A pheromone outweighs temperature in influencing migration of sea lamprey.

Cory O Brant,Weiming Li,Ke Li,Nicholas S Johnson

doi:10.1098/rsos.150009

Abstract

Organisms continuously acquire and process information from surrounding cues. While some cues complement one another in delivering more reliable information, others may provide conflicting information. How organisms extract and use reliable information from a multitude of cues is largely unknown. We examined movement decisions of sea lampreys (Petromyzon marinus L.) exposed to a conspecific and an environmental cue during pre-spawning migration. Specifically, we predicted that the mature male-released sex pheromone 3-keto petromyzonol sulfate (3kPZS) will outweigh the locomotor inhibiting effects of cold stream temperature (less than 15°C). Using large-scale stream bioassays, we found that 3kPZS elicits an increase (more than 40%) in upstream movement of pre-spawning lampreys when the water temperatures were below 15°C. Both warming temperatures and conspecific cues increase upstream movement when the water temperature rose above 15°C. These patterns define an interaction between abiotic and conspecific cues in modulating animal decision-making, providing an example of the hierarchy of contradictory information.

Highlights

Environmental cues and signals provide a constant input of information used by organisms in decision-making processes [1,2]
Water temperature is critical in influencing the timing of fish migration [3]. 2 Pheromones [4,5] are signals that may inform fish of mate readiness and/or habitat suitability [5]
Sexually mature female sea lamprey rely on a sex pheromone released by mature males (3-keto petromyzonol sulfate, 3kPZS) [9] to locate nesting mates [10]

Summary

Introduction

Environmental cues (e.g. abiotic information) and signals (e.g. an entity evolved by a sender that elicits an evolved behavioural response in a receiver) provide a constant input of information used by organisms in decision-making processes [1,2]. 2 Pheromones [4,5] are signals that may inform fish of mate readiness and/or habitat suitability [5]. The sea lamprey relies on environmental and conspecific cues during reproduction. Warmer water temperatures correlate with increases in locomotor activity of pre-spawn migrating sea lamprey, probably as an adaptation to reach spawning grounds before full maturation of gametes occurs [6]. Sexually mature female sea lamprey rely on a sex pheromone released by mature males (3-keto petromyzonol sulfate, 3kPZS) [9] to locate nesting mates [10]

Results

Discussion

Conclusion