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

Abstract

Crowding has a major impact on the dynamics of many material and biological systems, inducing effects as diverse as glassy dynamics and swarming. While this issue has been deeply investigated for a variety of living organisms, more research remains to be done on the effect of crowding on the behaviour of copepods, the most abundant metazoans on Earth. To this aim, we experimentally investigate the swimming behaviour, used as a dynamic proxy of animal adaptations, of males and females of the calanoid copepod Centropages typicus at different densities of individuals (10, 50 and 100 ind. l −1 ) by performing three-dimensional single-organism tracking. We find that the C. typicus motion is surprisingly unaffected by crowding over the investigated density range. Indeed, the mean square displacements as a function of time always show a crossover from ballistic to Fickian regime, with poor variations of the diffusion constant on increasing the density. Close to the crossover, the displacement distributions display exponential tails with a nearly density-independent decay length. The trajectory fractal dimension, D 3D ≅ 1.5, and the recently proposed ‘ecological temperature’ also remain stable on increasing the individual density. This suggests that, at least over the range of animal densities used, crowding does not impact on the characteristics of C. typicus swimming motion, and that a homeostatic mechanism preserves the stability of its swimming performance.

Quantitative comparison of 2D and 3D monitoring dimensions in fish behavior analysis

“…In fact, horizontal projections of fish paths exhibited less convolution compared to vertical ones, implying enhanced activity along the vertical axis in the case of free swimming. Thus, reducing monitoring dimensions would impact estimations of FD; this conclusion is consistent with earlier studies (Mahjoub et al, 2011;Uttieri et al, 2021). Thus, we can conclude that the movement of an organism in 3D space should be quantified by 3D factors.…”

Temporal dynamics of zooplankton community in an oyster farming area of the Yellow Sea in China via metabarcoding

“…While early studies of copepods are mainly on large copepods (Shimode et al, 2012;Gong et al, 2013), the roles of small and medium-sized zooplankton in marine ecosystems were gradually realized (Middelbo et al, 2019;Tarrant, 2020). Many studies have been conducted on tiny zooplankton species composition, community characteristics, and life habits (Tiselius et al, 2013;Van and Park, 2016;Uttieri et al, 2021). Paracalanus (4 OTUs identified in this study) and Centropages (2 OTUs) are the most common small and medium- sized copepods and are the main contributors to the richness copepods.…”

Twenty‐year trends of Centropages typicus (Copepoda, Calanoida) reproduction, feeding, population abundance and structure in the Gulf of Naples (Western Mediterranean Sea)

“…In the Gulf of Naples (Central Tyrrhenian Sea, Western Mediterranean Sea) , C. typicus is one of the four most conspicuous copepod species (Di Capua et al, 2022; Mazzocchi & Ribera D' Alcalà, 1995), and characterizes the zooplankton associations in late spring–early summer when it reaches peak abundances (Mazzocchi et al, 2012). Considering its wide distribution and the relative ease in manipulation, a large amount of information has been collected on the behavior, reproductive biology, and ecology of C. typicus across the Mediterranean Sea and the North Atlantic Ocean (Carlotti & Harris, 2007; Di Capua & Mazzocchi, 2004; Ianora et al, 2007; Uttieri et al, 2021). In addition, other studies have investigated the interlink between seasonal cycles of reproductive traits, population abundances, and environmental parameters (Carotenuto et al, 2006; Ianora et al, 1992).…”

“…Considering its wide distribution and the relative ease in manipulation, a large amount of information has been collected on the behavior, reproductive biology, and ecology of C. typicus across the Mediterranean Sea and the North Atlantic Ocean (Carlotti & Harris, 2007;Di Capua & Mazzocchi, 2004;Ianora et al, 2007;Uttieri et al, 2021). In addition, other studies have investigated the interlink between seasonal cycles of reproductive traits, population abundances, and environmental parameters (Carotenuto et al, 2006;Ianora et al, 1992).…”