Ballista Spider Discovered in Queensland Rainforests

A new spider species nicknamed the ballista spider has been discovered in the rainforests of far north Queensland, Australia. The spider belongs to the genus Propostira in the cobweb spider family Theridiidae, and it has not yet received a formal scientific name.

Taxonomy and Classification

The ballista spider is placed in the family Theridiidae, which is commonly known as the cobweb spider family. The genus Propostira includes spiders that build irregular webs and use silk-based prey capture methods.

Hunting Mechanism

The spider uses a spring-loaded web trap to launch green tree ants, Oecophylla smaragdina, into its web. The trap is triggered when the ant bites a silk cone, and the stored elastic energy in the silk is released rapidly. The ants have been recorded with accelerations of up to 1,367 metres per second squared, which is about 140 times the force of gravity. This acceleration is also about 15 times greater than the force experienced by fighter pilots.

Research and Observation

The behaviour was first observed in 2022 in far north Queensland by biomedical researcher Greg Anderson. Detailed study and footage were captured in early 2023 by Professor Ajay Narendra and postgraduate student Pranav Joshi using high-speed and infrared cameras. Researchers from Macquarie University and the University of Greifswald described the hunting strategy in Current Biology. Professor Ajay Narendra has stated that the snare stores elastic energy in silk and releases it quickly.

Important Facts for Exams

• Oecophylla smaragdina is the scientific name of the green tree ant.
• Theridiidae is the spider family commonly called cobweb spiders.
• High-speed cameras are used in biological studies to record rapid animal movements.
• Infrared cameras are used to observe behaviour in low-light conditions.

Scientific Context

Spider silk is a protein-based material known for high tensile strength and elasticity. Web-based prey capture is a common trait in many spider groups, including members of Theridiidae.