Post-mating shift towards longer-chain cuticular hydrocarbons drastically reduces female attractiveness to males in a digger wasp

Abstract

Females of most aculeate Hymenoptera mate only once and males are therefore under a strong competitive pressure which is expected to favour the evolution of rapid detection of virgin females. In several bee species, the cuticular hydrocarbon (CHC) profile exhibited by virgin females elicits male copulation attempts. However, it is still unknown how widespread this type of sexual communication is within Aculeata. Here, we investigated the use of CHCs as mating cues in the digger wasp Stizus continuus, which belongs to the family (Crabronidae) from within bees arose. In field experiments, unmanipulated, recently emerged virgin female dummies promptly elicit male copulation attempts, whereas 1-4days old mated females dummies were still attractive but to a much lesser extent. In contrast, old (10-15days) mated female dummies did not attract males at all. After hexane-washing, attractiveness almost disappeared but could be achieved by adding CHC extracts from virgin females even on hexane-washed old mated females. Thus, the chemical base of recognition of females as appropriate mating partner by males is coded in their CHC profile. Accordingly, differences in CHC profiles can be detected between sexes, with males having larger amounts of alkenes and exclusive long-chain alkanes, and within females specially according to their mating status. Shortly after mating, almost all of the major hydrocarbons found on the cuticle of females undergo significant changes in their abundance, with a clear shift from short-chain to long-chain linear and methyl-branched alkanes. The timely detection of virgin females by males in S. continuus could be advantageous within the narrow period of female emergence, when male-male competition is strongest.

Analysis of natural female post-mating responses of Anopheles gambiae and Anopheles coluzzii unravels similarities and differences in their reproductive ecology

“…This cuticular protein is likely expressed in the epicuticle, where it is postulated to bind to cuticular pheromones such as CHCs 48 . Because post-mating changes in the CHCs profiles affect female attractiveness in many monandrous insect species 80 , 81 , the An. gambiae -specific downregulation of genes related to chemical contact cues might reflect the occurrence of different post-mating signals in the two species.…”

Identification of a queen and king recognition pheromone in the subterranean termite Reticulitermes flavipes

“…Chemical communication is the foundation of nestmate and caste recognition, though other sensory modalities can also be involved ( 1 – 3 ). Most eusocial hymenopterans (ants, bees, and wasps) use colony- or species-specific blends of cuticular hydrocarbons (CHCs) to identify a variety of status conditions, including nestmates, mating status, age, caste, and fertility status ( 4 – 9 ), but blends of carboxylic acids, carboxylic esters, phenols, and alcohols are also used by some taxa ( 10 , 11 ).…”

Low Host Specialization in the Cuckoo Wasp, Parnopes grandior, Weakens Chemical Mimicry but Does Not Lead to Local Adaption

“…Such modification may involve chemical mimicry, chemical insignificance or chemical camouflage. Our study aimed to investigate which chemical strategy may be adopted by P. grandior, a cuckoo wasp species that is known to attack several host species even at a single nesting site [34], and, hence, may be limited in precisely matching its CHC profile with those of the hosts. In fact, CHC profiles are often species-specific in insects [13,47].…”

“…Therefore, we collected data on parasitism rates to evaluate its significance for chemical and behavioural differences. [34]. Bembix merceti, B. sinuata and B. zonata nested in an area of about 4 km 2 with overlapping nesting sites [35].…”