What primarily restricts the distribution of the Bombus vestalis in Scotland and northern regions?
Answer
The limited presence or lower density of the host species
While environmental and climate factors play a role, the definitive limiting factor for the range of the Bombus vestalis is the availability of its specific host, the Bombus terrestris. In northern latitudes, the host species becomes less frequent or faces environmental stressors that prevent it from maintaining the high-density colonies necessary for a parasite to successfully infiltrate. Since the parasite cannot survive without a host to do the work of rearing its brood, the rarity of the host in the north directly results in a decline in the prevalence of the Bombus vestalis, regardless of how suitable the flora might appear for foraging.
Related Questions
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