Parasitism, immune response, and egg production of the spearhead bluet (Coenagrion hastulatum) damselfly
: Kari M Kaunisto, Pipsa Kaunisto, Jaakko J Ilvonen, Jukka Suhonen
Publisher: CANADIAN SCIENCE PUBLISHING
: 2017
: Canadian Journal of Zoology
: 95
: 5
: 367
: 372
: 6
: 0008-4301
: 1480-3283
DOI: https://doi.org/10.1139/cjz-2016-0146
Theoretical models predict that parasites reduce reproductive success of their hosts, but very few empirical studies
have given support to this. Using the spearhead bluet (Coenagrion hastulatum (Charpentier, 1825)) damselfly, we tested how
immune response, wing length, and the number of both endo- and ecto-parasites affect egg production of host damselflies. The
study was conducted with four different populations in southwest Finland. We found a negative association between endoparasitic
gregarines and number of host eggs. Furthermore, immune response increased with the number of water mites, but
decreased with the number of eggs. Contrary to previous studies with other damselfly species, the number of ectoparasitic water
mites did not affect the number of eggs. Moreover, wing length, used as an indicator of individual size, was not associated with
egg numbers. The negative effect of gregarine parasites on egg numbers is likely to affect the composition of host populations,
i.e., damselflies that show higher resistance to these endoparasites will have more of their offspring represented in subsequent
generations. In future, more experimental research on the varying effects of different parasite species on the number of eggs is
needed.