The role of parasites in host species co-existence

What is it about?

In this paper we examined how endoparasitic gregarine parasites are distributed among two damselfly species which sometimes live together and sometimes alone. We investigated a total of 31 populations, 18 of which the two damselflies lived alone and 13 where they lived together. We found that parasitism was higher in Calopteryx virgo than in C. splendens. Interestingly, parasitism was almost non-existing in C. splendens when it lived alone. It seems that gregarine parasites are more likely to infect C. virgo. This indicates that gregarines either prefer this host species or it is not able to infect C. splendens as effectively as it can C. virgo. Other reasons explaining our results are also discussed in the paper.

Featured Image

Why is it important?

Here we highlight an interesting phenomenon of differential parasitism between two closely related host species that share the same habitat. Our results give support to the mechanism where parasites can help two competing species live in the same area. This paper also provides a possible example of a source-sink parasite system.