A history of species delimitation methods applied in the Sceloporus
grammicus species complex and what it tells us about the future
Jonathon C. Marshall
Department of Zoology, Weber State University, Ogden, UT 84408, USA; jonmarshall@weber.edu
The historical developments of species identification and delimitation methods have been played out and reflected in the Sceloporus grammicus species complex of México. Early mor-phological studies were followed by allozyme studies and soon scores chromosomal races were being described based on cytogenetic analyses in the 1970s and 1980s. These gave way to restriction fragment digest analysis in both mitochondrial and ribosomal DNA and then to DNA gene sequencing, ecological niche modeling, and now thoughts of next generation sequencing. The history of attempts to identify species boundaries in S. grammicus illustrates
the complex nature and intrinsic difficulty of delimiting species even as our technology and analytic prowess has exploded over the last half century. In many cases there is no ‘silver bullet’ to delimit species boundaries and the S. grammicus complex reminds us of the necessity of an integrative approach in understanding this nebulous entity we call a species.
SYSTEMATICS
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Does foraging plasticity favours adaptation to new habitats in fire
salamanders? Preliminary data
Raoul Manenti1, Mathieu Denoël2, Gentile Francesco Ficetola3
1Dipartimento di Bioscienze, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy;
raoul.manenti@unimi.it
2Laboratory of Fish and Amphibian Ethology, Behavioural Biology Unit, Department of Biology, Ecology, and
Evolution, University of Liège, Belgium
3Dipartimento di Scienze dell’Ambiente e del Territorio, e di Scienze della Terra Università degli Studi di Milano-
Bicocca, Piazza della Scienza 1, 20126 Milano, Italy
Predators often show strong plasticity of optimal foraging strategies. A major difference in foraging strategies occurs between sit-and-wait and active predators. Environmental condi-tions affect their efficiency, with active foraging behaviour being favoured when prey is scarce or its detection is difficult. Both phenotypic plasticity and local adaptations may cause a shift between the two strategies. Here we studied larvae of Salamandra salamandra originating from
either typical epigeous streams and from caves. We evaluated whether local adaptations or phenotypic plasticity determine the shift of foraging strategy between stream and cave pop-ulations. The foraging behaviour of larvae was evaluated using a full-factorial design, taking into account three test conditions: light, prey availability, and starvation (larvae with and with-out an available prey in darkness and light, sate or starved larvae tested in light and in dark-ness). Behaviour was recorded both visually and through video-tracking. Salamander larvae modified their behaviour in response to environmental conditions. When in the darkness, salamanders moved longer distances. Movements also increased in starving larvae, and with prey occurrence. Furthermore, larvae from cave populations showed higher behavioural plas-ticity than stream larvae, as they changed more their foraging strategy according to light con-ditions. Cave larvae also better exploited the space available in test environments. Variation of foraging behaviour was strong, and involved complex interactions between plasticity and local adaptations. When larvae were in conditions similar to the ones encountered in caves, plasticity enabled behavioural shifts toward an active foraging strategy. The higher behavioral plasticity showed by cave larvae supports the importance of this trait for the exploitation of novel environments, as caves are for epigeous fauna.
