Helena Ajuria (PhD, 2013)

Supervisor: Tom Reader

Helena finished her PhD in 2013 and returned home to Mexico to write papers and start a postdoc. Below, she describes her PhD project.

Research Interests

I am a PhD student and I’m interested in the behaviour of spiders. Spiders constitute a wide and highly varied group of organisms that can be used as systems to study numerous aspects of behaviour, ecology and evolution.

For my project I will be looking at the behaviour of the crab spider Synaema globosum in Portugal. Little is known about this species; therefore one of my aims is to do a general description of its life history. What we know is that S. globosum is a generalist sit-and-wait predator which sits on different types of flowers and catches different types of prey. Sit-and-wait predators spend less energy hunting for prey than active foragers; however they also catch prey less often, and it is thus important for them to find a hunting site that will maximise their net energy gain. 

S. globosum appears rather conspicuous on many flowers, since it is predominantly black in colour. However, it has markings on its abdomen that can be distinguished as red, yellow or white. If this polymorphism is genetic in origin, its maintenance could be influenced by several factors such as avoidance of predators, attraction of prey, disruptive coloration, and sexual selection.

My aims are to find out which cues S. globosum uses when choosing a hunting site and deciding how long to stay there, as well as which factors are responsible for the maintenance of the polymorphism in the species. I am carrying out a series of field and laboratory observations and experiments, which include surveys of spiders on different types of plants and their movement among them, observations and manipulations of flower attributes and prey frequency and abundance, rearing and crossing of spiders, mate preference experiments, observations of prey capture rates by different morphs and measurements of reflectance spectra of spiders.

My project is funded by CONACYT.