scholarly journals The critical thermal maximum of diving beetles (Coleoptera: Dytiscidae): a comparison of subterranean and surface-dwelling species.

2021 ◽  
pp. 100019
Author(s):  
Karl K. Jones ◽  
William F. Humphreys ◽  
Mattia Saccò ◽  
Terry Bertozzi ◽  
Andy D. Austin ◽  
...  
1980 ◽  
Vol 28 (1) ◽  
pp. 91 ◽  
Author(s):  
AE Greer

The critical thermal maximum temperature (CTMAX) has now been determined for representatives of 16 of the 21 genera of scincid lizards in Australia. Taxa from the warm interior of the country generally have a mean CTMAX greater than 39.5�C regardless of their behaviour or habitat. Taxa from the cooler periphery of the continent fall into two groups based on their behaviour and habitat: diurnal, surface- dwelling forms generally have a mean CTMAX above 39.5�C whereas crepuscular to nocturnal. or cryptozoic to fossorial forms, have a mean CTMAX below 39.5�C. The skinks of the interior probably evolved from ancestors occupying habitats most similar to ones now occurring on the periphery. In these more equable habitats. diurnal surface-dwelling forms, with their high CTMAX, would have been preadapted to invade the habitats of the interior, whereas crepuscular to nocturnal. or cryptozoic to fossorial forms, with their low CTMAX, may have had to overcome a thermal barrier to enter these habitats. This may account in part for the paucity of crepuscular to nocturnal or cryptozoic to fossorial skink lineages in the interior. Unlike most other lizard families, most skinks do not pant when heat stressed. The reasons for this are unknown.


1976 ◽  
Vol 40 (5) ◽  
pp. 683-687 ◽  
Author(s):  
G. L. Wright

The critical thermal maximum (the colonic temperature of heat-induced convulsion and righting reflex loss) and thermoregulatory response of male mice were examined following I, exposure to colonic temperature (Tco) 42 degrees C; II, a single exposure to the critical thermal maximum (Tco 44 degrees C); AND III, acclimation at ambient temperatures of 15 or 30 degrees C for 14 days. The critical thermal maximum (CTM) was greater in 30 degrees C acclimated mice than 15 degrees C acclimated mice but was unchanged in mice surviving exposure to Tco 42 degrees C or the CTM. The heating time to apparent breakdown of thermoregulation coincident with an explosive rise in the Tco during exposure to ambient temperature 40.8 degrees C was increased (100%) during the 48-h period following exposure to Tco 42 degrees. It appeared that mice exposed to severe, short-term heat stress (Tco 42 degrees) undergo a compensatory increase in their thermoregulatory cooling capacity with little or no change in the upper temperature tolerated. The animals did, however, exhibit the capability for adaptive adjustments of the upper thermal limit during extended exposure to the more prolonged and less severe environmental heat stress of acclimation at 30 degrees C.


2018 ◽  
Vol 16 (1) ◽  
Author(s):  
Manuela L. Brandão ◽  
Gisele Colognesi ◽  
Marcela C. Bolognesi ◽  
Roselene S. Costa-Ferreira ◽  
Thaís B. Carvalho ◽  
...  

ABSTRACT Changes in water temperature may affect the aggressive behavior of aquatic organisms, such as fish, either by changing some physiological mechanisms or by increasing the probability of encounters between individuals as a result of variation in their swimming activity. In our study, we evaluated the influence of increasing and decreasing temperature on the aggressive behavior of the Neotropical cichlid fish Cichlasoma paranaense. Firstly, we tested the critical thermal maximum (CTMax) tolerated by this species. Then, we tested the effect of decreasing or increasing the water temperature in 6o C (starting at 27° C) on the aggressive interactions of fish under isolation or housed in groups. We found a CTMax value of 39° C for C. paranaense. We also observe that a 6° C decrease in water temperature lowers swimming activity and aggressive interactions in both isolated and group-housed fish, as expected. On the other hand, the increase in temperature had no effect on the fish’s aggressive behavior, neither for isolated nor for grouped fish. We concluded that C. paranaense shows high tolerance to elevated temperatures and, in turn, it does not affect aggressive behavior. Nevertheless, we cannot dismiss possible effects of elevated temperatures on aggressive interactions over longer periods.


PLoS ONE ◽  
2017 ◽  
Vol 12 (7) ◽  
pp. e0179928 ◽  
Author(s):  
Marta Moyano ◽  
Caroline Candebat ◽  
Yannick Ruhbaum ◽  
Santiago Álvarez-Fernández ◽  
Guy Claireaux ◽  
...  

2008 ◽  
Vol 27 (1) ◽  
pp. 5-12 ◽  
Author(s):  
Elisa Guasti ◽  
Robert P. Speijer

Abstract. During the Paleocene–Eocene thermal maximum (PETM), low to mid-latitude planktic foraminiferal assemblages were characterized by blooms of the surface-dwelling Acarinina. Among this group a new ‘excursion taxon’ is identified, Acarinina multicamerata n. sp. Previously, this taxon was lumped together with Acarinina sibaiyaensis El-Naggar. Considering that A. sibaiyaensis already occurred prior to the hyperthermal event, both in open ocean and ocean margin deposits, it is proposed that these taxa are differentiated in order to avoid taxonomic and biostratigraphic ambiguities. Acarinina multicamerata n. sp. occurred exclusively during the PETM, hence this taxon represents an excellent biostrati-graphic marker of the PETM, while its common occurrence in various marine settings makes it an excellent marker of Subzone P5b or its new equivalent zone E1.


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