Tropical rumble or urban jungle: do frogs adjust their calls to different sensory conditions?

Background

Animals communicate with their conspecifics using all sorts of sounds, smells, but this can be challenging under certain sensory conditions. High noise levels or low light levels can for example limit communication distances. Many species seem to have dealt with these challenges by matching the properties of their communication signals to the sensory characteristics of their habitats. However, urban areas, such as cities, are rapidly replacing natural areas and this process forces many animal species to adapt their signals to changes in their sensory environment.

We study the sexual signal of tungara frogs in the context of urbanization at various sites throughout Panama. Males of this species call from water bodies to attract females and can be found in a range of different habitats, providing the opportunity to relate their call structure and behaviour to their local environment. For this project we want to compare males from tropical forest sites to males from urban sites. Do their calls differ between these two extremes? To what extend do forest and urban sites differ in nocturnal noise or light levels? We know that males respond to changes in background noise levels and we know that females are sensitive to differences in light levels, so we would expect differences in these sensory conditions to play a major role in driving sexual selection and signal evolution.

Approaches

This project involves fieldwork at night and can be physically challenging. Frogs in urban and forest populations will be recorded under controlled as well as field conditions and caught for various measurements. The acoustic environment will be quantified using automated recorders and light levels will be assessed with lux-meters. A minimum of 3 months fieldwork is required and restricted to the rainy season (April – November).

Supervision and information

Dr. Wouter Halfwerk
Room: H142, W&N building
Email:  w.h.halfwerk@vu.nl
Phone: +31 (0)20 – 59 82737

Prof. Dr. Jacintha Ellers
Room: H141, W&N building
Email:   j.ellers@vu.nl
Phone: +31 (0)20 – 59 87076