A new genus and new species of macronyssid mite (Mesostigmata: Gamasina: Macronyssidae) from Brazilian caves including molecular data and key for genera occurring in Brazil

A new genus and a new species of macronyssid mites is described based on material collected from caves in Minas Gerais state, Southeastern Brazil, and additional occurrences from caves in Rio de Janeiro (Southeast) and Pará (Eastern Amazon region). The new genus may be distinguished from other Macronyssidae genera by the combination of sternal shield with a distinct X-shaped area; sternal shield bearing three pairs of setae and two pairs of pores; sternal gland absent; anterior spur on coxa II lacking; adults with dorsal shield entire and j and J series complete; adults and protonymphs with setae J5 minute; males with strong-pores on dorsal shield and peritrema short extending from posterior margin of coxae II to the anterior margin of coxae IV. A key for genera occurring in Brazil is provided, as well sequences from the mitochondrial large subunit of ribosome (16S).

Chemical Recruitment for Foraging in Ants (Formicidae) and Termites (Isoptera): A Revealing Comparison

All termites secrete trail pheromones from their sternal gland, whereas ants use a variety of glands for this purpose. This and the diversity of chemical compounds that serve as trail pheromones among ants, and the uniformity of chemicals among termite trails, suggest a different evolutionary historical dynamics for the development of chemical mass recruitment in both taxa. Termites in addition show pheromonal parsimony. This suggest a single evolutionary origin of pheromone trails in Isoptera, whereas chemical mass recruitment among Formicidae seems to have evolved many times and in different ways. Despite these very different evolutionary histories, both taxa evolved chemical recruitment systems involving attractants and orientation signals, and at least two divergent decision making system for recruitment. This evolutionary analogy suggests that chemical mass recruitment is constraint by fundamental physical dynamic laws. Artificial intelligence including “mass intelligence” and “ant intelligence”, emulates mass recruitment in interacting virtual agents in search of optimal solutions. This approach, however, has copied only the “Democratic” recruitment dynamics with a single compound pheromone. Ant and termite evolution shows more sophisticated recruitment dynamics which, if understood properly, will improve our understanding of nature and applications of artificial “swarm intelligence”.

Skin, gland, and urine odors elicit intense investigation by male gray short-tailed opossums, Monodelphis domestica

Chemical signaling between animals of the same species is common among vertebrates. We have reported this phenomenon in the gray short-tailed opossum, Monodelphis domestica (Wagner, 1842). We now find that male opossums investigate odors derived from the mandibular and flank regions and from urine of male and female opossums and from the sternal gland of male opossums significantly more than distilled water. Males investigate female odors significantly more than male odors. They also investigate strange male odors significantly more than their own odors when similar body parts were compared. The males investigate female flank odors significantly longer than female urine odors when these were paired, but the time spent investigating other pairings of female odors was not significantly different. Furthermore, experimental males, unlike females tested in former studies, discriminate between urine of male and of female conspecifics when compared with water control. We hypothesize that male opossums require information about the presence of male conspecifics that recently traversed their home range to avoid potential conflicts. Urine from diestrous females signals the proximity of a female that has not already mated.

Evolution in the suite of semiochemicals secreted by the sternal gland of Australian marsupials

The nature and distribution of the components, and evolution of the suite of compounds, secreted by the sternal gland of marsupials were studied. Individuals from nine families (18 species) of marsupials and from the echidna were sampled over an 18-month period. The assay system used gas chromatography/mass spectrometry and utilised thermal desorption with cryofocusing. Parsimony analysis, constrained by an assumed phylogeny, was used to examine the evolution of the suite of compounds detected. Large interspecies variation in secretion composition was observed with acetic acid, short-chain (C6–C10) aldehydes, long-chain (>C15) hydrocarbons and 1,1-bis-(p-tolyl)-ethane being constituents of the secretion of most species. The suite of compounds, however, varied from three compounds in the yellow-bellied and feathertail gliders to 41 in the koala. The most complex suites of compounds were found in the brown antechinus, red kangaroo, tammar wallaby and koala. Radical differences were observed between the secretions of related species (for example, brown antechinus and mulgara, tammar and parma wallabies, wombat and koala). Compounds appeared and disappeared repeatedly across the phylogeny. No compound constituted a synapomorphy for the Australian marsupials and only one compound was considered a synapomorphy for the Diprotodontia.