Lead-phase and red-stripe color morphs of red-backed salamanders Plethodon cinereus differ in hematological stress indices:A consequence of differential predation pressure?

Throughout the animal kingdom there are species that have two or more phenotypic forms or ‘morphs＇, and many of these are amphibians. In North America, the red-backed salamander Plethodon cinereus can have either a red dorsal stripe or no dorsal stripe （lead-phase form）, and evidence to date indicates the lead-phase form incurs a greater number of attacks from predators. In a recent collection of 51 P cinereus, blood smears of both color morphs （35 red-stripe, 16 lead-phase） were examined to obtain numbers of circulating leukocytes （via light microscopy）, which can be used to indirectly estimate levels of stress hormones in vertebrates via a ‘hematological stress index＇, which is the ratio between the number of two leukocyte types （neutrophils and lymphocytes）. Our results showed that lead-phase salamanders tended to have greater numbers of circulating neutrophils and lower numbers of circulating lymphocytes than red-stripe morphs, leading to higher average neutrophil-lymphocyte ratios in lead-phase individuals. Since the salamanders were held （refrigerated） for 7 days before sampling, we cannot be certain if this effect is a stress reaction to the captivity or the normal level for this morph. However comparison with two sets of related salamanders that were captured and sampled immediately indicates the red-stripe salamanders were either not stressed from the captivity at all, or their white blood cell distributions had returned to normal after 7 days of captivity. Taken together, our results indicate that lead-phase forms of P. cinereus have higher stress levels than the red-stripe forms, which may be a consequence of their higher exposure to, and/or attacks from, predators. They may also indicate that the lead-phase form is less-suited to captivity than the red-stripe form of this species.

Modeling Habitat Suitability of the Red-backed Shrike(Lanius Collurio)in the Irano-Anatolian Biodiversity Hotspot

Identifying suitable habitats of species is essential knowledge to conserve them successfully.Human activities cause the reduction of population size and habitat suitability of many species.Red-backed Shrike is widespread in western Palearctic.However,the population of this specie has declined in its geographical range due to the loss of suitable habitats.Therefore,it is necessary to identify its suitable habitats and factors affecting species habitat suitability and to protect its reduction population size.The aim of the present study was to identify the suitable habitat of the Red-backed Shrike and determine the most important predictors of its suitable habitat in Irano-Anatolian biodiversity hotspot.To achieve this goal,species presence points were first collected and seven environmental variables related to climate,topography and anthropogenic activities,were used to construct the species habitat suitable model.Models were built using five distribution modeling methods:Maxent,GAP,GLM,RF and GBM in sdm package.Then the models were ensemble from 5 different models and the final model was constructed.The results of this study showed that the most suitable habitats of this species are in the western and northern parts of the area of study.The mean annual temperature with 41%contribution was the most important variable in constructing the habitat suitability model for this specie.In addition,climate variables with 75%contribution were identified as the most important habitat suitability factor for this specie.Also in relation to conservation of the Red-backed Shrike species in the Irano-Anatolian region,it can be stated that the extent of distribution and presence of this specie has been extended to the northern latitudes due to climate change.As a result,the temperature and climate factor should be given special attention in the management of bird habitats in this area.

Memory of conspecifics in male salamanders Plethodon cinereus： Implications for territorial defense

We investigated how exposure duration （time that two individuals initially interact） and separation interval （time be- tween the initial interaction and a subsequent interaction） affect recognition memory of conspecifics in male red-backed sala- manders Plethodon cinereus. Previous studies have demonstrated that this species aggressively defends territories. We recorded aggressive behavior to assess recognition memory, because aggression is more intense toward previously unencountered indi- viduals compared to previously encountered individuals in this species. We found that with 15-min exposures and 5-day separa- tion intervals, focal males did not spend significantly more time threatening ＇unfamiliar＇ intruders than ＇familiar＇ intruders. After either 8-hour exposures and 5-day separation intervals and 5-day exposures and 5-day separation intervals, focal males spent sig- nificantly more time threatening unfamiliar intruders than familiar intruders. These results suggest that male red-backed salaman- ders can remember familiar conspecifics （e.g., territorial neighbors） after at least an 8-hour exposure duration and that memory persists at least as long as 5 days. After 5-day exposure and 15-day separation intervals, we found no significant difference in ag- gressive behavior toward familiar and unfamiliar intruders. Long separation intervals （15 days） may lead either to loss of memory of previously familiar individuals or, alternatively, aggressive reassessment of individuals as only a change in behavior indicates positively that memory has occurred. Thus, variance in territorial defense within an individual may depend on its ability to recog- nize conspecific males .