Diego-Rasilla, F.J., Luengo, R.M. Magnetic compass orientation in common midwife toad tadpoles, Alytes obstetricans (Anura, Alytidae). J Ethol (2020). https://doi.org/10.1007/s10164-020-00653-3

https://rdcu.be/b4AFq

We provide the first evidence for y-axis magnetic compass orientation in Alytes obstetricans. Evidence for wavelengthdependent effect of light on magnetic compass orientation is also shown. In the first series of experiments, two groups of tadpoles were tested shortly after being collected from a pond with a natural shoreline and a clearly defined y-axis under two different lighting conditions (full-spectrum and long-wavelength light). Magnetic bearings from tadpoles tested under full-spectrum natural skylight displayed bimodal distribution along an axis that coincided with the magnetic direction of the y-axis in their home pond, while those tested under long-wavelength light failed to exhibit a consistent overall direction of orientation relative to the magnetic field, although a subset of tadpoles exhibited magnetic compass orientation that was rotated about 90° counter-clockwise of the magnetic direction of the y-axis in their home pond. In the second series of experiments, tadpoles were collected from a watering trough without a defined y-axis, trained to learn the direction of the y-axis in tanks with an artificial shore at one end and tested under full-spectrum natural skylight. Tadpoles from the two trained groups showed bimodal magnetic compass orientation along the shore–deep water magnetic axis of their respective training tanks. The present findings widen the number of species with y-axis magnetic compass orientation to include Alytidae, a family of primitive semiterrestrial frogs. 

Santos, Joana L.; Žagar, Anamarija; Drašler, Katarina; Rato, Catarina; Ayres, César; Harris, D. James; Carretero, Miguel A.; Salvi, Daniele: ‘Phylogeographic evidence for multiple long-distance introductions of the common wall lizard associated with human trade and transport’, Amphibia-Reptilia, 2018, DOI: https://doi.org/10.1163/15685381-20181040

The common wall lizard has been widely introduced across Europe and overseas. We investigated the origin of putatively introduced Podarcis muralis populations from two southern Europe localities: (i) Ljubljana (Slovenia), where uncommon phenotypes were observed near the railway tracks and (ii) the port of Vigo (Spain), where the species was recently found 150 km far from its previously known range. We compared cytochrome-b mtDNA sequences of lizards from these populations with published sequences across the native range. Our results support the allochthonous status and multiple, long-distance origins in both populations. In Ljubljana, results support two different origins, Serbia and Italy. In Vigo, at least two separate origins are inferred, from western and eastern France. Such results confirm that human-mediated transport is promoting biological invasion and lineage admixture in this species. Solid knowledge of the origin and invasion pathways, as well as population monitoring, is crucial for management strategies to be successful.

Silva-Rocha I. et al. (2018) Herpetological History of the Balearic Islands: When Aliens Conquered These Islands and What to Do Next. In: Queiroz A., Pooley S. (eds) Histories of Bioinvasions in the Mediterranean. Environmental History, vol 8. Springer, Cham. https://doi.org/10.1007/978-3-319-74986-0_5

Balearic herpetofauna represents a paradigmatic case of multiple biological invasions within the Mediterranean Basin, with a much higher number of alien amphibians (i.e. frogs and toads) and reptiles (i.e. lizards, snakes and turtles/tortoises) than native. The paleogeography of the Balearic Islands, located on Western Mediterranean between Spain and Sardinia, is complex, comprehending an ancient split from the continent during the late Miocene and Pleistocene climatic fluctuations connecting and disconnecting islands from one another (but not them to the continent) that eventually re-shaped the archipelago’s biota. The archipelago has been also influenced by humans since the Neolithic, being a cross-road for alien biota between North Africa and Southern Europe, which caused range regressions and extinctions in the native herpetofauna, nowadays restricted to one amphibian and two reptiles. During the last century, tourism development, the pet trade, and cargo transport of ornamental plants have produced a new wave of biological invasions. Recently introduced snakes are of particular concern, since the effect of predation may seriously threaten the remaining native reptiles in the main islands and endemic subspecies in surrounding islets. Balearic people have a negative social perception of such snakes, mainly due to the lack of familiarity with snakes among islanders but also to the herpetophobic attitude of many Mediterranean cultures. Here we review the herpetological invasions in the Balearic Archipelago and their impacts. We further discuss the on-going management actions on alien reptiles in this archipelago, namely the control of invasive snakes in Ibiza involving monitoring, trapping, environmental education and promotion of social participation.

Pérez i de Lanuza, G., Carretero, M.A. and Font, E. (2017), Intensity of male-male competition predicts morph diversity in a color polymorphic lizard. Evolution, 71: 1832-1840. https://doi.org/10.1111/evo.13256

Sexual selection is one of the main processes involved in the emergence and maintenance of heritable color polymorphisms in a variety of taxa. Here, we test whether the intensity of sexual selection, estimated from population sex ratio, predicts morph diversity in Podarcis muralis, a color polymorphic lizard with discrete white, yellow, orange, white-orange, and yellow-orange male and female phenotypes (i.e., morphs). In a sample of 116 Pyrenean populations and 5421 lizards, sex ratios (m/f) vary from 0.29 to 2.5, with the number of morphs for each sex ranging from 2 to 5. Male-biased sex ratios are associated with increased morph diversity as measured with Shannon’s diversity index. The main factor accounting for this relationship is male morph richness (i.e., the number of morphs). In contrast, female morph diversity is not related to sex ratio. These results suggest a relationship between the intensity of male intrasexual competition and male morph diversity. While other selective forces may interact with sexual selection in maintaining the color polymorphisms in P. muralis, this evidence suggests a complex evolutionary scenario possibly involving frequency-dependent selection of alternative reproductive tactics and/or complex balancing selection.

Diego-Rasilla, F.J., Pérez-Mellado, V. & Pérez-Cembranos, A. (2017). Spontaneous magnetic alignment behaviour in free-living lizards. Sci Nat, 104: 13. doi:10.1007/s00114-017-1439-7

The evidence from this study suggests that free-living lacertid lizards exhibit magnetic alignment behaviour, since their body alignments cannot be explained by an effect of the sun’s position. On the contrary, lizard orientations were significantly correlated with geomagnetic field values at the time of each observation. We suggest that this behaviour might provide lizards with a constant directional reference while they are sun basking. This directional reference might improve their mental map of space to accomplish efficient escape behaviour. This study is the first to provide spontaneous magnetic alignment behaviour in free-living reptiles. leer más >>>