The evolution of spider anti-predator defences: How to avoid being paralysed and eaten alive by wasp larvae. (APSF 20064)

APSF 20064 | Amount: $33,000 | Project Leader: L Lowe | Project Period:

A project undertaken at Macquarie University, and supervised by Lizzie Lowe.

Animals are locked in a perpetual evolutionary arms race, where prey must elude predators, and predators must outsmart their prey. Predator prey interactions have driven the evolution of a huge diversity of anti-predator traits. By studying this evolutionary arms race, we gain important insight into one of the primary sources of biological diversity.

As spiders are both predators and prey for a range of taxa, they have evolved a variety of adaptations, both defensive and offensive. While much attention has been paid to the evolution of spider predatory traits, their antipredator adaptations are less understood. For this project we will study the effectiveness of different anti-predator strategies, especially camouflage, in protecting spiders from predation by a specialised spider hunter, the mud dauber wasp. Traditionally, it has been difficult to objectively measure the rates at which spiders are preyed upon, however the mud wasps store all spiders in mud nests to feed their offspring, allowing us to collect and identify all prey collected by each wasp.

Our Null hypothesis is that mud dauber wasps show no particular preferences and hunt spiders relative to their availability. To test this, we will compare the spiders taken by each wasp with local spider communities to identify species that are seemingly protected from wasps and identify the strategies that afford this protection. Next, we will test whether prey preference is maternally influenced, by comparing prey preference of the second generation to their mothers’. Finally, we will use the order of spiders in each nest to assess whether a wasp’s preferences vary over time and/or with the availability of spiders. This will indicate whether they learn to overcome particular anti-predator defences. Our research will assess the selective pressures driving evolution of spider anti-predator traits and evaluate the effectiveness of camouflage against a specialised predator.