and they also lay trails of their own. In this example, the pitcher plant entices ants towards its traps by mimicking the pheromones. This would be a good strategy in its own right, but potentially of short-term use because once all the scouts had been captured there wouldn’t be any left to return to the nest and recruit other ants to the area. So, the pitcher plant cunningly ‘deactivates’ its traps sometimes, allowing the ants to escape and head home. The ants then return with more recruits, by which time the trap is active and deadly again. Some pitcher plants also use visual tricks to lure


prey. Recent research has shown that at least 13 species of Nepenthes pitcher plant perform a neat trick called fluorescence. Here, the rims of the pitchers absorb short


Many insects are attracted to these blue colours, and consequently are enticed by the traps


(ultraviolet) wavelengths of light and re-emit the light at longer blue wavelengths. Many insects are attracted to these blue colours, and consequently are enticed by the traps as well. Experiments have shown that the success of the plants in capturing prey decreases when these blue colours are removed from the traps. Carnivorous plants often live on low-nutrient soils and


so need to find other ways to obtain essential nutrients for survival. Otherwise, they live in environments like the tropics where there are often highly specialist and rich interactions between species that have evolved over long periods of time, enabling complex adaptations for survival to evolve. It is worth pointing out, however, that carnivorous species are not the only plants that dupe animals. Other types of plant trick insects into helping them reproduce. Orchids are most famous for this. As many as one-third of the 30,000 known orchid species deceive insects into pollinating their flowers. The flowers of most plants offer some sort of a reward


for pollinators, such as nectar or the pollen itself. In these cases, both parties obtain some benefit – the pollinator gets food or energy and the flower gets fertilised by the transfer of pollen. Many orchid flowers offer no reward. Ordinarily, this should mean that over time the pollinators will learn or evolve to ignore them – after all, why spend time visiting a flower that offers nothing for your services? However, orchid flowers frequently trick pollinators to


visit them nonetheless, sometimes in highly specialist ways. Bee orchids, for instance, present both the broad visual appearance of a female bee and the specific smell of a female bee, such that a male lands on the flower and tries to mate with it. In the process, he pollinates the flower. Another species of orchid from Hainan Island, China, also mimics the appearance and smell of bees to attract predatory hornets, which try to attack the flower but again are simply duped into acting as pollinators. Other orchids emit smells that mimic the odours of aphids, enticing hoverflies to visit and lay their eggs (hoverfly larvae often feed on aphids). Finally, one recent discovery revealed an orchid that seems to mimic human body odour, and by doing so entices mosquitoes to visit and act as pollinators!


Carnivorous plants often live on low-nutrient soils and so need to find other ways to obtain essential nutrients for survival


Animals often get much of the credit for complex


behaviours and dramatic interactions with one another, but while they might not be as fast or showy, when we delve into the lives of plants we see that many of them are equally as impressive and cunning in their means of survival and reproduction.


Martin’s new book Cheats and Deceits is reviewed on p.27. To win a copy email edenmag@edenproject.com with the answer to the following question. How do drongos cheat meerkats? See www.edenproject.com/mag-comp for full terms and conditions.


11


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32