Environmental variability directly affects the prevalence of divorce in monogamous albatrosses.

Francesco Ventura,Amanda Kuepfer,Paul M Lukacs,José Pedro Granadeiro,Paulo Catry

doi:10.1098/rspb.2021.2112

Abstract

In many socially monogamous species, divorce is a strategy used to correct for sub-optimal partnerships and is informed by measures of previous breeding performance. The environment affects the productivity and survival of populations, thus indirectly affecting divorce via changes in demographic rates. However, whether environmental fluctuations directly modulate the prevalence of divorce in a population remains poorly understood. Here, using a longitudinal dataset on the long-lived black-browed albatross (Thalassarche melanophris) as a model organism, we test the hypothesis that environmental variability directly affects divorce. We found that divorce rate varied across years (1% to 8%). Individuals were more likely to divorce after breeding failures. However, regardless of previous breeding performance, the probability of divorce was directly affected by the environment, increasing in years with warm sea surface temperature anomalies (SSTA). Furthermore, our state-space models show that warm SSTA increased the probability of switching mates in females in successful relationships. For the first time, to our knowledge, we document the disruptive effects of challenging environmental conditions on the breeding processes of a monogamous population, potentially mediated by higher reproductive costs, changes in phenology and physiological stress. Environmentally driven divorce may therefore represent an overlooked consequence of global change.

Highlights

Social monogamy is a widespread mating system, almost ubiquitous in birds, shared by over 90% of avian species [1] and present in some mammal species in the orders Primates, Macroscelidea and Carnivora [2]
As we found that divorce is triggered by breeding failure and that it yields reproductive benefits, our results strongly highlight that, in a long-lived monogamous seabird population, divorce is an adaptive strategy driven by the ‘win–stay, lose–switch’ information gathering process
To our knowledge, the first evidence of a significant influence of the prevailing environmental conditions on the prevalence of divorce in a long-lived socially monogamous population

Summary

Introduction

Social monogamy is a widespread mating system, almost ubiquitous in birds, shared by over 90% of avian species [1] and present in some mammal species in the orders Primates, Macroscelidea and Carnivora [2]. Across a wide range of species, divorce was found to be a strategy aimed at correcting for these sub-optimal partnerships, resulting in an improvement of the reproductive success of one or both members of the pair [4,5,6]. In long-lived seabirds, the benefits resulting from breeding with the same partner (improved experience and coordination between the pair members owing to mate familiarity) and the high mate survival probability (which limits the costs of waiting in vain for the reunion with the old partner), as well as the costs involved in attracting and pairing with a new mate, result in low divorce rates [3,7,11]

Objectives

Findings

Discussion

Conclusion