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Abstract

Two morphologically and genetically distinct salamander species (the crested newt, Triturus cristatus and the marbled newt, T. marmoratus) engage over a large area in the west of France where they hybridize at ca. 4%. The species interaction is characterized by ecological differentiation and limited gene flow beyond the F1 hybrid generation. Incompletely isolated species like these allow to investigate the genetic mechanisms and evolutionary forces that maintain their identity in the face of ongoing gene flow, to which a large mosaic hybrid zone provides excellent opportunities. A reanalysis of published morphological data supports the partial breakdown of the species barrier whereas extensive genetic data show that introgression is low yet asymmetric, in line with the dynamics of species replacement inferred earlier. The current work, with seven diagnostic nuclear markers studied for a large sample, revises the estimates of introgression in both T. cristatus (to 0.24%) and T. marmoratus (to 0.11%). Difficulties remain in the recognition of potential triploid hybrids versus backcross hybrids. Haldane’s rule is partially supported, but deeper analyses require the use of a molecular marker for sex that is not yet available.

Open Access
In: Contributions to Zoology

Abstract

Researchers have recently focused efforts on the study of animal personality and behavioural syndromes, exploring consistent behaviour variations and correlations. Dragonflies, with their diverse behaviours, have become good models to improve our knowledge on animal behaviour. Here, we addressed whether dragonfly larvae exhibit shy–bold behaviours, akin to personality traits or behavioural syndromes. We made a series of experiments where we restrained larvae and noted their behaviour — some larvae exhibited thanatosis, playing dead when touched, while others boldly reacted with aggression. Later, we tested how active the larvae were in a water channel by analysing their movement. These experiments were made in three trials with 15 days apart. Our results show that larvae display consistent behaviours over time, hence, they exhibit personalities in terms of predator avoidance behaviour. Nevertheless, we found little evidence for behavioural syndromes. The boldness of larvae was only partially correlated with larval activity in the experimental channel. In conclusion, dragonflies emerge as a potential model for insect personality, prompting future studies on how cognition and personality impact fitness in different environments. Unravelling whether behavioural syndromes are a true phenomenon in these insects awaits further investigation.

In: Behaviour

Abstract

The genetic identity and conservation status of lake ecotype of brown trout (Salmo trutta) populations in Slovenia’s Alpine lakes Bled and Bohinj have been subjected to changes due to historical stocking practices. We aimed to evaluate the genetic differentiation and origins of these populations to advise for correct conservation strategies. Using microsatellite and mitochondrial DNA analysis on 365 trout specimens, we explored the genetic diversity and structure of these populations, comparing them with potential originators. Results revealed distinct genetic profiles between Bled and Bohinj lake trout, with Bohinj lake trout closely aligned with the native Danubian lineage and Bled lake trout showing a hybrid composition, significantly influenced by hatchery-introduced Atlantic lineage strains. The genetic distinction between these populations underscores the complexity of their conservation, showcasing the impact of human-mediated introductions on natural populations. The urgent need for conservation measures to preserve the Bohinj population’s native genetic pool is highlighted, underlining the must to prevent the transfer of individuals from Lake Bled or elsewhere and to reconsider stocking practises in order to prevent further genetic dilution of these iconic European lake dwellers.

Open Access
In: Contributions to Zoology

Abstract

Plethodontids are organisms highly linked to variations in temperature and moisture in the environment. The major determinant of their body temperature is the interaction between microhabitat preferences and time of day. However, there are proposed differences in moisture and temperature preferences among age classes. This study examines how microhabitat exposure and time of day on the abundance, environmental and microenvironmental moisture and temperature, body temperature, and age demographics of Pseudoeurycea leprosa interact. Hatchlings appeared to be more abundant during the day, and their body temperature varied by microhabitat and time of day, the microenvironmental moisture of the sites that individual used were affected by the interaction between these variables. These results suggest segregation between age classes. Juveniles and adults may benefit by exploiting exposed microhabitats because their body temperature remains stable. These findings highlight the importance of understanding the responses of plethodontids to changes in their environment.

In: Amphibia-Reptilia

Abstract

Age and growth-related parameters provide a better understanding of life-history adaptations and trade-offs and can be studied in the wild through capture-mark-recapture (CMR) or sclerochronology (i.e., skeletochronology and counting growth marks on hard structures). In chelonians, skeletochronology is limited to carcasses, CMR is limited by time and funding constraints, but counting shell growth annuli (SGA count) is a cheaper and faster alternative. A long-term CMR study in Testudo graeca from south-eastern Romania allowed us to compare the age estimated by the two sclerochronology methods using carcasses, and calibrate the results with data obtained from recaptured tortoises. We found that the accuracy of SGA counts significantly decreased with time (i.e., years between captures and older individuals). Skeletochronology showed the best results with long bones (i.e., ulna, radius, femur), but overall underestimated the age when compared to SGA counts; we obtained comparable results from these two methods in tortoises up to 17 years old. The oldest age estimated by skeletochronology alone was 28 years, 30 years by SGA counts, and 40 years by SGA counts when calibrated by CMR. The growth models using age estimations from both skeletochronology and SGA counts were similar, highlighting their usefulness in monitoring growth trajectories. Our study showed that while age estimation in tortoises is challenging, a combination of methods can improve its accuracy.

In: Amphibia-Reptilia

Abstract

Animals often possess multiple distinct threat signals which indicate their level of aggressive motivation or resource holding potential. In contrast, the diversity of submission signals is considerably lower. Still, some social species exhibit multiple distinct submission signals which could have different strategic functions or serve to enhance signal transmission. In the current study, we examine submission signalling in the daffodil cichlid (Neolamprologus pulcher), a cooperatively breeding fish which produces two distinct submission signals: a tail quiver, and a head-up posture. Observing interactions within stable social groups revealed that submission signal selection depends on the location of the interaction, with tail quivers being preferentially displayed near the substrate, and head-up postures being deployed when the interaction takes place further away from the substrate. Our findings suggest that variation in submission signalling in daffodil cichlids may serve to enhance signal transmission across spatial contexts rather than to convey distinct information.

Open Access
In: Behaviour

Abstract

In iteroparous animals, it may be adaptive to adjust the amount of reproductive investment based on their current competitive ability. Male fiddler crabs use an enlarged major claw for claw-waving display in the breeding season. Males sometimes lose their claws, but they can regenerate a claw, which is an inferior weapon for male-male fights. Here, we compared the waving frequency between males with a regenerated claw (regenerated males) and with an original claw (original males) to examine the differences in the amount of reproductive investment. Regenerated males showed lower waving frequency than original males, but some regenerate males waved frequently before the optimal mating season where original males waved frequently. These results indicate that individuals with poor fighting ability that have lower chance of acquiring females invested less in waving, and may also have shifted their peak of mating period in order to avoid competition with original males.

In: Behaviour
Volume Editors: , , and
This interdisciplinary volume provides a comprehensive and rich analysis of the century-long socio-ecological transformation of Lake Naivasha, Kenya. Major globalised processes of agricultural intensification, biodiversity conservation efforts, and natural-resource extraction have simultaneously manifested themselves in this one location.

These processes have roots in the colonial period and have intensified in the past decades, after the establishment of the cut-flower industry and the geothermal-energy industry. The chapters in this volume exemplify the multiple, intertwined socio-environmental crises that consequently have played out in Naivasha in the past and the present, and that continue to shape its future.
This series publishes monographs on African social issues. The studies from various social scientific perspectives, are original works, and essential for scholars of African Studies. Africa is getting an increasing amount of interest from the academic world: the continent is developing at a rapid pace. To understand the changes and to learn more about the social history of Africa, the new series will shed light on the problems and possibilities of the continent from Senegal to Somalia and from Niger to South Africa. Titles will be published with local publishers as much as possible.