Nymphs of the common bed bug (Cimex lectularius) produce anti-aphrodisiac defence against conspecific males

Abstract

BackgroundAbdominal wounding by traumatic insemination and the lack of a long distance attraction pheromone set the scene for unusual sexual signalling systems. Male bed bugs (Cimex lectularius) mount any large, newly fed individual in an attempt to mate. Last instar nymphs overlap in size with mature females, which make them a potential target for interested males. However, nymphs lack the female's specific mating adaptations and may be severely injured by the abdominal wounding. We, therefore, hypothesized that nymphs emit chemical deterrents that act as an honest status signal, which prevents nymph sexual harassment and indirectly reduces energy costs for males.ResultsBehavioural mating assays showed that males mount nymphs significantly shorter time compared to females, although initial mounting preference was the same. In support of our hypothesis, nymphs experienced the same percentage of mating with sperm transfer as females if they were unable to emit (E)-2-hexenal, (E)-2-octenal 4-oxo-(E)-2-hexenal and 4-oxo-(E)-2-octenal, from their dorsal abdominal glands. We report that the aldehydes and 4-oxo-(E)-2-hexenal are detected by olfactory receptor neurons housed in smooth and grooved peg sensilla, respectively, on the adult antennae, at biologically relevant concentrations. Behavioural experiments showed that application of 4-oxo-(E)-2-hexenal or the two aldehydes at a nymph-emitted ratio, to a male/female pair during mounting initiation, decreased mating frequency to a rate comparable to that of a male/nymph pair.ConclusionsBy combining behavioural and sensory studies, we show that the nymph-specific alarm pheromone plays an important role in intra-specific communication in the common bed bug. Alarm pheromones are commonly looked upon as a system in predator/prey communication, but here we show that alarm pheromones may be used as multipurpose signals such as decreasing the risk of nymphal mating by males.See commentary: http://www.biomedcentral.com/1741-7007/8/117

Bed Bugs: Clinical Relevance and Control Options

“…Other researchers have suggested that pheromones may be used for the control of bed bugs (139,141,316), but such products may be some time off from entering the marketplace.…”

Mechanisms that contribute to the establishment and persistence of bed bug infestations

“…Once aggregations form within refuges, males will attempt to copulate with any conspecific of similar size Qohnson, 1941;Rivnay, 1932;Rivnay, 1933;Siva-Jothy, 2006;Usinger, 1966). Alarm pheromones prevent male-male and male-juvenile copulation events (Harraca et al, 2010b;Ryne, 2009). Males mount the dorsal side of the female and probes the female with his paramere (= intermittent organ) until piercing the female ectospermalage on the ventral side of the abdomen for ejaculation (Reinhardt and Siva-Jothy, 2007;Usinger, 1966).…”

Smelling your way to food: can bed bugs use our odour?

“…Bed bugs are repulsed by air movement and therefore do not use coupled anemotactic-chemotactic responses to direct their path (Aboul-Nasr and Erakey, 1968;Weeks et al, 2011) (V.H., personal observation on servosphere). Instead, bed bugs seem to use their antennal olfactory system to detect odorant cues at close range, such as during their intraspecific interactions (Siljander et al, 2008;Harraca et al, 2010a;Liedtke et al, 2011;Weeks et al, 2011).…”

“…For this purpose, odorant cues used by the bed bugs are considered novel constituents in the integrated bed bug management. Consequently, odours emitted by the bed bugs themselves, such as alarm pheromones and aggregation semiochemicals, have been recently investigated (Siljander et al, 2008;Harraca et al, 2010a;Liedtke et al, 2011;Weeks et al, 2011). In spite of the potential of host attractants for both targeted control treatments and surveillance, there is limited knowledge of the identity of these semiochemicals (e.g.…”