A simple,reliable method to determine the mean gait speed using heel markers on a treadmill

Gait speed is an essential parameter of gait analysis. Our study proposed a simple and accurate method to extract a mean gait speed during walking on a treadmill using only kinematic data from markers placed on the heels of the participants’ feet. This method provided an attractive, simple method that remains resistant to errors in treadmill calibration. In addition, this method required only two markers, since heel markers are essential to gait analysis, and the proposed method is robust enough to differentiate among various gait speeds (mean error <1%).     

Brevity is not always a virtue in primate communication

Semple et al. (Semple et al. in press, Biol. Lett. (doi:10.1098/rsbl.2009.1062)) argued that the ‘law of brevity’ (an inverse relationship between word length and frequency of use) applies not only to human language but also to vocal signalling in non-human primates, because coding efficiency is paramount in both situations. We analysed the frequency of use of signals of different duration in the vocal repertoires of two Neotropical primate species studied in the wild—the common marmoset (Callithrix jacchus) and the golden-backed uakari (Cacajao melanocephalus). The key prediction of the law of brevity was not supported in either species: although the most frequently emitted calls were relatively brief, they were not the shortest signals in the repertoire. The costs and benefits associated with signals of different duration must be appreciated to understand properly their frequency of use. Although relatively brief vocal signals may be favoured by natural selection in order to minimize energetic costs, the very briefest signals may be ambiguous, contain reduced information or be difficult to detect or locate, and may therefore be selected against. Analogies between human language and vocal communication in animals can be misleading as a basis for understanding frequency of use, because coding efficiency is not the only factor of importance in animal communication, and the costs and benefits associated with different signal durations will vary in a species-specific manner.     

Vocalisations of wild common marmosets are influenced by diurnal and ontogenetic factors

The vocalisations of wild common marmosets, Callithrix jacchus, were recorded to investigate whether call rate by individuals is affected by time of day, age, sex or dominance rank within a group. We also investigated how vocalisation pitch was affected by age, focussing on a single common call, the trill call. Adults vocalised more than juveniles or infants during the majority of daylight hours. Only the call rate of juveniles varied significantly over the day. No differences were found between either sex or dominance rank with respect to rate of vocalisations. The trill calls emitted by young wild common marmosets were of a higher pitch than those emitted by adults. We conclude that the auditory communication of wild common marmosets is related to the age of the animals, both in terms of call rate and the physical characteristics of their vocalisations.     

Phylogenetic relationships of Deschampsia antarctica (Poaceae): Insights from nuclear ribosomal ITS

Deschampsia antarctica E. Desv. is the only monocot in the Antarctic floristic zone. We evaluated the phylogenetic relationships of Deschampsia antarctica to other grasses using parsimony as the optimality criterion. Five different sets of gap, transversion and transitions costs were explored to analyze the effect of parameter choice on the phylogenetic results. Both internal transcribed spacers (ITS1 and ITS2) and the 5.8S subunit of nuclear ribosomal DNA were included in the analysis. A total of 43 species were analyzed including seven species of Deschampsia. Deschampsia antarctica forms a well supported group with five species of Deschampsia. Deschampsia does not appear monophyletic as D. flexuosa (L.) Trin. is not included in this clade. The clade to which D. antarctica belongs is sister to some Aveneae in all analyses. This study is the first contribution that evaluates the phylogenetic position of D. antarctica in relation to other species of Deschampsia.     

A new genus and species of Coenosiini from Costa Rica (Diptera,Muscidae, Coenosiinae)

Palpilongus gen. n. is herein described for one species – Palpilongus bifurcus sp. n., from Costa Rica, based on male and females. The striking morphological characters of the species – palpus very long, about as long as prementum; upper calypter truncate and very short and setae of male sternite 5 bifurcated, confirm that this new species is also a new genus in the tribe Coenosiini. Male and female terminalia were dissected and illustrated.     

The effects of two abundant ant species on soil nutrients and seedling recruitment in Brazilian Atlantic Forest

Ants can influence soil fertility and the spatial distribution of seeds, with possible effects on seedling recruitment. The ant species Pachycondyla striata Fr. Smith, 1858 and Odontomachus chelifer (Latreille, 1802) co-occur in many forest areas in the Neotropics. We assessed soil fertility and seed bank structure in soil samples close and distant (control) from ant nests in forest fragments. We also assessed the richness and abundance of seedlings on nests and control sites. In soil samples from ant nests, the concentration of phosphorus and potassium were respectively 55.6% and 36% higher than in control sites. Aluminium was 11–15% lower in soil samples from ant nests. In the greenhouse, soils from ant nests had higher plant abundance and species richness, but the same species composition in comparison with control sites. Although more plants emerged from soil samples of O. chelifer nests, in the field, the density and richness of seedlings were similar for the two ant species studied. Seedlings in the nest sites were, on average, 1.8 times more abundant and 1.6 times richer in species than in control sites. Our results showed that ant species can play a key role in seedling recruitment in forest fragments, where other animals with equivalent and positive effects, such as mammals, are missing.     

Camera Trap Observations of Nonhabituated Critically Endangered Wild Blonde Capuchins,Sapajus flavius (Formerly Cebus flavius)

Habituation presents major challenges for the study of wild primates, particularly in areas where threats such as hunting pressure and increasing forest fragmentation exist. This study describes the use of ground camera trapping to investigate nonhabituated blonde capuchins. Capuchins are arboreal animals, but often use the ground when foraging. Thus, we hypothesized that a ground-baited camera trapping station would be an efficient method to document the presence of capuchins, and to collect information about aspects of their social behavior and ecology. We conducted 92 systematic trapping days over 15 months (from December 2010 to February 2011 and from August 2011 to July 2012). The capuchins visited the trapping stations 43 times. All visits occurred between 05:13h and 17:32h, and lasted 3 min-2:03 h. Sixty-five percent of the photographs included our target species. Groups contained up to 46 individuals and were multimale-multifemale. We recorded no monkeys at the trapping stations during August and November (2011) and January (2012). Infants were more likely to be carried than not. Infants were carried by both sexes; however, 96% of photographs showed females as carriers. Adult males always arrived first at the camera trapping stations, suggesting that males led the group’s movements. The ground-baited camera trapping stations proved effective for confirming the presence of the blonde capuchins in the study site and for documenting aspects of their social behavior. The technique could potentially be used to provide comparative data among populations of this and other primate species in areas where habituation is difficult or risky to the primates.     

Classifying conservation targets based on the origin of motivation: implications over the success of community-based conservation projects

Community-based conservation (CBC) projects represent one approach to biodiversity conservation when working with indigenous and local people. This method aims to achieve conservation and development goals simultaneously, however whether both types of goals can be met or whether competition between the two precludes success is an issue of much discussion. Conservation targets are one of the most important elements upon which a conservation project is built. We propose that one way to link biodiversity conservation with human development goals is to consider people’s needs and interests in the selection of the conservation target. Here, we present three categories of conservation targets that vary according to the origin of motivation that drives indigenous and local people to conserve the target. According to the type of target selected, the level of participation, integration of traditional ecological knowledge, level of external intervention and long-term sustainability will vary. We encourage conservation practitioners to understand the motivations that lead indigenous and local people to participate in conservation projects, and to develop and design CBC projects from these incentives.