Insects in the order Hymenoptera (bees, wasps and ants) present an haplodiploid system of sexual determination in which fertilized eggs become females and unfertilized eggs males. Under single locus complementary sex-determination (sl-CSD) system, the sex of a specimen depends on the alleles at a single locus: when diploid, an individual will be a female if heterozygous and male if homozygous. Significant diploid male (DM) production may drive a population to an extinction scenario called "diploid male vortex". We aimed at studying the dynamics of populations of a sl-CSD organism under several combinations of two parameters: male flight abilities and number of sexual alleles. In these simulations, we evaluated the frequency of DM and a genetic diversity measure over 10,000 generations. The number of sexual alleles varied from 10 to 100 and, at each generation, a male offspring might fly to another random site within a varying radius R. Two main results emerge from our simulations: (i) the number of DM depends more on male flight radius than on the number of alleles; (ii) in large geographic regions, the effect of males flight radius on the allelic diversity turns out much less pronounced than in small regions. In other words, small regions where inbreeding normally appears recover genetic diversity due to large flight radii. These results may be particularly relevant when considering the population dynamics of species with increasingly limited dispersal ability (e.g., forest-dependent species of euglossine bees in fragmented landscapes).
Euglossine fauna of a large remnant of Brazilian Atlantic forest in eastern Brazil (Reserva Natural Vale) was assessed along an edge-forest gradient towards the interior of the fragment. To test the hypotheses that the structure of assemblages of orchid bees varies along this gradient, the following predictions were evaluated: (i) species richness is positively related to distance from the forest edge, (ii) species diversity is positively related to distance from the edge, (iii) the relative abundance of species associated with forest edge and/or open areas is inversely related to the distance from edge, and (iv) relative abundance of forest-related species is positively related to distance from the edge. A total of 2264 bees of 25 species was assessed at five distances from the edge: 0 m (the edge itself), 100 m, 500 m, 1000 m and 1500 m. Data suggested the existence of an edge-interior gradient for euglossine bees regarding species diversity and composition (considering the relative abundance of edge and forest-related species as a proxy for species composition) but not species richness.
When faced with the daunting and exciting task of studying biodiversity, one must necessarily come to terms with a few challenging knowledge gaps, the so‐called biodiversity shortfalls. Given that biodiversity is inherently multidimensional, it seems rather natural to admit that hitherto unrecognized shortfalls, on other distinct aspects of biodiversity, should be considered. Here, we introduce the Haeckelian shortfall, which has as its nexus organismal ontogeny, and refers to the relative scarcity of knowledge about the distinct semaphoronts of a substantial fraction of all known species. The Haeckelian shortfall has a profound relevance on the matter of total evidence, in the context of systematics, besides several indirect effects on the other shortfalls, as they all are intimately interconnected. The importance of studying distinct semaphoronts is crystal clear: Besides the purest and most descriptive access to the ontogeny of species (the idiographic aspect), assessing those semaphoronts will certainly promote the advancement of relevant nomothetic knowledge, contributing to an increasingly meaningful eco–evo–devo. Overcoming the Haeckelian shortfall is certainly a major challenge in our task of knowing and preserving biodiversity.
ABSTRACT. Taxonomy, cladistics analysis and description of a new species of Palpibracus Rondani (Diptera, Muscidae). Palpibracus Rondani is a Muscidae genus with 16 species, including P. darwini sp. nov. described from male specimens from Concepción, Chile. A cladistic analysis was performed based on 31 adult morphological characters and using 12 species as outgroup. This analysis shows Palpibracus as a monophyletic genus whose sister-group is Brachygasterina Malloch. The relationship among Palpibracus species was: (P. veneris ((P. albuquerquei (P. peruvianus, P. trivittatus)) (P. fasciculatus, P. nigriventris)) ((P. spicatus, P. uvivittatus) (P. lancifer (P. darwini sp. nov. (P. chilensis, P. confusus (P. pilosus (P. similis (P. separatus, P. carvalhoi)))))))). Palpibracus apicalis Malloch was placed tentatively in Psilochaeta Stein. A key to species of Palpibracus is also provided.
For 150 years O. anomala has been the only known species of Oligoneuria, the type genus of the Oligoneuriidae (Ephemeroptera). However, two species have been recently described and Oligoneuria has been proposed as a senior synonym of the genus Oligoneurioides. In the present paper, based on material from the Amazon and Brazilian Atlantic Forest, three new species are described, including information on all life stages. Given these new species, as well as the lack of cladistic support for the proposed synonymy between Oligoneuria and Oligoneurioides, a phylogenetic analysis was performed in order to address the relationships between all species and to test the status of Oligoneurioides. Our results show that the status of the genus is uncertain, mainly due to the lack of knowledge of the type species of O. anomala, known exclusively from a female subimago. Taking into account phylogenetic as well as taxonomic arguments, we propose that the genus Oligoneuria should be divided into three subgenera: Oligoneuria s.s., for O. anomala; Oligoneuria (Yawari) new subgenus, for Oligoneuria truncata sp.n.; and Oligoneuria (Oligoneurioides) for the remaining five species, including O. amandae sp.n. and O. mitra sp.n. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:A2AEE4B7-FEA8-4067-8F3B-666095EDB997.
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