Sex pheromones and trail-following pheromone in the basal termites Zootermopsis nevadensis (Hagen) and Z. angusticollis (Hagen) (Isoptera: Termopsidae: Termopsinae)

Abstract

In the context of an evolutionary study of the chemical communication in termites, sex pheromones and trail-following pheromones were investigated in two Termopsidae, Zootermopsis nevadensis and Z. angusticollis. In these species, in which the presence of sex-specific pheromones has been demonstrated previously, the chemical structure of the female sex pheromone has now been identified as (5E)-2,6,10-trimethylundeca-5,9-dienal and the male sex pheromone as (+)-or (-)-syn-4,6-dimethyldodecanal. The amount of sex pheromone was estimated at 5-10 ng per individual in females and 2-5 ng in males. Because these two sympatric species do not differ in their pheromonal chemical composition, reproductive isolation is probably mediated chiefly by differences in dispersal flight chronology. The trail-following pheromone was shown to be composed of the same compound as the male sex pheromone, that is syn-4,6-dimethyldodecanal. The compound syn-4,6-dimethyldodecanal was 10 times more active than the racemic (+/-)-syn + (+/-)-anti-4,6-dimethyldodecanal in eliciting trail-following. The amount of syn-4,6dimethyldodecanal was estimated at 0.1-0.5 ng per pseudergate. Regarding the phylogenetic aspects, the nature of the female sex pheromone of Zootermopsis is structurally akin to the trail-following pheromone of Mastotermes darwiniensis of Mastotermitidae and Porotermes adamsoni and Stolotermes victoriensis of Termopsidae. Interestingly, the nature of the trail-following pheromone of the Termopsinae Zootermopsis is clearly different from that of the Porotermitinae P. adamsoni and the Stolotermitinae S. victoriensis, which mirrors recent molecular data on the paraphyly of Termopsidae.

Communication and Social Regulation in Termites

“…While this appears to be true in some species (e.g., Peppuy et al 2004;, in others only pheromone quantities differ between congenerics (Bordereau et al 1993(Bordereau et al , 2010Connétable et al 2012). As a result, reproductive isolation is probably maintained by other mechanisms, such as the differential timing of the dispersal and contact species recognition cues (Connétable et al 2012), which are further discussed below.…”

“…However, these termites nonetheless have active sternal glands and successfully follow artificial trails (Sillam-Dussès et al 2009b;Bordereau et al 2010), which suggests that they may be using trails to orient themselves within the network of galleries located in the wood they inhabit. Trail-following behavior is sometimes considered to have originated from the recruitment associated with specific alarms, during which trail-following pheromone is used to guide the recruited nestmates to the disturbance site.…”

“…While all castes have sternal glands, which are also used for trail marking, only the imagoes of some species possess posterior sternal glands and tergal glands (Bordereau et al 2002;Quennedey et al 2004). In the basal families, both males and females (Termopsidae; Bordereau et al 2010) or exclusively males (H. mossambicus; Leuthold and Bruinsma 1978), produce sex pheromones. In the more advanced families, only the females call the males (Bordereau and Pasteels 2011).…”

Sex Pheromone and Trail Pheromone of the Sand Termite Psammotermes hybostoma

“…Fourth, both trail and sex pheromones most often consist of a single compound, not blends of compounds as in numerous other insects. However, some recent studies demonstrated the presence of minor components in addition to these major compounds (Sillam-Dussès et al, 2009Bordereau et al, 2010;Anani Kotoklo et al, 2010), suggesting that minor active components could have been overlooked in the past.…”

Sexual communication in the termite Prorhinotermes simplex (Isoptera, Rhinotermitidae) mediated by a pheromone from female tergal glands

“…The same is true for (3Z,6Z)-dodeca-3,6-dien-1-ol in Ancistrotermes pakistanicus and probably also for the diterpene neocembrene-A in Nasutitermes and Trinervitermes (Birch et al, 1972;McDowell and Oloo, 1984;Hall and Traniello, 1985). n-Tetradecyl propionate elicits attraction in Reticulitermes flavipes when offered to males in unnaturally high concentrations (Clément et al, 1989), and recently (E)-2,6,10-trimethylundeca-5,9-dienal was identified as female sex pheromone in Zootermopsis species (Bordereau et al, 2006). Among the contact gustatory stimuli, trilinolein was described as a specific compound for female tergal glands in Coptotermes formosanus (Bland et al, 2004).…”