Getting Our Hands Dirty
In a Nutshell
Field work! An essential part of gathering data from the wild.
Our study species, the wood tiger moth (Arctia plantaginis), has a broad distribution spanning roughly across the Boreal zone in the northern hemisphere. It is a habitat generalist and can be found anywhere from semi-open woodland to roadside vegetation. Although we do field work mostly in north Europe (Finland & Estonia), our excursions have reached out to Georgia, Switzerland, Japan and the United States.
The activity of field work peaks at northern mid-summer (June-July), when we collect adult moths using hand-held nets. Females can be found by following the activity of males and carefully searching the surrounding sites. Males can also be lured into traps baited with lab-reared females.
The data we collect fuels our understanding of population genetics, phenotypic variation and phenological development.
We also use the field as our own experimental chamber. Here, we use dummy models to test how natural predator populations respond to experimentally controlled variation in the traits of their prey.
- Emily Burdfield-Steel
- Juan Galarza
- Swanne Gordon
- Robert Hegna
- Hanna Kokko
- Carita Lindstedt
- Johanna Mappes
- Ossi Nokelainen
- Bibiana Rojas
- Katja Rönkä
- Janne Valkonen
- Rönkä K, Valkonen J, Nokelainen O, Rojas B, Gordon S, Burdfield-Steel E, Tasane T, Mappes J. 2020 Geographic mosaic of selection by avian predators on hindwing warning colour in a polymorphic aposematic moth. Ecology Letters. 23 (11) 1654-1663.
- Gordon S, Kokko H, Rojas B, Nokelainen O, Mappes J 2015. Colour polymorphism, torn apart by opposing positive frequency-dependent selection, yet maintained in space. Journal of Animal Ecology. 84(6)1555-1564.
- Galarza J, Nokelainen O, Ashrafi R, Hegna R, Mappes J 2014. Temporal relationship between genetic and warning signal variation in the aposematic wood tiger moth. Molecular Ecology. 23(20)4939-4957.
- Nokelainen O, Valkonen J, Lindstedt C, Mappes J 2014. Changes in predator community structure shifts the efficacy of two warning signals in Arctiid moths. Journal of Animal Ecology. 83(3)598-605.
- Hegna R, Nokelainen O, Hegna JR, Mappes J 2013. To quiver or to shiver: Increased melanisation benefits thermoregulation but reduces warning signal efficacy in the wood tiger moth. Proceedings of the Royal Society B. 280(1755):20122812.
The Novel World
Experimenting with predator-prey interactions using arbitrary signals
In a Nutshell
The initial evolution of aposematism has traditionally been studied by observing young, inexperienced predators.
However, this method can not separate out any genetically determined avoidance for partiuclar colours.
Thus, we developed the novel world method to study predator-prey interactions from a clean-slate. Specifically, we use artificial prey with arbitrary black-and-white symbols in a black-and-white world (see Lindström et al. 2001).
We use this method to test hypotheses about the initial selection pressures that the very first aposematic prey animals could have faced, and have subsequently addressed a range of questions about warning signals and mimicry (see a short video clip from novel world).
We have learned that not all warning signals are effective. Predators vary in their tendency to attack defended prey, which can select for weak warning signals in the prey population.
Our results also bring common generalizations into question. For instance, predators select for signal similarity between defended prey. But not automatically in every situation! The evolutionary dynamics between mimetic prey species and predators are conditional on the specific signals. The structure of the whole prey community also affects how strongly predators select for mimetic resemblance.
- Alatalo & Mappes 1996. Tracking the evolution of warning signals. Nature 383:708-710
- Riipi et al. 2001. Nature 413: 512-514. Multiple beneÆts of gregariousnesscover detectability costs inaposematic aggregations. Nature 413 (4), 512-514
- Endler & Mappes 2004. Predator mixes and the conspicuousness of aposematic signals. American Naturalist 163 (4), 532-547
- Mappes et al. 2005. The complex business of survival by aposematism. Trends in Ecology and Evolution 20:598-603-605
- Kokko et al. 2003. Alternative prey can change model–mimic dynamicsbetween parasitism and mutualism. Ecology Letters 6:1068-1076
- Rowland et al 2007. Co-mimics have a mutualistic relationship despiteunequal defences. Nature 448:64-66
- Ihalainen et al. 2012. Prey community structure affects how predators select for Müllerian mimicry. Proceedings of the Royal Society B. 279: 2099-2105
Photo Credits: Emily Burdfield-Steel, Ossi Nokelainen, Bibiana Rojas, Janne Valkonen