Table 2.

Costs and benefits of losing and winning a conflict over host manipulation and the observed outcomes of such conflicts

Conflict over	Parasite	Hypothetical costs of sabotage	Consequences of losing the conflict	Consequences of winning the conflict	Factors potentially favoring parasite in a conflict	Empirical outcomes of the conflict
Different definitive hosts	Either	Energetic costs	Death	Transmission		Intermediate host behaviour 55, 56 or one parasite persist in its host manipulation 55
Different transmission strategies	Trophically transmitted parasite	Energetic costs	Reducedtransmission	Transmission	Strength of host manipulation c	Suppression by the non‐trophically transmitted parasite in natural infections 59, 60, but not experimentally reproducible 60
Different transmission strategies	Non‐trophically transmitted parasite	Energetic costs, physiological harm to the host	Death b	Survival b	Priority d	See row above
Different developmental stages	Infective parasite	Energetic costs	Delayed transmission, competition, mate availibility a	Transmission at an optimal time point	Size, Priority	No 61/possibly very weak 63 suppression by the not yet infective parasite, complete40, 64 or partial40 suppression by the infective parasite
Different developmental stages	Not yet infective parasite	Energetic costs, physiological harm to the host	Death	Transmission, competition, mate availibility a		See row above

^aOnly applies in an intraspecific conflict and if parasites are of opposite sexes or hermaphroditic. Benefits depend on the likelihood of encountering a mate in the definitive host and the costs of failing to do so.

^bFitness consequences will depend strongly on how much of its potential reproduction a parasite has already realised prior to its host becoming infected by the manipulating parasite.

^cIn case of a non‐manipulating co‐infecting parasite for which ‘normal’ host behaviour would be optimal.

^dIn case of a vertically transmitted parasite.