It remains unclear how similar species sharing a small habitat can co-exist in the long term. The theory goes that the most capable species would survive while the others would disappear, but this is not always the rule even in small areas, such as lakes. The reason, according to recent research published in Nature, lies in sexual selection; more specifically, in how females only pick up individuals of their same species, even at certain costs.
‘Our model shows that species can stably coexist in the same habitat as long as two simple conditions are met,’ says Leithen M’Gonigle, co-author of the study. ‘First, the distribution of resources they use must not be uniform, so that groups of females with different mate preferences can occupy different resource hotspots. Second, females must pay a cost for being choosy, through reduced survival or fecundity.’
‘These costs turn out to be crucial for reinforcing species boundaries,’ explains co-author Rupert Mazzucco. ‘Because they prevent females with a particular preference from invading areas dominated by males they find unattractive.’
Therefore, biodiversity depends on how females keep species from interbreeding. The study particularly applies to frogs, crickets, grasshoppers and fish species.
Photo: Rafa Moskovita/stock.xchng
M’Gonigle, L., Mazzucco, R., Otto, S., & Dieckmann, U. (2012). Sexual selection enables long-term coexistence despite ecological equivalence Nature DOI: 10.1038/nature10971