Can Pheromones Contribute to Phylogenetic Hypotheses? A Case Study of Chrysomelidae.

Pheromones mediate species-level communication in the search for mates, nesting, and feeding sites. Although the role of pheromones has long been discussed by various authors, their existence was not proven until the mid-twentieth century when the first sex pheromone was identified. From this finding, much has been speculated about whether this communication mechanism has acted as a regulatory agent in the process of speciation, competition, and sexual selection since it acts as an intraspecific barrier. Chrysomelidae is one of the major Phytophaga lineages, with approximately 40,000 species. Due to this immense diversity the internal relationships remain unstable when analyzed only with morphological data, consequently recent efforts have been directed to molecular analyses to establish clarity for the relationships and found their respective monophyly. Therefore, our goals are twofold 1) to synthesize the current literature on Chrysomelidae sex pheromones and 2) to test whether Chrysomelidae sex pheromones and their chemical structures could be used in phylogenetic analysis for the group. The results show that, although this is the first analysis in Chrysomelidae to use pheromones as a phylogenetic character, much can be observed in agreement with previous analyses, thus confirming that pheromones, when known in their entirety within lineages, can be used as characters in phylogenetic analyses, bringing elucidation to the relationships and evolution of organisms.

Homoplasy-Based Partitioning Outperforms Alternatives in Bayesian Analysis of Discrete Morphological Data.

Bayesian analysis of morphological data is becoming increasingly popular mainly (but not only) because it allows for time-calibrated phylogenetic inference using relaxed morphological clocks and tip dating whenever fossils are available. As with molecular data, recent studies have shown that modeling among-character rate variation (ACRV) in morphological matrices greatly improves phylogenetic inference. In a likelihood framework this may be accomplished, for instance, by employing a hidden Markov model to assign characters to rate categories drawn from a (discretized) $\Gamma$ distribution and/or by partitioning data sets according to rate heterogeneity and estimating per-partition branch lengths, conditioned on a single topology. While the first approach is available in many phylogenetic analysis software, there is still no clear consensus on how to partition data, except perhaps in the simplest cases (e.g., "by codon" partitioning of coding sequences). Additionally, there is a trade-off between improvement in likelihood scores and the number of free parameters in the analysis, which rises quickly with the number of partitions. This trade-off may be dealt with by employing statistics that penalize overfitting of complex models, such as Akaike or Bayesian information criteria, or the more recently introduced stepping-stone method for marginal likelihood approximation. We applied the latter to three distinct matrices of discrete morphological data and demonstrated that sorting characters by homoplasy scores (obtained from implied weighting parsimony analysis) outperformed other partitioning strategies (anatomically-based and PartitionFinder2). The method was in fact so efficient in segregating characters by rates of evolution that no within-partition ACRV modeling was necessary, while among-partition rate variation was adequately accommodated by rate multipliers. We conclude that partitioning by homoplasy is a powerful and easy-to-implement strategy to address ACRV in complex data sets. We provide some guidelines focusing on morphological matrices, although this approach may be also applicable to molecular data sets.

A new species of the ant-hunter genus Tracheliodes Morawitz (Hymenoptera: Crabronidae: Crabronini) from Brazil.

Tracheliodes leclercqi sp. n., a new species of the ant-hunter genus Tracheliodes Morawitz, is described from southeastern Brazil. It closely resembles T. cutucu Cooper, 1988 and the main differences between the two species are presented. Photographs of type specimens of T. leclercqi sp. n., as well as of a female and a male paratypes of T. cutucu, are provided.

A new combination for the bembicine genus Selman Parker, 1929 (Hymenoptera: Crabronidae).

The identity of Monedula diana Handlirsch, 1890 is reassessed and the species is transferred to the monotypic genus Selman, which now includes two species, S. diana n. comb. and S. notatus (Taschenberg, 1870). The main differences between the two species are presented. Photographs of the holotype of Monedula diana are provided and its putative type locality is discussed. Also new distribution records are provided for S. notatus.

New genus of fossil apoid wasps (Hymenoptera, Apoidea) from the Cretaceous amber of Myanmar

ABSTRACT The new genus †Burmasphex is proposed for two fossil species, †Burmasphex sulcatus sp. nov. and †Burmasphex pilosus sp. nov., described from Myanmar Cretaceous amber. It exhibits many plesiomorphic features in relation to the extant Apoidea and is here provisionally allocated in the extinct family †Angarosphecidae.