Marike Louw

Background

The end of 2014 found me in awe of completing a BSc degree in Entomology (2012-2014). The next year I pursued a BSc Honours degree in Entomology, where I studied biological control involving the control of the invasive Eucalyptus beetle, Gonipterus, by an egg parasitoid, Anaphes nitens. Both these degrees were obtained at the University of Pretoria.

The promise of mountains, frogs, unfamiliar insects, and an opportunity to further my studies led me to the University of Stellenbosch to start my Masters degree in 2016.

Current research

Traditional capture-recapture methods used to estimate population sizes and densities of animals pose a few problems. To name a couple, to trap animals can be laborious and expensive, and the behaviour of animals can be affected by the presence of humans.

For visually cryptic species, such as the Cape Peninsula moss Frog, Arthroleptella lightfooti, employing mark-recapture methods can be particularly cumbersome. Males of this species call out with a three-pulse insect-like chirp. This attribute can be used to estimate population size and density of this species through a more recently developed method: acoustic Spatially Explicit Capture-Recapture (aSECR; see http://john.measey.com/aSECR).

Using an array of microphones to capture the calls of the frogs, the location of the calling frogs, as well as the number of calling individuals, can be assessed. This information, especially the spatial information as to the location of calling frogs, allows for accurate estimation of calling frog population density.

Male Arthroleptella lightfooti

Male A. lightfooti are smaller than females, and females can have a maximum length of 22mm! Photo credit: Res Altwegg

Chapter 1: I aim to assess how different degrees of invasion by Pinus pinaster affect the population densities of the highly endemic A. lightfooti on the Cape Peninsula.

Chapter 2: I aim to use aSECR methods to examine the calling behaviour of orthopterans in the presence of invasive P. pinaster. Can these trees be used to the advantage of the calling insects?