Circadian rhythms of sexual activities in moths: a review

Abstract

The circadian rhythm of behavior has interested many researchers in the past decades, yet amazingly little is known on the evolution of natural variation in circadian rhythms of behavior. Most research has been focused on identifying the circadian clock genes that form an intricate clock network, which turns out to be more complex with every discovery. To understand the importance of circadian rhythms of behavior in speciation, genetic analyses should be conducted on intra-and interspecific allochronic differentiation of behaviors. Many moth species show specific daily activity rhythms in their sexual activities, some species being sexually active early at night, while others are sexually active late at night. This differentiation has been suggested to have arisen to minimize communication interference between closely related species, as co-occurring and closely related species with overlapping sex pheromone blends show a temporal differentiation in their daily sexual activities. However, the genetic differentiation of this allochronic separation has barely been examined in any species so far. In this review I summarize studies conducted on timing of sexual activities in moths, and which factors have been found to influence this timing, with the aim to identify the gaps and challenges, to unravel the possible contribution of allochronic differentiation of sexual activities in moth speciation.

The Lutzomyia longipalpis complex: a brief natural history of aggregation-sex pheromone communication

“…The specificity of the message can be achieved in a multitude of ways including variation in overall composition, the presence and composition of stereoisomers [11, 12] or the ratio of specific components all of which may lead to qualitative and quantitative differences in the signal emitted [5, 13, 14]. Even subtle changes in the pheromone blend (the specific ratios of chemicals within a pheromone) [15] or partitioning of communication channels through temporal or seasonal differences in pheromone production and emission as well as shifts in circadian activity [16–18] may result in individuals being unable to detect one another [9, 18, 19] and thus lead to speciation. Other factors such as the interaction with host produced volatile chemicals and preferences for particular habitats could also contribute to serve as mechanisms that lead to the avoidance of cross attraction between closely related heterospecifics that exist in sympatry [18].…”

“…Therefore, the potential to accumulate pheromones in cuticular glands is small but the rather larger amounts of lipid containing vaculoles suggests that although pheromone production and release may be not be instantaneous but more gradual [32]. Small, but potentially significant variation in locomotor activity is observed across sympatric populations of L. longipalpis [97], however further studies exploring simultaneously circadian rhythms and pheromone release are necessary to exclude the hypothesis of some kind of temporal partitioning of communication channels such as that observed in moths [16, 98]. …”

Difference in diel mating time contributes to assortative mating between host plant-associated populations of Chilo suppressalis

“…In general, diel rhythms of mating activity are species-specific, and could play a key role in maintaining the reproductive isolation of closely related species1819. For example, it has been suggested that allochronic variation in mating activity is a key factor in the reproductive isolation of sympatric strains of the fall armyworm S. frugiperda 2144.…”

“…The timing of mating often has a diel rhythm, especially in insects121819. Although it has been suggested that differences in diel mating time can potentially induce allochronic reproductive isolation between laboratory-bred strains of the same species12, closely related species20, and host-associated populations2122, the evidence for this has so far been relatively equivocal.…”

Mate searching inEnnya maculicornis(Membracidae: Polyglyptini) initiated by females: behavioural and acoustic descriptions

“…For example, visual traits may be used to attract the attention of a potential mate (Harari & Brockmann, 1999;Li et al, 2017), chemical stimuli (pheromones) may play an important role in communication during courtship and mating (Sass, 1983;Kawazu & Tatsuki, 2002;Mazor & Dunkelblum, 2005;Sadek et al, 2012;Groot, 2014;Ma et al, 2017), and airborne (i.e. For example, visual traits may be used to attract the attention of a potential mate (Harari & Brockmann, 1999;Li et al, 2017), chemical stimuli (pheromones) may play an important role in communication during courtship and mating (Sass, 1983;Kawazu & Tatsuki, 2002;Mazor & Dunkelblum, 2005;Sadek et al, 2012;Groot, 2014;Ma et al, 2017), and airborne (i.e.…”