The consequences of co-infections for parasite transmission in the mosquito Aedes aegypti

1)Co-infections may modify parasite transmission opportunities directly as a consequence of interactions in the within host environment, but also indirectly through changes in host life-history. Furthermore, host and parasite traits are sensitive to the abiotic environment with variable consequences for parasite transmission in co-infections. (2)We investigate how co-infection of the mosquito Aedes aegypti with two microsporidian parasites (Vavraia culicis and Edhazardia aedis) at two levels of larval food availability affects parasite transmission directly, and indirectly through effects on host traits (3)In a laboratory infection experiment we compared how co-infection, at low and high larval food availability, affected the probability of infection, within-host growth and the transmission potential of each parasite, compared to single infections. Horizontal transmission was deemed possible for both parasites when infected hosts died harbouring horizontally-transmitting spores. Vertica...