Phylogenetic systematics of Yphthimoides Forster, 1964 and related taxa, with notes on the biogeographical history of Yphthimoides species.

Species losses are increasing and may have an impact on our understanding of patterns of evolutionary pathways and phylogenetic relationships among the groups being lost. The knowledge of such patterns can contribute to preventing future losses by identifying which lineages have higher or lower diversification rates, thus informing conservation strategies. Recent years have seen a significant growth in studies of butterfly systematics, allowing a better understanding of evolutionary relationships among most groups and revealing significant taxonomic chaos in several groups. One of the latter groups is the nymphalid subtribe Euptychiina (Satyrinae), which has been shown to include a number of non-monophyletic genera based on recent molecular phylogenetic analyses. Among others, these genera include Yphthimoides, which is widespread throughout the Neotropical region but particularly diverse in the southeastern Neotropics, and a pair of related genera, Pharneuptychia Forster, 1964 and Moneuptychia Forster, 1964. Using molecular data, this study scope and aims were to provide a phylogenetic hypothesis that corroborates Yphthimoides as presently conceived being non-monophyletic, a result reinforced by a comparative study of the male genitalic morphology. Our results also show that Pharneuptychia and Moneuptychia, plus a species misplaced elsewhere in the Euptychiina, Euptychoides castrensis (Schaus, 1902), form a well supported clade, and that the latter 'species' is a complex of cryptic species. We therefore propose a number of taxonomic rearrangements in the present work to resolve these issues: Yphthimoides eriphule (A. Butler, 1867) will be moved to a new genus; Y. affinis (A. Butler, 1867), Y. maepius (Godart, [1824]), Y. mimula (Hayward, 1954), Y. neomaenas (Hayward, 1967) and Y. mythra (Weymer, 1911) are being transferred to Malaveria Viloria & Benmesbah, 2021; Pharneuptychia innocentia (Godart, [1824]) will be moved to another genus to be described; and Euptychoides castrensis, Pharneuptychia romanina (Bryk, 1953) and Yphthimoides viviana (Romieux, 1927) are being moved to Moneuptychia. The dating of divergences points to a split between the ancestral lineage of Yphthimoides and its sister group, Carminda Ebert and Dias, inDias 1998, during the last half of the Miocene, around 11.86 Mya, and to the diversification of the Pharneuptychia during the same time 11.35 (±3.52) Mya. Biogeographic analysis showed that the most recent common ancestor of Yphthimoides started to diversify either in the the Brazilian Cerrado savannas or in a combined area of Cerrado and South Atlantic Forest, with a possible change in the ancestral habitat of Carminda. Furthermore, ancestral character mapping favors a savanna origin hypothesis over a forest origin hypothesis.

A new ant-butterfly symbiosis in the forest canopy fills an evolutionary gap.

Myrmecophilous butterflies can establish complex symbiotic relationships with ants. A caterpillar wandering among the brood of the aggressive ponerine ant Neoponera villosa was found inside the core of a nest built in the myrmecophytic bromeliad Aechmea bracteata. This is the first caterpillar found living inside a ponerine ant nest. Its DNA barcode was sequenced, and an integrative approach was used to identify it as Pseudonymphidia agave, a poorly known member of the subtribe Pachythonina in the riodinid tribe Nymphidiini. The cuticle of the tank-like caterpillar lacks projections or tubercles and is covered dorsally by specialized flat setae that form an armor of small plates. Ant-organs potentially related to caterpillar-ant signaling, such as perforated cupola organs and tentacle nectary organs, are present. These morphological traits, together with evidence of social integration (direct contact with host brood, protective morphology, slow movement, no host aggressiveness), suggest that P. agave is a symbiotic, social parasite of N. villosa, preying on its host brood. However, several knowledge gaps remain, including oviposition site, dependence on bromeliad association, steps to colony integration, and larval diet through development. Carnivory has been reported in all known members of the subtribe Pachythonina (caterpillars prey on honeydew-producing hemipterans) suggesting a shift to myrmecophagy inside the ant nests as a possible evolutionary transition.

North-south and climate-landscape-associated pattern of population structure for the Atlantic Forest White Morpho butterflies.

Atlantic Forest White Morpho butterflies, currently classified as Morpho epistrophus and M. iphitus, are endemic to the Atlantic Forest, where they are widely distributed throughout heterogeneous environmental conditions. Studies with endemic butterflies allow to elucidate questions on both patterns of diversity distribution and current and past processes acting on insect groups in this biodiversity hotspot. In the present study, we characterized one mtDNA marker (COI sequences) and developed 11 polymorphic loci of microsatellite for 22 sampling locations distributed throughout the entire Atlantic Forest domain. We investigated both the taxonomic limits of taxa classified as White Morpho and the structure and distribution of the genetic diversity throughout their populations. Genetic markers and distribution data failed to identify species diversification, population structure, or isolation among subpopulations attributed to different taxa proposed for the White Morpho, suggesting that the current distinction between two species is unreasonable. The Bayesian coalescent tree based on COI sequences also failed to recover monophyletic clades for the putative species, and pointed instead to a north-south oriented pattern of genetic structure, with the northern clade coalescing later than the southern clade. Northern samples also showed more intragroup structure than southern samples based on mtDNA data. Clustering tests based on microsatellites indicated the existence of three genetic clusters, with turnover between the states of Paraná and São Paulo. The north-south pattern found for the White Morpho populations is showed for the first time to a endemic AF insect and coincides with the two different bioclimatic domains previously described for vertebrates and plants. Population structure observed for these butterflies is related to climate- and landscape-associated variables, mainly precipitation and elevation.

Priors and Posteriors in Bayesian Timing of Divergence Analyses: The Age of Butterflies Revisited.

The need for robust estimates of times of divergence is essential for downstream analyses, yet assessing this robustness is still rare. We generated a time-calibrated genus-level phylogeny of butterflies (Papilionoidea), including 994 taxa, up to 10 gene fragments and an unprecedented set of 12 fossils and 10 host-plant node calibration points. We compared marginal priors and posterior distributions to assess the relative importance of the former on the latter. This approach revealed a strong influence of the set of priors on the root age but for most calibrated nodes posterior distributions shifted from the marginal prior, indicating significant information in the molecular data set. Using a very conservative approach we estimated an origin of butterflies at 107.6 Ma, approximately equivalent to the latest Early Cretaceous, with a credibility interval ranging from 89.5 Ma (mid Late Cretaceous) to 129.5 Ma (mid Early Cretaceous). In addition, we tested the effects of changing fossil calibration priors, tree prior, different sets of calibrations and different sampling fractions but our estimate remained robust to these alternative assumptions. With 994 genera, this tree provides a comprehensive source of secondary calibrations for studies on butterflies.

Loci under selection and markers associated with host plant and host-related strains shape the genetic structure of Brazilian populations of Spodoptera frugiperda (Lepidoptera, Noctuidae).

We applied the ddRAD genotyping-by-sequencing technique to investigate the genetic distinctiveness of Brazilian populations of the noctuid moth Spodoptera frugiperda, the fall armyworm (FAW), and the role of host-plant association as a source of genetic diversification. By strain-genotyping all field-collected individuals we found that populations collected from corn were composed primarily of corn-strain individuals, while the population collected from rice was composed almost entirely of rice-strain individuals. Outlier analyses indicated 1,184 loci putatively under selection (ca. 15% of the total) related to 194 different Gene Ontologies (GOs); the most numerous GOs were nucleotide binding, ATP binding, metal-ion binding and nucleic-acid binding. The association analyses indicated 326 loci associated with the host plant, and 216 loci associated with the individual strain, including functions related to Bacillus thuringiensis and insecticide resistance. The genetic-structure analyses indicated a moderate level of differentiation among all populations, and lower genetic structure among populations collected exclusively from corn, which suggests that the population collected from rice has a strong influence on the overall genetic structure. Populations of S. frugiperda are structured partially due to the host plant, and pairs of populations using the same host plant are more genetically similar than pairs using different hosts. Loci putatively under selection are the main factors responsible for the genetic structure of these populations, which indicates that adaptive selection on important traits, including the response to control tactics, is acting in the genetic differentiation of FAW populations in Brazil.

Exploitation of mitochondrial nad6 as a complementary marker for studying population variability in Lepidoptera.

The applicability of mitochondrial nad6 sequences to studies of DNA and population variability in Lepidoptera was tested in four species of economically important moths and one of wild butterflies. The genetic information so obtained was compared to that of cox1 sequences for two species of Lepidoptera. nad6 primers appropriately amplified all the tested DNA targets, the generated data proving to be as informative and suitable in recovering population structures as that of cox1. The proposal is that, to obtain more robust results, this mitochondrial region can be complementarily used with other molecular sequences in studies of low level phylogeny and population genetics in Lepidoptera.

Exploitation of mitochondrial nad6 as a complementary marker for studying population variability in Lepidoptera

The applicability of mitochondrial nad6 sequences to studies of DNA and population variability in Lepidoptera was tested in four species of economically important moths and one of wild butterflies. The genetic information so obtained was compared to that of cox1 sequences for two species of Lepidoptera. nad6 primers appropriately amplified all the tested DNA targets, the generated data proving to be as informative and suitable in recovering population structures as that of cox1. The proposal is that, to obtain more robust results, this mitochondrial region can be complementarily used with other molecular sequences in studies of low level phylogeny and population genetics in Lepidoptera.