Environmental influence on the locomotor activity rhythm of the sand-shore amphipod Talorchestia deshayesi

Nasri–Ammar

2012

Locomotor activity of the supra-littoral amphipod Talitrus saltator was studied in spring and autumn. Specimens were collected from two geomorphologically different beaches: Bizerte, in the North of Tunisia and the Gulf of Gabes in the South of Tunisia. The latter has the largest tidal amplitude in the Mediterranean basin. Adult individuals were collected by hand and transferred individually to actographs, equipped with an infrared recording system. These were placed in a controlled environment cabinet, where locomotor activity was monitored over a period of 16 days. The resulting endogenous rhythms of locomotor activity showed unimodal circadian and bimodal periods in amphipods from both Bizerte and Gulf of Gabes beaches. In spring, the unimodal activity pattern predominated at Gabes beach, whereas different patterns of activity (unimodal, bimodal, and plurimodal) were obtained among Bizerte population, with almost equal proportions. Highly significant differences between ultradian and circadian rhythmicities were revealed in both Bizerte and Gabes populations. These results are interpreted in the context of locomotor rhythm adaptation to the geomorphological conditions prevailing at the two collection sites.

“…This is consistent with the work of Williams (1982), who showed that the locomotor rhythm of T. saltator on British beaches is synchronized by dawn.…”

Section: Gabes (N¼30)supporting

confidence: 92%

Locomotor rhythm phenology ofTalitrus saltatorfrom two geomorphologically different beaches of Tunisia: Bizerte (North of Tunisia) and Gulf of Gabes (South of Tunisia)

Nasri–Ammar

2012

“…Dotted line in actograms represents the activity drift. Bohli et al 2006;Ayari & Nasri-Ammar 2012b), Orchestia gammarellus which is another detritivore species living in sympatry with O. montagui in Menzel Jmil (Jelassi et al 2013a(Jelassi et al , 2013bAyari et al 2015b), Deshayesorchestia deshayesii (Williams 1982(Williams , 1983Ayari & Nasri-Ammar 2012a), O. mediterranea and O. cavimana (Wildish 1970). our results revealed the presence of circadian and ultradian endogenous components in Orchestia montagui, with periods close to 24 and 12 h, respectively.…”

Section: Discussionmentioning

confidence: 47%

“…Supralittoral amphipods are usually nocturnal animals (Williamson 1954), such as shown in Orchestia gammarellus (Jelassi et al 2013a, b;Ayari et al 2015aAyari et al , 2015b, O. mediterranea and O. cavimana (Wildish 1970), Deshayesorchestia deshayesii (Williams 1982(Williams , 1983Ayari & Nasri-Ammar 2012a) and Talitrus saltator Ayari & Nasri-Ammar 2012b). Previous studies showed differences in the locomotor activity rhythm between genders in the same species, e.g.…”

Section: Introductionmentioning

confidence: 97%

Locomotor behaviour in males, females and groups ofOrchestia montagui(Amphipoda, Talitridae) in the supralittoral zone of Bizerte lagoon

Jelassi

Ghemari

et al. 2016

Locomotor activity rhythm of Orchestia montagui was investigated under constant darkness in a population collected in spring from the supralittoral zone of Bizerte lagoon (northern region of Tunisia) at Menzel Jmil in spring. This rhythm was recorded in individual and groups of animal by infrared actography every 20 min by multichannel data loggers, at a constant temperature of 18 ± 0.5 °C. According to double-plotted actograms, wave forms and periodogram analysis, results revealed different locomotor pattern. However, locomotor activity rhythm of males was more stable than females. Furthermore, the mortality was statistically higher in unmixed groups than in mixed groups.

“…Their activity was concentrated during the subjective night. This activity pattern was shown for many species of amphipods such as Orchestia gammarellus (Jelassi et al 2013a(Jelassi et al , 2013b, Deshayesorchestia deshayesii (Williams 1982;Williams 1983;Ayari & Nasri-Ammar 2012b), Orchestia mediterranea and Orchestia cavimana (Wildish 1970). In contrast, activity of Britorchestia brito occurred mainly during the subjective day.…”

Section: Discussionmentioning

confidence: 67%

“…Orchestia gammarellus (Jelassi et al 2013a;Ayari et al 2015), Orchestia mediterranea and Orchestia cavimana (Wildish 1970), Deshayesorchestia deshayesii (Williams 1982(Williams , 1983 Ayari & Nasri-Ammar 2012a), and Talitrus saltator (Williams 1980;Bohli et al 2006;Bregazzi & Naylor 1972;Nasri-Ammar & Morgan 2005a;Ayari & Nasri-Ammar 2012a, 2012b, whereas the tidal estuarine species Corophium volutator showed almost exclusively a semidiurnal tidal pattern (Hölmstrom & Morgan 1983) that in the sand beach amphipod Bathyporeia pelagica is modulated over a circadian period (Fincham 1970a(Fincham , 1970b.…”

Section: Introductionmentioning

confidence: 94%

Endogenous activity rhythm inTalitrus saltator,Britorchestia brito(Crustacea, Amphipoda) andTylos europaeus(Crustacea, Isopoda) from Barkoukech Beach (Tabarka, Tunisia)

Jelassi

Nasri–Ammar

2015

The locomotor activity rhythm of three supralittoral crustacean species, Tylos europaeus (terrestrial isopod) and Britorchestia brito and Talitrus saltator (amphipod, Talitridea), was investigated in Barkoukech Beach. The rhythm was monitored in individual animals in spring under continuous darkness and constant temperature.Results revealed that whatever the species, actograms and mean activity curves showed that specimens of Tylos europaeus and Talitrus saltator concentrated their activity during the subjective night; whereas, Britorchestia brito concentrated its activity during the subjective day. The three species exhibited a circadian locomotor rhythm with mean circadian period respectively equal to 24h41'±0h44', 24h46'±0h55' and 25h21'±1h16'.The most stable locomotor rhythm was found in Talitrus saltator (0.444±0.246).Furthermore, individuals of Tylos europaeus were significantly more active (10h47'±2h52') than the two amphipods.Differences in the activity patterns of the three species will be discussed as an adaptative strategy to respond to interspecific competitive interactions.