Song-type function during territorial encounters in male Cetti's Warblers Cettia cetti

During undisturbed singing, male Cetti's Warblers Cettia cetti sing constantly the same song type (S-song), which is stereotyped individually but differs between individuals. When facing a territorial dispute, males may start to sing a distinct song type (I-song) used only in this context. To evaluate the functional significance of these two song types in the communication system of Cetti's Warbler, two series of playback experiments were performed. When exposed to repeated S-songs of an extraneous male, most of the ten birds tested ceased to sing S-songs and used I-songs, generally while displaying aggressive reactions. After a while, they started to sing S-songs again but at a higher rate than before the playback. In a second series of experiments, seven birds were first exposed to a playback of S-songs and then to a second stimulation with three I-songs or with three further S-songs. The birds tended to approach the speakers in response to the first playback but, in most cases, withdrew from them after the second one. No significant differences in the reactions of the test birds were found between the trials using S-songs and those with I-songs. The present results indicate that the two song types constitute two signals associated with territorial behaviour; the song type emitted is probably dependent on the singer's level of aggressiveness.     

Taxonomy and evolution of European brown frogs

Phylogenetic relationships within the Euro-Mediterranean stock of the Rana temporaria species group (R. temporaria, R. iberica, R. cameranoi, R. macrocnemis, R. holtzi, R. dalmatina, R. graeca, R. latastei) were studied by (1) morphometric analysis, (2) osteological study and (3) electrophoresis. The three data sets were analysed independently and phenograms and cladograms examined for congruent patterns. The tree resulting from electrophoretic analysis is the most clearly resolved (and being also compatible with the other two) is assumed to represent the most likely phylogeny of the Mediterranean brown frogs. Patterns indicated by electrophoretic data matched the molecular clock-hypothesis. This suggests that the first split of the main stock of Mediterranean brown frogs separated ancestors of Rana temporaria and R. iberica from the others during the Late Pleistocene. A second split occurred separating the ancestors of what are currently the other big-bodied and the small-bodied brown frogs. The relationships between and within the three main stocks are discussed in the context of biogeographical and geological data.     

Detection of phytoecdysteroids by gustatory sensilla on chelicerae of the brown dog tick Rhipicephalus sanguineus

Ecdysteroids are polyhydroxylated steroids that act as moulting hormones in arthropods and regulate several important life‐cycle processes. Phytoecdysteroids are ecdysteroid analogues produced by some plants that disrupt the growth and development of insects feeding on them, and can be perceived by the taste receptors of insects. The present study tested the hypothesis that the blood‐feeding tick Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae) is capable of detecting phytoecdysteroids. By recording from the chelicerae, six phytoecdysteroids are tested: α‐ecdysone, 20‐hydroxyecdysone, ponasterone A, makisterone A, inokosterone and pterosterone. In unfed ticks, makisterone A and pterosterone elicit frequencies of neural impulses higher than in a negative control (a KCl solution at 10^?3m ), with detection thresholds of 10^?6m and 10^?12m , respectively. The spike amplitudes of the responses to these compounds, and also for 20‐hydroxyecdysone and ponasterone A, are higher than in the control, indicating that a different neurone may be involved: perhaps a deterrent cell, as observed in insects. In fed ticks, only pterosterone at 10^?4m remains active. In behavioural attachment assays, no difference is observed between electrophysiologically active compounds and the negative control. These results show the capability of R. sanguineus ticks to detect phytoecdysteroids, although they do not clarify the role of ecdysteroids in tick biology, for which further studies are required.     

Tracing Genetic Lineages of Captive Desert Tortoises in Arizona

Abstract: We genotyped 180 captive desert tortoises (Gopherus agassizii) from Kingman (n = 45), Phoenix (n = 113), and Tucson (n = 22), Arizona, USA, to determine if the genetic lineage of captives is associated with that of wild tortoises in the local area (Sonoran Desert). We tested all samples for 16 short tandem repeats and sequenced 1,109 base pairs of mitochondrial DNA (mtDNA). To determine genetic origin, we performed assignment tests against a reference database of 997 desert tortoise samples collected throughout the Mojave and Sonoran Deserts. We found that >40% of our Arizona captive samples were genetically of Mojave Desert or hybrid origin, with the percentage of individuals exhibiting the Mojave genotype increasing as the sample locations approached the California, USA, border. In Phoenix, 11.5% were Sonoran–Mojave crosses, and 8.8% were hybrids between desert tortoise and Texas tortoise (G. berlandieri). Our findings present many potential implications for wild tortoises in the Sonoran Desert of Arizona. Escaped or released captive tortoises with Mojave or hybrid genotypes have the potential to affect the genetic composition of Sonoran wild populations. Genotyping captive desert tortoises could be used to inform the adoption process, and thereby provide additional protection to native desert-tortoise populations in Arizona.     

Comparison of two sampling methods for domestic populations of Triatoma infestans in north-west Argentina

Abstract. In mud-and-thatch houses of Santiago del Estero Province, northwest Argentina, where no insecticides had been sprayed officially to control domestic infestations of the Chagas disease vector Triatoma infestans (Klug) (Hemiptera: Reduviidae), two knockdown (KD) insecticidal collection procedures were compared with the standard flush-out (FO) method for sampling T. infestans. Bugs were collected by FO using 0.2% tetramethrin in bedrooms of (1) 41 houses of Amama village employing 1 man-hour of capture effort per house, and (2) 19 houses of Trinidad and Mercedes villages employing 4 man-hours/house. From the same houses, 2-5 days after the manual FO collection, bugs were collected by KD indoor-spraying of deltamethrin 25mga.i./m² in Amama, or burning of one γ-HCH (=γ-BHC) fumigant tablet 3.1g of γ-isomer) per bedroom in Trinidad and Mercedes. The majority of infestations were detected by both methods, the proportion of positive houses being 81% at Amama and 95% at the other villages. Although the FO method was more sensitive, at least because it was applied first, the KD method detected infestations in 25% of houses where bugs were not found by FO. Bug densities estimated by FO or by subsequent KD in each house were significantly correlated: r = 0.795 for deltamethrin; r= 0.882 for y-HCH. Compared with FO collections of T.infestans large stages, i.e. adults plus fourth and fifth instar nymphs, the KD catch averaged 0.88x with deltamethrin and 0.57× with γ-HCH, regardless of the apparent population density of bugs per house. However, the KD method has practical advantages of speed and standardization.