Communication across species boundaries

Divergence in song discrimination

Songbirds learn their songs by listening and memorizing the songs of surrounding adults. How do juveniles learn the often variable songs of their own species while avoiding learning the sometimes similar songs of other species around them?

Species differences in auditory perception are thought to resolve this challenge, but we know remarkable little about how and why these differences arise. Using behavioral and physiological experiments in collared and pied flycatchers in their Swedish contact zone and across their ranges in Europe, we explore the causes and consequences of innate song discrimination.

Collaborators: Anna Qvarnström

Relevant papers:

5) Wheatcroft D & Qvarnström A (2017) Genetic divergence of early song discrimination between two young songbird species. Nature Ecology and Evolution 1, 0192

4) Wheatcroft D & Qvarnström A (2017) Reproductive character displacement of female, but not male song discrimination in an avian hybrid zone. Evolution 71, 1776

3) McFarlane SE, Söderberg A, Wheatcroft D, & Qvarnström A (2016) Song discrimination by nestling collared flycatchers during early development. Biology Letters 12, 20160234

2) Wheatcroft D & Qvarnström A (2015) A blueprint for vocal learning: auditory predispositions from brains to genomes. Biology Letters 11, 20150155

1) Wheatcroft D (2015) Reproductive interference via display signals: the challenge of multiple receivers. Population Ecology 57, 333-337

Geographic comparison

Europe-wide comparison of song discrimination of pied flycatchers (ongoing)

Collaborators: Malcolm Burgess, Alex Cantarero Carmona, David Idiaquez & Jesus Martinez-Padilla, Toni Laaksonen, Tomas Tuvillo & Marcel Visser

Neurogenomics of song discrimination

Song-induced gene expression in auditory brain regions (ongoing)

Alarm communication among species

Alarm calls used when confronting predators and other threats often differ greatly in sound across species. Paradoxically, however, they are often involved in communicating among species. What are the consequences of acoustic differences for signaling across species boundaries? How is communication preserved despite them?

Using experiments in Himalayan and Swedish bird communities, I've shown that learning, copying of other species' calls, and the use of specialized calls for specific threats can often, but not always, promote alarm communication among species.

Collaborators: Trevor Price, Anna Qvarnström, Mario Gallego-Abenza

Relevant papers:

4) Wheatcroft D, Gallego-Abenza M, Qvarnström A (2016) Species replacement reduces community participation in avian antipredator groups. Behavioral Ecology 27, 1499-1506

3) Wheatcroft D (2015) Repetition rate of calls used in multiple contexts communicates presence of predators to nestlings and adult birds. Animal Behaviour 103, 35-44

2) Wheatcroft D & Price TD (2014) Rates of signal evolution are associated with the nature of interspecific communication. Behavioral Ecology 26, 83-90

1) Wheatcroft D & Price TD (2013) Learning and signal copying facilitate communication among bird species. Proceedings of the Royal Society B 280, 20123070

Song divergence along latitudinal gradients

Formation of cooperative groups

Explaining why individuals take part in risky group behaviors is a persistent challenge in evolutionary biology. Why join in when others in the group might absorb the risk?

Here, we looked at the formation of anti-predator groups, called mobs. A set of field experiments using a variety of different types of threats suggested that the formation of some mobs depends on the presence of individuals whose nests are under direct threat. The intense activity of these "key" individuals incentivizes others to join in. Using a model of mob formation between two individuals, we show that incentivizing occurs when threats respond moderately strongly to being mobbed.

Collaborator: Trevor Price

Relevant papers:

4) Wheatcroft D & Price T (2018) Collective action promoted by key individuals. The American Naturalist 192, 401-414

3) Krams I, Bērziņš A, Krama T, Wheatcroft D, Iguane K, and Rantala MJ (2010) The increased risk of predation enhances cooperation. Proceedings of the Royal Society B 277, 513-518

2) Wheatcroft DJ & Krams I (2008) Response to Russell and Wright. Trends in Ecology and Evolution 24, 5-6

1) Wheatcroft DJ & Price TD (2008) Reciprocal cooperation in avian mobbing: playing nice pays. Trends in Ecology and Evolution 23, 416-419

Compositionality in call sequences