Two ants, two species, one mother

00:45 The ant queen that can produce two different species

Researchers have made an unusual observation that appears at odds with biology: an ant, known as the Iberian Harvester Ant can produce offspring of two completely different species. Many ants need to mate with other species to produce workers that are a genetic mix of the two, known as hybrids. But in Sicily, a team found hybrid worker ants but no trace of the father. They suggest that the one species present, Messor ibericus, is able to lay its own eggs, but also eggs of another species, Messor structor. These offspring can then mate to produce the hybrid workers. This strategy conflicts with several conventional definitions of what a species is, which may prompt a rethink of these already blurry concepts.

Research Article: Juvé et al.

News and Views: Ant queens produce sons of two distinct species

News: ‘Almost unimaginable’: these ants are different species but share a mother

09:33 Research Highlights

Humans are living longer but a life expectancy of a hundred appears out of reach — plus, how light pollution is making birds sing for longer.

Research Highlight: When will life expectancy reach 100? No time soon

Research Highlight: Bright city lights make birds around the world sing longer

11:42 How to keep bridges standing

Researchers have discovered that steel truss bridges possess a number of mechanisms that make them resilient to collapse, even after damage. Steel truss bridges are a common kind of bridge, but many are ageing and under increased pressure due to climate change and increased vehicle loads. To understand how damage affects these bridges a team of engineers built a scale replica of a bridge section and monitored how it coped when different sections were cut. They found six distinct resistance mechanisms that allowed the bridge to continue carrying heavy loads even with the damaged sections. They hope these data will help fortify existing bridges and inform the design of future bridges to help prevent catastrophic collapse.

Research Article: Reyes-Suárez et al.