Fish-eating Spiders discovered Worldwide

Spiders are traditionally viewed as predators of insects. Zoologists from Switzerland and Australia have now published a study that shows: spiders all over the world also prey on fish.

Fishing spider Dolomedes facetus captured fish (genus Xiphophorus) in garden pond near Brisbane, Queensland, Australia.
Credit: Peter Liley, Moffat Beach, Queensland, CCBY
Spiders are traditionally viewed as predators of insects. Zoologists from Switzerland and Australia have now published a study that shows: spiders all over the world also prey on fish. The academic journal PLOS ONE has just published the results.

Although viewed by ecologists as the classical predators of insects, researchers have become increasingly aware that spiders are not exclusively insectivorous. Certain larger-sized species supplement their diet by occasionally catching small fish. This shows a new study by zoologist and spider expert, Martin Nyffeler from the University of Basel, Switzerland and Bradley Pusey from the University of Western Australia. The researchers gathered and documented numerous incidents of spiders predating fish from all around the world.


Fish as a diet supplement
According to their systematic review, spiders from as many as five (5) families have been observed predating on small fish in the wild and three (3) more families contain species that catch fish under laboratory conditions. These so called semi-aquatic spiders typically dwell at the fringes of shallow freshwater streams, ponds or swamps. These spiders, some of which are capable of swimming, diving and walking on the water surface, have powerful neurotoxins and enzymes that enable them to kill and digest fish that often exceed them in size and weight. "The finding of such a large diversity of spiders engaging in fish predation is novel. Our evidence suggests that fish might be an occasional prey item of substantial nutritional importance," says Martin Nyffeler.


Based on this study, naturally occurring fish predation by spiders has been reported from all continents with the exception of Antarctica. Most incidents have been documented in North America, especially in the wetlands of Florida, where semi-aquatic spiders have often been witnessed catching and eating small freshwater fish such as mosquitofish. In order to catch its prey, the spider will typically anchor its hind legs to a stone or a plant, with its front legs resting on the surface of the water, ready to ambush. The fish will then be dragged to a dry place before the feeding process can begin which usually lasts several hours.
Source: Science Daily

90 Percent of Lemur Species Face Extinction (90% de los Lemures en Peligro de Extinción)

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Slipper orchids (subfamily Cypripedioideae) are another group with many species in peril.

An orchid of the genus Paphiopedilum
Entire branches of the tree of life are in danger of being wiped out: The majority of species in some groups of plants and animals are now on the "Red List" of the world's most threatened species.

The list, which is managed by the International Union for Conservation of Nature (IUCN) and was updated this week, shows that among the groups most at risk are lemurs and temperate slipper orchids.
Found only in Madagascar, 90 of the 101 species of lemur are threatened with extinction, the IUCN said. More than 20 percent of these small primates are listed as being critically endangered, meaning that they have a very high risk of extinction in the wild. The main threat stems from illegal logging of tropical forests, which has accelerated in the island nation in recent years.
Coquerel's Sifaka Lemur (www.newsobserver.com)
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Las orquideas Zapatillas de Venus o Zapatillas de Dama (subfamilia Cypripedioideae) son otro grupo con muchas especies en peligro.
Ramas enteras del árbol de la vida están en peligro de desaparecer: La mayoría de las especies en algunos grupos de plantas y animales están actualmente en la "Lista Roja" de las especies más amenazadas del mundo. 
Esta lista, que es administrada por la Unión Internacional para la Conservación de la Naturaleza (UICN) y que se actualizó esta semana, muestra que entre los grupos de mayor riesgo están los lemures y las orquídeas zapatilla de climas templados. 
Según la UICN, 90 de las 101 especies de lemures localizadas exclusivamente en Madagascar, están en peligro de extinción. Más del 20 por ciento de estos pequeños primates están listados como en peligro crítico, lo que significa que tienen un riesgo muy alto de extinción en estado silvestre. La principal amenaza proviene de la tala ilegal de los bosques tropicales, que se ha acelerado en dicha isla en los últimos años.

Lemur Pigmeo (Microcebus myoxinus)