Tortoise’s shell—a blessing and a curse. How tortoises cope with various obstacles?
2013
Аутори:
Golubović, AnaAnđelković, Marko
Arsovski, Dragan
Đorđević, Sonja
Iković, Vuk
Vujović, Ana
Bonnet, Xavier
Tomović, Ljiljana
Тип документа:
Конференцијски прилог (Објављена верзија)
,
© 2013 by the University of Pannonia
Метаподаци
Приказ свих података о документуАпстракт:
During 200 million years of evolutionary history, all chelonians are characterized by a well
developed, protective shell. Conserved during major evolutionary transitions (e.g. return to
the sea), shell likely provides substantial selective advantages. Conversely, heavy and rigid
shell poses a set of serious motion limitations, especially in terrestrial species during displacements
in rugged and complex environments. We examined how terrestrial tortoises overcome
various obstacles in their natural habitat. We compared several Balkan populations of
Hermann’s tortoises by placing individuals (app. 1100) in three types of challenging positions
to measure their performances.
Righting ability: males were more successful in righting themselves than females. Body size
influenced righting abilities only in females: smaller ones were more efficient. Individuals
with markedly domed carapace (increased instability) and shorter bridges (enlarging space for
leg movements) were more successful to right themselves.
Boldness to cross a steep step: animals from rugged environment were more prone to jump
from 50 cm high obstacle then ones from the flat habitat. Genders had similar success,
but adults showed more boldness to leap off the hedge than juveniles.
Disentangling themselves form thick vegetation: residents of Mediterranean macchia displayed
moderate pulling force and released themselves quickly by backwards movements.
Tortoises living in herbaceous habitats moved forward, deployed strong pulling force, ripping
on the substrate and were far less successful.
Individuals from different habitats, sex and age classes exhibited divergent and apparently
appropriate traits and strategies to overcome each locomotory challenge. We further speculate
that behavioural responses, as a response to morphological constraints, are shaped by
experience. These results may have conservation value and assist in improving translocation
strategies for endangered tortoise populations.
У:
- Programme and Abstracts: 17th European Congress of Herpetology; 2013 Aug 22-27; Veszprém, Hungary. University of Pannonia; 2013. p. 115.