Cuticular Hydrocarbons of <I>Kapala sulcifacies</I> (Hymenoptera: Eucharitidae) and Its Host, the Ponerine Ant <I>Ectatomma ruidum</I> (Hymenoptera: Formicidae)

Cuticular hydrocarbons from the ponerine ant Ectatomma ruidum Roger and a highly integrated eucharitid myrmecophile, Kapala sulcifacies (Cameron), associated with it, have been characterized. Ninety hydrocarbons were identified from the ant, 55 hydrocarbons from the female wasp and 54 hydrocarbons from the male wasp. The wasps and ants share 40 hydrocarbons. These shared 40 hydrocarbons represent 92.6% of their hydrocarbon composition for female Kapala, 84.3% for male Kapala and 67.7% for the ants. The wasps have a carbon number range of C27 to C35; the ants have a range of C23 to C35. Both species possess n-alkanes, C27 to C33 for the wasps, C23 to C34 for the ants. Both species also possess major quantities of Z-7- and Z-9 alkenes: C29 to C33 for the wasps; C23 to C35 for the ants. The female wasps possess a low amount of a conjugated C31 diene (neither the ants nor the male wasps possess this hydrocarbon), and the ants, but not the wasps, contain low quantities of nonconjugated dienes (carbon numbers of C23 to C29) with double bonds at Δ9, and Δ14. Both wasps and ants share homologous series of 3-, 5-, 10-, 11-, 12-, 13-, 15- and 17-methyl branched alkanes. Ants and wasps also share a homologous series of 3,7-dimethyl alkanes. Other internally branched dimethyl alkanes are found in both ants and wasps, but only 11, 15-DiMeC29 is shared. Wasps have 7, 15- and 10, 14-dimethyl alkanes while the ants have 15,19-dimethyl alkanes. Kapala sulcifacies and E. ruidum both possess hydrocarbons of the 5, X-, 11, X-, 12, X- and 13, X-DiMe series, but the compounds involved are not shared because they represent different compounds. Behavioral observations indicate that the ants accept the newly emerged adult parasitoids with no evidence of agonistic behavior for a period of time after adult eclosion. Nevertheless, the chemical deception is not completely efficient because young adult Kapala are soon ejected from the nest by transportation by their host. These transportations frequently occur after seizure at the base of the wasps’ characteristic scutellar spines, such structures allowing for easy transportation without injury for the parasite. Moreover, if no method of escaping the colony is provided, the ants ultimately attack the parasitoids. The substantial chemical overlap of the cuticular hydrocarbon profiles of the ants and wasps are discussed in the context of the social life of the colony.