Department of Biological Sciences, NUS
The evolution of enlarged chelicerae in the ant-mimicking jumping spiders
Speaker: Wong Boon Hui
Date: 12 April 2018, Thursday
Time: Time: 3pm
Venue: S3-05 DBS Conference Room
Supervisor: Assoc Prof Li Daiqin
Abstract: – Exaggerated weapons have persisted through the animal evolutionary tree, having evolved on multiple occasions. This study is to examine the evolution of weapons, which are the enlarged chelicerae, in the ant-mimicking jumping spiders, Myrmarachne spp., through the analysis of its allometry, trade-off, compensation, and selection mode across the phylogeny, with focus on the family Salticidae, followed by the genera Myrmarachne. As we established the evolutionary history, I will proceed to evaluate the cost and benefit of developing and carrying such weapon. Food resources and moulting behaviour are proposed as the cost while sexual selection, comprising male-male competition and female mate choice, is proposed as the benefit.
As to verify enlarged chelicerae being an honest signal, which is limited by cost, I will conduct experiment to show that nutritional level of the spider diet will affect the size of the chelicerae. As the spiders only carry weapons after their final moult, I will also investigate whether weapon size affects moulting duration, as moulting is known to be an energetically costly process.
As for the benefit, male-male competition is tested by pairing size-matched males against each other in contest experiments to test whether chelicera size affect contest outcome. Pairs of males will then be presented to females to see if female spiders have a preference over males with different chelicera sizes. These two experiments will indicate whether enlarged chelicerae are employed as honest signal for resource holding potential (RHP) and/or as mate potential.
All are welcome