Sperm competition is a fundamentally important component ofpostcopulatory sexual selection, and direct removal of rival malesperm from the female reproductive tract has been documented inat least three insect orders: Odonata, Orthoptera and Coleoptera(e.g. Siva-Jothy 1987; Ono et al. 1989; Gage 1992; Simmons 2001).Haubruge et al. (1999) reported a novel twist on sperm removal,a process they termed fertilization by proxy, in the red flour beetleTribolium castaneum. This study suggested that not only do malesremove previously stored sperm from females, but that males alsotranslocate rival males’ sperm when they subsequently mate withnew females. The mechanism they proposed was rival spermremoval by an array of chitinous spines located on the matingmale’s aedeagus, followed by translocation of these still viablesperm when this male subsequently mated with another female.Empirical evidence for this novel phenomenon was based ona physiological paternity marker involving resistance to the insec-ticide malathion, which in T. castaneum is due to a spontaneousmutation in a carboxylesterase enzyme that confers malathion-specific resistance (Dyte & Rowlands 1968; White & Bell 1988;Haubruge et al. 2002; Arnaud et al. 2005). The experimental designincludedthreeconsecutivecrosses:(1)amalathion-resistantvirginmalewasmatedwithamalathion-susceptiblevirginfemale,(2)thesame susceptible female was mated with a susceptible virgin maleand (3) the same susceptible male was mated with a new suscep-tible virgin female. Adult progeny collected from the two matedfemales were subjected to an insecticide-exposure bioassay(contact with 1% malathion in acetone) for 3 h. Paternity wasassigned based onwhether progeny died (indicating they had beensired by the directly mating, susceptible male) or survived(presumed to be sired indirectly by the resistant male). Haubrugeet al. (1999) reported that fertilization by proxy was quite common(occurring in 22% of sequential matings), and that in such cases,a surprisingly high percentage (53% on average) of offspring weresired by translocated sperm.To date, this study by Haubruge et al. (1999) remains the onlyevidence for rival sperm translocation, a phenomenon that couldpotentially counteract any fitness advantages that males may gainfrom sperm removal. As pointed out recently by Kelly (2006),replication studies traditionally have been undervalued in behav-ioural ecology, and consequently both confirmatory and contra-dictory results may be difficult to publish. However, verification ofkey empirical results should be standard operating procedure torigorously test any novel evolutionary hypotheses. Based on theimportant evolutionary implications of the phenomenon of spermtranslocation, we conducted a partial replication of the study byHaubruge et al. (1999), in which we exactly duplicated mostexperimental procedures but used a different paternity marker todifferentiate between the two potential sires.