Temperature regulates the switch between light-synchronized and unsynchronized activity patterns in the subtidal bivalve Pinna nobilis

Abstract

The present study reports new knowledge into the biological rhythms of subtidal bivalves using the fan mussel Pinna nobilis as model. The objective was determining which factor(s) provoke the change between two different patterns observed in the annual cycle of this species: P1, characterized by the individuals opening and closing their valves following the presence and absence of ambient light and P2, characterised by a behaviour independent of the presence of light. Magnetoresistive sensors were installed on 8 fan mussels to record gaping activity in laboratory conditions. Different temperature and light treatments were applied. Results showed temperature as the factor modulating the change between behavioural patterns. The individuals switched to P1 when temperature reached 24.5º C. In this pattern, individuals are entrained by light showing a circadian rhythm linked to the daily light treatments. During P2, the circadian rhythm was missing or very weak, contrary to in situ observations. The results of the present study contribute to understand the biology of the species in order to plan new conservation strategies. Furthermore, the observed relationship between temperature and P1 is of interest to develop captive breeding of fan mussels. Altogether, this information is especially relevant in view of the recent mass mortality of P. nobilis occurred in the western Mediterranean.

Suspended culture of Pinna rudis enhances survival and allows the development of a seasonal growth model for Mediterranean Pinnids

“…Therefore, recently transplanted individuals need time to attach to the bottom, which makes them more vulnerable to drag forces or predators. Hence, a natural attachment to hold them, anti-predator cages, or an artificial extension of the byssus to fix the individuals to the seabed (Hernandis et al, 2018), appears to be necessary to maximize survival.…”

Population, Aquaculture and Transplantation Applications of Critically Endangered Species Pinna nobilis (Linnaeus 1758) in the Mediterranean Sea

“…P. nobilis can be cited to be a summer breeder species according to the classification by Boolotian et al (1962) considering spawning in terms of comparison of spawning periods (Table 1). These differences may occur due to depth, thermocline position, degrees of latitudes and other regionals (Hernandis et al, 2018). As for the collection of sexually mature individuals, it is necessary to choose periods when condition index is high and muscle index low (Acarli et al, 2015;Angel-Dapa et al, 2015;Acarli et al, 2018).…”

The nocturnal life of the great scallops (Pecten maximus, L.): First description of their natural daily valve opening cycle

“…Besides the direct response to natural or anthropogenic stressors, several studies monitoring gaping behaviors over time, have shown cyclical patterns at different time scales, linked to extrinsic factors [ 22 – 24 ]. Circadian rhythms (periodicity cycle “τ” = 24.0h) in valve gaping, with a clear opening difference between day and night, have been reported for many bivalves, including freshwater and marine species, in various environments from temperate to tropical to Arctic waters.…”

“…These findings were supplemented by Hernandis Caballero et al . [ 24 ] showing that temperature regulates the switch between these seasonal trends. Oyster gaping activity seems driven by a complex association of solar and lunar cycles, exhibiting circadian and seasonal rhythms with nocturnal activity in autumn–winter and diurnal activity in spring–summer [ 22 , 36 ].…”