Investigations into the cold resistance of the eggs and larvae of Boophilus decoloratus (Koch, 1844), Boophilus microplus (Canestrini, 1888) and Margaropus winthemi Karsch, 1879.

Of all these limiting factors climate plays the most important role and determines the ecological and geographical distribution and the seasonal activities of a species (Imms, 1931; MacLeod, 1936). Within the climate complex temperature plays a fundamental role, a species being confined within a specific temperature range (Odum, 1963). An environment favourable to a given species can be determined by the temperatures prevailing in the biotopes specific to the organism. Not only the average daily and the average yearly temperature, but also its range of variations are reflected in the physiology of the given species (Andrewartha & Birch, 1954). Theiler (1948) lists the following as limiting factors for ticks:-