The main function of symbiotic actinobacterias in fungus-farming ants (Formicidae: Myrmicinae: Attini) is to protect the cultivated fungus against the pathogenic fungus Escovopsis spp. The microorganisms with the highest antimicrobial potential are actinobacterias, specifically Pseudonocardia and Streptomyces. These actinobacterias have demonstrated greater aggressiveness against the pathogen compared to other free-living actinobacterias, suggesting a selective process for strains with greater effectiveness in controlling the mycoparasite. Hypotheses explaining the coevolution between attinis and actinobacterias suggest that Pseudonocardia is a specialist symbiont that has coevolved with attinis, while Streptomyces is a mutualist recurrently adopted from the environment. In addition to actinobacterias, other microbial groups such as yeasts and bacteria with antimicrobial potential have been reported. The diversity of biomolecules synthesized by attini microsymbionts suggests that the microbiota of these insects could be an underexplored source of biotechnological resources with potential for combating agricultural and clinical diseases. This review addresses the antimicrobial potential of the microbiome associated with fungus-farming ants, and also analyzes aspects of coevolution, eco-physiological roles, and the diversity of microorganisms with antimicrobial potential.

Effective disease management hinges on an accurate understanding of the ecological and epidemiological underpinnings of the pathosystem. New epidemics may prompt consideration of whether knowledge gaps or changes to the pathosystem warrant revision of management strategies. Pierce's disease of grapevines is highly episodic in coastal Northern California vineyards, with modest incidence in most years punctuated by occasionally severe epidemics.To better understand what was driving a developing epidemic in the region, we revaluated what is known about the ecology and epidemiological role of the dominant vector, the blue-green sharpshooter Graphocephala atropunctata. We monitored vector spatiotemporal dynamics at 32 vineyards over three years, surveyed plant community composition in the adjacent habitat to understand its link to vector recruitment, and quantified patterns of natural infectivity for the pathogen Xylella fastidiosa. Overall, the results were consistent with past studies of G. atropunctata ecology. For example, the scale of dispersal from source habitat and seasonal patterns in activity were generally similar to those documented in prior studies. The results also confirmed the influence of adjacent plant community composition on G. atropunctata activity in vineyards, and the role of riparian habitat and select plant taxa as vector sources. Nonetheless, further consideration of the epidemiological significance of certain features of the pathosystem may be warranted, especially those related to seasonality in X. fastidiosa infection in vectors. A marked increase in infected G. atropunctata late in the season likely reflects pathogen acquisition from infected grapevines, which may have implications for disease management strategies.

This study describes the natural history and multitrophic interactions of the highly restricted Andean butterfly species Catasticta truncata (Lathy & Rosenberg, 1912) from the urban and surrounding areas of Loja in southern Ecuador. The immature stages of the butterfly are described and illustrated, and the host plant is identified as Phoradendron nervosum Oliv. (Viscaceae), an aerial-stem hemiparasitic shrub that parasitizes trees of Salix humboldtiana (Willd) (Salicaceae). Multitrophic interactions that this species maintains in the urban ecosystem are described. One interaction includes a predator, Ambastus villosus Stal, 1872 (Reduvidae). In addition, and for the first time for the genus Catasticta Butler, 1870, the presence of an endoparasitoid wasp (Ichneumonidae) and a hyperparasitoid (secondary parasitoid) wasp Pediobius sp. (Eulophidae), both potentially undescribed species, are documented. Flowers from plants in the Asteraceae family are visited by adults of C. truncata.This new information highlights the ecological roles of these butterflies in the green areas within the city of Loja. Finally, due to the highly restricted distribution of this species within Loja's green areas and the striking beauty of adults, along with this butterfly being a component within 4 trophic levels in the urban ecological network, this butterfly could be a flagship for the city of Loja. Local actions that help the conservation of this species should positively affect the organisms that interact with it and positively influence the well-being of the city's inhabitants in general.

Este estudio describe la historia natural e interacciones multitroficas de la especie de mariposa andina altamente restringida Catasticta truncata (Lathy & Rosenberg, 1912), de las áreas urbanas y circundantes de Loja en el sur de Ecuador. Se describen e ilustran los estados inmaduros de la mariposa, y se identifica la planta hospedera como Phoradendron nervosum Oliv. (Viscaceae), un arbusto hemiparásito de tallo aéreo que parasita árboles de Salix humboldtiana (Willd) (Salicaceae). Se describen las interacciones multitroficas que esta especie mantiene en el ecosistema urbano. Una de las interacciones incluye un depredador, Ambastus villosus Stal, 1872 (Reduvidae). Además, y por primera vez para el género Catasticta Butler, 1870, se documenta la presencia de una avispa endoparasitoide (Ichneumonidae), y una avispa hiperparasitoide (parasitoides secundarios) Pediobius sp. (Eulophidae), ambas especies potencialmente no descritas. Los adultos de C. truncata visitan las flores de plantas de la familia Asteraceae. Esta nueva información resalta la importancia ecológica de estas mariposas en las áreas verdes dentro de la ciudad de Loja. Finalmente, debido a su distribución altamente restringida en las áreas verdes de Loja, y la belleza llamativa de los adultos, junto con su papel importante dentro de cuatro niveles tróficos en la red ecológica urbana, esta mariposa podría ser un símbolo de conservación para la ciudad de Loja. En donde las acciones locales que ayuden a su conservación deberían afectar positivamente al resto de los organismos que interactúan con ella, e influirá positivamente en el bienestar de los habitantes de la ciudad en general.

Aggression is an essential component of survival and fitness, although the expression of aggression behaviors can also carry fitness costs. As a result, aggressive behaviors vary significantly across animals and are likely acted on by natural selection to produce this variation. Aggression, and associated traits like nestmate discrimination, both complex traits, have well studied genetic components, with links to genes involved in processes like neuronal function, metabolism, and hormone and cuticular hydrocarbon (CHC) production and reception. However, whether and how natural selection acts on these genes to produce variation across species is not fully understood. Using a comparative genomics approach, we analyzed natural selection in ants (Hymenoptera: Formicidae) with candidate genes previously linked to these traits. We find that aggression is associated with shifts in selection intensity, including positive selection on neurotransmitter receptors, and that ants with low levels of nestmate discrimination experience positive or relaxed selection on several CHC genes. Interestingly, we find that most candidate genes analyzed experience positive selection across ants, regardless of aggression level or discrimination ability. Our results shed new light on the means by which natural selection may act to produce variation in aggression across the ants.

The evolution of sociality in insects has been predicted to reduce effective population sizes, in turn leading to changes in genome architecture, including higher recombination rates, larger genomes, increased GC-biased gene conversion (gBGC), and greater intragenomic variation in GC content to maintain castes through differential methylation. As the number of sequenced insect genomes continues to grow, it remains an open question which, if any, of these genomic features are consistent across social insect genomes. A major challenge to determining such commonalities has been the lack of phylogenetically controlled analyses across independent origins of sociality. Of the 15 Hymenoptera species for which recombination rate was available, social species had higher rates of recombination. Next, we conducted a broader analysis of genome architecture by analyzing genome assemblies for 435 species of Hymenoptera and 8 species of Blattodea to test if GC content, genome size, distribution of CpG sites or codon bias repeatedly differed between social and nonsocial species. Overall, there was little support for predictable changes in genome architecture associated with sociality across Hymenoptera, after accounting for phylogenetic relationships. However, we found a significant negative relationship between sociality and GC content within the family Apidae and a significant negative relationship between sociality and genome size within the family Halictidae. In all, these results suggest that unique origins of social behavior may produce unique trends in genomic architecture. Our study highlights the need to examine genome architecture across independent origins of social behavior.

Chrysomelinae species have a striking ecological specialization due to their trophic selection on plants usually belonging to the same botanical family. Calligrapha (Chevrolat) (Coleoptera, Chrysomelidae) is a diverse genus that comprises about 80 species distributed in most of the American continent. Cytogenetic studies of Calligrapha refer to 18 species with a modal diploid chromosome number 2n = 23 = 22 + XO (male) and a meioformula n = 11 + XO (male). A population of C. polyspila (Germar) from República Oriental del Uruguay shows 2n = 24 = 22 + Xy_p (n = 12 = 11 + X/y_p, male), which is coincident with the karyotype currently considered as the ancestral one. We performed for the first time a detailed karyotype analysis in specimens of C. polyspila from Argentinean natural populations. We described the male karyotype and analyzed the meiotic behavior and frequency and distribution of chiasmata. We also examined the chromatin organization and constitution by determining the amount, composition, and distribution of constitutive heterochromatin and the number and location of nucleolus organizer regions. The presence of a novel 2n in C. polyspila from República Argentina allows proposing different trends of karyotype differentiation that may have occurred in the Argentinean and Uruguayan allopatric populations. Our results provide more information on the karyology of Chrysomelinae and contribute to discussing the evolutionary significance of the different cytological features and the fixed chromosomal variants observed in these South American populations of C. polyspila.

Graphical Abstract

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) is a global invasive pest attacking soft-skinned fruit. The specialist larval parasitoid wasp, Ganaspis brasiliensis (Ihering), was recently approved in Europe and the United States for classical biological control releases against D. suzukii. Rearing methods are essential for supporting innundative releases but current methods using fresh fruit are costly and susceptible to variation in host quality. To develop an artificial rearing system, we first compared the performance and development of D. suzukii and G. brasiliensis on fresh raspberries and blueberries and then on various artificial diet shapes and volumes. Drosophila suzukii had 1–2 days shorter development times in raspberry than blueberry, whereas Ganaspis adult development time was similar in both fruit and averaged 25 days. Parasitism rates by G. brasiliensis were significantly higher in blueberry than raspberry in both small and large resource patches. We found that D. suzukii preferred to lay eggs in full sphere diet shapes than in flat diet circles or semisphere diet, and in the first trial with wasps parasitism was only found on D. suzukii larvae in the full sphere shape of raspberry diet. Comparison of parasitism on full sphere raspberry and blueberry diets found higher parasitism in raspberry compared to blueberry diet. Our results indicate potential for further improvement of artificial rearing systems for G. brasiliensis to allow more cost-effective and reliable rearing for biological control programs.