Dancing to the rhythms of geological time: the biorhythm capabilities of Polychaeta in a geological context

Abstract

Errant polychaete worms in the Orders Eunicida (family Eunicidae) and Phyllodocida (families Nereidae and Polynoidae) exhibit a highly developed biorhythmic capability. The Pacific palolo worms are well known for a precisely timed annual breeding event in which mass spawning occurs at a particular time of day, on one day per year, that day having a fixed relationship to the lunar period. Nereidae and Polynoidae exhibit photoperiodic responses that determine the breeding season by regulation of oocyte growth. Nereis virens shows short-term cycles of foraging activity; automated recording of these patterns has revealed four distinct behaviour rhythm phenotypes: circadian, tidal, lunidian and arrhythmic, the last phenotype being expressed during the photoperiod induced growth diapause. The Eunicids and Phyllodocids are represented in the fossil record by scolecodonts, their fossilised jaws. There was a major radiation of these polychaetes during the Ordovician and the earliest suggested polychaete fossils are from the Cambrian. The simultaneous expression of tidal and circadian rhythmicity is characteristic of intertidal animals and it is likely that this complex behavioural repertoire was found in the ancestors of modern terrestrial forms, such as tetrapods and arthropods, prior to their emergence onto land during the Carboniferous and Silurian periods at least 400 Ma. The period of the earth's rotation, and hence day length and tidal period, has long been known to be increasing, and additionally the moon to be retreating from the earth, due to the phenomenon of tidal friction caused by the gravitational interactions between the moon and the earth. These changes are significant over a geological time scale. Consequently, the length of day was substantially less (and the number of days in a year more) than at present in the Cambrian and Ordovician periods. Recent theoretical analysis of the period of the earth's rotation suggests that the day length prior to a critical period (t crit ) around 1800 Ma may have been stable, with a length of only 4 h. At that time a period of more rapid change in the dynamics of the rotation was initiated. The implications of this theory for the evolution of the biological clock are discussed.

Tidal, Daily, and Lunar‐Day Activity Cycles in the Marine PolychaeteNereis virens

“…At no time did we observe the spontaneous switch between tidal and lunarday activity as described by Olive et al (2005) under the same treatment regime, nor were any phase shifts apparent due to feeding (depicted by the stars in Figure 2a). However, a completely unexpected behavioral activity pattern was observed in one animal (see black trace in Figure 2a), which displayed what is an overt endogenous circadian (24.4 h) pattern of activity.…”

“…A pilot study by Olive et al (2005) has indicated that N. virens possesses short-term biological rhythm capabilities. When wild collected worms were maintained in the laboratory under constant light (LL), they displayed outof-burrow feeding phased to a simulated tidal cycle (STC) with a period of 12.4 h (semi-diurnal tidal).…”

“…Such an organism would have occupied mostly shallow seas and lagoons in which tidal cycles would have been as important ecologically as the solar day (Olive et al, 2005) and where the period or the "circadian" day may have been much shorter than what it is now (i.e., 20 -22 h) (Krasinsky, 2002;Tauber et al, 2004). The behavioral and eventually molecular timekeeping mechanism in this clade is, therefore, of particular evolutionary significance in understanding the circadian timepiece in higher eukaryotic models such as Drosophila and mouse.…”

Lunar banding in the scleractinian coral Montastraea faveolata: Fine‐scale structure and influence of temperature

“…For example, direct variations in lunar light intensity, from illumination as low as 1.25 × 10 −5 μ E m −2 s −1 (new moon or starlight) to 2.99 × 10 −3 μ E m −2 s −1 (zenith of full moon), are postulated to cause shifts in lunar rhythms in the spawning of marine organisms on a global basis, including echinoids ( Diadema spp. [ Muthiga , 2003; Coppard and Campbell , 2005]), annelids (palolo worms [ Caspers , 1984; Olive et al , 2005]), and fish [ Austin et al , 1975; Gladstone , 2007; Pisingan and Takemura , 2007].…”

Taxonomia, reprodução e desenvolvimento de Diopatra neapolitana Delle Chiaje, 1841 (Onuphidae, Annelida)

“…A ordem Eunicida é uma das mais diversificadas dentro dos poliquetas errantes, cujos animais são caracterizados principalmente pela presença de um complexo aparelho bucal endurecido por mineralização ou esclerotização, formado por mandíbulas ventrais e maxilas dorsais (Paxton, 2006) É uma das ordens com registro fóssil mais extenso e melhor estudado, principalmente devido à possibilidade de fossilização do aparelho bucal endurecido dos indivíduos, formando microfósseis chamados de escolecodontes (Olive et al, 2005). Onuphidae é uma das principais famílias dessa ordem, compreendendo anelídeos majoritariamente bentônicos, com maior representatividade nas zonas entremarés, que produzem o tubo onde habitam (Paxton, 1986).…”