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ants
Elder and young males of Cadiocondyla obscurior struggling (Photograph: Sylvia Cremer, IST Austria)
Ant "weddings" can be rather perilous for some ant males. This was now revealed by scientists of the University of Regensburg, Germany. Most ant species reproduce and spread when winged ant queens and males start their "wedding flight", male ants competing "peacefully". However males from the ant Cadiocondyla obscurior behave in a quite different way: elder and younger males often fight it out who eventually is able to reproduce and give his genes to the next generation. But surprisingly there are not only direct deadly clashes between single individuals but rather a kind of indirect "chemical warfare". While the winged males  in the colony participate in display flights alike males in other ant species a second form of males exists which have no wings.

Whether large tarantula spiders are capable of secreting silk from their feet or not has for some years been controversial. A paper from 2006 in the renowned journal Nature appeared to show that tarantulas were able to secrete silk from their feet. However, this claim was refuted in a 2009 paper that found no silk remains from crawling tarantulas when the usual silk secreting spinnerets in the abdomen were sealed. But perhaps the original claim was correct. In a recent issue of the Journal of Experimental Biology, scientists from the University of Newcastle in the UK give evidence of silk secretion from the feet of three different tarantula species.

To catch very large prey, the arboreal ant, Azteca andreae, which live in a mutualistic association with a host plan, gather on side by side on leaf edges with their mandible open. When a prey lands on the plan they grab it with their mandibles which together with the hairy underside of the leaf acts as Velcro preventing prey, weighing up to 13,000 times as much as the ant, to escape.

The study recently published in PLoS One by French and Spanish biologists investigated the predatory behaviour of the ant Azteca andreae in French Guiana. The and lives in a close mutualistic relationship with its host, Cecropia obtuse, which in return for the ant’s protection from herbivores offer it accommodation in its hollow stems and nectar from extrafloral nectar bodies. However, the nectar is relatively poor in proteins and amino acids, so the ants supplement it by active hunting.

 

Great tit
The great tit (Parus major) shows consistent individual variation in problem solving abilities. Photo uploaded to Wikimedia Commons by Luc Viatour.
A new study on problem-solving in great tits reveals that individual birds show consistent performances across seasons and for both a food-related string and a lever pulling problem. Thus it appears that cognitive abilities vary as much among birds as it does among humans. 

 

Older studies have shown that some animals in nature show an impressive ability to solve problems right from the jumping spider who solves complicated geometrical problems to ambush its prey to the chimpanzees that modify sticks to scoop out termites. Birds seem particularly ingenious with the Caledonian crow as virtual Albert Einsteins with their ability to modify wires into hooks to lift food out of small buckets. However, even more mundane birds, such as the great tit, show innovative foraging behaviour. The great tit for instance learned how to open milk bottles at the time when they were placed in front of houses in the mornings.

New findings show that the lantern shark employs luminescence on its belly to camouflage itself in the water column. The deep water shark can control the intensity and wavelength of the light it emits ventrally so that it matches the downwelling light from the above. This phenomenon known as counter-illumination has been described from a few other species such as shrimps and squids but not previously from large vertebrae predators.

 

Most light in the aquatic environment comes directly from the sun, i.e. from above and as anybody who has dived can testify to then this mean that everything moves above you in the water column has a very distinct silhouette against the downwelling sunlight.  This makes it very difficult to remain hidden. Some luminescent shrimps and squids have therefore developed a method of directing their light emissions  downward to act as counter-illumination to hide their silhouettes from predators. However some sharks hunts from above and therefore would also benefit from counter-illumination.