Abstract:
The nature of species and the way in which they are identified is of vital importance to biology. Generally these issues are approached with a strong bias toward the human perceived differences amongst organisms and with a preconception about how species arose, and therefore what their characteristics should be. This approach, imbedded in its own language and keywords determines the types of questions many biologists ask, the way they carry out research and their interpretation of the data collected.
It is argued here that a species concept that is to reflect the biologically real groupings in nature, should be based on the biological properties by which such groups cohere. These cohesion systems are expressed in the interactions of conspecifics of complementary sex which lead to fertilisation. Paterson (1978, 1980, 1985) has termed them specific-mate recognition systems and they form the basic defining property of species under his recognition concept of species.
This concept can be applied to the very many situations where organisms form groupings imperceptible to humans, known as cryptic species. Such species are often important medical or agricultural pests, the correct knowledge of which is vital for successful and responsible control. New Zealand leafrollers comprise such a group in which morphologically defined taxa have been found to consist of a number of groups with different reproductive systems. They were identified by differences in long range chemical signals that pass between males and females. The use of genetic data to investigate the biological consequences of these differences was able to confirm the existence of several species within previously defined taxa.