represent non-incidental gut bacteria and whether abundant and shared taxa are true gut symbionts. Graphical Abstract Pictures of odonates adopted from Norske Art databank under Creative Commons License (CC BY 4.0).

A new monotypic genus of ichneumonine parasitoid wasps (Hymenoptera, Ichneumonidae, Ichneumoninae) is described from Peru; Capitojoppagen. nov. is described to accommodate Capitojoppaamazonicasp. nov. The new genus is morphologically very distinctive and can be easily separated from all known ichneumonine genera. By describing Capitojoppa from the lowland rain forests of Peru, we aim to draw attention to the considerable diversity and morphological variation of the Amazonian ichneumonine fauna.

Males of Calopteryx splendens use two alternative mating tactics, territoriality, and non-territoriality. These different mating tactics are shown to vary between males within the same population and previous studies have shown that territorial males have considerably higher fitness than non-territorial males. In this paper, we tested whether the wing spot size as sexual ornament, wing length, relative wing spot size, asymmetry in wing length, asymmetry in wing spot size, or asymmetry in relative wing spot size differed between the territorial and non-territorial males. We sampled C. splendens males, representing both mating tactics, from a river system in south-west Finland. According to our results, territorial males have larger wing spot than non-territorial males. In contrast, there were no differences in the other tested traits between the territorial and non-territorial males. In conclusion, our data show that the size of pigmented wing spots may predict the alternative mating tactic of C. splendens males.

Trophic interactions are at the core of several key ecological processes and theories as they determine the flow of material and energy within and across communities and habitats. Odonates provide a rich and diverse taxonomic group with several features (e.g. trophic position, hunting behavior, olfaction) that make them a very interesting biological model for the study of trophic interactions in aquatic and terrestrial habitats. Moreover, odonates undergo incomplete metamorphosis with aquatic larvae and terrestrial adults, which provides opportunities to investigate ontogenetic diet variation and trophic links between aquatic and terrestrial systems. They are also important predators regulating prey populations and mediating community processes such as trophic cascades. Finally, recent studies on odonates have pioneered whether local adaptation and phenotypic plasticity can counterbalance the negative impacts of global change on resource acquisition and fitness. This chapter reviews recent studies investigating the trophic features and role of odonates in aquatic and terrestrial ecosystems as well as their importance for investigating the impact of global change on trophic ecology, local adaption, and community processes. Many of the insights highlighted in this chapter go beyond odonates and have helped to advance key concepts in trophic ecology.

Abstract Trophic interactions are at the core of several key ecological processes and theories as they determine the flow of material and energy within and across communities and habitats. Odonates provide a rich and diverse taxonomic group with several features (e.g. trophic position, hunting behavior, olfaction) that make them a very interesting biological model for the study of trophic interactions in aquatic and terrestrial habitats. Moreover, odonates undergo incomplete metamorphosis with aquatic larvae and terrestrial adults, which provides opportunities to investigate ontogenetic diet variation and trophic links between aquatic and terrestrial systems. They are also important predators regulating prey populations and mediating community processes such as trophic cascades. Finally, recent studies on odonates have pioneered whether local adaptation and phenotypic plasticity can counterbalance the negative impacts of global change on resource acquisition and fitness. This chapter reviews recent studies investigating the trophic features and role of odonates in aquatic and terrestrial ecosystems as well as their importance for investigating the impact of global change on trophic ecology, local adaption, and community processes. Many of the insights highlighted in this chapter go beyond odonates and have helped to advance key concepts in trophic ecology.

We describe three new species of the previously monotypic genus Creagrura Townes from Central and South America: C. alejandromasisi sp. n. and C. rogerblancoi sp. n. from Costa Rica and C. allpahuaya sp. n. from Peru, all of which emphasise the unknown parasitoid insect diversity yet to be revealed in the tropics. Host relationships of the two Costa Rican species are described in detail. In addition, it is inferred that the Creagrura wasps find and oviposit in the caterpillar when it is exposed at night, rather than when it is concealed during daylight hours.

Sexes often differ in foraging and diet, which is associated with sex differences in size, trophic morphology, use of habitats, and/or life history tactics. Herein, strikingly similar diets were found for adult sexes of a dragonfly (Leucorrhinia intacta), based on comparing 141 dietary taxa identified from the metabarcoding of mitochondrial DNA archived in feces. Arthropods in > 5% of samples included five species of dipterans, two hemipterans, two spider species and one parasitic mite. The mite was not traditional prey as its presence was likely due to DNA contamination of samples arising through parasitism or possibly via accidental consumption during grooming, and therefore the mite was excluded from diet characterizations. Common prey species were found with statistically indistinguishable frequencies in male and female diets, with one exception of an aphid more often found in male diets, although this pattern was not robust to corrections for multiple statistical tests. While rare prey species were often found in diets of only one sex, instances of this were more frequent in the more oft-sampled females, suggesting sampling artefact. Sexes did not differ in the mean prey species richness in their diets. Overall, sexes showed statistically indistinguishable diets both on a prey species-by-species basis and in terms of multivariate characterizations of diet composition, derived from presence-absence data of prey species analyzed via PERMANOVA and accumulation curves. Males and females may have similar diets by being both opportunistic and generalist predators of arthropods, using the same foraging habitats and having similar sizes and flight agilities. Notably, similarities in diet between sexes occur alongside large interindividual differences in diet, within sexes. Researchers intending on explaining adaptive sex differences in diet should consider characteristics of species whose sexes show similar diets.

The Neotropical Polysphincta dizardi species-group is revised. We describe seven new species from South America: P. bonita sp. nov., P. cosnipata sp. nov., P. inca sp. nov., P. macroepomia sp. nov., P. organensis sp. nov., P. pichincha sp. nov., and P. teresa sp. nov. In addition, we provide a diagnosis and an identification key to all species of the group.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

To understand the diversity and strength of predation in natural communities, researchers must quantify the total amount of prey species in the diet of predators. Metabarcoding approaches have allowed widespread characterization of predator diets with high taxonomic resolution. To determine the wider impacts of predators, researchers should combine DNA techniques with estimates of population size of predators using mark-release-recapture (MRR) methods, and with accurate metrics of food consumption by individuals. Herein, we estimate the scale of predation exerted by four damselfly species on diverse prey taxa within a well-defined 12-ha study area, resolving the prey species of individual damselflies, to what extent the diets of predatory species overlap, and which fraction of the main prey populations are consumed. We identify the taxonomic composition of diets using DNA metabarcoding and quantify damselfly population sizes by MRR. We also use predator-specific estimates of consumption rates, and independent data on prey emergence rates to estimate the collective predation pressure summed over all prey taxa and specific to their main prey (non-biting midges or chironomids) of the four damselfly species. The four damselfly species collectively consumed a prey mass equivalent to roughly 870 (95% CL 410-1,800) g, over 2 months. Each individual consumed 29%-66% (95% CL 9.4-123) of its body weight during its relatively short life span (2.1-4.7 days; 95% CL 0.74-7.9) in the focal population. This predation pressure was widely distributed across the local invertebrate prey community, including 4 classes, 19 orders and c. 140 genera. Different predator species showed extensive overlap in diets, with an average of 30% of prey shared by at least two predator species. Of the available prey individuals in the widely consumed family Chironomidae, only a relatively small proportion (0.76%; 95% CL 0.35%-1.61%) were consumed. Our synthesis of population sizes, per-capita consumption rates and taxonomic distribution of diets identifies damselflies as a comparatively minor predator group of aerial insects. As the next step, we should add estimates of predation by larger odonate species, and experimental removal of odonates, thereby establishing the full impact of odonate predation on prey communities.