Development of Olfactory Behavior in Captive Ring-Tailed Lemurs (Lemur catta)

We conducted a long-term research project (1996–1999) on developmental aspects of olfactory behavior in ring-tailed lemurs to document the ontogenetic sequence of olfactory behavior, including the possible presence of sexual differences, and the maturation of scent-marking. The subjects were a group of 18 lemurs housed in the Pistoia Zoo (Tuscany, Italy), which we observed during 1,735 h via all-occurrences sampling, scan-animal sampling and ad libitum sampling methods. We determined the time sequence of olfactory exploration and of scent-marking patterns, and investigated sexual differences in timing and frequency. We also followed the development of scent-marking through the juvenile and adolescent phases taking into account the two aspects of motor control and of the acquisition of social competence. On the whole, we found that olfactory investigation appears and matures earlier than scent-marking. Moreover, olfactory investigation of conspecifics appeared later than substrate exploration, and seemed to follow a sequence of increasing level of acceptance by the receiver. Social play is very important for the maturation of the gestural component of scent-marking. The olfactory behavioral pattern appeared to mature during the juvenile and adolescent phases. Although sexual maturation had obvious influence on the development of olfactory behavior, the onset of scent-marking patterns was only partially parallel to sexual maturation.     

Multiple Environmental Controls on Cockroach Assemblage Structure in a Tropical Rain Forest

Arthropod abundance and diversity are remarkable in tropical forests, but are also spatially patchy. This has been attributed either to resources, predators, abiotic conditions or disturbances, but whether such factors may simultaneously shape arthropod assemblage structure is little known. We used cockroaches to test for multiple environmental controls on assemblage structure in 25 km² of Amazonian forest. We performed nocturnal, direct searches for cockroaches in 30 plots (250 m × 2 m) during two seasons, and gathered data on biotic and abiotic factors from previous studies. Cockroach abundance increased with dry litter mass, a measure of resource amount, while species richness increased with litter phosphorus content, a measure of resource availability. Cockroach abundance and species richness decreased with ant relative abundance. Cockroach species composition changed along the gradient of: (1) soil clay content, which correlates with a broad differentiation between flood‐prone and non‐flooded forest; (2) soil relative moisture, consistent with known interspecific variation in desiccation tolerance; and (3) according to the abundance of ants, a potential predator. Turnover in species composition was correlated with abiotic conditions—sorting species according to physiological requirements and to disturbance‐related life history traits—and to ants' selective pressure. Cockroach abundance, diversity, and composition seem to be controlled by distinct sets of environmental factors, but predators which were represented by ants, emerged as a common factor underlying cockroach distribution. Such patterns of community structure may have been previously overlooked by undue focus on single or a few factors, and may be common to tropical forest arthropods.     

Adh 1 first intron polymorphisms in Argentinean populations of Ceratitis capitata

DNA size polymorphisms were utilized in a study of 24 natural populations of Ceratitis capitata Wiedemann (Diptera: Tephritidae) from Argentina. The first intron of alcohol dehydrogenase 1 gene (Adh₁) was amplified using exon priming intron crossing‐polymerase chain reaction. Three size variants were detected among the 307 samples analyzed. To better differentiate the size variants, further digestion of PCR products with the EcoRI restriction enzyme was carried out. Complete nucleotide sequences of the three‐allele variants were obtained and single changes, insertions, deletions, and EcoRI recognition sites were located. Population allele frequencies were analyzed and a global mean heterozygosity (He) of 0.33 was obtained. In most populations, observed allelic frequencies conformed to Hardy–Weinberg expectations. Significant differences between provinces and sampling sites within these provinces, and among some populations were found. The average number of insects exchanged among populations (Nm) was estimated and high values were observed between Argentina and populations from two African countries (Morocco and Kenya), Australia, and Hawaii (Kauai). Pest introduction sources and dispersion patterns in Argentina are discussed based on these results as well as on available bibliographical data.     

Higher-level snake phylogeny inferred from mitochondrial DNA sequences of 12S rRNA and 16S rRNA genes

Portions of two mitochondrial genes (12S and 16S ribosomal RNA) were sequenced to determine the phylogenetic relationships among the major clades of snakes. Thirty-six species, representing nearly all extant families, were examined and compared with sequences of a tuatara and three families of lizards. Snakes were found to constitute a monophyletic group (confidence probability [CP] = 96%), with the scolecophidians (blind snakes) as the most basal lineages (CP = 99%). This finding supports the hypothesis that snakes underwent a subterranean period early in their evolution. Caenophidians (advanced snakes), excluding Acrochordus, were found to be monophyletic (CP = 99%). Among the caenophidians, viperids were monophyletic (CP = 98%) and formed the sister group to the elapids plus colubrids (CP = 94%). Within the viperids, two monophyletic groups were identified: true vipers (CP = 98%) and pit vipers plus Azemiops (CP = 99%). The elapids plus Atractaspis formed a monophyletic clade (CP = 99%). Within the paraphyletic Colubridae, the largely Holarctic Colubrinae was found to be a monophyletic assemblage (CP = 98%), and the Xenodontinae was found to be polyphyletic (CP = 91%). Monophyly of the henophidians (primitive snakes) was neither supported nor rejected because of the weak resolution of relationships among those taxa, except for the clustering of Calabaria with a uropeltid, Rhinophis (CP = 94%).      

Univariate estimates of sexual dimorphism: The effects of intrasexual variability

The difference between male and female values of quantitative traits depends on the distribution of the variables within each sex, increasing with the rise in the difference between male and female average values and with the decrease of the dispersion of measurements in both sexes. This paper deals with the sensitivity of some widely used indices (relative difference between male and female mean values (MDI), Student's t, and the so-called Bennett-Chakraborty-Majumder D coefficient) with respect to intrasexual variability. The Kolmogorov-Smirnov distance (KS) is suggested here as a further index of dimorphism, although it is not usually utilized for this purpose. The theoretical approach is accompanied by the analysis of empirical data (metric variables obtained from a sample of present Sardinians) and by computer simulations under various assumptions. Indices based on the difference between male and female average values are not able to evaluate fully the various aspects of dimorphism. Student's t proved to be an adequate measure of whole sex differences, both in real and in simulated samples, as intrasexual variability is included in its formulation. The D index also proved to be a good measure of undivided sexual dimorphism, as it is the result of formal examination, and from application to empirical or to simulated cases. The Kolmogorov-Smirnov distance gave the best performance both in formal examination and in the whole simulation results, as it takes into account intrasexual variability, and is applicable to any kind of distribution. In simulated cases it was sensitive to variations of means and variances, and it was able to evaluate variance dimorphism. Since the last three indices measure the combined effect of size and variance dimorphism, the joint use of the MDI index is suggested in order to isolate the relative contribution of the difference between the means. Am J Phys Anthropol 109:501–508, 1999. © 1999 Wiley-Liss, Inc.     

Chemical, biological and immunological characterization of separated electrophoretic components of human chorionic somatomammotropin (HCS).

Purified HCS preparations ofter show heterogeneity when assayed by electrophoresis, although they may be considered homogeneous according to other criteria (N-terminal amino acid analysis, gel filtration and ultracentrifugation patterns, etc.). Using DEAE-cellulose chromatography, the two main components corresponding to various degrees of hormone amidation were separated. The deamidation kinetic of the electrophoretically slower migrating component was studied and found to be sensitive to temperature and, to a lesser extent, to pH. Denaturing agents strongly increased the deamidation rate, while no effect was found by raising the ionic strength. No difference was evident between the two components and the parent hormone when compared (on a weight basis) in a specific HCS radioimmunoassay system. Even the precipitin reaction in agar gel with an anti-human growth hormone (HGH) serum did not show variations in cross-reactivity versus HGH. Moreover, groups of guinea pigs immunized with the single HCS components, gave antibodies reacting identically with the components and the parent HCS. The prolactin-like activity of the two components differed when determined by the pigeon crop-sac asay: the slower migrating component proved to be less active than the more deamidated one. On the other hand, the activity in two different radioreceptor assays (employing membranes from rabbit mammary gland and rat ventral prostate) was greater for the faster migrating component.     

Reconciliation and consolation in captive bonobos (Pan paniscus)

Although reconciliation in bonobos (Pan paniscus) has previously been described, it has not been analyzed heretofore by the postconflict (PC) match-control (MC) method. Furthermore, although reconciliation has been investigated before in this species, consolation has not. In this study we analyzed agonistic and affiliative contacts in all sex-class combinations to clarify and reevaluate the occurrence of reconciliation in bonobos via the PC-MC method. We also investigated the occurrence of consolation by analyzing the victims' triadic contact tendency (TCT), the influence of the sex of victims, and the relative occurrence of consolation and reconciliation. We collected 167 pairs of PC-MC observations in a captive group of bonobos (in Apeldoorn, The Netherlands). The conciliatory tendency (CCT) we obtained was tendentially lower than the mean value previously found for Yerkes captive chimpanzees. Close relationships, which were present in all female-female (FF) and some male-female (MF) dyads, positively affected reconciliation rates. When only adult PC-MC pairs (157) were considered, the mean TCTs and CCTs did not differ significantly. When we focused on types of PC affiliative contact, in the case of consolation we found a striking preference for sociosexual patterns. As to the relative occurrence of consolation and reconciliation, the highest level of the former was found in the absence of the latter. When reconciliation took place, consolation generally preceded it, suggesting that consolation may be a substitutive behavior. Our findings suggest that even if reconciliation remains the best option, consolation may be an alternative substitute for reconciliation that is used to buffer the tension originating from an unresolved conflict. Reconciliation and consolation are complex phenomena that are probably related to the life history of a group. Given that few studies have been conducted on this subject, we can not at this time make any generalizations regarding conflict resolution in certain species by comparing results among studies.     

MIQE précis: Practical implementation of minimum standard guidelines for fluorescence-based quantitative real-time PCR experiments

The conclusions of thousands of peer-reviewed publications rely on data obtained using fluorescence-based quantitative real-time PCR technology. However, the inadequate reporting of experimental detail, combined with the frequent use of flawed protocols is leading to the publication of papers that may not be technically appropriate. We take the view that this problem requires the delineation of a more transparent and comprehensive reporting policy from scientific journals. This editorial aims to provide practical guidance for the incorporation of absolute minimum standards encompassing the key assay parameters for accurate design, documentation and reporting of qPCR experiments (MIQE précis) and guidance on the publication of pure 'reference gene' articles.