Reproductive allocation and tubercle size in Conopholis americana (Orobanchaceae).

Abstract

In parasite-host coevolution, amelioration or tolerance of host defenses may require allocation of resources by the parasite that are then unavailable for reproduction. Squawroot [Conopholis americana (Orobanchaceae)] is an achlorophylous obligate root parasite of Quercus spp. The plant consists of a perennial underground tubercle attached to a host root. The tubercle produces annual aboveground reproductive stalks. The parasite reproduces solely by seed. This investigation examined the relationship between tubercle size and reproductive allocation as measured by the number of seed capsules produced and total capsule dry weight. No significant relationship was discovered. Tubercle size may be a response of the parasite to host defensive measures.