Artificial light at night alters the sexual behaviour and fertilisation success of the common toad

Jan 14, 2020Environmental pollution (Barking, Essex : 1987)

Artificial light at night changes mating behavior and fertilization success in common toads

AI simplified

Circadian Biology on OpenScience ↗PubMed ↗DOI ↗

Abstract

In 2016, Artificial Light At Night (ALAN) affected nearly 23% of the Earth's surface.

ALAN disrupts natural light cycles, impacting nocturnal species that rely on dark periods for essential activities.
Common toads exposed to higher levels of light (0.1 or 5 lux) took longer to pair with females and broke mating pairs before egg laying.
The fertilization rate for males exposed to 5 lux was reduced by 25% compared to controls.
Salivary testosterone levels remained unchanged in males exposed to ALAN, despite observable changes in breeding behavior.
These findings indicate that ALAN may reduce reproductive fitness in amphibians, necessitating further investigation into its long-term effects.

AI simplified

Artificial Light At Night (ALAN) is an emerging pollution, that dramatically keeps on increasing worldwide due to urbanisation and transport infrastructure development. In 2016, it nearly affected 23% of the Earth's surface. To date, all terrestrial and aquatic ecosystems have been affected. The disruption of natural light cycles due to ALAN is particularly expected for nocturnal species, which require dark periods to forage, move, and reproduce. Apart from chiropterans, amphibians contain the largest proportion of nocturnal species among vertebrates exhibiting an unfavourable conservation status in most parts of the world and living in ALAN polluted areas. Despite the growing number of studies on this subject, our knowledge on the direct influence of nocturnal lighting on amphibians is still scarce. To better understand the consequences of ALAN on the breeding component of amphibian fitness, we experimentally exposed male breeding common toads (Bufo bufo) to ecologically relevant light intensities of 0.01 (control), 0.1 or 5 lux for 12 days. At mating, exposed males took longer than controls to form an amplexus, i.e. to pair with a female, and broke amplexus before egg laying, while controls never did. These behavioural changes were associated with fitness alteration. The fertilisation rate of 5 lux-exposed males was reduced by 25%. Salivary testosterone, which is usually correlated with reproductive behaviours, was not altered by ALAN. Our study demonstrates that ALAN can affect the breeding behaviour of anuran species and reduce one component of their fitness. Given the growing importance of ALAN, more work is needed to understand its long-term consequences on the behaviour and physiology of individuals. It appears essential to identify deleterious effects for animal populations and propose appropriate management solutions in an increasingly brighter world.

Full Text

Full text is available at the source.

View full text (XML) ↗View full text ↗

Artificial light at night alters the sexual behaviour and fertilisation success of the common toad

Abstract

Full Text

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief

Abstract

Full Text

Related papers

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief