The impact of rheotaxis and flow on the aggregation of organisms

Abstract

Dispersed populations often need to organize into groups. Chemical attractants provide one means of directing individuals into an aggregate, but whether these structures emerge can depend on various factors, such as there being a sufficiently large population or the response to the attractant being sufficiently sensitive. In an aquatic environment, fluid flow may heavily impact on population distribution and many aquatic organisms adopt a rheotaxis response when exposed to a current, orienting and swimming according to the flow field. Consequently, flow-induced transport could be substantially different for the population members and any aggregating signal they secrete. With the aim of investigating how flows and rheotaxis responses impact on an aquatic population’s ability to form and maintain an aggregated profile, we develop and analyse a mathematical model that incorporates these factors. Through a systematic analysis into the effect of introducing rheotactic behaviour under various forms of environmental flow, we demonstrate that each of flow and rheotaxis can act beneficially or detrimentally on the ability to form and maintain a cluster. Synthesizing these findings, we test a hypothesis that density-dependent rheotaxis may be optimal for group formation and maintenance, in which individuals increase their rheotactic effort as they approach an aggregated state.

Intent matters: how flow and forms of information impact collective navigation

“…[ 31 ]); (ii) the impact of flow on the ability of a solo navigator to reach some target destination (e.g. [ 33 ]). Following this, we explore how the different forms of flow impact on collective navigation for the various submodels summarized in table 1 .…”

Intent matters: how flow & forms of information impact collective navigation

“…This section is structured as follows. We first ensure that our model recapitulates well-known results about: i) the effectiveness of collective navigation over individual navigation in a non-flowing environment (e.g., [31]); ii) the impact of flow on the ability of a solo navigator to reach some target destination (e.g., [33]). Following this, we explore how the different forms of flow impact on collective navigation for the various submodels summarised in Table 1.…”

“…No reuse allowed without permission. ability of a solo navigator to reach some target destination (e.g., [21]). Following this, we explore how the different forms of flow impact on collective navigation for the various submodels summarised in Table 1.…”