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How many species of insects exist? Umeå University researcher, Genoveva Rodríguez-Castañeda, found that in tropical mountains there are six times more insects than shown in global calculations. The insects in these areas are also highly specialized in their choice of food.

"Our results urge ecologists to account for biogeographical variation when extrapolating in order to obtain global estimates," she says.

Up until now researchers have calculated insect global diversity to be highest at tropical latitudes and the estimates for total number of insect species in the world ranges from five to ten million species. However, these calculations are based from indices derived from plant insect interactions measured in tropical lowlands of Papua New Guinea. Genoveva Rodríguez-Castañeda examined if there was geographical variation in the nature of plant-insect interactions across elevation and if these differences were relevant for global estimates of insect diversity.

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Ants are not out of their weight class when defending trees from the appetite of nature's heavyweight, the African elephant, a new University of Florida study finds.

Columns of angered ants will crawl up into elephant trunks to repel the ravenous beasts from devouring tree cover throughout drought-plagued East African savannas, playing a potentially important role in regulating carbon sequestration in these ecosystems, said Todd Palmer, a UF biology professor and co-author of a paper being published in the journal Current Biology.

"It really is a David and Goliath story, where these little ants are up against these huge herbivores, protecting trees and having a major impact on the ecosystems in which they live," Palmer said. "Swarming groups of ants that weigh about 5 milligrams each can and do protect trees from animals that are about a billion times more massive."

The mixture of trees and grasses that make up savanna ecosystems are traditionally thought to be regulated by rainfall, soil nutrients, plant-eating herbivores and fire, he said.

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Pseudomyrmex ferruginea (Acacia ants):
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Evolutionary biologists overturn long-held kin-selection theory.

Altruistic behaviour, such as sterile worker ants caring for the offspring of their queen, evolves only between related individuals through what is known as kin selection — or so many evolutionary biologists have thought since the 1960s.

They argue that the standard theory of natural selection cannot explain the evolution of eusocial groups of organisms such as bees and ants, because the sterile workers in those groups do not themselves reproduce.

A two-part mathematical analysis, published in Nature this week, overturns this tenet by showing that it is possible for eusocial behaviour to evolve through standard natural-selection processes.

Kin selection is based on 'inclusive fitness', the idea that, for example, sterile workers can accrue reproductive benefits by helping their relatives. In doing so, they help shared genes to survive and get passed on to the next generation. This provides a route for eusociality to evolve.

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A worker Harpegnathos saltator (a jumping ant) engaged in battle with a rival colony's queen:

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A York University doctoral student who discovered a new species of bee on his way to the lab one morning has completed a study that examines 84 species of sweat bees in Canada. Nineteen of these species -- including the one Jason Gibbs found in downtown Toronto − are new to science because they have never been identified or described before.

Gibbs' expansive study will help scientists track bee diversity, understand pollination biology and study the evolution of social behaviour in insects. It is also much anticipated by bee taxonomists who, like Gibbs, painstakingly examine the anatomy (morphology) of bees to distinguish one type of bee from another.

Bees are responsible for pollinating many wildflowers and a large proportion of agricultural crops. As much as one of every three bites of food that humans eat, including some meat products, depends on the pollination services of bees. Sweat bees are common visitors to a wide range of plants, including fruit and vegetable flowers in Toronto gardens. Sweat bees − named for their attraction to perspiration − can be smaller than 4 mm in length, often have metallic markings, and make up one-third to one-half of bees collected in biodiversity surveys in North America. Complete species descriptions of 84 metallic sweat bees in Canada are included in Gibbs' study, "Revision of the metallic species of Lasioglossum (Dialictus) in Canada." It was published August 31 by the peer-reviewed journal Zootaxa as a single issue.

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