Bees behave like criminals and could help catch them

New research using bumblebees to refine and test a technique used to catch serial killers has implications for wildlife conservation, fighting malaria and combatting bioterrorism.

Writing in the Journal of the Royal Society Interface, Biologists Dr Nigel Raine and Dr Steven Le Comber at Queen Mary, University of London used a technique called geographic profiling (GP) originally developed by Professor Kim Rossmo from Texas State University, a former detective and co-author, to help police narrow down suspects by looking at the locations of serial crimes.

Although it has been successful in practice, it is difficult for criminologists to test and improve GP scientifically because they can't ethically conduct controlled studies of criminals. But the better the technique, the more precisely the police can locate the criminal.

So Raine and his colleagues took GP into the laboratory and found that it helped to predict the entrance to a beehive from the locations of the artificial flowers visited by the bees. Furthermore, the technique allowed the researchers to distinguish different foraging strategies that the bees might be using. According to the study, for example, one likely strategy simply involves choosing the nearest new flower at each step from the nest.

The researchers say their findings have implications for bee conservation. Although there are 25 species of bumblebee in the UK, most of these are in decline as changes in agriculture have eroded their natural habitats. "Since records began, 3 bumblebee species have already become nationally extinct" says Raine. The great yellow bumblebee (Bombus distinguendus), for example, one of 5 species officially listed as priorities for conservation action by the government, is now found in only a handful of places such as the outer Hebrides. GP could help conservationists locate bumblebees' nests, a difficult task according to Raine, as they are usually underground and the bees may travel up to 2km from the nest.

Although this is the first controlled study of GP, Raine explained that "the approach works well for very different animals: from bees and bats to great white sharks". Following on from this work, the scientists plan to use GP "to study the distribution patterns of illegal snares in Zimbabwe" and to examine "how geographic profiling might assist in efforts to fight malaria by locating breeding sites".

GP uses two opposing insights to create a geoprofile that shows where a serial criminal is likely to live. Most crimes are committed near an anchor point, usually the criminal's home. 70% of arsons happen within 2 miles of the arsonists home, for example. However, there is also a buffer zone centred on the anchor point where there are few opportunities to commit a crime. For the bees, there is a energy cost attached to foraging further from the nest while the buffer zone might reflect the cost of attracting parasites and predators to the nest, according to Raine.

The researchers point out that while criminologists have no control over where crimes are committed, biologists can test GP under different conditions by experimentally controlling factors such as the distribution and density of the flowers. According to Rossmo, the research is relevant to analysing "track data from GPS monitored offenders" and "provides a foundation for possible future applications of geographic profiling to bioterrorism".

Is generosity just showing off?

Ever wondered why men usually pay the bill on a first date? An evolutionary psychologist might point out that men on dates also tend to leave unusually large tips and that gives us an important clue.

More specifically, two related evolutionary theories could give us the answer. The first, sexual selection, predicts that because females have a greater investment in parenting, they tend to prefer males who seem likely to provide resources and commitment. Males, meanwhile, have co-evolved to behave so as to give every appearance of being able to provide and care for their partner.

The problem is that, where behaviour is concerned, appearances can be deceptive. Is he really so wealthy and caring? Costly signalling theory, however, predicts that costliness is a reliable indicator of honest behaviours. The more it costs a man to appear capable and committed, for example, the more likely that he really is.

These theories might explain why male chimpanzees use food-sharing to show off to sexually receptive females. But do they really tell us anything about the way we behave? Wendy Iredale, at the University of Kent, and her colleagues decided to investigate by looking at charity donations in the presence of attractive members of the opposite sex.

They asked men and women (heterosexual undergraduates specifically) to play a series of games in which they could earn up to £24. They were then given the option of making a costly act of generosity - donating a percentage of their earnings to charity - either in private or observed by an attractive man or woman.

The results, published last week in the journal Evolutionary Psychology, showed that men are substantially more charitable when observed by the attractive female. As predicted by evolutionary theory, women's donations did not vary. However, scientists still don't know what exactly this generosity signals (caring or wealth, for example) or whether women actually find altruistic men more attractive.

Sexual selection also predicts that males evolve a preference for mates who appear to be fertile and, correspondingly, that females will co-evolve attributes that reliably signal their fertility. An example is breast size and symmetry which, so the argument goes, are honest indicators of fertility. And in case anyone needs convincing that men tend to respond to this particular adaptation, Nicolas Guegen from the Universite de Bretagne Sud studied drivers passing an attractive female hitch-hiker. The results, published in Perceptual and Motor Skills last December, showed that men are more likely to stop if her bra cup size appears to be C rather than A. Women stopped equally frequently in either case.

So what does all this tell us? Obviously, we've also evolved the intelligence and capacity for self-reflection to rise above these kinds of thing to a large extent. They don't fundamentally limit the decisions we make and nor do they excuse poor behaviour. But it's interesting to see residual influences of our evolutionary past still cropping up and being used to test general theories of behavioural evolution. Does anyone have any other examples?