Ecophysiological and behavioural responses to salinity and temperature stress in cyclopoid copepod Oithona davisae with comments on gender differences

Abstract

The gender differences in reaction to salinity (3-50) and temperature (6-26°C) stress were studied in the thermophilic cyclopoid copepod Oithona davisae, introduced in the brackish temperate Black Sea since 2001. Both females and males possessed similar salinity tolerance ranges (6–40) irrespective of the salinity change rate, and females displayed a striking osmotic control upon sharp (18-40 and 40-18) salinity shocks. By contrast, the temperature response of males and females were different. Torpidity was recorded at a temperature below 10°C in males collected both in warm and cold seasons, as well as in summer-autumn females whilst in females grown up at the beginning of winter the locomotor parameters were high even at 6°С. The total metabolic rate of summer-autumn and winter females was determined by the level of basal metabolic rate and energy expenditures due to motor activity. In winter females that maintained high activity at low temperature, the total and basal metabolic rates, differing by 2.3 times at all temperatures within the range of 8–28°C, varied in accordance with the temperature coefficient Q10 of about 2, whereas in summer-autumn females at low temperatures total metabolic rate decreased to the basal level. The plasticity of both males and female to wide ranges in abiotic conditions provide an adaptive strategy to sustain the spreading of O. davisae in diverse environments.

Homeostatic swimming of zooplankton upon crowding: the case of the copepod Centropages typicus

“…At even much higher values (up to 80 ind. ml −1 ), the cyclopoid Oithona davisae showed metabolic rates in proportion to the temperature although the motor activity parameters were unaffected by short-term crowding [64,65]. The density levels adopted in the present experiments could consequently be used in observational and behavioural studies or in rearing conditions without expected consequences on animal health or motion patterns.…”

Optimization of salinity levels for the culture of cyclopoid copepod Dioithona oculata (Farran, 1913) with respect to total population, reproduction, development and adult longevity

“…Swarms of D. oculata have also been reported from areas with high salinity fluctuations (Kurt, 2018; Thompson, 1991). Another cyclopoid copepod often reported from a similar habitat Oithona davisae could withstand a wider range of salinity from 6 to 40 ppt (Svetlichny et al, 2021). The adaptation of copepods to highly fluctuating salinity conditions is facilitated through osmoregulation (Bayly & Boxshall, 2009; Svetlichny & Hubareva, 2014) by regulating the concentration of intracellular free amino acids in their body (Burton & Feldman, 1982; Goolish & Burton, 1989) and the capacity to survive at different salinity levels is mostly species specific.…”

Two-way bioinvasion: tracking the neritic non-native cyclopoid copepods Dioithona oculata and Oithona davisae (Oithonidae) in the Eastern Mediterranean Sea

“…Our study did not find an association between salinity and O. davisae abundance. However, physiological experiments have shown that O. davisae is highly adapted to tolerate a wide salinity range (3-40) (Svetlichny & Hubareva, 2014;Zagami et al, 2018;Svetlichny et al, 2020).…”